art, vpm & sat faq handbook iss h

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Guardian Engineering Centre, Merlin House, Brunel Court, Guardian Engineering Centre, Merlin House, Brunel Court, Guardian Engineering Centre, Merlin House, Brunel Court, Guardian Engineering Centre, Merlin House, Brunel Court, Village Farm Industrial Estate, Pyle, Wales, CF33 6BL, UKVillage Farm Industrial Estate, Pyle, Wales, CF33 6BL, UKVillage Farm Industrial Estate, Pyle, Wales, CF33 6BL, UKVillage Farm Industrial Estate, Pyle, Wales, CF33 6BL, UK

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ART, VSS & SATART, VSS & SATART, VSS & SATART, VSS & SAT FAQ HandbookFAQ HandbookFAQ HandbookFAQ Handbook

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CONTENTS

1 Foreword by John McGrath, Sales and Marketing Director ...............................................................................................2

2 Addressable Release Tool (ART) ......................................................................................................................................3

2.1 Why run an ART in the toolstring? ............................................................................................................................3

2.2 What are common applications for ARTs? ................................................................................................................4

2.3 What types of ART are available?..............................................................................................................................4

2.4 How does the ART work? ..........................................................................................................................................5

2.5 Where can an ART be run in the toolstring? ..............................................................................................................6

2.6 What Guardian tools can I combine with an ART and in what order? .......................................................................7

2.7 How do I run multiple ARTs in the same string? .......................................................................................................7

2.8 What head types are available? ..................................................................................................................................7

2.9 What ART equipment is required to perform a job? ..................................................................................................7

2.10 What does the ART look like electrically? .................................................................................................................7

2.11 What track record does the ART have? ......................................................................................................................9

2.12 How many ARTs are in the field? ..............................................................................................................................9

2.13 With what tractors has the ART been run? .................................................................................................................9

2.14 Has an ART ever been released inadvertently or accidentally?..................................................................................9

2.15 Which service companies have run ARTs? ................................................................................................................9

2.16 Can the ART be used in wells containing H2S or CO2? ...........................................................................................10

2.17 What is the maximum perforating gun I can run with an ART? ...............................................................................10

2.18 What happens if the shooting line shorts after perforating – can I still release if the gun string becomes stuck? ....10

2.19 What procedures do I need to be aware of before initiating an ART release? .........................................................11

2.20 What fishing grapple do I require for the ART-C? ...................................................................................................12

2.21 What fishing grapple do I require for the ART-H/T? ...............................................................................................13

2.22 What is the maximum ART load before, during and after release? ..........................................................................14

2.23 How do I release an ART? .......................................................................................................................................14

2.24 What happens if there is a cable insulation or continuity problem – can I still release? ..........................................15

2.25 Can I reverse the ART motor and reset the ART after release? ...............................................................................16

2.26 Why can’t I reverse the ART motor? .......................................................................................................................16

2.27 Can I release an ART at surface? .............................................................................................................................16

2.28 Can I run and release the ART upside down? ..........................................................................................................16

2.29 How often should I service the ART? ......................................................................................................................17

2.30 How much weight do I need below the ART to enable a successful release? ..........................................................17

2.31 How long does it take to re-build an ART-C/H tool? ...............................................................................................17

2.32 Do I need special training to service an ART? .........................................................................................................17

2.33 Is Guardian able to provide ART maintenance training? .........................................................................................17

2.34 Does Guardian provide ART servicing and tool repair? ..........................................................................................18

2.35 What tools do I require to re-build an ART-H/T tool? .............................................................................................18

2.36 What spares do I require to rebuild an ART tool?....................................................................................................18

2.37 What maintenance products are recommended for the re-build of an ART tool? ....................................................18

3 ART Specifications ..........................................................................................................................................................20

4 ART Applications and Release Case Studies ...................................................................................................................21

5 Voltage Protection Modules (VPM) ................................................................................................................................23

5.1 Why run a VPM in the toolstring? ...........................................................................................................................23

5.2 For what applications would I use a VPM in my toolstring? ....................................................................................23

5.3 Where do I position the VPM in the toolstring? .......................................................................................................24





5.4 Is the VPM run above or below an ART? ................................................................................................................24

5.5 What is a VSS – Voltage Sensing Switch? ...............................................................................................................24

5.6 Where should correlation tools be run – above or below the VPM? ........................................................................24

5.7 What head types are available? ................................................................................................................................25

5.8 Can I obtain a VPM for a specific operation? ..........................................................................................................25

5.9 What additional equipment do I need to run a VPM-A/B/F? ...................................................................................26

5.10 What servicing equipment is required for the VPM-A/B/F? ....................................................................................26

5.11 Which VPM tool do I run to electrically disconnect the downhole toolstring from the tractor? ..............................26

5.12 Can I run more than one VPM-G in a toolstring?.....................................................................................................28

5.13 What VPM-G equipment do I need? ........................................................................................................................28

5.14 What servicing equipment is required for the VPM-G? ...........................................................................................29

5.15 Are there additional safety procedures when running a VPM-G? ............................................................................29

5.16 What is the procedure to enter ‘Tractor or Safe’ Mode? ..........................................................................................30

5.17 What is the procedure to enter ‘Fire or Log Mode? .................................................................................................30

5.18 What is the fault light LED for on the VCP surface control panel? .........................................................................30

5.19 What happens if the VPM surface control panel (VCP) is switched off whilst the tractor is powered up? ..............31

5.20 What types of VPM are available? ...........................................................................................................................32

6 VPM Specification ...........................................................................................................................................................33

7 Shock Absorber Tool (SAT) ............................................................................................................................................34

7.1 Why run an SAT in the toolstring? ...........................................................................................................................34

7.2 What diameter tools are available? ..........................................................................................................................34

7.3 What load will a SAT take? .....................................................................................................................................34

7.4 Is the SAT H2S rated? ..............................................................................................................................................34





FIGURES

Figure 1-1 – Sectional View of the ART-H - Addressable Release Tool ..................................................................................4

Figure 2 ART Operting Instructions (inside lid of portable ACP) ............................................................................................5

Figure 2-2 - ACP Surface Control Panel ....................................................................................................................................6

Figure 2-3 - ART/ACP Electronic Block Diagram ....................................................................................................................8

Figure 2-4 - ART Downhole Electronics ...................................................................................................................................8

Figure 2-5 - ART-C (1” OTIS) Fishing Head ..........................................................................................................................12

Figure 2-6 - ART-H 1 3/16” OTIS Fishing Head .......................................................................................................................13

Figure 2-7 - ART-H Fishing Head Assembly ...........................................................................................................................13

Figure 2-8 - ART-H Schematic - Before Release .....................................................................................................................14

Figure 2-9 - ART-H Schematic- After Release ........................................................................................................................14

Figure 2-10 - Section of ART-H Fishing Head and Grapple System .......................................................................................15

Figure 5-1 - Fuse Rating Time .................................................................................................................................................26

Figure 5-2 - VPM-G Block Diagram........................................................................................................................................28

Figure 5-3 – VPM-A Control Panel (19” Rack-Mount)* .........................................................................................................29

Figure 5-4 – VPM-B Control Panel (Suit-Case)* ....................................................................................................................29

Figure 7-1 – Shock Absorber Tool (SAT-A), 2 1/8” .................................................................................................................34

TABLES

Table 2-1 - Recommended Maintenance Products ...................................................................................................................19

Table 5-1 - VPM Toolstring Position .......................................................................................................................................24





Figure 1-1 – Sectional View of the ART-H - Addressable Release Tool





1 Foreword by John McGrath, Sales and Marketing Director

The last two decades have seen a marked drive within the oil and gas industry to improve well-site safety and

increase oil and gas recovery from developed and exploration wells. This impetus has led to rapid advances in drilling technology, spearheaded by activities in directional drilling and an increase in horizontal, or long reach wells.

