aspen hysys dynamics by aspen technology inc. olga by spt ... · pdf filebillington process...

Billington Process Technology AS

Per BillingtonCEO

Arne M GulbraarVP Process Safety

Aspen HYSYS® Dynamics by Aspen Technology Inc.OLGA by SPT Group AS- a Schlumberger SubsidiaryOLX™ by Billington Process Technology AS

WEBINAR Overpressure Protection verifications of Oil and Gas production inlet facilities

«Value adding apps for process simulations»

Session 1 starting 09:00 CET Session 2 starting 16:00 CET

Session ID/Access code = 437‐726‐653Use the phone numbers at the end of the email invite to join the conference call.

Session ID/Access code = 931‐414‐756Use the phone numbers at the end of the email invite to join the conference call.

Q&A: Questions in writing by E-mail to [email protected]

Billington Process Technology ASPage2

• BPT incorporated 1998, in Norway

• BPT engineers have completed 200+ oil & gas offshore projects

• BPT provides independent and trusted 3rd

party specialist consultancy services to the upstream market

• BPT specializes in overpressure protection studies using linked simulations. Fulfilling API requirements

• BPT turns knowledge into software, shared through licensing

• Use BPT Toolkit to optimizeasset performance, ensure process safety and enhance engineering efficiency

• The BPT Toolkit integrates with world leading process simulators

• Securing your existing software investments

Company Overview


BPT Key Offerings: Software, Studies & Solutions

Webinar focus


Overpressure Protection

Verifications of Oil and Gas production inlet facilities.

E‐mail : [email protected] Phone : +47 67 56 99 90

Visiting Address: Løkketangen 20, Sandvika


Content

• Introduction – Overpressure Protection

• Requirements– PSV Sizing

• Scenarios

• BPT Tools & Methods:

– BPT PSX™

– BPT OLX®

– BPT EXT™

• Case Study/Examples

Tools&

Methods

Scenarios

PSVSizing

Require-ments


Introduction, overpressure protectionProcess safety preferred designs:

1. Inherent safe design Design pressure handles all events

3. Unconventional solution Primary safety barrier - PSD (instrumented) Secondary safety barrier- HIPPS (instrumented)

“Correct” sizing of the PSV’s are vital

2. Conventional pressure protection Primary safety barrier - PSD(instrumented) Secondary safety barrier- PSV(mechanical)


Tools &

Methods

Scenarios

PSVSizing

Require-ments

API Std 520 Part ISizing and Selection

API Std 526, Flanged Steel PRV’s

+++

API RP 14CAnalysis, Design, Installation, andTesting of Basic Surface Safety Systems

for Offshore Production Platforms

API Std 521, Pressure relieving and depressuring SystemsNorsok P-002

«Gaps» in existing tools for complex multiphaseflow scenarios …

…iterative work process required?

….EXPERTS REQUIRED !!

Typical challenges in theupstream oil & gas:

Long subsea tie-backsLong wells

HP/HT wellsBullheading required?

Retrofit of existinginfrastructure

What if I could just enter basicinput design PSV data, and

then let the simulator calculateand adjust derating factors

automatically?

=>Complex multiphaseflow phenomena

must be designed for


Basic requirements


API Standard 520 Part I – Mass FluxAnnex B.1 Development of Flow Equations:

B.1.1.2.b).. that the actual flow through a PRV can be adequately estimated by determining the theoretical maximum flow through the nozzle..

.. and then adjusting this theoretical flow to account for deviations from ideality

B.1.1.3 …The general volumetric energy balance for isentropic nozzle flow of a homogeneous fluid forms the basis for the mass flux calculation…

Annex C.1 Sizing for Two-phase Liquid/Vapor Relief

C.1.2.2 The equations presented in C.2.1 are based on the Homogeneous Equilibrium Method [4], which assumes the fluid mixture behaves as a “pseudo single phase fluid,” with a density that is the volume averaged density of the two phases.

This method is based on the assumption that thermal and mechanical equilibrium exist as the two-phase fluid passes through the PRV…


API Standard 520 Part I - Flow equationCapacity, W [kg/s]

Keyparameters Comment

Status vsavailable tools

Theoretical Mass Flux [kg/sm2]

CompositionsPressureTemparature

Homogenous EquilibriumMethod (HEM) Direct Integration Leung Omega method

Commonly available

Discharge area[m2]

Pressure(Lift)

Main nozzle bore in the body is basis for calculating dischargearea in API Std 520 Part I.

Commonly available

Capacity correctionfactors[ - ]

CompositionsPressureTemparatureGeometry

Discharge coefficient Backpressure correction Combination correction Viscosity correction

Commonly beingmanually entered, not suited for transient simulations.BPT PSX™ : Automatic adaption


API Standard 520 Part I – Effective vs Rated

5.2.1 PRVs may be initially sized using the equations presented in 5.6 through 5.10 as appropriate for vapors, gases, liquids, or two-phase fluids. These equations utilize effective coefficients of discharge and effectiveareas that are independent of any specific valve design. In this way, the designer can determine a preliminary PRV size.

