Well Integrity Technical Section

Hi all, 

An offshore gas well producing from a depleted carbonate reservoir with high permeability (~10 mD)  has a sustained casing pressure is A-Annulus. During annulus integrity test of A-Annulus, pressure dropped suddenly to 0 psi and then increased to full SITHP indicating that A-Annulus is in direct communication to the reservoir. The well is completed with a 7" liner with a liner packer (7" x 9 5/8") and a PBR (4 1/2" x 7"). The leak point is not confirmed, but we tend to believe it is the PBR due to its metallurgy of 13Cr material compared to the rest of the completion which is 22Cr. A restriction was encountered above the PBR, meaning the reservoir cannot be isolated with a mechanical plug in the liner.
We opted for a well kill with a calcium carbonate LCM pill to isolate the reservoir. However, we could not go high in the size of the calcium carbonate additive particles due to the risk of plugging at the restriction level to avoid further complications (how serious is this risk ?). 

We pumped 3x100 bbls of calcium carbonate pills with SLB safecarb 10 , the pills did not provide any seal and the Annulus pressure built up to full reservoir pressure as usual. We then used a combination of calcium carbonate pill and Form-A-Block which prodived a partial seal. We managed the A-Annulus pressure for a year now through continuous venting to the flare to keep it below B-Annulus MAASP, but over time the pressure is increasing which indicates the seal is degrading and we must plan another well kill. This time the kill pill needs to be more effective as we have the flare won't be available for 30 days therefore continuous venting will not be possible in this period. 

Any experience with a similar situation, what are your recommendations for a better sealing efficiency? 

Best Regards,
Ghassen Yahyaoui 
PT - Amilcar Petroleum Operations 
Tunis- Tunisia

That's an interesting challenge.
Can you provide a wellbore schematic and the pressures you are dealing with?

The reservoir pressure is estimated to be 1000 psi, the current DHG pressure is 850 psi, and the SITHP is 650 psi. The annulus pressure at the continuous vent is 70 psi, and the B-Annulus MAASP is 400 psi. 

Attached the schematics. 

Original Message:
Sent: 09-03-2024 09:31 AM
From: Bruce Jankura
Subject: Well Kill for highly permeable gas well with Tubing to A-Annulus leak

That's an interesting challenge.
Can you provide a wellbore schematic and the pressures you are dealing with?

Hello Ghassen,

I hope you are doing fine.

As I think that you are not sure about the restriction size, I would run a gauge cutter to try to find an idea about the restriction. After that and if there is enough room for it I would run an inflatable packet and spot cement on top of it with a CT. If the restriction doesn't allow you to do this, I would contact companies like Wellcem or Seal-Tite and see the options to firstly seal the leaking point on the PBR. Some of there products are pressure activated and hence will only solidify on the leak point. I have used some of there products and they are good but once solidifies it is hard solid like cement so discuss with them the options and the risks. Also, Interwell is good providing tailor-made solutions to fix this type of issues, I would also check with them. Finally, I have never dealt with them but I know that  Bisn have some methods to seal tubing-annulus communications. 

I hope this is of any use for you.

Thanks and regards,

Faisal Alnakeeb

Well Integrity Team Leader

Original Message:
Sent: 09-03-2024 09:52 AM
From: Ghassen Yahyaoui
Subject: Well Kill for highly permeable gas well with Tubing to A-Annulus leak

The reservoir pressure is estimated to be 1000 psi, the current DHG pressure is 850 psi, and the SITHP is 650 psi. The annulus pressure at the continuous vent is 70 psi, and the B-Annulus MAASP is 400 psi. 

Attached the schematics. 

Original Message:
Sent: 09-03-2024 09:31 AM
From: Bruce Jankura
Subject: Well Kill for highly permeable gas well with Tubing to A-Annulus leak

That's an interesting challenge.
Can you provide a wellbore schematic and the pressures you are dealing with?