In this new and even more hostile world, traditional wireline logging operations have adopted techniques such as coiled tubing, pipe conveyed logging and more recently, downhole tractors. The increase in demand for wireline operations in horizontal or highly deviated wells has compounded existing problems in these types of operation,

namely the ability to guarantee successful release from the cable head of a stuck toolstring (or tractor), and the ability to prevent the high tractor voltages and currents from reaching armed ballistic devices such as perforating guns or setting tools. The above problems are especially apparent when running powered downhole tractors in horizontal wells. However, it should also be stated that they are not limited to horizontal wells, but can equally

occur in vertical or deviated holes.

In order to meet the global challenge of improved well-site safety and to offer an alternative solution to costly rig

lost-time (fishing for broken cable, stuck logging tools, swollen guns or partially set plugs), Guardian Global Technologies has developed a range of innovative and complimentary downhole protection systems. The products which make up these systems are designed to operate in the sphere of deviated wells, tractor operations in horizontal wells and general wireline applications, such as production logging and perforating.

Controlled via a compact surface panel and robust telemetry system, the Addressable Release Tool (ART) removes the uncertainty involved in breaking the weak-point by using an electro-mechanical system to achieve a

controlled downhole release of a stuck toolstring. Complementing the ART wireline applications is a range of Voltage Protection Modules (VPM) that block or prevent unwanted voltages and currents from damaging production logging tools or accidentally detonating explosive wireline devices during perforating or plug setting operations.

The VPM and ART range of safety products provide the ultimate in downhole protection, since they operate as complementary tools. The VPM acts as an electrical safety device during perforating and production logging

operations, while the ART provides a mechanical safety system enabling the controlled release of stuck downhole tools. The purpose of this handbook is to provide concise information on the operation and associated field applications

of the ART and VPM tools based on frequently asked questions (FAQs) received by GGT’s technical department. The booklet also provides information on a number of field case studies.





2 Addressable Release Tool (ART)

2.1 Why run an ART in the toolstring?

The Addressable Release Tool (ART) is designed for use in high deviation or horizontal wells and enables the wireline

engineer to affect a controlled release of all, or part of a stuck tool-string, without having to break the weak-point. The ART

allows the engineer to employ the conventional method of attempting to free the stuck toolstring by increasing the cable head tension to the ‘maximum safe pull’. If the tool cannot be freed using this method, the engineer can then use the controllable and safe option of activating the ART’s unique electro-mechanical system to release the cable and head from the stuck toolstring. This method improves wellsite safety and reduces rig downtime by eliminating the inherent problems of wireline

operations in deviated wells. That is, the engineer’s ability to ‘work-down’ enough tension to break the weak-point at the head, without parting the cable at surface or at some indeterminate point in the well.

None of the ART product range uses explosives in its operation. This both improves safety and allows selective (positive/negative) perforating below the ART. More specific applications and benefits are listed below.

a) Weak-points do not guarantee a clean fishing neck

Personally I don’t trust mechanical weak points to give me a clean fishing neck as I’ve had it where there was still a strand of wire sticking out of the head and we couldn’t get the grapple on. We then had to run an

LIB to see the wire and then box it off before trying to fish again. At that point we knew that we had a loose piece of wire at the cable head. People are far happier to release an ART as they are sure that they will get the worst part – the cable, out of the hole.

b) Weak points release over too large a range

The range within which weak points release is so large that you invariably get one going way to the left of the bell curve and releasing early. This makes you down rate your weak point further and limits what you

can do.

c) An ART release saves time and is safer

When you pull the weak point you have to barrier off the deck and have meetings and all permits to do as you will be pulling a lot of tension and the wire is going to spring back. It will generally take a few hours to get all this organised – and this is all downtime. As there is no real over pull when you release an ART you can save hours here and have a safer operation on deck.

d) The cable is worked too long with a weak point

No one wants to pull the weak point for the reasons stated above so they work the tool for many hours and

end up work hardening the cable over the top sheave and it may then break there. What normally happens though is that on a subsequent job when there is a large overpull the cable breaks in the hole at the point where it was previously work hardened. I’ve had this happen more than once to me. Using and ART saves a bunch of time and protects the cable for future jobs.

e) You don’t get stuck as often with an ART

If you are tying a 100% weak point then you will have much more pull available as you pull out of the

well. At TD this may equate to 50-100% increase, but you rarely get stuck on TD. It’s generally at a nipple, WEG, sliding sleeve etc. With a weak point you always only have a fixed amount of pull regardless of where you are in the well. With an ART the amount of pull that you have increases the shallower you get as the weight of the cable is recovered as additional pull. The chart below is part of our standard

presentation and provides a clear illustration. The blue line is the over pull that you get with a standard weak point on 7/32 cable at 7,000m. The red line is the over pull available at any particular depth using the ART with a 100% weak point and not working the cable more than 65% of it tensile strength. The green line is the over pull if you pull





up to the cable’s tensile strength. Normally you would never do this, but there may be a case where you still want to have this option even if it does trash the cable. You don’t have this option with a weak point.

Figure 2-1 – ART Advantage Chart

2.2 What are common applications for ARTs?

• Release of stuck downhole tractors

• Release of partially set plugs/packers

• Release of damaged gun strings (for example swelling)

• Release of stuck production logging tools

• Planned and deliberate release of a toolstring element in the well

• Applications in deep wells, where stronger weak-points are required

• Pump down operations where a string weak point is required to prevent guns being pumped off the end of the line as they pass as restriction.

2.3 What types of ART are available?

The ART-C has an OD of 1 11/16” and is rated to 15,000 psi and 177°C (350°F). The tool is primarily designed for use in conjunction with production logging and data acquisition equipment. It has a safe working load of two tonnes and can

withstand a fishing load (post-release) of ten tonnes. The ART-C uses a 1” OTIS fishing head and utilises GGT’s proprietary high voltage isolation electronics, making it suitable for use with high voltage downhole operations (tractors). The ART operation is controlled on surface using an ART control panel (ACP), which is capable of controlling up to seven ART-Cs in a toolstring.

The ART-H is a 2 1/8” tool diameter and is rated to 15,000 psi and 177°C (350°F). The tool is designed for use in conjunction with downhole-tractor devices where the controllable release of all or part of a stuck tool-string, set plug or

expanded gun string is required. The tool is specifically intended for use above a downhole tractor, but can also be deployed below. The tool can also be deployed with electric-line equipped coiled tubing. The ART-H is designed to withstand the high voltages used to drive downhole tractors and is able to carry a maximum safe working load of three tonnes and a fishing





load (post-release) of ten tonnes. The ART-H operation is controlled on surface using the same ART control panel (ACP) as the ART-C. Up to seven ART-Hs can be run in a toolstring

The 3 3/8” MRT is a multi-conductor (10) version of the ART for use with open-hole logging equipment.

2.4 How does the ART work?

All ARTs use a downhole electro-mechanical system (grapple and fishing head) to release from a stuck toolstring, and

incorporate a number of fail-safe mechanisms to prevent accidental release. The engineer controls the ART operation using

a surface control panel (ACP), which communicates with the downhole tool on the wireline cable via a robust digital telemetry system. When the decision has been made to activate the ART and release from the stuck tool, the surface control panel (ACP) is connected to the wireline cable, which then establishes communication with the ART(s) in the toolstring.

The engineer selects which ART is to be released, before ‘arming’ the ART; this confirms downhole communication and status. Once armed, the ‘release’ sequence can be activated by pushing the release button on the ACP. The ACP signals the tool to switch on a downhole motor which activates the release mechanism. This actuation enables the upper portion of the

ART to release from the fishing head assembly. The engineer is able to check the progress of the operation using LED status indicators and a display showing the ART tool current. Note that the principle of operation of the ART-C is the same as that of the ART-H, -T and -I, however the mechanical details are different. For further details please review the ART mechanical and electronic description in the associated manuals.

