考虑启动压力梯度和注采比的不稳定压力动态特征

CHARACTERISTICS OF TRANSIENT PRESSURE WITH THRESHOLD PRESSURE GRADIENT AND INJECTION-PRODUCTION RATIO

王庆霞 黄金凤 尹洪军

Wang Qingxia Yin Hongjun Huang Jinfeng

大庆油田有限责任公司, 黑龙江大庆 163712 大庆石油学院, 黑龙江大庆 163318

建立了考虑启动压力梯度和注采比因素的均质油藏数学模型。用数值方法对其求解。绘制并分析了不稳定压力动态典型曲线。研究表明,启动压力梯度和注采比对压力动态影响较大。对于开井压力降落情况,注采比小于1时,压力及其导数曲线均上翘,生产压差增大;注采比大于1时,压力及其导数曲线均下掉,生产压差减小。对于关井压力恢复情况,启动压力梯度和注采比越大,井底压力恢复得就越高。在低渗透油藏的测试资料分析中,考虑启动压力梯度和注采比的影响是十分必要的。

The mathematical model with threshold pressure gradient and injection-production ratio is constructed.The model is solved by numerical method.The characteristics of transient pressure curves are plotted and analyzed.The study shows that threshold pressure gradient and injection-production ratio have remarkable effect on characteristics of transient pressure.For the case of pressure dropdown test,pressure and its derivate type curves show the trend of rising when the injection-production ratio is less than 1.0,and the pressure drop of production also get increased;vice versa,pressure and its derivate type curves show the trend of declining when the injection-production ratio is higher than 1.0,and the pressure drop of production get reduced.For the case of pressure buildup test,the pressure buildup more highly as the threshold pressure gradient and injection-production ratio gets higher.Therefore,it is necessary to consider these factors in well test analysis.

10.3969/j.issn.1000-7393.2003.06.018