注CO_(2)对地层油高压物性影响规律实验研究

Experimental study on the effect of CO_(2) injection on high pressure physical properties of formation oil

注CO_(2)地层油的高压物性是分析CO_(2)驱油与埋存机理、优化其技术方案的基础。针对DQ油田M区块,采用脱水原油和天然气样品配制的模拟地层油开展实验,探索注CO_(2)对地层油高压物性的影响规律。结果表明,注CO_(2)使地层油的饱和压力和溶解气油比升高、体积系数和膨胀率增大、密度和黏度降低;CO_(2)注入越多,地层油高压物性的有利于变化程度越大。从地层油物性变化程度和经济角度,M区块进行注CO_(2)开采原油时,注CO_(2)占比以1.00~1.40为宜,相应注气压力为17~20 MPa。

The high pressure physical properties of CO_(2) injection formation oil are the basis for analyzing the mechanism of CO_(2) displacement and storage and optimizing its technical scheme.In the M block of DQ oilfield,simulated formation oil was prepared with dehydrated crude oil and natural gas samples to explore the effect of CO_(2) injection on the high pressure physical properties of formation oil.The results show that CO_(2) injection can increase the saturation pressure and dissolved gas-oil ratio of formation oil,increase the volume coefficient and expansion rate,and reduce the density and viscosity of formation oil.The greater the CO_(2) injection,the greater the favorable change degree of formation oil high pressure physical properties.From the perspective of physical property change of formation oil and economy,when CO_(2) injection is used to produce crude oil in block M,the proportion of CO_(2) injection is appropriate to be 1.00~1.40,and the corresponding gas injection pressure is 17~20 MPa.