Impact of reservoir, fracturing fluid and proppant characteristics on proppant crushing and embedment in sandstone formations

Abstract Hydraulic fracturing is regarded as an effective tool to stimulate the reservoir and ensure economic production of gas. The process of exploitation of these resources is largely influenced by small spheres called proppants. The main goal of hydraulic fracturing is to generate a wide fracture network in the medium. Injecting proppants at higher concentrations into these fractures tends to maintain conductivity by keeping them open, so that smooth flow of fluids into the wellbore is ensured. Hence, proppants are required to possess sufficient strength to sustain the closure pressures acting upon them. Propped fracture conductivity is affected by processes such as crushing of proppants, creation of fines and proppant embedment. The process of proppant crushing and embedment are further aggravated by the properties of the reservoir, fracturing fluid and the proppants. The objective of this paper is to review the different experimental studies conducted on sandstone formations to analyse the effect of factors that intensify the process of proppant crushing and embedment. A fracture conductivity system, as per API standards, is commonly used in such investigations. A brief overview of various aspects of hydraulic fracturing is followed by the discussions on the factors that damage the conductivity of the cracks in the formation. The effect of each parameter that aggravates crushing and embedment mechanisms are reviewed with significant evidence. Some other predominant mechanisms that damage the conductivity of the fractures are also highlighted. Then, the recent advancements made in such laboratory scale investigations are discussed.