考虑启动压力梯度的致密气藏压裂井产能分析

Production Analysis of Hydraulic Wells in Tight Gas Reservoir Considering of Start-up Pressure Gradient

通过室内实验和数值模拟方法,探讨致密砂岩气藏启动压裂梯度的现象及其对产能的影响。对影响产能的多参数进行敏感性分析和优化。实验测试表明,DLK致密砂岩气藏存在动压力梯度,储层渗透率增加,启动压力梯度减小,二者呈指数关系变化,并绘制形成了启动压力梯度和渗透率的关系图版。建立了考虑启动压力梯度的两相三维渗流数学模型。通过产量拟合计算表明,储层的渗透率、裂缝长度、生产压差是影响压后效果的关键因素。启动压力梯度虽然存在但是对产能的影响较小。

The start-up pressure gradient and relation of multi parameters such as fracture parameters and formation parameters versus gas production had been experimentally and numerically investigated. The start-up pressure gradient in DLK tight gas reservoir decreases with increasing permeability, the relation of them is approximately shows the exponent function relation. Three dimensional, two phase flow model and considering of start-up pressure gradient are established. Based on the well productivity match, the results show that permeability, fracture length, and production pressure difference are the key influence factors on gas rate, and the start-up pressure gradient effects upon the productivity is less.