Numerical Simulation Study on the Flow Properties of Materials for Plugging While Drilling in MWD

Abstract

The method of plugging while drilling has been one of the commonly used methods to control formation loss during drilling. The damage to materials for plugging while drilling to MWD has become a complex problem. For many years, field engineers had insufficient knowledge of the passing performance of materials for plugging while drilling in measurement while drilling (MWD). In the existing research, the blocking mechanism of materials for plugging while drilling to mud screen during the flow process is still unclear. In this study, we use computational fluid dynamics coupled with discrete element method (CFD–DEM) to investigate materials’ plugging mechanism while drilling. The results show that the migration process of lost circulation materials (LCMs) in the mud screen can be divided into three stages, displacement, retention, and accumulation of LCMs. The blocking mechanism of LCMs on the mud screen comes from two aspects. One is from the bridging of LCMs with larger particle size in the holes of the mud screen. Another source is the difference between the entry speed and the overflow speed of LCMs. The particle size and mass fraction of LCMs and the viscosity and displacement of the fluid affect the flow properties of LCMs from these two factors, respectively.