2 Industry Overview Thyl Kint

8/12/2019 2 Industry Overview Thyl Kint

http://slidepdf.com/reader/full/2-industry-overview-thyl-kint 1/15

Flow Assurance An Industry Oriented Introduction

Thyl E. Kint

18 April 2006



T.Kint, 18 April 20062

Flow Assurance: An Industry Oriented IntroductionContent of Presentation

• What is it?• Why does it matter?

• Industry Examples.• Conclusions.




Flow Assurance: An Industry Oriented IntroductionWhat is it?

“Engineering process by which all flow systems in anoilfield are assured to perform effectively and optimally.”

• Flow regime (slugging, liquid hold-up, velocity, etc.)• Flow temperature (As key parameter for the following)• Wax (Flow reduction and/or blockage)

• Hydrates (Flow reduction and/or blockage)• Emulsions and Foam (Flow reduction and process upsets)• Asphaltenes (Flow reduction and equipment performance)• Scale (Flow reduction and equipment performance)

• Erosion / Corrosion (Integrity of the flow condui ts)• Energy (flow rate, boosting)• Start-up / shut down and transients (Variation of all the above)• Evolut ion over life of field (Variation of all the above)

Key Issues which need addressing include:




Flow Assurance: An Industry Oriented IntroductionWhy does it matter?

• Flow assurance problems are to the oilfield whatcardiovascular disease is to the human body.

•Flow assurance problems can be as damaging to theperformance of oilf ields, the wellbeing of oil companiesand the reputation of petroleum professionals as aheart attack, a stroke or thrombosis...

• Just as the human propensity to cardiovasculardisease, some oilfields are naturally more much moreprone to problems than others.

• Both can strike when least expected and, once its toolate, even the best doctors often can not help…

• In both cases prevention is preferred to remediation…




Flow Assurance: An Industry Oriented IntroductionExample I: When you have (almost) all the problems at once!

Parameters:• 66 wells with 45 ESP Producers & 21 Water

injectors spread over wide area.• Commingled production from more than 10

horizons with viscous crude ranging from 13 o

to 31 o API and 3 to 300 cP with changing blend.• Wax content ranging from 3.2% to 6.5% and

Asphal tene content ranging from 0.6% to2.6%

• Wax Appearance Temperature ranging from<-5 oC to +55 oC and pour point ranging from0oC to +30 oC.

• Strong tendency to form emulsions and foam• Very cold winters with surface temperatures

to -25 oC and seabed temperature ~ -1 oC.

Design:• 3 Wellhead Platforms producing multi-phase flow through a network of over 30 km of insulated

flowlines to a central FPSO.• Facility designed for 80,000BOPD - 350,000BFPD - 320,000BWIPD - 16MMCFDG with top process

Temperature at 115 oC.• “ Water cycling” with large volumes of water produced to FPSO and re-injected from FPSO to

WHP’s.• ESP power from central facili ty.




Flow Assurance: An Industry Oriented IntroductionExample I: When you have (almost) all the problems at once!Flow Assurance Solution:• Central processing on FPSO.• Limited heating on central gathering wellhead platform.•

Insulated buried pipe-in pipe flowlines.• Entire process plant 100% lagged & insulated.• Normal operation above 55 oC with 12 hour “ no-touch time” at all

times vs highest pour point of 30 oC.• Displacement to water for prolonged shutdowns.• Hot water circulation for cold start-up.• Chemical injection for emulsions and asphaltenes.• Routine pigging for wax deposition.Key Learnings:• You never have enough fluid for testing.• There is not enough science to reliably predict all scenarios.• When it gets too complex “ good sense engineering” is essential.




