When a deepwater well, offshore West Africa, was experiencing high GOR the operator initially chose to cycle the well production on and off to allow the reservoir to re-saturate with oil while shut-in, and then re-open the oil flow to the FPSO until the GOR became unacceptably high for the facilities. However, this temporary solution had caused a significant decrease in production.
Diagnostic surveys showed gas entry from the top of the open hole gravel pack completion. The operator, working with multiple service companies, engineered a solution, which required installing retrievable straddle isolation assemblies.
Installation and assembly of this straddle necessitated accurate depth control and “force-with-finesse”. Welltec’s combination of Well Tractor® and Well Stroker® offered the best solution, as it could exert the required force at the specific depth.
The first run was a drift run, then the lower packer was run with the Well Tractor® and set. The next run was the first joint of the assembly and the Well Tractor® was run to ensure the toolstring was seated into position and to compress the Well Stroker® piston. The Well Stroker® stroked down to ensure the RS2 latch had been fully seated and then sheared the GS running tool pin to release the toolstring from the assembly. The subsequent runs involved conveying and stroking the various joints and packers into position, resulting in a complete; sixteen successful runs.
The operation took only 15 days, which was 30 says less than originally anticipated by the operator. As a result of the intervention, gas production was reduced and oil production increased multifold.
To learn more about the technology applied please view the Mechanical Solutions brochure or read the full case story: Installation of straddle packer saves 30 days.