鄂尔多斯盆地东部盒8段气水两相驱替渗流特征及影响因素分析

DISPLACEMENT EXPERIMENTS OF GAS AND WATER WITH SANDSTONE MICRO-MODELS OF HE-8 RESERVOIR IN THE EAST OF OREOS BASIN AND THE MAJOR FACTORS AFFECTING THE GAS DISPLACEMNT EFFICIENCY

针对鄂尔多斯东部地区盒8段储层低孔低渗、非均质性较强及渗流特征复杂等性质,通过在该地区利用真实砂岩模型进行微观气水两相驱替实验,得出其驱替方式渗流路线主要表现为3种形态:均一网状渗流路线活塞式驱替方式;非均一网状与交织状非活塞式驱替方式;复杂渗流路线非活塞式驱替方式。对实验现象进行分析,明确了储层砂岩中软组分含量、物性及残余水饱和度是影响驱替渗流方式及效率的主要因素。研究成果为更好地认识东部盒8段渗流规律提供了理论依据。

The Upper Palaeozoic gas reservoirs in the east of Ordos Basin are typical tight sandstone reservoirs with low permeability,whose features are complex curves of seepage flow.Displacement experiments of gas and water with the natural sandstone micro-models of He-8 reservoir were made.The results indicate that there are three forms about seepage flow curves: The displacement characters were(1)homogeneous、mesh and mainly piston-type;(2)Not homogeneous,intertwined and mainly inpiston-type;(3)erratic mainly inpiston-type.The major factors affecting the gas displacement efficiency are the soft components,porosity,permeability and saturation of residual water.