Optimization Design of In-Situ Upgrading for Oil Shale via Steam Injection Based on Response Surface Method

Abstract

In order to improve the effect of in-situ upgrading for oil shale via steam injection, the optimization of development parameters has been carried out. In this study, a central composite numerical simulation experiments program was designed based on response surface method (RSM). The significances and interactions of injection rate, steam temperature and well space were analyzed for the cumulative oil-steam ratio, then the optimal development parameters were determined. The results show that the regression model obtained by RSM has strong reliability. The cumulative oil-steam ratio is relatively low for the in-situ upgrading via steam injection in traditional way. The effect of steam temperature on cumulative oil-steam ratio is the most significant, followed by injection rate and well space, and the interactions between various parameters are not obvious. The maximum cumulative oil-steam ratio can reach 3.64 × 10−3, which is consistent with the RSM model result, when the optimized values of steam temperature, injection rate and well space are 600 °C, 30 t/d and 7.3 m respectively. The research provides theoretical basis for the application of in-situ upgrading for oil shale via steam injection.