Optimization analysis of factors affecting hydrocarbon gas drive based on orthogonal experimental design

Abstract

To improve the ultimate recovery of reservoirs and to increase the economic benefit of oilfields, we feel obliged to study on various factors affecting the development effect of hydrocarbon gas injection and its influence in terms of ultimate recovery. Thus, we can formulate a reasonable and feasible scheme on effective implementation of hydrocarbon gas drive. Take Q28 fault-block as an example; five main factors affecting the development effect of hydrocarbon gas injection have been screened out, four different levels of each influence factor has been set up; the orthogonal experiment method has been adopted to design 16 different combination schemes of 5 factors. Numerical reservoir simulation predicted the final recovery under the different combination schemes. Following are the range analysis and variance analysis of entire results so that the major and minor factors affecting the final recovery and the best range of each factor can be confirmed. The order sequence from major to minor factors: gas injection slug size, gas injection time, gas–water ratio, pressure level, and injection rate. This method is significant on its guidance for hydrocarbon gas injection in this area.