特高含水期新型水驱特征曲线

NEW WATER-FLOODING CHARACTERISTIC CURVES AT THE STAGE OF EXTRA-HIGH WATER CUT

特高含水期油水相对渗透率比与含水饱和度在半对数坐标中偏离直线关系,导致应用传统的水驱特征曲线时,曲线发生上翘,影响可采储量预测。基于特高含水期油水相对渗透率比与含水饱和度在半对数坐标上呈二项式函数变化的特征,推导了特高含水期一种新型的水驱特征曲线,表征为累计产水量与累计产油量在半对数坐标上呈二项式函数关系,并提出了与之相应的可采储量预测方法。以濮城油田沙一段油藏为应用实例,利用新方法计算了该油藏可采储量,并与其他方法计算结果进行了对比,结果接近。表明新方法对于特高含水期可采储量预测具有一定适用性。

Relationship between the ratio （Kro/Krw） and water saturation （Sw ） on the semi-logarithm coordinate deviates from the straight line at the stage of the extra-high water cut, thus the adopted traditional water drive characteristic curves show up upwards and furthermore affect the prediction of the recoverable reserves. Based on the characteristic of the binomial function change between Kro/Krw） and Sw on the semi-log coordinate at the stage, a new water drive curve is derived, which is characterized by the binomial function relationship between the accumulative water and oil productions on the semi-log coordinate. In addition, the new predicting method for the corresponding recovera- ble reserves is presented. Taking Member Shal reservoir in Pucheng Oilfield in Reference 5 as an example, with the help of the new method, the recoverable reserves are calculated, and moreover comparing with the computed results in Reference 5, the results are accordant with each other. The achievements show that the new method is applicable and suitable for the prediction of the recoverable reserves at the stage of the extra-high water cut.