压裂裂缝间距优化设计  

Optimization of Fracture Spacing for Hydraulic Fracturing

作　　者：张矿生 唐梅荣 陈文斌 徐创朝 杨典森[2] 周再乐 ZHANG Kuang-sheng;TANG Mei-rong;CHEN Wen-bin;XU Chuang-chao;YANG Dian-sen;ZHOU Zai-le(Institute of Oil and Gas Technology Research,Changqing Oilfield,CNPC,Xi'an 710021,China;Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,Wuhan 430071,China)

机构地区：[1]中国石油长庆油田油气工艺研究院,西安710021 [2]中国科学院武汉岩土力学研究所,武汉430071

出　　处：《科学技术与工程》2021年第4期1367-1374,共8页Science Technology and Engineering

基　　金：国家自然科学基金(2017ZX05069,2016ZX05050)。

摘　　要：在多裂缝压裂设计中,如何合理设置水力裂缝间距、最大限度形成缝网是储层改造过程中的关键问题。水力裂缝的形成会在裂缝周围产生诱导应力使得储层的应力差得到改善。根据单条水力裂缝诱导应力的解析解提出一种简便的裂缝间距设计方法,从而能最大限度促进复杂缝网形成。以平面二维水力裂缝的线弹性应力场为基础,采用应力叠加的方式来计算,通过调整水力裂缝间距将储层应力差缩小至能够形成缝网的范围以内,构建最佳的射孔簇间距。当单条水力裂缝净压力足以使原有水平主应力方向发生反转时,应力反转区的宽度即为最佳裂缝间距;当单条水力裂缝不足以使水平应力发生反转时,可通过两条裂缝间诱导应力的叠加协同效应,使得裂缝之间地层的水平地应力差降低至缝网形成的门限应力差以内,使中间新插入的裂缝能够形成网状裂缝,据此来进行缝间距优化;当进行多级压裂时,所有水力裂缝所产生的诱导应力可以依次相互叠加获得,然后进行裂缝间距优化;通过研究,提出储层改造的最佳裂缝距的计算方法,可为水平井多级压裂工艺参数的优化设计提供参考。In the design of multi-fracture fracturing,reasonably setting the hydraulic fracture spacing and maximum formation of fracture network is the key to reservoir reconstruction.The formation of hydraulic fracture could produce induced stress around the fracture,which can improve the stress difference of reservoir.According to the analysis of the induced stress of a single hydraulic fracture,a simple design method of fracture spacing was proposed,with which the formation of complex fracture network can be promoted.Based on the linear elastic stress field of planar two-dimensional hydraulic fractures,the stress difference of reservoir can be reduced to the range of fracture network by adjusting the spacing of hydraulic fractures,and the optimal perforation cluster spacing be constructed.Results show that if the net pressure of a single hydraulic fracture was sufficient to reverse the original horizontal principal stress direction,the width of stress reversal zone was the optimal fracture spacing,or if it was insufficient,the superimposed synergy effect of induced stress between the two fractures could be used to reduce the difference in horizontal geostress among fractures into the threshold stress difference formed by the fracture network.Meanwhile,the newly inserted fractures in the middle could form network fractures,and the fracture spacing could be optimized accordingly.When multi-stage fracturing was carried out,the induced stress generated by all hydraulic fractures could be obtained by sequential superimposition,and then the fracture spacing was optimized.Therefore,the new calculation method provided a reference for the optimization design of multi-stage fracturing process parameters of horizontal wells.

关 键 词：水平井 多级压裂 诱导应力 缝间干扰 缝间距优化 

分 类 号：TE353.4[石油与天然气工程—油气田开发工程]