5.2.4 The rated coefficient of discharge for a PRV, as determined per the applicable certification standards, is generally less than the effective coefficient of discharge used in API 520 ...…This allows the rated capacity of most valve designs to meet or exceed the estimated capacity for preliminary sizing determined per the API 520 calculations.

5.2.5…It is important to remember that the effective area and the effective coefficient of discharge are used only for the initial selection…

The actual orifice area and the rated coefficient of discharge shall always be used to verify the actual capacity of the PRV. In no case should an effective area be used with a rated coefficient of discharge for calculating the capacity of a PRV. Similarly, an actual area should not be used in conjunction with an effective coefficient of discharge.


API Std 521 - Causes of Overpressure

API Standard 521, 6th Edition, January 2014 Closed outlets (4.4.2)

Overfilling (4.4.7)

Failure of Automatic Control (4.4.8)

- Inlet Control Devices and Bypass Valves

- Outlet Control Devices

- Fail-stationary Valves

- Choke valve failure

Abnormal Process Heat or Vapor Input (4.4.9)

- Inadvertent valve opening

- Check Valve Leakage or Failure

Cooling or Reflux Failure (4.4.3)

Absorbent Flow Failure (4.4.4)

Accumulation of Noncondensables (4.4.5)

Entrance of Volatile Material into the System (4.4.6)

Internal Explosions or Transient Pressure Surges (4.4.10)

Chemical Reaction (4.4.11)

Hydraulic Expansion (4.4.12)

Fires (4.4.13)

Heat Transfer Equipment Failure (4.4.14)

Electric Power Failure (4.4.15)

Overpressure Prevention During Maintenance (4.4.16)

4.2.6 Role of Instrumentation in Overpressure Protection: Fail-safe devices, automatic start-up equipment, and other conventional instrumentation should not be a substitute for properly sized PRDs as protection against single jeopardy overpressure scenarios…

4.3.2 Effects of Pressure, Temperature, and Composition

Pressure and temperature should be considered to determine individual relieving rates, since they affect the volumetric and compositional behavior of liquids and vapors. ….

During pressure relieving, the changes in vapor rates and relative molecular masses at various time intervals should be investigated to determine the peak relieving rate and the composition of the vapor.


Scenarios


Typical Upstream Oil & Gas Challenges

• Subsea tie-backs• Large volumes, multiphase flow transients...

• Riser base liquid accumulation during shut-in...

• From oil production to gas/condensate....

• Long wells, HP/HT wells• Bullheading required for hydrate prevention and

temperature control….

• Large volumes, multiphase flow transients …

• Revised production strategies• From depletion to gas injection assisted

production …

• High GOR wells coupled with high reservoir pressure…


PSV challenges in Modification/Retrofit Projects

• Limitations in existing PSV / Flare capacity

• PSV inlet piping

• PSV capacity

• PSV tail piping

• Retrofit with:

• Additional PSV capacity ? (Additional valves/increased orifice areas)

• Pilot operated (or balanced bellows) to allow forincreased backpressure?

• New PSV tail piping to reduce built-up backpressure?

• Pilot operated with remote sensing to mitigate inletpiping pressure drop?

• New PSV’s on separator inlet piping?

Retrofit required?=> Project sanction may often depend on the evaluations of required modifications of the flare system…

• NB: Impact from Separator conditions:

Overfilling….

Liquid carry-over through nozzle to PSV’s…

Risk of blockage (after separator internalsrevamping…?)

Gives immediate multiphase relief


Tools & Methods


Method(BPT Best Practice)

Personnel with in depth and hands-on inter-discipline experience of the technical requirements provided by international standards as well as Company specific requirements

Method developed in cooperation with Statoil, and accepted by many Operator companies.

Use of State of the art, rigorous dynamic tools (HYSYS and Petro-Sim) and integrated with multiphase pipeline simulator (OLGA)

This coupled with sound and conservative estimates/assumptions where required to safeguard the quality of the simulation results.


Tools(BPT Best Practice)

Target: Do it right first time and avoid unnecessary and expensive modification work in later project stages, whilst improving utilization of your asset within its integrity limits without compromising plant regularity, safety or production potential

BPT OLX ®for linking of OLGA to processsimulator

BPT PSX™for modeling ofPSV’s

OLGA® from SIS for multiphasepipieline &riser

HYSYS® or Petro-SIM® for processfacilities

+ BPT EXT™for efficientEXCEL reporting

InletSeparator

ProductionChoke HP Flare

K.O.Drum

FlareTip

Riser No.1

To Gas Treatment13-EV002

13-PCV001

13-EV001

20-LV01

20-PV03B

20-EV02

20-EV01

20-PSV-02A/B…

RiserEV

20-PV-03A

20-XV01

20-LV02

From Riser #2 & 3 …

20-PIT-01

Tie-Back

Field X

Riser Base

13-PIT-01

InletEV

LOWPressureSpec.

