Following the successful proof of concept of the closed system dual casing perforate, wash and cement for environmental plug application in 2018 (SPE-193989-MS), the same system was optimized for 2 subsea wells to isolate a gas sand behind 2 casings (9-5/8" × 13-3/8" × 16" open hole).
Learning from recent operations, it was discovered that there is significant improvement achievable with specialized gun system, and refined washing and cementing parameters. Such improvement was critical to the success of the annular remediation and thus, the long-term isolation of the gas sand.
The first successful closed system dual casing perforate, wash and cement for annular isolation is discussed and evaluated in this paper.
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