Once released, a standard fishing neck remains to facilitate further recovery operations. Due to the presence of ‘O’ rings and depending upon well pressure, approximately 100 pounds of cable tension at the head is required to pull apart the upper and lower section.

Figure 2-1 ART Operating Instructions (inside lid of portable ACP)





Figure 2-3 - ACP Surface Control Panel

2.5 Where can an ART be run in the toolstring?

• Conventional Wireline Operations: During Production Logging (PL) or data acquisition operations, the ART is normally deployed at the head of the toolstring, thereby effectively replacing the conventional cable weak-point. All ART tools have a direct through-wire linking the upper and lower head connections and in non-operating mode the tool draws only a few micro-amps from the line. It should be noted that in order for the ART tool to operate, it generally

requires direct wire connectivity to the cable head. A maximum of up to seven ARTs can be positioned anywhere within the logging toolstring; assuming that there is a direct connection to the cable for each of them. This provides the field engineer with the ability to release from a specific section of the string, for example, below a nuclear fluid density

tool.

• Tractor Operations: During horizontal or highly deviated well operations, ARTs are normally deployed above and below the downhole tractor. As with conventional wireline operations, additional ARTs can then be placed in the toolstring if required.

• Perforating or Setting Tool Operations: In this scenario, it is normal practice to position the ART above the correlating device, that is, the gamma-ray (GR) tool, casing collar locator (CCL) or GR/CCL combination. Guardian also recommends the use of a shock absorber when running the ART with perforating guns. If required, the ART can

also be positioned below the correlation tool, however this is dependent on whether the correlation tool circuitry degrades the ART control signal such that the ACP cannot communicate effectively with the ART. It would be therefore necessary to perform a surface test in order to simulate the system, with the ART positioned below the correlation device and connected to the ACP using the correct length and type of wireline cable to be used during the

job.





2.6 What Guardian tools can I combine with an ART and in what order?

The ART family of tools can be operated with the Gun Brake System, Instrument Dynamics Controller, Powered Swivel Joint and Voltage Protection Module (VPM-E and VPM-G). Tools which contain an integral VSS (VPM ad GBS) must be

deployed below the ART (and also below any other non-VSS containing tools). If it is required to deploy more than one tool containing a VSS within a toolstring, then all VSSs except the lowest one should be bypassed. Different VSSs / VPMs are available for different applications – see section 2.18.

2.7 How do I run multiple ARTs in the same string?

In order to allow several ARTs to be run in the toolstring, each ART has a user selectable address that is used to

communicate and identify itself to the ART Control Panel (ACP). The address is set in the tool by means of an internal four-way DIP-switch. Therefore when running multiple ARTs in a toolstring, it is important to set the addresses before running in

the well and care must be taken to note the address and related position of each ART within the toolstring, in order to prevent the release of the wrong ART!

All tools are supplied from manufacture and rental with a default address set to one. If more than two tools are deployed in a single tool string it is vital to ensure that none of the tools is set to the same address.

2.8 What head types are available?

Guardian is able to provide a range of head types to suit the field requirements of the ART, from standard designs to client-

specific heads. These include:

1. Standard Go ‘A’ type mono pin. 2. Modified or reversed Go ‘A’ type mono pin.

3. Standard GO B (1 5/8 Acme) 4. BA-A3 (OTA). 5. BA-A2

6. Schlumberger MH21/22. 7. Client Specified.

2.9 What ART equipment is required to perform a job?

Downhole

1. ART – One or more (up to a maximum of seven) tools can be combined and addressed in a toolstring.

2. Some form of VPM (Voltage Protection Module) or VSS (Voltage Switching Sub) may be required. 3. A Shock Absorber (such as the Guardian SAT) should be run below the ART when perforating.

Surface

1. ACP – ART Surface Control Panel 2. 110 volt or 240 volt mains lead 3. Leads to connect ACP to wireline cable

4. Fishing equipment: i. 1” grapple for fishing ART-C

ii. 1 3/16” grapple for fishing ART-H/T/I

2.10 What does the ART look like electrically?





Electrically the ART is through-wired upper to lower head, with a high-impedance Line Isolation Board connected to the through-wire.

Figure 2-4 - ART/ACP Electronic Block Diagram

The ART/ACP system block diagram highlights the main functions of the surface and downhole electronics. The surface ACP consists of two boards which provide the power supply, processor and signal control electronics. The downhole

electronics of the ART also consists of two boards, one providing the power supply, telemetry and control circuitry and the second supplying the line isolation circuitry. The Line Isolation Board (LIB) is used to disconnect the internal electronics from the line unless the line voltage is within pre-determined limits.

Figure 2-5 - ART Downhole Electronics





2.11 What track record does the ART have?

The first ART commercial operation was successfully carried out in 1997, and as such, Guardian’s range of ART tools have many years proven field experience in a variety of differing operations, from tractoring through to perforating. ARTs have completed hundreds of jobs on a global basis, and are currently operated by all of the major oil service companies together with many regional and independent service companies. During tractor operations in the highly safety conscious sector of the

North Sea, some operators and service companies stipulate that a wireline operation will only proceed if the ART and VPM safety devices are deployed in the toolstring.

There are no known reports of any ART releasing prematurely or not releasing when intended.

2.12 How many ARTs are in the field?

As of 2008, GGT has approximately 200 sets of ART equipment operating in the field; this is a combination of purchased and rental tools. This number increases annually by approximately 20.

2.13 With what tractors has the ART been run?

ARTs have been run with tractors from the following companies:

• AkerKvaerner (Maritime Well Service);

• Computalog/Precision Drilling/Preussag;

• Welltec;

• Sondex;

• Smartract;

• Schlumberger.

2.14 Has an ART ever been released inadvertently or accidentally?

GGT has never experienced an accidental or inadvertent release of an ART during downhole operations.

2.15 Which service companies have run ARTs?

Amongst others, the following companies run ART tools:

• Baker Atlas

• Computalog

• Expro

• Asmary

• Halliburton

• Maersk

• Maritime Well Services (AKWS)

• Precision Drilling

• Preussag

• Read Well Services

• Redneckz

• SmartTrac

• Sondex

• Schlumberger

• Weatherford

• Wellserve





• Welltec. Operating companies include:

• BP

• Amoco

• Exxon

• Conoco

• Norsk Hydro

• Phillips

• Maersk

• PDO – Oman

• Shell

• SINOC

• COSOL

• Statoil – Norway

2.16 Can the ART be used in wells containing H2S or CO2?

All ART tools are manufactured using NACE specification (MRO175) materials for use in wells containing H2S/CO2. ART operations in hostile environments and those containing high concentrations of H2S or CO2 should be discussed on a well-by-well basis. Please contact Guardian’s sales or technical support department for more information.

2.17 What is the maximum perforating gun I can run with an ART?

This is rather like the proverbial question ‘How long is a piece of string’! It depends on many factors, including gun length,

diameter, charge loading, pressure, well deviation, toolstring position and so on………. For all gun-strings we recommend running a shock-absorber such as a SAT (see section 7).

2.18 What happens if the shooting line shorts after perforating – can I still release if the gun string becomes stuck?

The ART operation is controlled from surface using the ART control panel (ACP) providing a negative 82-volt supply to drive the electronics and motor in the ART. Therefore in a basic perforating string, with no selective perforating system, if

the shooting line shorts to ground after perforating with a negative gun, the ART may not function correctly. This is because any motor voltage or current sent from surface will be shorted to ground. To overcome this and remove the potential problem of a shorted perforating line, a number of solutions have been developed

by Guardian. These are known as VSSs (Voltage Sensing Switch) or VPMs (Voltage Protection Modules). Generally, the difference is that a VSS is designed to enable another piece of equipment (e.g., ART, GBS) to operate under specific circumstances (eg. A shorted firing line) whereas a VPM is designed to protect a piece of equipment from voltages or

currents within a toolstring; however, due to the wide variety of applications of these products, this distinction does not always hold true!

