高效预测气藏产能的线化双重介质模型

Efficient linear dual-medium model for production prediction

压裂后储层产能预测是评估压裂效果和评价开发经济性的基础.提出合理、高效、高精度产能预测模型对非常规气藏开采而言意义重大.借鉴水力压裂过程中微地震监测结果,考虑缝网空间分布特征,提出了基于线化缝网模型假设的产能预测理论.在双重介质假设下建立了渗流模型方程,借助数值计算方法,自主开发了渗流模拟程序和产能预测程序,并搭建了软件模拟平台.结果表明,与传统三线性模型相比,本文提出的产能预测模型更优,具体体现在:理论基础更加合理,所基于的线化缝网假设更加符合微地震监测结果;产能预测效率更高,是传统方法所需计算时间的千分之一甚至万分之一,预测效率大幅提升;产能预测精度与现有模型相当或更高.提出的模型与方法将有助于压裂后煤层气和页岩气等气藏产能的预测评估.

Production prediction(PP)is the basis for assessing the fracturing effect and exploitation value of a reservoir.A reasonable,efficient,and accurate PP model is vital for exploiting unconventional gas reservoirs.Referring to microseism monitoring results,a new PP model was proposed based on the linear fracture-network assumption,which considers the distribution properties of fractures.The flow model equations were developed based on the dual-medium assumption.Then,the simulation and prediction program were developed by numerical methods,and a software platform was built.The results show that the proposed PP model outperforms the traditional tri-linear model.The main advantages are as follows:the theoretical basis of the proposed model is more reasonable,which is more consistent with the microseism monitoring results;the proposed PP model is more efficient,with a prediction time that is less than onethousandth or even one ten-thousandth of that of the traditional model;and the proposed model has similar or higher accuracy than the traditional model.The proposed model can provide valuable guidance for predicting and assessing gas reservoir production,including shale and coalbed gas.