Mechanism And Optimization Of Parameters By Flooding After HDC Huff-and-puff In Heavy Oil Reservoir

Aiming at the problem of low recovery of crude oil reservoirs using conventional oil recovery method in the bottom water heavy crude reservoir of XB faulted block in Jiangsu Province,this paper puts forward a method of EOR by HDC(H-Horizontal well,D-viscosity-reducing agent,C-carbon dioxide)stimulation,based on the core displacement model and three-dimensional numerical model.In this paper,the mechanism of EOR by HDC stimulation was studied by orthogonal test,and the related parameters were optimized.It is found that in several displacement schemes of core displacement simulation,the effect of carbon dioxide flooding is the worst,the recovery rate is 29.9%,the effect of reducing viscosity flooding is second,the yield is 33.6%,the yield of the viscosity-reducing agent/carbon dioxide is the highest,reaching at 40.3%;at the same time,after using the HDC method,the first huff and puff effect of HDC is the best,with the increase of huff and puff,its huff and puff effect decreases in turn;the first huff and puff the highest day production of oil l reached 17 m~3,the water content dropped to 11.5%,after four rounds,the highest day production of oil to 4.3m~3,water content has reached 78%.In addition,we also compare the carbon dioxide displacement effect of core displacement and the carbon dioxide displacement result of three-dimensional numerical model,the mechanism of reducing viscosity agent/carbon dioxide joint flooding is found to be carried out by the carbon dioxide gas and its gas-specific properties,carry the viscosity-reducing agent in the reservoir,and improve the sweep range of the viscosity-reducing agent.Viscosity reducing agent in the range of viscosity-reducing agent,carbon dioxide supplemented by heavy oil viscosity.Based on the fine geologic model,22 sets of solutions were designed to optimize the total amount of viscosity reduction agent/carbon dioxide injection,the relationship between the two ratios,injection speed,soaking time of HDC Huff-and-Puff technology.Through numerical simulation results,the final selection of injection viscosity-reducing agent 300t,900t carbon dioxide,injection speed 150 t/d,15 days to soak,soak 4 rounds,a total increase in oil production5930 m~3.Based on the optimization of HDC Huff-and-Puff parameters,injection well optimization and injection fluid optimization were carried out.The simulation results show that the cumulative production of HDC,carbon dioxide,viscosity-reducing agent and carbon dioxide displacement schemes are 7524 m~3,16712 m~3 and 18680 m~3.Through the research of this paper,we have a preliminary understanding of the mechanism of EOR by HDC stimulation,and according to the actual situation of the oil field,optimized the HDC Huff-and-Puff correlation parameter,set up a set of feasible HDC Huff-and-Puff Development plan for the XB block,at the same time it has certain reference meaning to the similar block development.