变井筒储存的三重介质油藏试井解释方法研究

Well test interpretation method for triple meduim reservoir with variable wellbore storage

建立了由基岩系统、裂缝系统和溶洞系统组成的三重介质油藏的试井解释模型 ,采用Laplace变换进行求解 ,并给出了考虑变井筒储存和表皮效应的压力计算方法。讨论了介质间窜流、弹性储容比及变井储参数对压力响应的影响。在半对数曲线上出现 3条直线和 2个台阶 ,双对数导数曲线表现为 2个下凹部分 ,分别表示裂缝系统和基质孔隙系统向溶洞系统的窜流。提出了利用遗传算法进行自动拟合的试井解释方法 ,并编制了实用软件。

A mathematical model for well test interpretation of triple medium reservoir was established. In consideration of the connection of vugs with well bore in allusion to triple medium reservoir composed of basement rock, fracture and cavern, the mathematical model was solved with the Laplace transform and numerical Laplace reverse evolution methods. The influences of storage-to-volume ratio and cross-flow factor of basement rock, fracture and cavern on pressure response were analyzed. There are three lines and two steps on the semi-log graph, and there are two concaves in log-log derivative graph. These features express the channeling of fracture and basement pore systems towards the cavern. An automated matching interpretation method for test well using genetic theory was presented, and an applied software was developed. The practicability and reliability of the new method were identified by the field data analysis.