Chemically-Induced Pressure Pulse for Unconventional Gas Modelling and Experimental Investigation

摘要

There is tremendous potential for tight gas plays to provide long term energy all over the world because of the vast resource base that these formations contain. Horizontal drilling and multi-stage hydraulic fracturing technologies have allowed significant gas to be produced from shale gas and tight sand formations. However, the primary recovery factors have been less than 20% which implies the compelling need for advanced technologies. The significance of this research effort is to provide a cost effective stimulation technique that potentially replaces costly multi-staged hydraulic fracturing in shale gas and tight sand formations. This paper discusses Experimental findings and FDEM modelling of a novel stimulation method based on exothermic chemical reaction, Chemically Pulsed Fracturing (CPF), winner of World Oil Award for best production chemicals 2015. The method entails triggering an exothermic chemical reaction in-situ to generate localized pressure sufficient to create fractures around the wellbore, therefore, increase the SRV and improve gas production. Actual tests of pulsed fracturing conducted in lab scale using several block samples (Shale, carbonate, and sandstone) compared with modeling work using a three-dimensional hybrid finite-discrete element (FDEM) core are presented. Multiple fractures were created using the new technique in Shale, Indiana, Berea, and cement block samples. Fracturing was also tested, using cement block samples, under different biaxial stresses.