THEORY AND METHOD OF IN-SITU CONVERSION OF SHALE OIL BY CHEMICAL THERMAL

The huge potential of shale oil makes this resource an important energy alternative to improve the balance between energy supply and demand. In this sense,its development and economic utilization have regained significant attention. The in-situ conversion is the best technology recommended for the exploitation of continental shale oil in China. However,the current low-maturity shale oil and underground in-situ conversion/modification methods of oil shale mainly face bottlenecks such as low thermal efficiency,high pollution risk,and reservoir subsidence instability. Therefore,on the basis of analyzing the advantages and disadvantages of various in-situ conversion/modification methods of shale oil,the temperature,time conditions,and structural evolution characteristics of hydrocarbon generation from shale oil cracking are summarized. Consequently,a thermal in-situ mining theory of shale oil chemicals is suggested. This theory uses the reaction of calcium oxide and water to provide heat for the in-situ conversion of organic matter. Hence,considering the principle of material and energy balance,the theory and method of this thermal in-situ conversion for shale oil chemical production are proposed. And the technical feasibility of the method is demonstrated by analyzing temperature level,heat supply,and solid-phase volume change. The results of the heat-solid-phase material balance analysis and the high-pressure calcium oxide hydrolysis test show the technology is efficient theoretically. Therefore,some mining methods using calcium oxide are proposed such as surface coating modification of calcium oxide powder,calcium oxide microspheres,calcium oxide hydroxyl injection liquid,and high-pressure air calcium oxide powder injection.