正韵律底水油藏纵向非均质影响数值模拟研究

Study on the Effect of Vertical Heterogeneity in the Positive Rhythm Reservoir with Bottom Water on Numerical Simulation

非均质性是储层沉积、成岩等地质过程综合作用的结果 ,是影响油气田产量、最终采收率的重要因素。储层分为正韵律、反韵律及复合韵律三类,对各类韵律储层进行数值模拟前期研究认为,正韵律储层的油气采出程度较反韵律或者复合韵律油藏都差,是一种极不理想的油藏。在开发此类油藏时,试图从地质学角度找到影响正韵律储层采出程度的因素,并认识其影响规律。此项研究以渗透率级差、突进系数及变异系数等三个渗透率参数为基础,定量地表征储层纵向非均质性强度,并运用数值模拟方法,分析了纵向非均质性强弱对正韵律底水油藏剩余油饱和度、含水上升规律及采出程度的影响,从而总结出纵向非均质性对驱油效率的影响规律。研究认为,正韵律储层,其渗透率级差越小,纵向非均质性越弱,油藏驱油效率相对较高,开发生产效果相对较好,但含水上升规律基本无变化。

Heterogeneity is the comprehensive effect of reservoir deposition and diagenesis in the geological process.It is the most important factor of influencing the production of oil and gas field and the ultimate recovery efficiency.The reservoirs may be divided into three types： positive rhythm reservoirs,inverted layered reservoirs and composite rhythm reservoirs.Earlier numerical simulation research on each type of rhythm reservoirs shows that the positive rhythm reservoirs are the worst among these three types for their lowest degree of reserve recovery.When this type of oil reservoir is developed,the influencing factors of the degree of reserve recovery should be found out on geology and the rules should be known.The strength of vertical heterogeneity in reservoir is characterized quantitatively based on three permeability pa rameters ：permeability differential,coefficient of permeability variation and permeability dash.Effect of the vertical heterogeneity on the saturation of remaining oil,the incremental law of water cut and the degree of reserve recovery in the positive rhythm reservoir with bottom water is analyzed by numerical simulation method.Then the effect law of the vertical heterogeneity on oil displacement efficiency can be summarized.The research shows that smaller permeability differential brings weaker vertical heterogeneity,and higher oil displacement efficiency and better production result,but there is no change on the incremental law of water cut basically in the positive rhythm reservoirs.