1. VPM-F - The VPM-F is run below the ART and completely blocks the flow of negative current and voltage and so

isolates the ART control signal from any short below the ART and VPM sub. However, in this arrangement, only positive polarity perforating can be employed. The VPM-F can also be user-configured to block positive voltages for other applications.

2. VPM-B – The VPM-B is deployed when an ART is operated with the DynaEnergetics RF Safe detonating system.

The VPM-B passes the low level signals through to the DynaEnergetics detonating switch, but when subjected to a higher voltage, will cause the rupturing of a fuse which disconnects the tools below. This enables the ART to be

powered by preventing the ART supply voltage being dissipated through the DynaEnergetics system. Selective





perforating is available with this tool. Once the fuse has been ruptured, it is not possible to reconnect the gun string without coming out of the hole (see also VSS-H).

3. VSS-B - The VSS-B is designed to be deployed when selective (+ve and –ve) perforating is required using

standard, resistorised detonators. The VSS is run below the ART and uses various voltage sensing elements and protection circuitry to allow the engineer to ‘shoot’ on both positive and negative polarity, whilst also acting as a

high impedance device when looking up from the top of the perforating string. Therefore if a short appears in the gun below the VSS, the ART will function normally as the VSS prevents the ART from 'seeing' the short-circuit below it. When shooting using positive polarity, only the forward bias of a diode (0.7 volts) has to be broken down

before the tool will pass current to the detonator. However when shooting on negative polarity, additional protection circuitry has to be broken down, requiring approximately -130volts before the circuit will allow current to pass to the detonator.

4. VSS-D - The VSS-D is designed to be used when selective perforating is required using a voltage-sensitive RF Safe detonator (e.g., HES RED detonating system). The VSS-D is similar to a VSS-B but has a lower current-carrying capability and a lower voltage leakage at temperature.

5. VSS-H - The VSS-H is deployed when an ART is operated with the DynaEnergetics RF Safe detonating system. It

operates in a similar manner to the VPM-B, but contains a sophisticated switching element rather than a fuse. This means that the VSS-H can be deployed below a tractor/VPM-G to allow multiple Safe/Fire switching cycles of the

VPM and the firing of a ballistics device between each VPM cycle.

6. VPM-G – The VPM-G is designed as a safety device to be deployed when running ballistics devices below a high voltage downhole tractor. The device contains multiple switches, which, under surface control, positively ground

the gun firing line so that even if the tractor malfunctions, the guns cannot be fired. Once the gun is on depth, the VPM is operated to connect the firing line so that the ballistics device can be triggered. The VPM-G contains an integral VSS-B, D or H as required.

2.19 What procedures do I need to be aware of before initiating an ART release?

Use of the ART to release a stuck toolstring should only be contemplated once all normal tool retrieval techniques have been exhausted. The logging engineer should follow Service Company fishing protocols and discuss the various fishing options with the company man and office based personnel wherever possible. There are several conditions that might affect the decision to release the ART, such as: -

• Have the guns been fired? It is unlikely that an operator would want to drop armed and loaded guns?

• What is the standard operational procedure for the Service Company or Operator during fishing operations? Perhaps they insist on a ‘cut and thread’ for all fishing operations?

• Where in the well the string is stuck - open-hole, across critical safety valves or the BOP’s (rig or wireline)?

• Is there a nuclear device, chemical cutter or any other hazardous device tool below the ART?

• Is the correct fishing grapple and associated equipment available to fish the toolstring?





Having established that the ART is to be released, follow the manual guidelines on the ART operation, a brief description is given in section 2.15 below. Once the ART motor has been activated, indication that the tool has been released may be given

in a number of ways: –

• Current limit LED lights (when released, the tool is likely to short circuit at the lower head);

• Current drops to zero;

• Current meter shows a kick;

• Tension on surface kicks;

• Tools above the ART can be retrieved from well;

In order to ‘pull-off’ from the ART, it is necessary to exert a minimum over-pull of approximately 100lbs at the ART to free

the upper section. This may translate to substantially more at surface in a highly deviated and doglegged well due to cable drag along the well’s trajectory.

2.20 What fishing grapple do I require for the ART-C?

• 1” fishing head fitted to ART-C

Figure 2-6 - ART-C (1” OTIS) Fishing Head ART-C Fishing Grapple P/N: 116-00272





2.21 What fishing grapple do I require for the ART-H/T?

• 1 3/16” fishing head fitted to ART-H/T/I

Figure 2-7 - ART-H 1 3/16” OTIS Fishing Head

ART-H Fishing Grapple P/N: 116-00084

Figure 2-8 - ART-H Fishing Head Assembly ART-H Fishing Head Assembley P/N: 116-00086





What is the maximum ART load before, during and after release?

• Before Release: The maximum working load of the ART-C is 2 tonnes, whereas the ART-H/I/T is rated to 3 tonnes.

• During Release: The recommended maximum load during the release operation of the ART and the stuck toolstring is 400 lbs. The ART will operate satisfactorily above this limit (up to the maximum safe working load), however release at very high loads may result in some damage to the fishing head/dogs.

• After Release: Once the upper section of the ART has been removed from the well, there are no specific restrictions on

fishing operations, except that the maximum fishing load should be limited to no more than 10 tonnes. Once the upper section of the ART is removed from the well, a standard 1” or 1 3/16” OTIS fishing head remains; depending on ART type. Fishing operations can then commence depending upon the service and oil companies fishing protocol.

Figure 2-9 - ART-H Schematic - Before Release

Figure 2-10 - ART-H Schematic- After Release

2.22 How do I release an ART?

1. Disconnect all surface panels and power supplies from the logging cable. Connect the ACP to the wireline cable at surface using the BNC connector.

2. Set ACP selector switch to ‘Safety’ position and switch on. After about 5 to 7 seconds, the current meter should read 10 to 12mA.





3. Check indication on ACP front panel LED’s (current meter which should read no more than 12mA plus any other

current drawn by the toolstring). These will initially scroll RED and after a short delay, will indicate which ART(s) are

connected and responding to the panel by a continuous GREEN LED.

4. The cable can be slacked off completely, however there the maximum tension at the tool head should not exceed 400

lbs.

5. Select which ART tool is to be released by means of the ACP selector switch, 1 to 7.

6. The selected tool LED will flash GREEN for a short period whilst it is being addressed and will then turn steady

orange. At this point the ‘ARM’ button is enabled.

7. Press the GREEN ‘ARM’ button on the ACP. After a short delay the ‘ARM’ LED will illuminate continuous RED

indicating acceptance of the arming command. At this stage it is possible to abort tool release by switching the

selector switch back to safety or switching off the panel.

8. To release the tool press the RED ‘RELEASE’ button. After a short delay the corresponding tool LED and the ‘MOTOR RUN’ will light continuous red. A tool current between 40mA and 120mA indicates operation of the release

motor; this current is dependent on well pressure and temperature. Indicators to suggest that the tool has been released are given in section 2.12.

2.23 What happens if there is a cable insulation or continuity problem – can I still release?

A total failure of insulation anywhere in the wireline cable or tool head will prevent operation of the ART. If the ACP panel

is connected and powered up, a cable problem may be indicated if none of the LED’s is green with the switch in the ‘Safety’ position, and the line current is substantially more than 12mA (check display). If cable insulation appears to have been lost, check line resistance using both polarities of an ohmmeter. Powering up any logging tools, correlation or downhole tractors in the toolstring can also be used to confirm potential cable problems. Similarly, if cable continuity is lost, the ACP will not

be able to communicate with the downhole ART and so a release will not be possible.

