致密低渗气藏压裂水平井数值模拟

Numerical simulation of fractured horizontal well in tight low-permeability gas reservoir

在压裂水平井的数值模拟过程中,应重点考虑储层的应力敏感和压裂裂缝闭合的影响。首先建立某致密低渗气藏的一口压裂水平井概念地质模型,对气井的开发动态进行历史拟合,通过单井生产历史拟合,确定了储层相关参数,为开发动态预测提供依据。利用该模型,研究了考虑不同应力敏感、不同采气速度情况下,压裂水平井的开发动态,得到相关数据。认为应力敏感对开发动态指标影响很大,需要在开发指标上进行调整来尽量减小其影响。对于存在应力敏感的低渗气藏,气井的初期配产不能太大,可根据产量指标与经济效益结合得到最优采速。另外,致密低渗气藏在进行压裂水平井数值模拟过程中,应考虑裂缝闭合造成的导流能力下降,可减小由此引起的开发动态预测的偏差。

During the process of numerical simulation of fractured horizontal well,the impact of reservoir stress sensitivity and induced fracture closure should be primarily focused.Based on the conceptual geological model of one fractured horizontal well in some tight gas reservoir,established in early stage,the history matching of development behavior of gas well was conducted.According to production history matching of individual well,relevant reservoir parameters were determined,which helps to predict the development behavior.The development behavior of fractured horizontal well under circumstances of varying stress sensitivities and gas recovery rates was studied and subsequent data was obtained by using this model.It is believed that stress sensitivity greatly influences develop-ment behavior indexes and it is necessary to modify the development index to minimize the impact.For those low-permeability gas reservoirs with stress sensitivity,the initial proration of gas well should be controlled.In other word,the optimum recovery rate should refer to production index and economic benefit.Moreover,during the process of numerical simulation of fractured horizontal well,flow conductivity decline caused by fracture closure should be taken into consideration,which can decrease the prediction error of develop-ment behavior due to such move.