低渗透非均质气藏压裂水平井产量预测研究

STUDY OF HORIZONTAL WELL PRODUCTION IN NON-HOMOGENEOUS LOW PERMEABILITY GAS RESERVOIR AFTER FRACTURING

致密储层普遍存在非均质性以及气体在运移时存在启动压力梯度。为了准确致密气藏压裂水平井的产量综合应用当量井径、等值渗流阻力等原理,建立了考虑启动压力梯度、储层平面非均质、裂缝干扰、储层与裂缝相耦合的气藏压裂水平井非稳态产量计算模型。利用四川盆地某致密气藏水平井的资料进行了模拟结果表明在其它条件相同的情况下,启动压力梯度使压裂水平井的生产效果变差,将非均质储层处理成均质储层会导致产量明显偏高。

On the basis of previous studies,using Equivalent Well Model and Equivalent Percolation Resistance Method and considering the anisotropy of matrix permeability and start-up pressure gradient and mutual interference between the cracks,this paper provides the steady-state productivity formulation for horizontal wells fractured in low permeability gas reservoir. Then it compares the productivities between finite flow cracks and infinite ones,,between homogeneous gas reservoirs and heterogeneous ones,between when there is start-up pressure gradient in the matrix and when there is not. And several important factors affecting the horizontal well productivity after fracturing. The results show that the effects of the resistance to flow in cracks,heterogeneity in matrix and start-up pressure gradient could not be ignored,they will decide fractures' number,distribution and flow conductivity.