1 3 Presentation PTC Barrier Philosophy

8/10/2019 1 3 Presentation PTC Barrier Philosophy

1/19

Barrier Philosophy for Wells on Gas lift

and

Ways of Reducing HSE Risks

Alan Brodie Feb 2011

For more info visit www.ptc.as


2/19

Introduction

Gas Lifted Well Integrity Management

Incremental HSE risks

Case histories

The impact of getting it wrong

Solutions to incremental HSE risks

Image used with the permission of J Bellarby


3/19

Oil and Gas Well Integrity Management

Basic Requirement

Risk of hydrocarbon release from a well is ALARP

(As Low As Reasonably Practicable)

Which means using:

Best available equipment Current industry best practices

To achieve this most OPCOs usually adopt:

Double independent barrier pressure containment envelope

In natural flow example shown:

Primary barrier outlined in red Secondary barrier outlined in blue

With Acceptance criteria defined for each element e.g:

ISO 13679 procedures for testing tubing connections

Leak criterion for gas: 9 cc/15 min

Image used with the permissi

on of J Bellarby


4/19

Gas Lifted Well Integrity ManagementKey differences # 1 ( tubing integrity)

With many gas lift valves

Primary well containment barrier is compromised

ISO 17078-2 Flow control devices for side-pocket mandrels

These devices are designed and intended to prevent reverse flow

through a flow control device. They are not designed nor intended to

provide a tight shut-off pressure safety seal or to be a part of thesafety system.

Allowable leak rate

6883 ml/10 mins

Compare this to acceptance criteria for packers

ISO 14310-- Downhole equipment -- Packers and plugs

Allowable leak rate 20cc /10 mins

ISO 14310



5/19

Gas Lifted Well Integrity Management

Key differences # 2 ( High pressure gas inventory)

High pressure gas in tubing / production casing annulus Question:

What precautions are taken at well sites re gas bottles:

Store safely away from areas with:

High risk of dropped objects

Potential sources of radiant heat

Carefully manage logistic and numbers

Potential volume of gas in annulus of each well:

Equivalent of > 1000 industrial gas bottles

Even where DHASVs used typically >100

Lift gas lines / valves from HP header to annulus:

Pass thru area with Relatively high risk of dropped objects

Many potential sources of radiant heat

Other risks associated with leakage from inner to outer annulus

Are production casing threads gas tight?

Image u

sed with the permission of J Bellarby

The first

gas bottle

explodes


6/19

Gas Lifted Well Integrity ManagementGetting it wrong (1)

Piper Alpha Disaster N Sea 1988:

Gas lift was widely used,

Wasnt the root cause but it exacerbated the situation

SCSSSVs generally closed

But Gas lift check valves didnt

Gas lift lines parted between isolation valve and wellhead

Due to radiant heat from nearby fires

Wells flowed naturally via annulus

NB It appears the wells structural integrity

was relatively unaffected despite the

severity of the incident



7/19

Gas Lifted Well Integrity ManagementGetting it wrong (2)

Outer Annulus Pressure build up

Onshore gas lifted well shut in

Lift gas leaked from the inner to the outer annulus

Outer annulus pressure built up to lift gas pressure (1700-1950 psi) Well restarted and heated up by 76 F

Trapped pressure increased to 7700psi

Outer annulus casing ruptured

Flying debris damaged the HP gas line

Contents of inner annulus vented and ignited

Question

How easily could this happen on your wells?

#1 Source of info: www.wellintegrity.net


8/19

Gas Lifted Well Integrity ManagementReducing the HSE risks (1) ( tubing integrity)

Employ qualified well barrier gas lift valves

Operating Valves

Unloading Valves

Tested to the same allowable leak rate as packers etc

Erosion test the valves to ensure:

They will remain well barrier valves for the life of well

Not just to pass a factory acceptance test (FAT)



9/19

Gas Lifted Well Integrity ManagementReducing the HSE risk (High pressure gas inventory)

Down-hole Annulus Safety Valves (DH ASVs)

Introduced after Piper Alpha in some parts of world

To reduce the volume of gas topsides is exposed to

Still typically equivalent of >100 gas bottles !!

Shallow set dual path packers

Integral check valve or sliding sleeve

Usually not designed to be gas tight

Always requires a full workover to replace on failure

DH ASV reliability issues Apparently many wells closed in due to failed DH ASVs

Problems with packer technology in thermal cycling

Integral check valve reliability challenges

Reputedly often difficult to retrieve


10/19

Gas Lifted Well Integrity ManagementReducing the HSE risk (High pressure gas inventory)

PTCs fresh approach to DH ASVs

Dual Packer technology designed for thermal cycling 4 110 deg C

Client supplied SCSSSV attached above

ISO-14310-V1 equivalent leak rate on gas side

Solid body compact packer design

Up to 10 control lines pass-through

Single trip retrieval using Sondex cutter


11/19

Gas Lifted Well Integrity ManagementReducing the HSE risk (HP lift gas inventory)

Eliminate the potential for annulus venting

Using Surface Annulus Safety (SAS) valve

Set in the wellhead VR profile

Employs PTC Safelift GLV check valve design

No erosion across metal / metal seal faces Performance exceeds that delivered by DH ASV

