Oil well casing cement flash setting problem causes and identification strategy based on cheese model

Abstract

AbstractThis paper deals with oil well cementing flash setting problem definition, interpretation and localization via PABM (phenomenon analysis-based method) and Swiss cheese model investigation. Cementing is the most critical job throughout the well realization process; it presents the face of the well during production or abandonment. Within cement job some, problems come out and could lead to lose the well objectives, and it can be classified as cementing program’s awkward or operational hitches. This work is oriented toward operational stage, even if cement program and preparation seem in the rules of the art, the execution stage can interrupt the smooth running of cement job. Flash setting is one of the most critical problems that could be occurred, and it can be recognized by the prior increases in pressure to reach unpumpable stage. Identifying flash setting phenomenon and distinguishing them from other operational comportment stay hard task and present the heart of this work. Consequences could be varied from simple cement left inside casing to total free pipe of the annulus. PABM together with cheese model is proposed to be used for deep analysis of flash setting problems and points out the real causes, if they exist, rather than flash setting. The method proposed includes five steps, description of the operation, phenomenon, assumptions, cheese model and conclusion. The three first steps construct operation scrutiny, and the fourth step represents PABM. In this latter method, assumptions will pass through a selective process made from operation facts, and only the adequate assumption reaches the last layer of the model. Practical cases have been detailed to point out the merit of this method and distinguishing flash setting from other related cement problems.