Figure 2-11 - Section of ART-H Fishing Head and Grapple System





2.24 Can I reverse the ART motor and reset the ART after release?

Having followed the correct sequence of events and activated the ART release button, once the ART motor is running (and until the tool actually releases) the release process may be aborted by switching off the ACP. This will reset the downhole

tool electronics but it will not reverse the motor to put the release mechanism back in its original position. Therefore once released, the ART motor cannot be reversed under surface control in order to reset the tool downhole.

2.25 Why can’t I reverse the ART motor?

The motor used in the ART is bi-directional, requiring a positive voltage to go clockwise and a negative voltage to turn anti-

clockwise. However, the downhole ART electronics and motor control is designed to respond to a fixed set of negative pulses and commands from the surface ACP and to only output a negative voltage motor signal, so no matter what polarity signal is sent from the surface, the motor will only rotate in one direction and cannot be reversed. Therefore, in order to reverse the ART motor, the ART has to be disassembled and the motor ‘fly-leads’ disconnected and attached to a positive

voltage and current from an external power supply.

2.26 Can I release an ART at surface?

Guardian strongly recommends not performing demonstration or ‘confidence boosting’ test releases of the ART-H or ART-C at surface. The setup required is complex and it is far more likely that a tool will not release successfully due to a problem with the setup than with the tool itself. If the ART is run through its complete release sequence on surface, which requires

the tool to be pressurised, as a confidence-boosting exercise then the tool will have to be disassembled and rebuilt. This then leaves the question, will the tool operate successfully having been rebuilt? The ARTs have a 100% record since 1997 when deployed within their operating envelope and for this reason we do not recommend surface release testing of the ART.

Pre-job functional testing as described within the Operations and Maintenance Manual confirms tool operation all the way through to motor run. Over the years this has proved a highly effective pre-job test. If a full release test is required however, it should be performed in the following manner.

1. The entire operation needs to take place in a pressure vessel capable of pressurising the tool to around 5000psi (all

ARTs and MRTs require well pressure to operate fully) and into which cable connections can be introduced.

2. The pressure vessel requires a nitrogen accumulator to ensure that pressure remains above 1000psi with a volume increase in the pressurised fluid volume of 21cuin (350cc).

3. If the pressure vessel is vertical or sub-vertical it requires sufficient length to be able to attach weight bars to provide an axial load to the ART’s lower head of a minimum of 200lbs. (The tool may release with lesser weight

but this is the minimum guaranteed to release the tool). 4. If the pressure vessel is horizontal then a spring/piston mechanism must be designed, built and attached the ART’s

lower head such that when the vessel is under pressure, the piston moves to the bottom of the vessel, elongating the

springs and putting a load of at least 200lbs on the ART’s lower head.

5. Once the ART is installed into a suitable pressure vessel, the operational release instructions from the manual

should be followed. Following release, the Lower Feed-through Assembly in an ART-H/T/F/J (p/n 303-00057) will be severed and will require replacement.

2.27 Can I run and release the ART upside down?

The ART is supplied with either client specified upper and lower connections or more typically with ‘GO-A female’ upper head and ‘GO A male’ lower head. Due to this arrangement it is difficult, though not impossible, to run the ART upside down depending on the pin and head arrangement of the tools run above and below the ART. Due to the direct feed-through wire design of the ART, it is however possible to operate the ART upside down and to activate a release using the surface

control panel (ACP).





2.28 How often should I service the ART?

Correct guidelines for the full maintenance of the ART-C & H are outlined in the respective maintenance and operations manual. The preventative maintenance scheme suggested for use with all Guardian equipment is divided into three phases.

• Pre/Post-Job Maintenance

The pre/post-job maintenance covers tool operational checks, wellsite calibrations, primary pressure seal maintenance and general condition.

• Routine Tool Maintenance (RTM)

Routine Tool Maintenance procedures are designed to be carried out every 6 jobs or two months if the equipment has been used infrequently. More frequent maintenance is recommended if the equipment is used in hot or high pressure environments. This should be scheduled according to maintenance policy. RTM is divided into electrical and mechanical

tasks - RTM(E) and RTM(M). It covers all seal maintenance and the correct operation of sensors.

• Tool Verification Check (TVC)

The Tool Verification Check is a set of in-depth tests and measurements designed to ensure that the tool is operating correctly within specification. The TVC should be carried out every 12 - 15 jobs or 6 months as appropriate. For more information on the RTM and TVC maintenance, please refer to the respective manual.

2.29 How much weight do I need below the ART to enable a successful release?

To affect a successful release of an ART-H/J/F/T around 100 lbs is required to pull off the top section of the ART from the

fishing assembly. It is therefore recommended to have at least 200 lbs of weight beneath the toolstring when operating the ART, although generally it will release with far less than this. In situations where the toolstring is stuck, this is not an issue. However, when the client wishes to ‘intentionally drop’ an element or section of the toolstring in a well, if the toolstring is not anchored in any way (that is, it is not stuck) and is therefore ‘floating’, a successful release cannot be guaranteed with

less than 200 lbs. An ART-C/G requires around 50-70lbs and an MRT up to 400lbs.

2.30 How long does it take to re-build an ART-C/H tool?

The time taken to rebuild an ART is dependent on experience and prior knowledge of the ART mechanical assembly, with the ART-H/T being more involved than the ART-C. A trained technician should complete the operation within approximately 3 to 4 hours; however, the first re-build for someone who is not familiar with the tool may take up to 8 - 10

hours.

2.31 Do I need special training to service an ART?

No specific special training is required to service the ART. Guardian provides complete and detailed manuals on the maintenance and operation of the ART range of tools. These manuals include complete instructions on how to disassemble

and re-assemble the tools, with detailed, exploded, 3D assembly diagrams, electronic and mechanical drawings, spare parts lists and ‘O’ ring lists. However, we do offer and recommend a training course at Guardian or on-site training at our client’s location. Guardian cannot be held responsible for tools that are incorrectly maintained or serviced.

2.32 Is Guardian able to provide ART maintenance training?

Yes. Guardian will provide technician and engineer service training. This can be run at Guardian’s facility in the UK or at the client’s office. Please contact our sales office on [email protected] for a quotation.





2.33 Does Guardian provide ART servicing and tool repair?

Yes. Guardian provides a full maintenance and tool repair facility at its manufacturing and design base in the UK. On reception of the tool, trained technicians will evaluate what work is required, the cost of which is then quoted by the sales and marketing group. Note that no work will be carried out on the tool until the customer has been advised and agreed the

costs. Guardian has a policy statement in place to turnaround all repairs within a 10 working-day period.

2.34 What tools do I require to re-build an ART-H/T tool?

Complete sets of the few special service tools specific to each type of ART, and Redress Kits comprising parts required for servicing, are available from Guardian. The maintenance sections of each manual detail other recommended hand tools.

2.35 What spares do I require to rebuild an ART tool?

Due to the robust design of the ARTs, minimal parts are required to rebuild a tool after release. Spare part usage will

therefore depend on specific well conditions. The user should check the condition of the feed-through wires, exposed ‘O’ rings and the condition of the fishing grapple after fishing. For complete information on the operation and maintenance procedures for the ART (see Question 2.28), please refer to the relevant ART manual (Section 7). The manuals also contain

full listings of Recommended Spares.

2.36 What maintenance products are recommended for the re-build of an ART tool?

The following table provides a list of products recommended for use in servicing and maintaining the range of ART tools.

