页岩水平井体积压裂设计的一种新方法

页岩水平井常采用体积压裂技术获得产能,压裂形成的缝网体积、渗透率是影响压裂效果的关键因素。目前页岩体积压裂设计借用产能预测模型优化缝网参数,此模型较复杂,不便于现场应用。根据等效渗流原理,将页岩储层压裂后形成的缝网系统等效为一个高渗透带,建立了体积压裂缝网参数与施工规模关系模型,提出了体积压裂设计的3个步骤:体积压裂可行性研究、数值模拟优化缝网参数和施工参数优化。根据QY2页岩油水平井特征,进行了体积压裂设计和现场实施。结果表明:压裂形成的高渗透带对产能的贡献最大;高渗透带数量、体积和渗透率增加,压裂后的累积产量和采出程度逐渐增加,存在最优的高渗透带参数。现场应用表明这种设计方法方便实用,可以推广。

A Novel Design Method for Stimulated Reservoir Volume Fracturing in Shale Horizontal Wells

The technology of the stimulated reservoir volume(SRV) fracturing are often used in shale horizontal wells to obtain deliverability.The fracture network volume and permeability are critical to postfracture response.The design for SRV employs productivity prediction model which is complex and inconvenient in application to optimize fracture network parameters at present.The relation model between the fracture network parameters and hydraulic fracturing treatment sizes is established with the fracture network equivalent to a high permeable zone by using the principle of seepage rate equal effects.The method and steps for SRV in shale horizontal wells are put forward also,including feasibility study about SRV in shale reservoir,optimizing fracture network parameters in numerical simulation and treatment sizes.According to the characteristics of QY2 shale oil horizontal wells,the new design method is implemented.The result shows that the high permeable zones have the biggest contribution to flow potential in shale wells,and the cumulative production and degree of reserve recovery increase slowly with the augment of clustering number,volume,permeability of the high permeable zones.There exsit the optimal high permeable zone's parameters.Field application shows that the design method is convenient and can be generalized to other shale horizontal well fracturing design.