低渗透储层原油吸附对渗流的影响

Effect of adsorption of crude oil on fluid transfusion in low permeability reservoir

通过静态吸附实验和岩心流动实验研究了大庆低渗透储层原油在岩石表面吸附的机理及其对油水渗流的影响。实验表明,原油中沥青质和非烃组分可以被岩石表面吸附,形成吸附层。吸附层的存在减小了岩心的孔隙半径,增大了油水流动阻力。粘度相同的含有沥青质的模拟原油与精制油在相同实验条件下,流动曲线差别较大。在原油/岩石体系中,原油在岩石孔隙表面的吸附层厚度将达到孔隙半径的30%以上,在原油/地层水/岩石体系中,油膜厚度与孔隙半径的比值随着渗透率的降低而增大,特低渗透岩心中吸附层厚度可达到孔隙半径的10%,一定程度上降低了油相和水单相渗透率。

The adsorbed mechanic and the effect on oil/water transfusion of crude oil in Daqing low permeability reservoir were researched by the method of static adsorption experiment and core flooding experiment.The experimental results indicate that the asphaltene and non-hydrocarbon components of crude oil can be adsorbed on the rock surface to form adsorption layer.The adsorption layer makes pore radius and fluid permeability decrease.Under the same test condition,the flow curve of simulated crude oil with asphaltene and non-hydrocarbon components is different from the refined oil with the same viscosity.In crude oil/core system,the thickness of adsorption can be up to 30% of core pore radius.And in crude oil/water/core system,thickness of crude oil on surface of pore increases with permeability decreasing and can be up to 10% of core pore radius.Adsorption can decrease oil or water permeability.