Wellcem and our partners are in a position to help oil and gas operators solve Sustained Casing - Casing Annulus Pressure (CCA) problems.
We have completed over 350 jobs with a success rate of 96.5%. Jobs have been completed in the Americas, Europe, Asie, Africa and Oceania. We have materials and personnel in place to respond to the required needs within any given region.
The Problem
Sustained Casing Pressure is usually defined as unintended pressure in a contained annulus resulting from the communication from pressurized form or gas resulting in pressure build up in the subject annulus that is measurable at the wellhead.
SCP rebuilding after having been bleed down and is not caused by wellbore temperature fluctuations is a clear sign that the well integrity has been compromised.
Read and download our Case Studies:
Causes of SCP
The leading causes usually are issues in the casing casing annulus or the tubing casing annulus. Causes for SCP In the Annular communication paths are generally the following:
A) Flow stream communication path
- Tubing connection leak
- A hole within the production tubing
- Parting of the tubing string
- Leak in gas lift mandrels, chemical injection mandrels or control lines
- Packer seal leak
- Seal, penetration, or connection leaks in the tree or wellhead
B) Annular communication paths:
-
- Production casing hanger leak
- Tubing hanger leak
- Production casing string failure (Collapse, connection leak, hole due to corrosion, liner top failure)
- Cement seal failure in an outer annulus combined with a casing leak in the production casing string
- An uncemented section in an outer annulus combined with a casing leak in the production casing string
C) Potential flow paths into the outer annuli (e.g., B to C):
- Cement seal failure
- Exposed formation sections
- Casing string leaks
Common Cement Problems leading to SCP
Damage to cement from operational activities such as pressure testing, squeezing, or fracturing
- Thermal cycling
- Micro-annulus and channeling
- Cracking/micro-fractures due to stress loading conditions
- Weak cement bonding to the casing or formation
- Lost circulation during cementing
- Cement channeling due to ineffective mud displacement (Resulting in a conduit between different depths)
Remediation Methods
- Workover – ultimate solution - expensive
- Pressure Management – Not a permanent solution
- Lubricate – in weighted brine or mud - Temporary
- Circulation – of weighted brine or mud - Temporary
- Annular Intervention
- Internal casing patch
- Cement injection*
- Resin injection
* Note: Traditionally limited success
Wellcem Resin Solution - ThermaSet Resin
- ThermaSet® is a thermosetting resin
- Consistency as thin oil, density as seawater
- Immiscible with water
- Curing time can be accurately controlled
- Density and viscosity can be tuned
The set product is:
- Durable, it seals and bonds well
- Proven to last in typical oil & gas well conditions
- Flexible
- Impermeable
SCP in the B-Annulus
Solution
- A specific ThermaSet recipe was designed for this well.
- 3,5 m3 of fluif was evacuatred from B-Annulus with the help of Nitrogen prior to pumping ThermaSet.
- 3 m3, 1,9 SG ThermaSet pill was fed into the B-Annulus from surface with the help of a centrifugal pump.
Results
Successfully inflow tested the B-Annulus for 48 hpurs - No flow or pressure builkd-up on B-annulus
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