论文部分内容阅读
裂缝型碳酸盐岩油藏CO2驱后采收率的高低主要取决于CO2从裂缝到基岩的流动,因此CO2分子从裂缝向基岩中原油的扩散作用会影响采油速度。在CO2驱中泡沫CO2显示了其在提高宏观驱油效率方面的作用。然而,泡沫剂是提高还是降低了从基岩到裂缝的采油速度还需要确定。一个裂缝模型中研究了油藏条件下裂缝型碳酸盐岩油藏CO2驱过程中泡沫CO2对采油速度的影响。这个裂缝模型通过把水驱后的岩心塞置于带有环空的不锈钢壳电解槽的环空中制作而成。裂缝被注入的CO2气以及同时注入的CO2气和泡沫剂溶液充满,或者在岩心塞外注入水和泡沫剂。利用压力衰减法来确定人造海水、地面脱气原油和CO2泡沫剂水合溶液中CO2的体积扩散系数。同时注入CO2气和水合泡沫剂溶液的采收率比单独注入CO2时的采收率略高。在人造海水和水合泡沫剂溶液中测得的CO2的体积扩散系数表明在实验条件下被测泡沫剂对CO2的渗透没有太大影响。油藏条件下对于CO2-人造海水和CO2-地面脱气原油系统而言,可以预测体积扩散系数与之前出版的文献资料中的值相似。
The recovery rate of CO2 flooding in fractured carbonate reservoirs depends mainly on the flow of CO2 from the fractures to bedrock. Therefore, the diffusion of CO2 molecules from the fractures to the crude oil in the bedrock will affect the oil recovery rate. Foam CO2 in CO2 flooding shows its role in improving macro flooding efficiency. However, whether foaming agents increase or decrease oil recovery from bedrock to fracture needs to be determined. In a fracture model, the effect of CO2 on oil recovery during carbon dioxide flooding in fractured carbonate reservoirs under reservoir conditions was studied. The fracture model is made by placing a water-flooded core plug in an annulus with an annular stainless steel cell cell. The CO2 gas injected into the fracture and the CO2 gas and foam solution injected simultaneously are filled, or water and foam are injected outside the core plug. The pressure decay method was used to determine the volumetric diffusion coefficient of CO2 in artificial seawater, ground-derived crude oil, and CO2 foam hydration solution. At the same time, the recovery of CO2 gas and hydrated foam solution was slightly higher than that of CO2 alone. The volumetric diffusion coefficients of CO2 measured in artificial seawater and hydrated foam solutions indicate that the measured foams do not have much effect on CO2 permeation under experimental conditions. For reservoir systems of CO2-man-made seawater and CO2-ground degassing crude oil systems, the volume diffusivity can be predicted to be similar to the previously published literature.