存在直线断层的复合模型试井曲线特征研究

鲜有文献报道井附近存在直线断层（尤其是断层位于复合油气藏内区）对试井解释的影响，因此，从渗流力学理论出发，首先建立考虑表皮和井筒储集的无限大地层两区径向复合油气藏试井解释数学模型，并通过拉氏变换对模型进行求解，再利用镜像反映原理和叠加原理研究存在直线断层的复合油气藏的无因次井底压力及压力导数曲线特征及影响因素。研究表明，当井到断层距离小于1/2内区半径时，无因次压力导数曲线将由无限作用径向流的0.5水平线变为内区受断层影响的1.0水平线和外区受断层影响的值为M₁₂水平线；当井到断层距离大于1/2内区半径时，无因次压力导数曲线将由无限作用径向流的0.5水平线变为反映外区特征的值为M₁₂水平线和反映外区受断层影响的值为M₁₂的水平线。

Characteristics of Well Test Curves Corresponding to a Combined Reservoir with Linear Faults

There are few reports in the literature on the effects of linear faults on well test interpretations, especially for linear faults located within combined oil and gas reservoirs. To address this gap, we have constructed a mathematical model for interpreting well tests from infinite formation combined oil and gas reservoirs with two radial zones based on seepage mechanics. Solutions for this model were obtained via Laplace transformations; the principles of image theory and superposition were then used to study the dimensionless bottom hole pressure and pressure derivative curves corresponding to combined oil and gas reservoirs that contain linear faults, along with the factors affecting these curves. The results of this study are as follows:when the distance between a fault and well is less than half the radius of the inner area, the dimensionless pressure derivative curve changes from the 0.5 horizontal line, indicative of an infinite-acting radial flow, to the 1.0 horizontal line, indicative of a faultaffected inner area, and the value that shows the fault's impact on the outer area is the M₁₂ horizontal line. When the distance between a fault and well is more than half the radius of the inner area, the dimensionless pressure derivative curve shifts from the 0.5 horizontal line, corresponding to an infinite-acting radial flow, to the M₁₂/2 horizontal line, which shows the characteristics of the outer area, and the value that is indicative of the fault's impact on the outer area is the M₁₂ horizontal line.