碳酸盐岩稠油热采水平井试井解释模型及压力动态特征

Well Testing Interpretation Model and Dynamic Pressure Characteristics of Horizontal Well Heavy Oil Thermal Recovery in Carbonate Reservoir

针对碳酸盐岩稠油油藏建立了三重孔隙介质两区复合油藏水平井试井解释模型,通过垂直线源沿水平井井身进行积分,利用Laplace变换和Fourier有限余弦积分变换求解得出水平井的压力解,并进行了压力响应及参数敏感性分析。碳酸盐岩稠油热采水平井的压力导数曲线在测试时间足够长的情况下一般具有多个水平段、过渡段和"下凹"等特征:水平段是压力在不同介质中传播时的径向流的反映;过渡段是压力传播到两区界面时的反映,其出现时间与加热半径有关,当其较小(如R_D=5)时,过渡段通常出现在裂缝径向流时期,当其较大(如R_D=250)时,其通常出现在缝-洞径向流或孔-缝-洞径向流时期;"下凹"是介质间窜流的反映,其主要受弹性储容比和窜流系数等参数的影响。

Aiming at the characteristics of carbonate heavy oil reservoir,horizontal well testing interpretation model for the triple porosity media of two zone composite reservoir is established,and through the vertical line source integrated along the horizontal wellbore,by using Laplace transformation and Fourier finite cosine integral transformation,the horizontal well bottom-hole pressure is obtained,and corresponding pressure response characteristics and sensitivity of parameter are analyzed.The pressure derivative curve of triple media thermal recovery two zone composite horizontal well testing interpretation model has features of several horizontal lines,the transition stage and several 'concave' if the test time is long enough:horizontal lines are the reflection of radial flow occurring in different media;the transition stage is the reflection of the pressure transmitting to two zone interface,its occurring time related to the size of dimensionless inner zone radius.When R is small(such as RD=5),the transition stage usually occurs in the fracture radial flow stage,when it is large(such as RD=250),its usually occur in fracture,hole radial flow stage or pore,fracture,cavity radial flow stage;the 'concave' is a reflection of cross-flow between the media,which is mainly affected by the elastic storage capacity ratio and cross-flow coefficient.