esp applicationn in rag

7/17/2019 ESP Applicationn in RAG

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RAG. AUSTRIA.ENERGIE

Christian Burgstaller

[email protected]

Rohöl-Aufsuchungs AG

Schwarzmoos 28, A-4851 Gampern

www.rag-austria.at

Application of an

ESP for Gas WellDeliquification –

RAG’s Experiences




Overview

• Company information

• RAG’s gas well deliquification applications and strategy

• ESP for gas well deliquification

• Automatic fluid level measuring device (MURAG-20)

• Results of ESP installation

• Conclusions

Gas Well Deliquification Conference | Groningen | 15-16 Oct. 2013 2




Overview RAG Austria

• Oldest Austrian E&P Company(since 1935)

• ~ 1000 wells drilled in Austrian concession area

• Currently 90 oil wells and 150 gas/UGS wells on production

• Operations / JVs also in Germany, Hungary and Poland

• Biggest gas fields converted to Underground Gas Storages (UGS)

• Challenges in gas production: tail end production with low pressurereservoirs (5 – 10 bar res. pressure) and liquid loading

• Focus on optimising ultimate recovery with new technologies





4

Overview of GWD Applications in RAG

ESP

Sucker Rod Pump

Progressive Cavity Pump

Plunger Lif t

Chamber Lift

Use smaller tubing / Velocity Strings

Capillary Strings for Foam Injection

Backside Foam Injection / Foam Sticks Treatment

Surface Gas Compression

Water lifted Current / planned applications

20 to 70 m3/d 0 1

1 to 10 m3/d 2 3

70 to 200 m3/d 1 1

5 to 40 m3/d 1 2

0,5 to 15 m3/d 16 20

0,5 to 10 m3/d 50 50

0,5 to 20 m3/d 80 80

0,5 to 2 m3/d 1 1

0,5 to 20 m3/d 10 13

Require externalenergy

Increasing WGR

Gas Well Deliquification Conference | Groningen | 15-16 Oct. 2013




Strategy for GWD using Downhole Pumps• Need flexible system if WGR is higher than expected

• Use of PCP‘s at water rates of 5 – 40 m³/d (depth range 1300-1700 m)

•

Sucker Rod Pumps with new gas separation technology (VSP, etc)• Small ESP‘s at water rates > 70 m³/d

• Pumps running dry – very critical with PCP and ESP

• Apply new technologies for automatic fluid level control

ESP: 70-200 m³/d of water SRP: 20-70 m³/d of water PCP: 5–40 m³/d of water





ESP for Gas Well Dewatering – Case Study

• Weizberg Field (Upper Austria)

• Reservoir pressure = 168 bar, perforations at 1721-1733 m

• High WGR: 100 m³/d water @ 10.000 m³/d gas

• Wells were produced with sucker rod pumps (yrs. 1994-95)with max. run times of 4 months

• Problems: gas-locked pumps due to insufficient control of fluidlevel, gas break throughs causing valve problems

• Planned dewatering method: ESP with Variable Speed Drive incombination with Automatic Fluid Level Measuring Tool forautomatic control of fluid level





7

Variable Speed Drive (VSD)Fluid levelmeasuring tool

ESP cable

Gas production

Water production

Chemical injection valve

ESP with Gas Separator andDownhole Sensors (Intake andDischarge Press., Temp.)

Completion

schematics -

Weizberg 3

Fluid level is

continuously

measured





8

Fluid level measurement with a fully automatic,

electronic device (MURAG-20)

• Uses complex signal structure

• Signal is generated purely electronically (no gas gunrequired)

• Signal is propagated in annulus

• Fluid level is identified automatically by analysis of thereflected signal pattern (including frequency analysis)

• Fluid level is permanently displayed and availablevia 4 - 20 mA interface for SCADA systems





9

Automatic fluid level measurement –MURAG-20 components

Analyzer

Measuredfluid level

Transducer

Signal processing





10

Automatic fluid level measurement - MURAG-20

Signal

Transducer • Signal

electronicallygenerated

• Zero emissions

• 5000 psi

•

CE certified• ATEX certified:

II 2G Ex d IIB T4





11

Automatic fluid level measurement – Responseon change of ESP speed (Oil well example)

VSD Frequency [Hz]

Fluid Level [m]





12

Permanent Bottom Hole Pressure from Fluid Level• Comparison of downhole pressure curves (Sucker Rod Pump)

Well flowing: Match pressure from downhole gaugewith simple black oil correlation

After shut-in: Difference depends on calculation effort,possible to match downhole gauge

with transient mult i-phase flow modeling





ESP for GWD - Well Weizberg 3

Transducer

• Well on production since

July/2012

• Water production via tubing

~ 130 m³/d (~820 bbl/d)

• Gas production via annulus~ 4500 Nm³/d (~ 160 Mscf/d)

• Production is limited by water

disposal capacity in the field





• Fluid level rises with increasing ESP speed increase ingas production results in gassy liquid column

• Measured fluid level agrees with calculated fluid level

from downhole pressure gauge within 10 m despite gassy column

Fluid level [m]

VSD frequency [Hz]

Gas rate [m³/hr]

Water rate [m³/hr]BHFP [bar]

Casing press. [bar]

Well Weizberg 3 –

Response on change of ESP speed




RAG. AUSTRIA.ENERGIEWell Weizberg 3 –

Bottom Hole Pressure from Fluid Level

• Bottom Hole Flowing Pressure calculated from measured

fluid level using multi-phase flow correlation agrees well

with downhole gauge

BHFP [bar] from Downhole Gaugeat pump intake

BHFP [bar] calculated from

Fluid Level




RAG. AUSTRIA.ENERGIEWell Weizberg 3 –

Fluid level response on ESP shut-off

• Automatic fluid level measurement shows immediate

response on shut-off of the ESP

• Accurate control of fluid level is permanently given

Fluid level [m]

VSD frequency [Hz]

Gas rate [m³/hr]

Water rate [m³/hr]

BHFP [bar]

Casing press. [bar]





17

Automatic Fluid Level Measurements - Applications in Gas Well Deliquification

•

Combined with Downhole Pumps (ESP, PCP, SRP)• Possible to set and maintain a desired fluid level

• Prevents pumps running dry – increases pump run times

• In combination with Variable Speed Drives (VSD) – allows forautomatic control of production rate and fluid level

• Safely make full use of available pump capacity

• The device is mounted at the wellhead

•

therefore easy trouble-shooting• system is not sensitive to high well temperatures

like downhole pressure sensors






Conclusions

Downhole Pumps combined with automated fluid

level measurement make the following possible• Permanent control of fluid level and bottom hole pressure

• Continuous, automatic adjustment of artificial lift systems

(oil production and gas well deliquification)• Protection of downhole equipment and improved run

times

An economic application of an ESP for gas welldewatering has been achieved.

18

esp applicationn in rag

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