Valves tested to API 6A PSL 3G PR2

Fire tested to API 6FB and API 6FD

Achieving V0 with gas as test medium

Valves replacable without workover



12/19


Actuator module holds check valve open throughout life

Protecting seal faces from chattering

Modular design facilitates actuator detachement

In case of annulus line damage

Leaving check valve intact in wellhead



13/19


> 250 SAS valves installed

In use in GOM and N Sea

Gas lifted wells with failed DH-ASVs previously had to be closed in

Awaiting workover

Now permitted to remain on stream If SAS valves are installed

And if well barrier accredited gas lift valves are used

Increasingly recognised by OPCOs as:

required for achieving ALARP risk in gas lifted wells

Some OPCOs even using them in combination with DH ASVs Their interpretation of ALARP


14/19

Gas Lifted well integrity MgtReducing the HSE risk (trapped annulus)

Automated annulus pressure management Unique VR Plug / sensors can be installed on all annuli

Continual annulus P&T measurement

Wireless (HART protocol) / wired link to control room

Wireless module detaches safely under impact Leaving VR plug / sensor in wellhead

Annuli can be bled down automatically via M-SAS valves

Before closing again to ensure well integrity


15/19

Gas Lifted well integrity mgtReducing the HSE risk

Automated annulus pressure bleed down PTC gas lift valve derivatives

One way (outer to inner) valves

Pre set opening pressures (MAASP)

Installed in special casing pups below wellhead New wells only

Not just for gas lifted wells

Ideal for subsea wells

Typically casings are not cemented into previous shoe track To provide option for pressure to bleed off into formation

Deploying annulus bleed valves would reduce this HSE risk


16/19

Conclusions

HSE risks in well completions are managed to be ALARP

Gas lift introduces significant additional HSE risks cf any other lift method:

GLVs can be primary well containment envelope weak link

Enormous inventory of high pressure gas introduced to hazardous area

Potential for lift gas leakage into outer annuli

New technologies developed to address these concerns:

Well barrier gas lift valves and unloading valves

Wellhead VR profile actuated Surface Annulus Safety (SAS) valves

ISO-14310-V1 equivalent leak rate DH ASVs Wellhead VR profile pressure temperature sensors

Trapped annulus pressure relief valves


17/19

Final thought

Lets do a little role playing exercise :

Youre sat in the office next month and your phone rings

Its your CEO on the line

He tells you he has been invited to a meeting with the government

To discuss a recent safety incident involving a gas lifted well

He asks you

Can I confidently say our designs ensured the risks were ALARP

Whats your answer .................


18/19

Feb. 2011 2011 Gas-Lift Workshop 18

Copyright

Rights to this presentation are owned by the company(ies) and/or author(s) listedon the title page. By submitting this presentation to the Gas-Lift Workshop, theygrant to the Workshop, the Artificial Lift Research and Development Council(ALRDC), and the American Society of Mechanical Engineers (ASME), rights to:

Display the presentation at the Workshop.

Place it on the www.alrdc.com web site, with access to the site to be as directed by

the Workshop Steering Committee. Place it on a CD for distribution and/or sale as directed by the Workshop Steering

Committee.

Other uses of this presentation are prohibited without the expressed writtenpermission of the company(ies) and/or author(s) who own it and the WorkshopSteering Committee.


19/19

Feb. 2011 2011 Gas-Lift Workshop 19

Disclaimer

The following disclaimer shall be included as the last page of a Technical Presentation or Continuing Education Course.A similar disclaimer is included on the front page of the Gas-Lift Workshop Web Site.

The Artificial Lift Research and Development Council and its officers and trustees, and the Gas-Lift Workshop SteeringCommittee members, and their supporting organizations and companies (here-in-after referred to as the SponsoringOrganizations), and the author(s) of this Technical Presentation or Continuing Education Training Course and theircompany(ies), provide this presentation and/or training material at the Gas-Lift Workshop "as is" without any warrantyof any kind, express or implied, as to the accuracy of the information or the products or services referred to by anypresenter (in so far as such warranties may be excluded under any relevant law) and these members and theircompanies will not be liable for unlawful actions and any losses or damage that may result from use of any

presentation as a consequence of any inaccuracies in, or any omission from, the information which therein may becontained.

The views, opinions, and conclusions expressed in these presentations and/or training materials are those of theauthor and not necessarily those of the Sponsoring Organizations. The author is solely responsible for the content ofthe materials.

The Sponsoring Organizations cannot and do not warrant the accuracy of these documents beyond the sourcedocuments, although we do make every attempt to work from authoritative sources. The Sponsoring Organizationsprovide these presentations and/or training materials as a service. The Sponsoring Organizations make norepresentations or warranties, express or implied, with respect to the presentations and/or training materials, or anypart thereof, including any warrantees of title, non-infringement of copyright or patent rights of others,merchantability, or fitness or suitability for any purpose.

1 3 Presentation PTC Barrier Philosophy

Documents

Transcript of 1 3 Presentation PTC Barrier Philosophy