Evaluation of rock-clearing effect and structure optimization design of cuttings bed breaker

During the drilling of extended-reach wells and long horizontal wells, broken cuttings easily accumulate on the low side of the wellbore annulus to form a cuttings bed, which can easily lead to drill pipe buckling, increased drilling tool friction and torque, abnormal equivalent circulating density, or even drilling accident. The cuttings bed breaker can effectively agitate the deposited cuttings bed and improve wellbore cleaning. Taking the cuttings bed beaker as the research object, the research on quantitative evaluation of rock cleaning effect and structure optimization design were carried out. The rock-clearing mechanism of the cuttings bed beaker was revealed by using computational fluid dynamics, and a set of methods on evaluating the rock-clearing effect of the cuttings bed beaker were established. Based on quantitative evaluation, the blade structure with best rock cleaning effect was determined, the influence of the blade structure parameters on the rock clearing effect was analyzed, and then the structure parameters were optimized. The research shows that among the three types of blade structures, the anti-spiral blade cuttings bed beaker has the best rock-clearing effect, and its rock-clearing effect can be significantly improved by increasing the helix angle and optimizing the number of blades. This research provides a theoretical basis for the structure optimization design of cuttings bed beaker.