Study on the feasibility of the heat treatment after shale gas reservoir hydration fracturing

Abstract

Hydraulic fracturing is typically required before shale gas production. Residual fracturing fluid in the reservoir leads to a hydration reaction and weakens the fracturing effect. To address these problems, an additional process during the reservoir heat treatment at the time point after hydraulic fracturing and before formal extraction is proposed, namely, heat treatment after shale gas reservoir hydraulic fracturing, and analysis of the Sichuan Longmaxi Shale is used as an example. The feasibility of the method has been demonstrated by observing the changes in porosity, permeability, tensile strength and other parameters of hydrated shale after heating and exploring the influencing factors and change laws associated with each parameter. Experiments can be conducted to verify that after heating the hydrated shale, the heating temperature, heating rate and holding time are positively correlated with shale porosity, permeability and tensile strength. After shale hydration, the elastic modulus, yield limit and compressive strength decrease; after hydrated shale heat treatment, the compressive strength decreases slightly, while the elastic modulus and yield limit increase, but they are lower than those of the original shale. The changes in the parameters have a positive effect on shale gas production, and this method is theoretically feasible.