含油砂体多组合油层注水开发压力恢复曲线解释

INTERPRETATION STUDIES ON PRESSURE BUILD?UP CURVES FOR RESERVOIRS COMPOSED OF MULTIPLE OILY SANDY BODIES DURING WATER-FLOODING PERIOD

注水开发之后地下出现了许多新情况 ,因为井内各油砂体内注水受效程度千差万别。以叠加原理为基础而形成的求解方法不能把已观察到的情况纳入原始模型之中。为此 ,提出了一种新的解决方法 ,即 :先把系统在注采井距之半处分割 ,并设置为外边界封闭条件 ;再把脱气油砂体、见水油砂体内的多相流动依据渗流力学原理化解为“扩充单相”流动。最后 ,把已观察到的新情况及分割、扩充后的结果一并纳入定解条件中去 ,经直接求解得到了压力恢复表达式。以此为基础 ,在多种条件下可计算出各自的曲线 ,为解释工作提供了理论依据。特别是文内提出的“第三段”应用方法 。

In the water injection stage,some new spectacles can be observed,because the water_flooding effects are very different in relative sandy bodies.The solving approach based on superposition principles may lose some needed information,so that a new method is presented.The water_invaded sandy bodies have to split up in the middle positions among injectors and producers,and the bounded conditions to be set up.The multiphase flows in gas_oil and water_oil sand bodies were changed into enlarged single_phase flows.The observed information and enlarged results are all put into the boundary and initial conditions.A set of analytical formulas may be obtained by solving a partial differential equation,and many kinds of pressure build_up curves can be plotted on the basis of diverse parameter combinations.This work not only could be used to enriching our knowledges for interpretations but also indicates the application of 'third segments',which is very favorable for discovering remainingoil in the ineffective oily sandy bodies by using water_flooding.