Flow Assurance: An Industry Oriented IntroductionExample I: When you have (almost) all the problems at once!The management of emulsions:

P 50 ES P P o w e r R e q u i r e m e n t s v s . Ti m e

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

11,000

12,000

13,000

14,000

0 1 - 0 7

- 0 4

0 1 - 0 7

- 0 5

0 1 - 0 7

- 0 6

0 1 - 0 7

- 0 7

0 1 - 0 7

- 0 8

0 1 - 0 7

- 0 9

0 1 - 0 7

- 1 0

0 1 - 0 7

- 1 1

0 1 - 0 7

- 1 2

0 1 - 0 7

- 1 3

0 1 - 0 7

- 1 4

0 1 - 0 7

- 1 5

0 1 - 0 7

- 1 6

Ti m e

P o w e r

R e q u

i r e

d

( k w

)

ESP w / em u l s ' n

ESP w /o em u l s ' n

12 M W = In s t a l l ed Des ign ESP Pow er Capac i t y

Ad ju s te d , A ve r a g e , P 50 ESP Pow er r e qu ir em en tc o n s i d e r i n g e m u l s i o n c o n t r o l a n d c h e m i c a l u s a g e .

Ty p i c al Em u l s i o n V i s c o s i t y C u r v e

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

% Water

V i s c o s

i t y F a c t o r

O i l i n Wa t e r

Wa t e r i n O i l

• Analysis and tests are critical.• There is l imits to tests and analysis.• One must use “ practical” engineering.




Flow Assurance: An Industry Oriented IntroductionExample II: Even with the best engineering efforts…Parameters:• Large deepwater gas - condensate

reservoir.• No wax, no aquifer, “ no nasties” .

Design:• State of the art flow assurance design.• Remote subsea development with dual

un-insulated flowlines.• Hydrate control by continuous methanol

injection.• Dynamic process control in lieu of slug

catcher. Also low manned solution.• Plan to choke at platform but option to

choke at subsea trees.

Gas Wells & Manifold in ~ 900m water

2 x 16” x 35km Wet Gas Flowlines

Gas processingand

compression platform

24” Dry Gas Export Li ne

CALM BuoyFor Condensate Export

Gas Wells & Manifold in ~ 900m water

2 x 16” x 35km Wet Gas Flowlines

Gas processingand

compression platform

24” Dry Gas Export Li ne

CALM BuoyFor Condensate Export




Flow Assurance: An Industry Oriented IntroductionExample II: Even with the best engineering efforts…

Actual (Initial) Outcome:• Dynamic slug catcher did not work.• Required set of young “ Playstation” operators to manually control flow on

the fly! Platform thus required high manning. Also, apart from productionupsets, uncontrolled slugs regularly slammed leaks at flanges of production headers!

• Actual gas take-off lower than planned and too low for stable flow in dualline (slugging) but too high for production in single line (erosion andback-pressure).

• Dual line problems were reduced by choking at trees thereby reducingdensity and increasing velocity for better flow regime. However, soon, itappeared that subsea chokes were not durable and needed replacement…

• Methanol contamination of condensate caused economic penalty on valueof condensate.

Key Learnings:• Even with the best engineering efforts things can go wrong.• Robustness is important.• There is significant risk to new technology solutions.




Flow Assurance: An Industry Oriented IntroductionExample III: Analysis is not the same as Design!Parameters:• Phased deepwater development.

• Phase 1: Long distance remote gas.• Phase 2: Floating production facility

for liquids & oil with gas to shore.• Huge range of parametric flowassurance work comparing variousdual and single phase 1 flowlines.

• Many fixed assumptions such asmethanol for hydrate control, etc.

Outcome:• A one day review workshop by three

experts produced a totally differentphase 1 configuration. (2 unequalsize flowlines, recycled Glycol, etc.)

Key Learnings:• Analysis does not produce a design, it supports and verifies it.• Beware of huge multi-phase flow parametric studies!• There is no mult i-phase software which designs a flow system configuration.




Flow Assurance: An Industry Oriented IntroductionExample IV: Multi-phase flow is Mult i-disciplinary.