HIGHPressure

Spec.

13-XV001

RiserXV

Manifold


Related extensions (“apps”) in BPT Toolkit

BPT EXT™ Excel add-in allowingdata series to be updated in onego and multiple scenarios to be compared

BPT PSX™ is a unique API 520 9ed

compliant PSV rating model saving workload, improving predictions and safeguarding plant integrity

BPT OLX® is the only commercially available OPC connection allowing seamless integration between OLGA® V7.x and Petro-SIM or HYSYS®


Case Study / Examples


Ex 1 – Maximum Allowable Separator Pressure

Dimensioning scenario’s:

• Inadvertent valve opening of Wing Valve with Choke wide open (first error)

1. Base case: OLGA model of subsea flowline and riser, HYSYS for topside

2. Sensitivity 1: HYSYS model of subsea flowline and riser

3. Sensitivity 2: Pressure at riser top specified and kept a shut-in pressure (“steady state” type simulation)

Case study:

• Tie-in of new high GOR(~20 000 Sm3/Sm3) flowline to existing facility.

• Maximum topside arrival pressure =Restricted shut-in pressure (PSD)

• Task: Verify separator pressure to be within design limits for the selected design


Ex 1 – Maximum Allowable Separator Pressure - Video…


[ % of Design P ]

[ % of Vessel ID ]

[ kg/s ]

Test Separator conditions upon inadvertent opening at time ~30s

Ex 2 – Start-up of “Bullheaded” High GOR well Initial condition:

• Well “bullheaded” with diesel prior to start-up to reduce pressure below defined limit and to avoid hydrate formation during start-up.

Then:

• Inadvertent valve opening of Wing Valve with Choke wide open (first error).

Separator Pressureaccumulates

Separatoroverfilling Onset of

Wellstreamrelief

«Bullhead» liquidrelief period

Multiphase/Liquiddominated PSV relief

VapourDominated PSV relief

Multiphase/Gasdominated PSV relief


Then:

• Inadvertent valve opening of Wing Valve with Choke wide open (first error).

(ref slide 27)

Initial condition:

• Well “bullheaded” with diesel prior to start-up to reduce pressure below defined limit and to avoid hydrate formation during start-up.

Ex 2 – Start-up of “Bullheaded” High GOR well

PSV modeled with Relief ValveUnit Op.

(Kd tuned towards capacity given in vendor datasheet for blocked outlet case => “Wellstream GOR”

PSV modeled with BPT PSX™A higher separator pressure is predicted from onset of overfilling, since PSX adjusts and calculates a lower capacity during the Multiphase/Liquid dominated relief period

PSV modeled with BPT PSX™A higher separator pressure is predicted from onset of overfilling, since PSX adjusts and calculates a lower capacity during the Multiphase/Liquid dominated relief period


Ex 3 – Maximum allowable choke size



• Inadvertent valve opening of Wing Valve with Choke wide open (first error) AND “collapsed”(related consequence..?)

Case study:

• Production strategy: Reservoir depletion

• Task: Find maximum allowable choke capacities across field life.

Show in graph as function of declining BHP

Maximum allowable«collapsed» choke

capacity

Maximum allowable «intact» chokecapacity PLUS credit for reduced ongoingbackground production

Maximum allowablecapacity«intact» choke


Ex 4 – Maximum allowable Flare relief rates



• Base case: HYSYS model of subsea flowline and riser

• Sensitivity: Pressure at riser top specified and kept at shut-in pressure (“steady state” type simulation)

Case study:

• Tie-in of new high GOR (>10 000 Sm3/Sm3) flowline to existing facility.

• Maximum topside arrival pressure =Full shut-in pressure

• Task: Verify flare relief rates to be within design limits for the selected design

Flare relief (% of design) HYSYS used to model thesubsea flowline and riser

Flare relief (% of design)Pressure at riser top

specified and kept at shut-in pressure (“steady state”

type simulation


Ex 5 – Maximum allowable Flare relief rates


BPT PSX™ - video


Summary Introduction

Overpressure Protection

Requirements

PSV Sizing

Scenarios

BPT Tools & Methods:

BPT PSX™

BPT OLX®

BPT EXT™

Case Study/Examples

Conceptual studies

Compressor design studies

Turbo Expander design & off-design studies

Online/Offline tools for operational support, predictive maintenance and allocation

BPT Toolkit Presentation

Q&A : Questions by e-mail to [email protected]

Upcoming Webinars from BPT(Please provide feedback in

questionnaire):

E‐mail : [email protected] Phone : +47 67 56 99 90

Visiting Address: Løkketangen 20, Sandvika


Copyright

Copyright of all published material including photographs, drawings and images inthis document remains with BPT or it contributing partners. Therefore, neither thewhole nor any part of this document shall be reproduced in any form nor used inany manner without express prior written permission from BPT. No trademark,copyright or other notice shall be altered or removed from any reproduction.


Q&A

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