Product Part Number Size Application

Lubriplate 930AA 302-00001 14oz Tin Lubrication of mechanical parts only or where lubricant will not be in

close proximity to electronics boards or components. Should not be used where gasses given off at temperature could come into contact with electronics systems.

Lubriplate 930AA 302-00001 100ml

Tube

Lubriplate 1444 302-00031 14oz Tube Lubrication of threads and seals – general application.

Liquid O-ring 101 302-00030 1 lb. Tin Lubrication of threads and seals – general application (Preferred).

Silicone Grease 302-00002 100gr Tube

Pressure and fluid inlet ports where high retention under temperature is required. e.g., PWH Pressure Inlet Port, ART Pressure Balance Port. Do not use on threads. May be used on o-ring seals.

Loctite 242 302-00004 10ml

Tube

Used to lock fasteners (> M4 Thread) which may require future

release. Not recommended for use on any fastener < M4 thread. Do not use on plastic components.

Loctite 601 302-00005 10ml Tube

Used to lock small metallic components permanently in place. Not normally used during maintenance. Do not use on plastic components.

DC200/50 302-00035 1 l. Tub Oil filling of pressure tool buffer tubes and pressure balanced tools. e.g., PWH buffer tube.

Paratherm NF 302-00036 1 l. Tub Oil filling of pressure tool buffer tubes and pressure balanced tools.

e.g., PWH buffer tube. (Preferred)

RTV 302-00016 100ml Tube

Used to secure massive components against vibration & shock.

Loctite 638 302-00039 50ml As for Loctite 601 but where gaps exist between parts.

Sn96 303-00018 250gr Solder used for standard temperature (<350F/177C) boards. 0.015” Dia.

Sn05 303-00137 250gr Solder used for High-temperature (>350F/177C) boards. 24 SWG.





Table 2-1 - Recommended Maintenance Products





3 ART Specifications Please see the applicable data sheets for product specifications. These can be viewed and downloaded via our website

www.ggtg.net or by contacting [email protected].





4 ART Applications and Release Case Studies Client A:

An ART-H was deployed during a perforating operation (2 7/8” HSD guns run on mono-cable) to a total depth of 18,600 feet and with a max deviation of 65º. Due to the depth and deviation of the well, the service company was concerned that safety

would be compromised if the toolstring became stuck, as the engineer would have limited ability to pull off the weak point as the maximum safe load on the cable would be exceeded. This problem was compounded by the deviation of the well and the ability of the winch-man to work down enough cable tension to the head in order to be able to break the weak point. The deployment of the ART therefore provided the service company with the additional contingency and safe option of pulling

off from the gun-string using the electro-mechanical release system in the event of a stuck tool. Client B:

The oil operator requested the use of an ART during perforating operations in under-balanced gas wells due to historical problems of swelling and burst guns. Although specialist ‘gas guns’ were employed, the potential for gun swelling remained with the possibility of the guns becoming stuck in the BOP stack or when entering the wireline entry guide. The use of an

ART-H therefore allowed the operator the opportunity to ‘drop’ the guns if they became stuck after perforating. Client C:

A European service company which routinely ran ARTs on downhole tractor operations for other clients, made a presentation on the benefits of running ARTs to the major middle eastern operator which had just awarded it a new contract. At the time the operator was not interested in running the ART but the service company policy was to run them anyway.

During a plug-setting operation in a horizontal well, the tractor was run with ARTs above and below. The shear stud failed to part and stuck the setting tool and tractor in the well. Jars had been run below the tractor and were triggered several hundred times without success over an eight hour period. The service company then suggested activating the release tool, although they were unsure if it would release having been subjected to the severe jarring. The operator agreed and the

release tool run below the tractor was activated. The tractor was retrieved and the setting tool abandoned, saving the operator either the cost of a tractor or the cost of a fishing trip – a minimum of $250,000. The operator now insists on running ARTs with all tractor operations.

Client D: Running a plug and setting tool below a tractor into a long-reach horizontal well on the Norwegian CS, the plug became

lodged just above setting height. A decision was taken to set the plug at this depth and retrieve the setting string which contained an ART above the tractor. The plug partially set and the setting string could not be removed. Following substantial jarring, the release tool was triggered and the cable and head retrieved from the well. The tractor and setting tool

were then fished on drill-pipe. Releasing the ART significantly reduced the risk of parting the cable at surface and an extended or impossible fishing operation. Client E:

An ART-C was deployed in a 1 11/16 “ production logging operation due to the requirement of logging through a ‘Y’ tool. Due to the excess debris in the well during pumping and the potential for the fullbore flowmeter to become clogged, the

ART-C would allow the engineer the ability to release from the stuck toolstring and pass through the ‘Y’ tool.

Client F:





The ART-H has been deployed on numerous horizontal well ‘tractor’ operations in the North Sea. Due to the horizontal well

operations, the ability to be able to pull-off from the weak-point is severely compromised. Applications for the ART-H have included perforating, plug setting and production-logging operations. The addressable nature and design of the ART-H enables the tool to be deployed above and below the tractor. This allows the tractor to be retrieved from a stuck toolstring, or in the situation where a tractor becomes stuck, to allow the wireline and head to be retrieved without having to try and break

the weak point. Client G:

An operator needed production logging and particular fluid identification data from a well with increasing water cut. The operator was very reluctant to run the operation due to known tubing damage and debris in the well. The main concern was that the fullbore flowmeter or centraliser would become stuck if debris built up in the roller arms (spinner) or bowspring

(centraliser) and prevented them from closing properly, thereby increasing the risk of a stuck toolstring. The service company suggested deploying two 1 11/16” ART-Cs, one below the logging head, and a second below the radioactive fluid density (Cesium 137) tool. An ART-C was positioned below the nuclear tool in order to increase the chances of retrieving

the source if the tool stuck. The ARTs gave the operator sufficient confidence to run the operation and the service company generated over $35,000 total revenue. A specially modified telemetry cartridge was used in this application to allow negative voltage to be applied to the lower of the two ARTs.





5 Voltage Protection Modules (VPM)

5.1 Why run a VPM in the toolstring?

Voltage Protection Modules (VPMs) are an essential safety tool in the current wireline, tractoring or coiled tubing market, as they provide protection against excessive line current or voltages from damaging, destroying or detonating sensitive

toolstring components. VPMs are deployed to protect production-logging tools or provide additional ballistic safety when running perforating or setting tool operations on wireline.

In its simplest form, the VPM-A/B/F is designed to perform a designated task depending on the type of operation and client requirement. The VPM can therefore be configured to block or pass current in either polarity (VPM-F) or alternatively limit the voltage that the tool will pass to a set value, using various voltage sensing elements (VPM-A/B). The VPM-F is used as an additional safety device when running ARTs, as the tool can be configured to block the negative (-) 82 volt control signal

from reaching the perforating guns or setting tool. The VPM-A/B can be used in either conventional wireline operations or during tractor jobs in order to limit the voltages reaching sensitive elements of the toolstring.

With the increase in horizontal well drilling, the VPM has found a particular niche in downhole tractors operations by blocking the associated high voltage and currents from reaching production logging, perforating or setting strings. To achieve this, the VPM-G uses a surface control panel (VCP) and a set of downhole rotating cam/switches to control the connection of the lower head of the VPM to the toolstring above. It is therefore possible for the engineer to initiate a surface

controlled physical connect and disconnect of the firing line whilst tractoring. VPMs therefore provide an additional and completely independent protective safety system during tractor operations. One of the key strengths of the VPM-G is that whilst it operates in conjunction with the ballistics system and tractor, its control system is independent of both.