Parameters:• Attempted acquisition of a static deepwater oilfield in the mid 90’ies.• Remote subsea technology identified as enabling feature for acquisition.• Demonstration of lifetime flow assurance was key requirement.Events & Outcome:• Reservoir engineering input from single tank + wellbore flow model.• Huge flow assurance study with testing and multi-phase flow modeling effort

with transients etc. to demonstrate viability of 50km remote subsea oildevelopment using dual flowlines.

• Developed aggressive proposal for acquisition.• During presentation to management reservoir engineer advised “ I did not

understand that was how you were using my data. The tank model is not arealistic model of actual pressure decline. ”

• Acquisition abandoned and field eventually developed by original owner

using a spar.• Major investment in “ integrated” reservoir modeling plus flowline simulationtool.

• Just a few years later integrated tool abandoned with each discipline usingits own tools.




Flow Assurance: An Industry Oriented IntroductionExample IV: Multi-phase flow is Mult i-disciplinary.

Key Learnings:• Flow assurance for the design of a remote subsea development requires

the reservoir engineer, the production engineer (well-bore), the flowlineengineer and the process engineer to work in an integrated fashion.

• Integrated analysis tools exist, but each discipline typically resists usingtools other than “ what they are used to” .

• An educated coordinating party, with enforcement authority to force thedisciplines together, is essential to tackle a complex remote multi-phaseflow design problem.




Flow Assurance: An Industry Oriented IntroductionExample V: When limits of technology are reached!Parameters:• Large heavy oi l; HP/HT; 25,000’ deep &

tight reservoir; in 2,500m waterdepth.• 22 o API, very low GOR, 12cP, 33 oC WAT,

-5 oC pour point.• 120 oC and 20,000psi reservoir condit ions.• Needs concept for development…

Events :• Initial parametric study helps with

understanding but does not “generate

concept”.• Educated multi-disciplinary “design”effort coupled with focused reservoir, wellbore and multi-phase flow analysisproduces a narrow range of developmentconcepts.

•No “ outcome” yet…Key Learnings:

• Analysis alone does not deliver a design..• Boosting is essential for economic

development.

Hybrid Riser

6” Gas Export Pipeline

FPSO~700,000bbl

Dual 10” Production Flowlines

Distribution Unit

Power & Control Umbilicals

Taut SyntheticMooring System

SuctionAnchor

Suction Base

Process Plant135KBFPD105KBOPD24MMCFDG

Water Depth Between 8,100’ and 8,200’ at site.

Multi-PhasePumping Station

Horizontal SS Trees

UTA

Looped 10” Production Flowline




Flow Assurance: An Industry Oriented IntroductionExample V: When limits of technology are reached!Key Learnings: (Continued)• In 25,000’ reservoir and 2,500m water

depth hydrostatics are critical. E.g.Even with 20,000psi reservoirpressure, 10,000psi equipment works.

• With HP/HT reverse Joule Thompsoneffect can apply and expansion cangenerate an increase in temperature!

• This helps with flow assurance (asdoes boosting), but beware oftemperature rating of downholeequipment.

• Liquid dominated systems, as always,are much more cool down friendly.

• Sizing boost ing solutions is a delicateaffair. Even more so when nearbubble point, as too much drawdownserves only to break out gas.

• Ultimate learning still to be had asfield not yet developed…




Flow Assurance: An Industry Oriented IntroductionConclusions• Understanding the science of f low assurance and multi-phase flow

is a necessary condition for the design of long, remote, cold, orsubsea oil and gas flow systems but;

• It is not a sufficient condition as flow assurance science and multi-phase flow analysis does not produce a design…

• Testing and analysis are essential to solve flow assuranceproblems but;

• Sometimes in flow assurance, there are too many parameters such

that a problem can not be entirely solved by testing and analysis…Experience based engineering is also a key ingredient.• Even with the best engineering, things can go wrong. Hence,

robustness and flexibility are key ingredients of successful flowassurance designs.

• A mutli-disciplinary approach is essential to successfully designcomplex oil and gas flow assurance systems.

• Subsea boosting! It’s coming to an offshore oilfield near you…

Documents

2 Industry Overview Thyl Kint