Experiences and Learnings from the Deployment of Cement Packer Technology in Seplat

Abstract The search for additional oil in most brown fields (as part of short-term oil gains) typically involves the review of idle wells to ascertain the integrity and reusability. Some of these wells with depleted reserves in the primary target zones require costly workovers to target shallower reservoirs. The wells often have Production packers at depths deeper than the targeted shallower reservoirs. To maintain the standard two-barrier (Production packer and Casing head valve) A-annulus policy as part of well integrity, the need for a barrier in between the Production packer and Casing head becomes imperative. Cement packer technology is a cheap and rigless alternative to developing oil and gas opportunities. The technology targets oil/gas reservoirs that lie above the production packer (single or dual) and creates a new annular barrier above the existing production packer through bull heading of cement slurry through the production tubing and finally into casing-tubing annulus above the production packer. This paper presents the learnings acquired after the careful candidate selection, operational challenges and solutions proffered to achieve outstanding results with the cement packer technology. The learnings presented in this paper cut across two scenarios where a tubing punch was used to create tubing and annulus-A communication in one instance while a sliding sleeve deeper than the shallower reservoir was used in another instance. These operations were carried out in a single string and dual string setup. The learnings cuts across program design, accurate cement volume calculation, cement placement methods, and operations supervision. Many successful cement packers have been carried out in SEPLAT with attendant challenges. The WRFM team reviews the use of idle wells and identifies optimally placed wells that can be used for accelerated production of shallower reservoirs. The two jobs were designed, economically screened, and executed with the well services team and 3rd party vendors to achieve target results (production and well integrity).