High definition optical method for evaluation of casing - Cement microannulus (CCMA)

During the well-cementing setting phase, a change in temperature or pressure could fail the cement sheath or the occurrence of the microannulus at the interface between the cement and the casing, or between the cement and formation. Microannuli is a big issue in many oilfield's well-cementing operations, thus often results in production reduction and an increase in remedial cost. However, the key to successful long term well integrity of casing-cement microannulus is to understand and evaluate the hydraulic sealing of cementing annulus by detecting existing or potential fluid movements within the well that may exist between the casing and formation after the cement job. This article aims to demonstrate a new way of evaluating and understanding the behavior of microannulus sealing function of the cement sheath-casing interface using the high-resolution optical device as a function of cement curing age and pipe lengths. The technical benefit of this novel experiment is to quantify the primary functional purpose of the cement which is supporting the casing and to seal the annulus to the flow of fluid. The experiment was carried out using API Class H cement.