Multiple wells
3-in-1 case story
Challenge
Sustained Casing Pressure (SCP)
Solution
Welltec Saturn Expander
Result
Consistent SCP mitigation
Sustained Casing Pressure (SCP) is a common challenge in the oil & gas industry, creating issues related to well integrity and safety. Remediation strategies can be costly, the extremes of which can include a time-consuming recompletion.
When one of our clients in Central and East Asia (CEA) was experiencing SCP stemming from cement porosity in multiple wells, the Welltec® Saturn Expander was proposed as a means of rapid remediation.
This solution is an e-line deployed local casing expander, which works by extending an expandable cone to locally dent the casing and densify the cement behind it, creating a low-permeability interval, eradicating micro-annuli, and reinstating the existing cement as an effective annular barrier. This creates a more secure and reliable wellbore structure that reduces the risk of gas leakage.
The technology has proven to be a crucial tool in support of sustainable oil & gas production, preventing the release of greenhouse gas emissions.
This case story features diverse well environments and casings from three different operations in CEA.
As with most operations, full systems integration testing was conducted prior to each of the following interventions.
For example, testing in relation to operation #1 utilized a Welltec Saturn Expander 534 with a 5.75" expander head, confirming success in remediation of a prior cement porosity of ~20%.
Operation #1
Challenge: A well with a 7” casing and B-annulus pressure issues. Pre-operation bleed-off from 36 bar to zero in 20 minutes, producing four liters of black liquid. No H₂S detected.
Solution: Welltec Saturn Expander 5.75” tool deployed to produce 15 indentations across five target zones – three per zone.
Result: Following a 12-hour build-up period, bleed-off was carried out from 14 bar to zero in 2 minutes, producing 0.5 liters of black liquid with no H₂S detected – sample sent for testing.
Following an additional 17-hour build-up period, bleed-off was carried out from 8 bar to zero within one minute, zero H₂S detected – during four hours of venting, no liquid was produced/collected.
Operation #2
Challenge: Gas injector with a 10-3/4” casing, SCP in the annulus at 92 bar. The client had designated the well for sidetracking as a result of this issue.
Solution: Welltec Saturn Expander 8.25” tool was deployed to produce 18 indentations across six zones – three per zone.
Result: From 92 bar to zero with zero SCP maintained even after two years of full gas injection. Sidetracking cancelled.
Operation #3
Challenge: A well with a 7” casing exhibiting B-annulus pressure buildup of 80 bar.
Solution: Welltec Saturn Expander 5.75” to create 18 indentations across six target zones – three per zone.
Result: The results were impressive, as the B annulus was largely sealed off, and the pressure was significantly reduced from 80 Bar down to 3 Bar.
The Welltec Saturn Expander has proven to be a crucial tool in support of sustainable oil & gas production, preventing the release of greenhouse gas emissions, and consistently eliminating SCP, or reducing it to a trace level only.
As an e-line deployed technology, the Welltec Saturn Expander provides a time-efficient and cost-effective remediation solution even for some of the extreme challenges highlighted.
Furthermore, this approach facilitates a targeted restoration of well integrity and SCP elimination.
This collective case story underscores the broad role to be played in enhancing well integrity and performance by effectively resolving annular pressure problems and enabling continued well operations.
Welltec® Saturn Expander
Stop unwanted gas, oil or water flow due to microannuli or local channeling in the cement behind casing