The VPM (using the voltage sensing switch, see section 5.5) also allows the continued operation of an ART if the perforating line becomes shorted after perforating. The VPM acts as a high impedance device when looking up from the top of the perforating string and prevents the ART from 'seeing' any potential shorts in the firing line below it. The VPM and

ART range of safety products therefore provide the ultimate in operational safety, by operating as complimentary electrical and mechanical tools. In this context, the VPM acts as an electrical safety device during perforating and production logging operations, whereas the ART provides the mechanical system enabling the controlled release of stuck downhole tools.

5.2 For what applications would I use a VPM in my toolstring?

• Protection of logging tools from over-voltage;

• Isolation of perforating or setting equipment from excessive line voltages;

• Equipment protection during well-tractor operations;

• Additional safety during standard wireline (or coiled-tubing) perforating operations;





5.3 Where do I position the VPM in the toolstring?

Operation VPM Tool Position

Wireline Data Acquisition VPM-A/B/G all run above logging or data acquisition tools.

Coiled Tubing VPM-A/B/F/G all run above logging, perforating guns or setting tools.

Tractor Operations VPM-A/B is run above the tractor. VPM-G must be run below the tractor and ART, since the VPM-G is used to

disconnect the lower head (firing line) from the tractor.

Perforating operations All VPMs should be run above perforating guns or setting tools. Note that Shock absorbers should be run as standard between guns and VPM in order to

provide shock protection.

ART Combination VPM-F, VSS and the VPM-G are all run below the ART. For additional

information see question 5.4 below.

Table 5-1 - VPM Toolstring Position

5.4 Is the VPM run above or below an ART?

During a combined ART operation, the VPM-G (or stand-alone VSS tool) must be run below the ART, as the VPM-G or VSS provides a high impedance barrier to any short circuit in the firing line. Similarly the VPM-F, which blocks negative polarity, must also be run below the ART. If the toolstring then becomes stuck after perforating and the firing line develops a short, the VSS/VPM-F allows the continued release operation of the ART by preventing the short affecting the negative

voltage control signal of the ART.

5.5 What is a VSS – Voltage Sensing Switch?

The Voltage Sensing Switch (VSS) is run below the ART in order to allow the continued operation of an ART if the firing line becomes shorted after perforating. The VSS uses protection circuitry to allow the engineer to ‘shoot’ on both positive

and negative polarity (as long as the surface perforating system is able to provide a voltage greater than –130 volts to overcome the negative protection circuitry), whilst also acting as a high impedance device when looking up from the top of the perforating string; the VSS circuitry therefore prevents the ART from 'seeing' the short below it.

The VSS is built into the VPM-G tool as standard, however it is also available as a stand-alone tool to be run with ARTs when the additional functions and protection of the VPM-G are not required, such as during conventional wireline logging operations.

See section 2.18 for details on the types of VSS which are available.

5.6 Where should correlation tools be run – above or below the VPM?





When correlating, it is normal practice to position the VPM above the correlating device, that is, the gamma-ray (GR) tool, casing collar locator (CCL) or GR/CCL combination. If required, the VPM may be positioned below the correlation tool,

however this is dependent on whether the correlation tool circuitry degrades or corrupts the VPM control signal such that the VCP cannot communicate effectively with the downhole VPM. There could also be issues regarding protective circuitry in the correlation tool that might affect the VPM. It would therefore be necessary to contact technical support at Guardian or consult with the supplier of the correlation tool to confirm tool compatibility.

5.7 What head types are available?

Guardian is able to provide a range of head types to suit the field requirements for the VPM, from standard designs to specific client heads. These include:

1. Standard Go ‘A’ type mono pin

2. Modified or reversed Go ‘A’ type mono pin 3. BA-A3 (OTA) 4. Schlumberger MH21/22

5. Client Specified.

5.8 Can I obtain a VPM for a specific operation?

The VPM-A/B/F is typically run during conventional wireline and ballistic type operations, but can also provide additional safety during tractor operations. The tool is configured according to client’s specification, based on the requirement to limit, block or pass a designated range and polarity of voltage and current.

The VPM-A/B/F can be configured to pass positive voltages for positive polarity perforating and block negative voltages or vice-versa. The specification of voltage limit and shooting polarity is generally client specific and so will depend upon the

application and equipment in use. In its ‘limiting’ function, the VPM works by connecting a discharge cell across the line to chassis ground. This cell reversibly breaks down and places a very low resistance between line and ground whenever a pre-set voltage is exceeded.

The VPM is fitted with two cells, with differing voltage ratings, which may be selected by means of internal jumpers. The maximum voltage that can be applied to tools below the VPM is therefore limited to the nominal breakdown voltage of the selected cell.

The discharge cells can withstand significant currents for a limited period of time and will therefore generally provide protection for a sufficient period of time for the over-voltage to be manually or automatically removed.

Should the over-voltage continue for an excessive period of time, a fuse connected between the upper head and the protection circuit/lower head provides additional protection. In the event of significant current for an extended period of time, the fuse will rupture providing further protection for tools below the VPM.

The series fuse is intended to protect the discharge cell from high continuous currents if the operator does not observe the fault causing over-voltage, and remove the power. The fuse will operate if sufficient current is passed through it for a time dependant on the current and ambient temperature. The set value of 3A will allow continuous operation of toolstrings with

power consumption up to 750mA at 177°C. The fuse manufacturer’s information for the operating time variation against current and temperature is given in Figure 5.1 below. If the over-voltage is removed prior to fuse rupture, the discharge cell will automatically reset.





An option is provided to short out the fuse using a second internal jumper. In the non-fused mode the VPM provides protection against brief over-voltage events and will recover once the condition is removed. In this condition continuous

over-voltage will cause an irreversible open circuit in the discharge cell that will then require replacement.

100mS

10mS

250mA

1S

10S

100S

20C

170C

750mA500mA 1A

80C

Figure 5-1 - Fuse Rating Time

5.9 What additional equipment do I need to run a VPM-A/B/F?

• No surface equipment is required.

• A shock absorber should be run between the perforating guns and the VPM.

5.10 What servicing equipment is required for the VPM-A/B/F?

A full list of service tools required is given in the applicable Operations and Maintenance Manual.

5.11 Which VPM tool do I run to electrically disconnect the downhole toolstring from the tractor?

The VPM-A/B/F is designed to be run with tractors, however they do not disconnect the lower head of the VPM from the

tractor, but use various voltage sensing elements to block or limit voltages and currents. Alternatively, the VPM-G is a protection device designed specifically for deployment when running perforating guns, other ballistic devices or production logging tools below a downhole tractor. It is essentially a surface controlled ‘electrical switch’, in which the surface control panel (VCP) is used to switch between ‘safe/tractor’ and ‘fire/logging’ modes of operation. In addition, the tool provides a

positive indication to the engineer of the VPM downhole switch status. With the VPM in ‘safe’ mode, up to 1000vac/1500vdc can be applied at the upper head of the tool with no voltage appearing at the lower head. With the VPM in Log/Fire mode, any data from CCL and GR correlation tools can be acquired and guns attached below the VPM can be

fired. The VPM can be deployed with both positive and negative firing guns.





A key-switch on the VCP front panel controls the enabling/disabling of the VCP and tractor power panel, allowing only one

panel to be enabled at any one time. The choice of enabled panel is governed by the key-switch position and is under the engineer’s control.





Figure 5-2 - VPM-G Block Diagram A bypass resistor is optionally available to transmit CCL signals across the VSS when the VPM is in Fire/Log mode.

5.12 Can I run more than one VPM-G in a toolstring?

No, unlike the ART, the VPM tool is at present (November 2012) not addressable.

