文东深层低渗透油藏微观剩余油形成机理研究

Study of Formation Mechanism of Micro Remaining Oil in Low Permeable Reservoir of Third Section of Shahejie Formation in Wendong Area

文东沙三中油藏是典型的深层高压低渗复杂断块油藏,储层具有启动压力梯度,渗流规律不同于中高渗储层,通过岩心观测、岩石薄片、铸体薄片、扫描电镜以及压汞资料,分析储层微观孔隙结构特征的基础上,采用真实储层模型进行微观水驱油实验,研究微观孔隙结构与驱油效率的关系及其微观剩余油形成机理。

The formation mechanism and controlling factor of remaining oil were demonstrated in this paper through the reservoir structure,micro pore and throat network and micro displacement test.Saturated water in the rock flows fast but uniformity because of the deep reservoir,strong diagenesis,low permeability and high heterogeneity.The driving pressure is very low because of the pore structure with serious heterogeneity.The sweep area of injected water can hardly be increased and nearly no effect on oil displacement efficiency can be seen when increasing the injected pressure and velocity.Bypassing is main form of remaining oil and heterogeneity of the reservoir pore structure is major factor that affects the oil displacement efficiency.