超低渗油藏动态毛管压力研究(英文)

Study of Dynamic Capillary Pressure in Ultra-low Permeability Reservoir

毛管压力对储层油水两相的渗流有重要影响。通过实验研究了超低渗储层的渗流阻力特征。在此基础上建立了考虑动态毛管压力的超低渗透储层油水两相渗流数学模型。分析了动态毛管压力的敏感因素和动态毛管压力对油水两相渗流的影响。研究表明:超低渗透油藏毛管压力的动态效应明显。动态毛管压力的τs因数或注入速度越大,动态毛管压力越大;水驱前缘处动态毛管压力最大,动态毛管压力的存在阻碍了油水前缘的推进速度,降低了产油量;对于水湿超低渗透油藏,动态毛管压力使含水率上升更快,而对于油湿性油藏来说,动态毛管压力的存在降低了含水率上升速度。研究成果对于认识超低渗透油层的油水两相渗流规律具有重要意义。

Capillary pressure has a great influence on the percolation of oil-water two-phase. The features of seepage resistance in ultra-low permeability reservoir are studied by experiment. A percolation numerical model of oil-water two-phase which considers the dynamic capillary pressure is established. Finally, the sensitive factors of dynamic capillary pressure and the effects of dynamic capillary pressure on oil-water two-phase seepage are ana- lyzed. The results show that the dynamic effect of capillary pressure is obvious in ultra-low permeability reservoir. When the coefficient r~ of dynamic capillary pressure or the injection rate is larger, the dynamic capillary pressure will be bigger. The existence of dynamic capillary pressure hinders the fihting speed of waterflood front and reduces the oil production. The dynamic capillary pressure makes the moisture content rise faster for water wetting reservoirs while it reduces the rising velocity of moisture content for oil wetting reservoirs. This study will be beneficial to re- vealing the percolation law of ultra-low permeability reservoir