| Due to China's "rich in coal,poor in oil and little in gas" resource endowment,the dependence of crude oil on foreign countries has also constantly reached a new record.For China,it is urgent to speed up the exploration of oil security measures.At present,China's dependence on foreign crude oil has reached more than 70%,far higher than the international safety warning line,becoming the world's largest oil importer.At the same time,China's natural gas export progress is now more than 40%.The oil and gas energy security situation is very serious,which has become a "neck sticking" problem.Therefore,to actively promote the research and development of oil shale in-situ transformation technology is of great strategic significance to improve the geological reserves and technical reserves of China's oil resources and firmly grasp the energy security in our own hands.The breakthrough and large-scale industrial application of oil shale in-situ transformation technology will set off a "oil shale oil and gas revolution" just like the "shale oil and gas revolution" in the United States.The "oil shale oil and gas revolution" will also have a significant impact on the energy pattern of China and the world,and play an important role in promoting the economic and social development of the country.In this paper,the Fuyu Changchun ridge area of Songyuan City,Jilin Province is taken as the research area.By using the computer numerical simulation method,the numerical simulation is carried out under the conditions of four gas supply speeds of the ground experimental device for oil shale in-situ production,two models of parallelWell Group and nine models of steady-state simulation and two models of transient numerical simulation.The ground experimental device for oil shale in-situ production is adopted Numerical simulation,the main conclusions and understanding are as follows.(1)It is found that the velocity field and temperature field simulated by the test device have radial structure,and the radial structure of temperature field is probably caused by the radial structure of heating gas flow.The heating process of oil shale samples is inhomogeneous,which may cause the inhomogeneity of oil shale rock deformation and have an important impact on the heating effect of oil shale rock.(2)For the simulation device,the increase of gas injection speed can make the heating efficiency increase approximately linearly,so in the cost allowable range,increasing the flow rate as much as possible can effectively improve the heating efficiency;expanding the gas injection opening angle can not actually improve the heating efficiency,but increase the heat loss.(3)The transient simulation results of model A and model B indicate that the heating process of oil shale has three stages: initial heating,continuous heating and stabilization.When the oil shale is heated to 100 days,the temperature field tends to be stable.(4)The distance between production well and combustion well has a certain influence on the temperature field of oil shale.The increase of production wells can effectively improve the heating effect.At the same gas supply speed,the heating effect of model B is better than that of model A.(5)There is a close relationship between the optimal injection well and the gas supply speed.The larger the gas supply speed is,the larger the optimal well spacing is.In the case of model A and model B,the optimal well spacing is 5m when the gas supply speed is 15m/s.There are some innovations in the following two aspects:(1)it is found that there is radial structure in the temperature field and flow field of oil shale,which provides a reference for the construction of large-scale ground devices.(2)It breaks through the difficult problems of large model and micro structure numerical simulation,andreveals the influence of well spacing,distance between heat injection well and production well,gas supply speed and other parameters on the heating effect of oil shale. |
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