Effect of Fracture Fluids in Tight Gas Formations

摘要

This report describes the methods and presents the results of a laboratory investigation of the effects of various fluids such as liquid carbon dioxide, aqueous carbon dioxide, water and proprietary fracture fluids on Devonian shales under simulated down-hole conditions. The effects are evaluated by in situ measurements of permeability, before and after treatment with fluid, under various applied pressures and pressure differentials. The nature and extent of the 'skin effect' was evaluated by examination of the microstructure of the shale. The general conclusion of the work reported here is that all fluids examined reduce shale matrix permeability. The relationship of this reduction to production capability is discussed but remains unknown.