5.13 What VPM-G equipment do I need?

The following equipment is required:

Downhole 1. VPM-G

2. When perforating, we recommend that a shock absorber (such as a Guardian SAT tool) be run between the VPM and guns.

Surface 3. VCP – VPM Control Panel or MPP-B (Multi-Purpose Control Panel) 4. Relay box to disable tractor panel (this item will depend upon client specification and requirements – it may

therefore be built into the VCP, or external to the VCP)

5. 110 volt or 240 volt mains lead 6. Leads to connect ACP to wireline cable





Figure 5-3 – VPM-A Control Panel (19” Rack-Mount)*

Figure 5-4 – VPM-B Control Panel (Suit-Case)*

* PowerTrac is a trademark of AkerKvaerner a/s.

5.14 What servicing equipment is required for the VPM-G?

A full list of service tools and equipment is provided in the maintenance section of the manual.

5.15 Are there additional safety procedures when running a VPM-G?

The VPM system is designed for use with ballistic equipment, the operation of which is outside the control of Guardian Global Technologies. Therefore no specific instructions for use are given. In addition, the safe use of the VPM system is





entirely in the hands of the client engineer and she/he should thoroughly familiarise him/herself with operation of the system prior to active deployment.

It is essential however, that all Standard Operating Procedures (SOP’s) set out by the service company and the operating oil company are observed when running the VPM system or performing operational checks of the combined VPM/VCP and powered tractor system on surface. Under no circumstances should an operational check of the system be made on the

surface WITH ARMED PERFORATING OR SETTING TOOLS CONNECTED. If LIVE guns are connected to the string, the tractor and VCP panel should only be engaged once the toolstring is at least 100 feet below the surface or subsea BOP.

Once the toolstring has reached a safe depth below the BOP’s, connect the VCP panel to the tractor panel via the external relay box using the umbilical cords. By using an external relay box, the VCP acts as the ‘Master’ controller and dictates whether the VCP or the tractor panel is connected to the wireline cable and downhole tools. The tractor panel can only be enabled and connected to the wireline when two conditions are met, namely:

1. The VCP has successfully cycled the VPM and detected that the micro-switches are in the ‘safe’ position. 2. The VCP safety switch key has been manually switched from enable to disable.

When the above two conditions are met, a relay inside the VCP sends the output line high (+12volt) to activate the external relay, which disconnects the VCP and connects the tractor panel to the downhole tools. If however, only one, or neither of the above conditions are met, the VCP output remains low and so disengages the external relay box, disconnects the tractor

panel and connects the VCP panel to the downhole tools. The requirement of positive relay activation acts as another safety measure, as the external relay panel will disconnect the tractor panel from the downhole tools if the VCP panel fails or is switched off.

5.16 What is the procedure to enter ‘Tractor or Safe’ Mode?

Once the VPM has been powered and the panel has completed its diagnostics, the front panel ‘SAFE’ button is pressed.

This sends a digitally encoded secure command to the tool which echoes it back to the panel to confirm receipt. Once the

tool has put itself into safe mode, it signals the panel. A continuous Green LED indicates to the engineer that the tool is in safe mode.

5.17 What is the procedure to enter ‘Fire or Log Mode?

To put the VPM into the Fire/Log mode, press the Red FIRE button on the VCP front panel. This sends a digitally encoded

secure command to the tool which echoes it back to the panel to confirm receipt. Once the tool has put itself into ‘FIRE’

mode, it signals the panel. A continuous Red LED indicates to the engineer that the tool is in fire mode.

5.18 What is the fault light LED for on the VCP surface control panel?

If the VCP detects an error in the system, the three LEDs (fire, safe and fault) on the front of the VCP panel will flash continually. In this condition, the VCP does not know what status (safe or fire mode) the VPM tool is in and therefore the

tractor control panel cannot be enabled. This failure may be caused by the detection of a number of errors:

1. Cable insulation or continuity failure. 2. The position of the downhole micro-switches cannot be determined; this could be related to a micro-switch failure

of if the motor has switched the cam off mid cycle before it has activated the switches. 3. Failure of tools above the VPM, for example head insulation. 4. Surface problem, for example collector failure.





In order to clear the fault light, the VCP panel must be shut down and powered up again. If the problem cannot be resolved on the surface, the toolstring should be removed from the well following all SOP’s.

5.19 What happens if the VPM surface control panel (VCP) is switched off whilst the tractor is powered up?

If the VCP is switched off during tractoring, the master control relay will also become disabled, which will in turn

disconnect the tractor panel, removing power to the downhole tractor. Some types of tractor disconnect their lower head while tractoring. Therefore, if the VCP disconnects the tractor power

panel prematurely, the tractor may remain with its lower head disconnected. This situation would prevent the VCP putting the VPM in safe mode and re-enabling the tractor power panel (no communication to the VPM would be possible). Therefore, if a power-cut occurs during tractoring and the tractor’s lower head remains disconnected, the VCP will not allow re-enabling of the tractor panel as the state of the micro-switches will be unknown. In this event, the tractor panel can be

forced to the enabled state by depressing the button on the rear of the VCP. Pressing this button will sound an alarm. This emergency enable system should only be used with EXTREME CAUTION – used incorrectly it could result in firing of the ballistics device.





5.20 What types of VPM are available?

The table below shows the types of VPM available together with their operating characteristics.

VPM-A VPM-B VPM-E VPM-F VPM-G

Diameter: 1 11

/16" 1 11

/16" 3 3/8" 1

11/16" 2

1/8"

Temp Rating: 177 177 177 177 177

Pressure Rating: 20k 20k 15k 15k 20k

Length: 8" 8" 12" 8" 27"

Heads: GO A GO A Custom GO A GO A

Description: Passes +ve and -

ve voltage to a

pre-set limit

Passes +ve

and -ve

voltage to a

pre-set limit

Disconnects &

grounds tools

below via

switch

Blocks all of

one polarity;

passes all of

the opposite

polarity.

Disconnects &

grounds tools

below via

switch

Panel Required: No No Yes No Yes

+ve Pass Range: 0 - 145 / 300vdc5

0 - 20vdc None4

0 - 1000vdc 1

None4

+ve Block Limit: 145/300 - 10005

20-1000 1000vdc4

1000vdc 2

1000vdc4

-ve Pass Range: 0 - 145 / 300vdc5

0 - 20vdc None4

0 - 1000vdc 2

None4

-ve Block Limit: 145/300 - 10005

20-1000 1000vdc4

1000vdc 1

1000vdc4

Switch Disconnect: No No Yes No Yes

VSS Inc: No No Yes No Yes

-ve Pass Range: N/A N/A 130 - 1000vdc 3

N/A 130 - 1000vdc 3

-ve Block Limit: N/A N/A 0 - 130vdc 3

N/A 0 - 130vdc 3

Notes

1: When set to Negative block

2: When set to Positive block

3: When switched to 'Log' mode

4: When switched to 'Safe' mode

5: 145 / 300 user selectable





6 VPM Specification

Please see the applicable data sheets for product specifications. These can be viewed and downloaded via our website www.ggtg.net or by contacting [email protected].





7 Shock Absorber Tool (SAT)

7.1 Why run an SAT in the toolstring?

The SAT is designed to cushion more sensitive elements within a toolstring – e.g. gamma tools, release tools – from the shock generated by a perforating gun. The SAT is also an inexpensive method of extending the fatigue life of components within a perforating string and avoiding an expensive and time-consuming failure of a downhole tool.

7.2 What diameter tools are available?

The SAT is available in 1 11/16”, 2 1/8” and 3 1/8”.

7.3 What load will a SAT take?

The smaller tools are designed to take a static load of 1350lbs (620kgs) at a displacement of 0.75”. The larger will take a

load of 2200lbs (1000kgs) with a displacement of 1.5”.

7.4 Is the SAT H2S rated?

Yes - the tool is manufactured from NACE specification (MRO-175) materials, and the springs used are Inconel for full H2S resistance.

Figure 7-1 – Shock Absorber Tool (SAT-A), 2 1/8”

art, vpm & sat faq handbook iss h

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