四重介质油藏渗流模型与试井曲线

Flow model and well test curves for quadruple-media reservoirs

在发育缝洞型四重介质的碳酸盐岩油藏中,其大裂缝和微裂缝的渗流机理不同,以往建立的常规多重介质试井模型不能适应四重介质油藏试井解释需求。因此,基于基质、微裂缝、溶蚀孔洞和大裂缝组成的四重介质,建立物理和数学模型,并利用Laplace变换、Stehfest数值反演等方法进行求解,得到实空间解,进而绘制试井曲线。分析表明:四重介质油藏压力导数曲线的过渡段将出现3个"凹子",其深浅以及出现时间的早晚受弹性储容比和窜流系数的共同影响;弹性储容比影响"凹子"的宽度和深度,窜流系数影响"凹子"出现的时间,同时对"凹子"的深度和宽度也有一定的影响;决定四重介质油藏试井曲线特征的参数较多,曲线对参数的变化比较灵敏;含有微裂缝和大裂缝的缝洞型碳酸盐岩油藏,更适合用四重介质试井模型进行解释。

For fractured-vuggy quadruple-media carbonate reservoirs with micro-fractures and fractures, the percolation mechanism of large-scale fractures is inconsistent from the small-scale fractures. Using conventional multiple media models to explain quadruple-media reservoirs is inappropriate. A quadruple-media physical and mathematical model based on matrix, micro-fractures, vugs and fractures was established. By means of Laplace transformation and numerical inversion of Stehfest, the real space solution was obtained, and well test curves were drawn up. The result shows that three concaves tend to be present in the pressure derivative curve of the quardrule-media reservoir, of which the amplitude is affected by the interporosity flow coefficient and capacitance coefficient. The width and depth of the concaves are influenced by capacitance coefficient, and the timing and the ampli-tude of concave are affected by interporosity flow coefficient. More parameters present in the quadruple-media reservoirs well testing curves, and curves are more sensitive to the change of parameters. It is suitable to use the quadruple-media well testing models to interpret fractured-vuggy carbonate reservoirs with fractures and micro-fractures.