Evidences of Poor Cement Displacement Jobs
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Cementing operation is one of the most challenging tasks in the completion phase of oil and gas wells. Many problems here are related to cement- displacement process, blending, additives, and the entire design of the cementing operation. Failure of primary cement jobs leads to expensive remedial cementing work like squeezing and plugging.This thesis work was focused in finding evidences of poor cement displacement jobs by considering three basic quantities related to cement displacement namely; the annular volume to be cemented, volume of cement pumped and the resulting height of cement in the annulus. Five successful- and four failed cement jobs (cases) were used to accomplish this study. The analysis (calculations and ontology engineering) of all failed cases was done using excel software.Well schematics for planned and completed cement jobs were also presented for each case to verify the existence of poor cement jobs (for failed cases) and of good cement jobs (for successful cases).Enhanced understanding and knowledge of well cementing operation found through this study is helpful in forecasting similar failures in future cement jobs and hence reduce the failures related to the cement displacement process and the associated costs of remedial jobs.