Development of an ultra-lightweight coconut shell-based proppant for hydraulic fracturing of subterranean formations

Abstract

Hydraulic fracturing (HF) has seen a considerable increase in interest for the purpose of improved oil recovery. HF creates high conductive conduits between wellbores and reservoirs by a pressurized fluid mixed with proppants. The problem of most popular fracturing fluid (i.e., slickwater) is the high settling rate of common proppants, e.g. sand, which results in small effective propped fractures. Ultra-lightweight (ULW) proppants are easily transported by slickwater and can cover further fracture area. However, ULW proppants cannot provide enough strength at high closure pressure. This study developed a moderately high strength, chemically modified and reinforced composite proppant (CMRCP) which is composed of chemically modified coconut shell, composite material, and epoxy resin. Investigating the performance of new ULW proppant was conducted using laboratory and simulation works such as characterization, quality and mechanical evaluation, simulation mechanical response of particles under compression, fracture conductivity, and HF design. Characterization indicated that the coating layers of CMRCP provide thermal stability of 297.5 °F. Also, quality tests revealed that CMRCP is a neutral buoyant proppant with lower bulk density than frac sand, glass beads, ULW-1.75, and ceramic. Desirable strength (i.e., 8,000 psi) and conductivity (i.e., 791 mDft) from mechanical tests and fracture conductivity were observed, respectively. The results showed an improved performance than Brady sand and its counterpart (i.e., ULW-1.25). The results of strength tolerance and fracture conductivity of CMRCP were 25% and 77% higher than ULW-1.25. Furthermore, experimental and simulation of proppant’s mechanical response with different geometries approved that round geometry provides further strength. Finally, HF design shows that the new product can realise high cumulative production, net present value, and return on investment. This study introduced a new ULW proppant that has moderately high strength, resistant to high temperature, easy to get, light, and cost effective, and it can be used as proppant for HF of subterranean formations.