Experimental Investigation of Particle Size Degradation and Plugging Efficiency of Three Granular Lost Circulation Materials

Abstract

This work delineates a comprehensive study of one of the main problems that contributes towards nonproductive time (NPT) in a drilling operation, which is lost circulation. The focus of this study was to investigate the performance of walnut, graphite, and marble, which are three widely used and industry-available granular lost circulation materials (LCMs). Additionally, the study aimed to establish a particle size selection guideline for better operational performance and plugging efficiency. Four water-based carrier fluid systems (water–bentonite mix, water–polymer mix, and two polymer–salt systems) were tested with the LCMs in this study. Dry and wet particle size degradation studies were conducted on all the LCMs with the different carrier fluid systems to study their compatibility and efficiency. The effect of the carrier fluid type was proven to be significant only on marble particles size degradation; walnut and graphite were not affected by the carrier fluids and showed consistent size degradation performance with all fluids. The results of this work led to newly developed particle size selection guidelines to enhance plugging efficiency—guidelines that are custom-made for each material by taking into consideration the rate of the degradation and type of material and by correlating the findings with fracture width. Applying this method of investigation to the current lost circulation management practice can help resolve many lost circulation incidents by effectively and efficiently selecting the appropriate LCM.