X区块低渗油藏注气可行性研究

为研究X区块低渗油藏注气混相驱油的可行性,通过室内实验探讨了原油相态特征和注入气与地层流体的相态特征,开展细管实验测试了注入气与地层流体的最小混相压力,为X区块低渗油藏注CO2和注伴生气可行性提供基础。实验主要得到以下结论:该区块原始地层压力为31.1 MPa,饱和压力为11.03 MPa;注CO2在保压、降黏膨胀和抽提方面的效果好于注伴生气;两种气体注入与地层流体不能实现一次接触混相驱,可以实现多级接触混相,压力分别为27.85 MPa和29.2 MPa。细管实验的驱替效率在94.2%,确定了CO2与原油的最小混相压力为23.56 MPa,由此可见X区块油藏适合注CO2混相驱油,为目标区块后续注CO2驱油提供了理论依据。

Feasibility study of gas injection in low permeability reservoirs of X block

In order to study the feasibility of gas-injection miscible flooding in the low-permeability reservoir in X block,this paper analyzes the phase characteristics of crude oil and the phase characteristics of injected gas and formation fluid through laboratory experiments.The minimum miscible pressure provides the basis for the feasibility of CO2 injection and associated gas injection in the low permeability reservoirs in X block.The experiment mainly obtained the following conclusions:the original formation pressure in the block was 31.1 MPa,and the saturation pressure was 11.03 MPa;the effect of CO2 injection on holding pressure,viscosity reduction and expansion and extraction was associated with injection associated gas;two kinds of gas injection and formation fluid one-time contact miscible flooding cannot be achieved,and multi-stage contact miscible flooding can be achieved with pressures of 27.85 MPa and 29.2 MPa,respectively.The displacement efficiency of the thin tube experiment was 94.2%,and the minimum miscible pressure of CO2 and crude oil was determined to be 23.56 MPa.Therefore,X block reservoirs are suitable for CO2 miscible flooding,providing a theoretical basis for subsequent CO2 flooding in X block.