Experimental Characterization of Palm Kernel Shell as Wellbore Strengthening Material for Depleted and Loss Circulation Zones

Abstract

Abstract With a continued growth in the discovering of new reserves at deeper depths in mature fields, drilling through the depleted and already producing zones is already posing a loss circulation problem as well as other wellbore instability problems such as stuck pipe. Considering the cost of loss circulation materials and its effectiveness the need to source materials locally for LCMs becomes imperative. This research work investigated palm kernel shell as a local material to be used as loss circulation material, the processed palm kernel shell was sieved into different particle sizes and added in various mass ratio to the formulated mud. The mud weight, filtration test and permeability plugging test was done to experimentally characterize the mud based on its effectiveness as a loss circulation material. Palm kernel shell with blends of other industry loss circulation material was also considered to ascertain the blended LCMs effectiveness as compared to the palm kernel shell mud samples. From the experiments conducted, the mud weight of palm kernel shell mud samples ranges from 11ppg to 11.4ppg in different particle size distribution. The total filtrate loss and the filter cake thickness ranges between 5.0ml to 8.6ml and 1mm/32-inch to 2mm/32-inch respectively. The permeability plugging test of the Palm kernel shell mud samples has a range of total filtrate volume of 8.9 ml to 11ml, as well as filter cake thickness of 3mm/16-inch to 4.5mm/16-inch. In a comparative analysis, the blend LCMs, i.e. the palm kernel shell and Mica, palm kernel shell and graphite have a better sealing and filtrate loss properties than the palm kernel shell mud samples. It is therefore recommended that more research should be carried out on the blends of palm kernel shell and other LCMs as it will be cost effective when compared to the imported LCMs.