Hello Faisal, 

Cementing is not an option as we are planning to do a workover next year to change the completion, and it would complicate the situation. Thanks for sharing your experience with the sealing options, I will investigate that. 

Best Regards,

Ghassen Yahyaoui 

Original Message:
Sent: 09-04-2024 04:25 AM
From: Faisal Al-Nakeeb
Subject: Well Kill for highly permeable gas well with Tubing to A-Annulus leak

Hello Ghassen,

I hope you are doing fine.

As I think that you are not sure about the restriction size, I would run a gauge cutter to try to find an idea about the restriction. After that and if there is enough room for it I would run an inflatable packet and spot cement on top of it with a CT. If the restriction doesn't allow you to do this, I would contact companies like Wellcem or Seal-Tite and see the options to firstly seal the leaking point on the PBR. Some of there products are pressure activated and hence will only solidify on the leak point. I have used some of there products and they are good but once solidifies it is hard solid like cement so discuss with them the options and the risks. Also, Interwell is good providing tailor-made solutions to fix this type of issues, I would also check with them. Finally, I have never dealt with them but I know that  Bisn have some methods to seal tubing-annulus communications. 

I hope this is of any use for you.

Thanks and regards,

Faisal Alnakeeb

Well Integrity Team Leader

Original Message:
Sent: 09-03-2024 09:52 AM
From: Ghassen Yahyaoui
Subject: Well Kill for highly permeable gas well with Tubing to A-Annulus leak

The reservoir pressure is estimated to be 1000 psi, the current DHG pressure is 850 psi, and the SITHP is 650 psi. The annulus pressure at the continuous vent is 70 psi, and the B-Annulus MAASP is 400 psi. 

Attached the schematics. 

Original Message:
Sent: 09-03-2024 09:31 AM
From: Bruce Jankura
Subject: Well Kill for highly permeable gas well with Tubing to A-Annulus leak

That's an interesting challenge.
Can you provide a wellbore schematic and the pressures you are dealing with?

Hello Ghassen,

When I say spot cement on top of the IP, I mean to do it below the completion. This doesnt hinder you from POOH the completion later.

Regarding the sealant, what they do sometimes for the PBR is to spot a base (for example, HEC) then the sealant then squeeze it with another fluid on top. They can control the solidfying time by either being the product pressure activated or temperature/time activated. Be careful because I have used these products and once they solidify they are hard like cement.

Thanks and regards,

Faisal Alnakeeb

Well Integrity Team Leader

Original Message:
Sent: 09-05-2024 04:14 AM
From: Ghassen Yahyaoui
Subject: Well Kill for highly permeable gas well with Tubing to A-Annulus leak

Hello Faisal, 

Cementing is not an option as we are planning to do a workover next year to change the completion, and it would complicate the situation. Thanks for sharing your experience with the sealing options, I will investigate that. 

Best Regards,

Ghassen Yahyaoui 

Original Message:
Sent: 09-04-2024 04:25 AM
From: Faisal Al-Nakeeb
Subject: Well Kill for highly permeable gas well with Tubing to A-Annulus leak

Hello Ghassen,

I hope you are doing fine.

As I think that you are not sure about the restriction size, I would run a gauge cutter to try to find an idea about the restriction. After that and if there is enough room for it I would run an inflatable packet and spot cement on top of it with a CT. If the restriction doesn't allow you to do this, I would contact companies like Wellcem or Seal-Tite and see the options to firstly seal the leaking point on the PBR. Some of there products are pressure activated and hence will only solidify on the leak point. I have used some of there products and they are good but once solidifies it is hard solid like cement so discuss with them the options and the risks. Also, Interwell is good providing tailor-made solutions to fix this type of issues, I would also check with them. Finally, I have never dealt with them but I know that  Bisn have some methods to seal tubing-annulus communications. 

I hope this is of any use for you.

