Advances in Cement Packer Slurry Design Using Liquid Cement Latex: Offshore Nigeria Delta Case Study

摘要

The deployment of a coiled tubing(CT)conveyed cement packers for accessing bypassed hydrocarbon/ marginal reserves through rigless through-tubing well intervention presents economic potential for mature field access and optimization.They provide a good means of zonal isolation of the last reserves in an existing wellbore.However,zonal isolation is challenging in highly deviated wells.These shortcomings are predominantly related to slurry density control,displacement efficiency,well architecture(completion jewelry),poor cement bonding in the annulus between the tubing and production casing,and issues with pulling the CT out of hole while maintaining the differential pressure between the well head and casing head pressures(estimated top of cement in the casing annulus).Recently,the application of liquid cement latex(LCL)additive for cement packer completions using CT has shown remarkable success.LCL cement additive is a liquid additive designed to lower equivalent circulating density(ECD)and impart excellent fluid-loss control,high-temperature suspension properties,and acid resistance to cement slurries.This paper summarizes the operational and logistical process of executing a cement packer with conventional cement and LCL additive in a highly deviated well,offshore Niger Delta.In addition,the applications,features,and benefits of LCL with associated spacer fluid is detailed.The operational and logistical benefits of using LCL is discussed,concentrating on its ease of transportation and pumping,minimal equipment requirements,consistent slurry properties,and reduced environmental exposures.Best practices recommendations are also be made for cement packer placement,supported by the executed successful deployment in the offshore Niger Delta using LCL.