Abstract
One of the most challenging issues during drilling operations is lost circulation, which can cause several problems that could lead to increasing the non-productive time (NPT) and drilling cost. Wellbore strengthening techniques have been applied as a well-known approach to increase the mud weight window by improving mud cake properties or adding lost circulation materials (LCMs) to the drilling fluid. The success-to-failure ratio of remedial or preventive solutions during the field operation is highly dependent on the appropriate selection of wellbore strengthening strategy. Initial studies, which have often focused on trial and error and operational practices, have not provided a clear understanding of fundamental mechanisms and performance of LCMs in strengthening of a formation. Hence, in the last decades, several analytical and numerical studies, as well as experimental evaluations have been performed by numerous researchers to simulate the fluid loss process and LCM effectiveness. Conducting a comprehensive and well-designed experimental investigation can be a more applicable and cost-effective approach to select proper wellbore strengthening method and recommend the best drilling fluid formulation to treat the loss zone. The aim of this paper is to present an overall review on the various published experimental investigations, to assess the different aspects of lost circulation and wellbore strengthening theory. This extensive literature review collects limitations, advances, and differing opinions from experts. It also broadens the scope for future work and helps in solving industrial problems from an operational point of view.
NSTL
Elsevier