Thanks and regards,

Faisal Alnakeeb

Well Integrity Team Leader

Original Message:
Sent: 09-03-2024 09:52 AM
From: Ghassen Yahyaoui
Subject: Well Kill for highly permeable gas well with Tubing to A-Annulus leak

The reservoir pressure is estimated to be 1000 psi, the current DHG pressure is 850 psi, and the SITHP is 650 psi. The annulus pressure at the continuous vent is 70 psi, and the B-Annulus MAASP is 400 psi. 

Attached the schematics. 

Original Message:
Sent: 09-03-2024 09:31 AM
From: Bruce Jankura
Subject: Well Kill for highly permeable gas well with Tubing to A-Annulus leak

That's an interesting challenge.
Can you provide a wellbore schematic and the pressures you are dealing with?

Consider and risk assess if a casing or tubing expansion tool (mechanical deformation) might be an option at the right depth. It could mitigate the annulus leak path.

Marco op de Weegh
CCUS Wells Manager / Discipline Lead
Wells Engineering Principal
EBN rep. - FEED Aramis Technical Committee Member

E


EBN B.V. Daalsesingel 1, 3511 SV Utrecht. Registered office: Utrecht 14026250. VAT NL001726614B01. This e-mail and any attachments are strictly confidential and may be legally privileged. If you are not the intended recipient, please inform the sender (marco.weegh-op-de@ebn.nl) immediately, do not copy or retain this e-mail, use its contents or disclose them to any unauthorized third party without consent.

Original Message:
Sent: 9/4/2024 5:26:00 AM
From: Faisal Al-Nakeeb
Subject: RE: Well Kill for highly permeable gas well with Tubing to A-Annulus leak

Hello Ghassen,

I hope you are doing fine.

As I think that you are not sure about the restriction size, I would run a gauge cutter to try to find an idea about the restriction. After that and if there is enough room for it I would run an inflatable packet and spot cement on top of it with a CT. If the restriction doesn't allow you to do this, I would contact companies like Wellcem or Seal-Tite and see the options to firstly seal the leaking point on the PBR. Some of there products are pressure activated and hence will only solidify on the leak point. I have used some of there products and they are good but once solidifies it is hard solid like cement so discuss with them the options and the risks. Also, Interwell is good providing tailor-made solutions to fix this type of issues, I would also check with them. Finally, I have never dealt with them but I know that  Bisn have some methods to seal tubing-annulus communications. 

I hope this is of any use for you.

Thanks and regards,

Faisal Alnakeeb

Well Integrity Team Leader

Original Message:
Sent: 09-03-2024 09:52 AM
From: Ghassen Yahyaoui
Subject: Well Kill for highly permeable gas well with Tubing to A-Annulus leak

The reservoir pressure is estimated to be 1000 psi, the current DHG pressure is 850 psi, and the SITHP is 650 psi. The annulus pressure at the continuous vent is 70 psi, and the B-Annulus MAASP is 400 psi. 

Attached the schematics. 

Ghassen,

I had a similar problem when perf guns went off low order while POOH and burst my tubing and stuck the guns.  Offshore platform and no rig planned. 

We pumped Halliburton's tempblok into both annulus and tubing with a plug about 3000 ft long on each side.  Circulated down annulus taking returns from casing.  We did not bullhead the reservoir. The gel is hard to remove from perfs as it stops flow into the pores. 

Temblok is a cross link gel that is very stable but can be easily removed with a mill and acid. Every service company has a version of this chemical under various names.  It is designed for a specific temperature range and 'strength'.  Our 3000 psi high pressure well was leak free for 3 years until a jackup rig could repair the well. 

We cleaned out gel on the inside down to top of fish.  Then we cut tubing above gel in annulus and easily washed over the tubing removing the gel without acid. Now with a rig we could weight up fluid, kill the well, repair the well, and restore the well to production.  Well came on fine with no long term damage.

I have a 'generic' version of the procedure if you would like to see it email me at SPE address.

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Dan Gibson
aka The Well Doctor
Completion & Well Integrity Advisor
Houston, Texas
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