井底产量受压缩系数影响的弹性不稳定渗流特征

Unsteady porous flow mechanism affected by productivity compressibility of the bottom of well

弹性不稳定渗流的动力来源主要是岩石及液体的弹性能量,当井底定产量生产时,往往忽略井底产量由于液体压缩系数而产生的弹性变化,致使动态预测时井底压力计算偏小。考虑井底产量受压缩系数影响,对弹性不稳定渗流时的井底定产量进行"变产量"处理,再结合压降叠加原理,得到了井底压力不同的预测结果。从原始地层压力、渗透率、原油黏度、储层厚度、产量、生产时间6个方面分析了井底产量受压缩系数影响对井底压力预测结果的敏感程度,经验证,考虑压缩系数与不考虑压缩系数的井底压力偏差最高可达10%,对实际生产动态分析会产生一定程度的影响。

The main power driving the oil flowing to the bottom of well are the rock and liquid elastic energy. Generally, invariable productivity of well is defined in elastic reservoir, but the productivity actually is variable because of the liquid compressibility. Therefore, the pressure of the bottom of well forecasted is lower in the production. Considering the effecting of the liquid compressibility for the ＂invariable productivity, the invariable productivity is altered based on the instantaneous well pressure. So the different well pressure is calculated by using the rule of superposition of pressure drop. Then 6 aspects are analyzed for the difference, and they are initial reservoir pressure, permeability, oil viscosity, thickness, productivity and production time. The result is that the difference affects the production plan of oil field in a certain extent because sometimes it even gets 10% value.