塔河油田碳酸盐岩缝洞型油藏高压物性及最小混相驱压力实验研究

Experimental study on PVT and the minimum miscible pressure of carbonate fractured-cavity reservoirs in Tahe Oilfield

选择塔河油田典型油藏区块(稠油S48单元和稀油S86单元)碳酸盐岩缝洞单元作为研究对象,利用地层流体高压物性测试实验及细管实验论证注气混相驱在塔河油田提高采收率的可行性。结果表明:CO_2改善地层油物性参数的效果比干气好;稠油S48单元注气驱替无法达到混相条件,只能实施注CO_2非混相驱;稀油S86注CO_2可以实现混相驱,其最小混相压力为26.30 MPa,该压力值远小于本单元的原始地层压力,并取得较好的提高采收率效果。

The typical reservoirs(S48 unit of heavy oil and S86 unit of light oil)in Tahe oil blocks are chosen to be as the research objects in this paper.The high pressure physical test of formation fluid and the slim-tube experiment are used to demonstrate the feasibility of gas miscible flooding for improving oil recovery in Tahe Oilfield.The results showed that the effect of CO2 to improve physical parameters of formation oil is better than that of the dry gas.The CO2 gas miscible displacement can not be achieved for heavy oil of S48 unit.Nevertheless,the CO2 miscible flooding for light oil of S86 unit can be implemented with higher improved recovery rate and the value of the minimum miscible pressure is 26.30 MPa,which is much smaller than the original formation pressure.