水平井分段多簇压裂裂缝扩展数值模拟  

Numerical simulation of fracture propagation of multi-cluster fracturing in horizontal wells

作　　者：何右安[1,2] 高武彬 路敏[1,2] HE Youan;GAO Wubin;LU Min(Research Institute of Exploration and Development,Petro China Changqing Oilfield Company,Xi an 710018,China;State Key Laboratory of Exploration and Development of Low Permeability Oil and Gas Fields,Xi an 710018,China)

机构地区：[1]长庆油田分公司勘探开发研究院,陕西西安710018 [2]低渗透油气田勘探开发国家工程重点实验室,陕西西安710018

出　　处：《中国矿业》2021年第5期200-206,共7页China Mining Magazine

基　　金：国家重大科技专项“鄂尔多斯盆地致密油开发示范工程”项目资助(编号:2017ZX05069);中石油股份有限公司重大科技专项“长庆油田5000万吨持续高效稳产关键技术研究与应用”项目资助(编号:2016E-05)。

摘　　要：目前,非常规储层复杂裂缝扩展数值模拟的裂缝形态多为二维形态,并且将注入地层中的压裂液视为纯液体,但实际压裂液中有支撑剂的存在,导致模拟结果与现场实际结果存在较大差异,难以直接应用于现场优化设计。因此,本文基于三维位移不连续法,考虑压裂液、支撑剂在井筒和水力裂缝中的流动情况,建立了三维分段多簇压裂数值模型,采用Newton-Raphson法求解数值模型,分析了压裂液排量、黏度、砂比和簇间距等工程因素对多裂缝扩展的影响规律。结果表明,高黏度、高排量的压裂容易形成多条宽而短的裂缝,有利于支撑剂运移形成高导流通道,而低黏度和低排量的压裂会形成多条窄而长的裂缝,影响支撑剂的运移和压裂效果。随着砂比的增加裂缝高度逐渐变大、长度变小,此时裂缝中支撑剂分布浓度增大、远端裂缝缝宽变小,裂缝内流体和支撑剂流动受阻会导致砂堵现象;随着簇间距增大,裂缝间应力阴影效应减小,各裂缝更容易独立扩展,当簇间距减小时,中间裂缝扩展受到抑制且缝宽变小。研究结果可为水平井分段多簇压裂优化设计提供理论指导。At present,the fracture morphology of complex fracture propagation numerical simulation in unconventional reservoirs are mostly two-dimensional,and the fracturing fluid injected into the formation is regarded as pure liquid.However,the existence of proppant in the actual fracturing fluid leads to a great difference between the simulation results and the actual field results,which is difficult to be directly applied to the field optimization design.Therefore,based on the three-dimensional displacement discontinuous method and considering the flow of fracturing fluid and proppant in the wellbore and hydraulic fractures,a three-dimensional multi-cluster fracturing numerical model is established.The numerical model is solved by Newton-Raphson and the fracturing is analyzed.The influence of engineering factors such as fluid displacement,viscosity,sand ratio and cluster spacing on the growth of multiple cracks are studied.The results show that high-viscosity,high-displacement fracturing is easy to form multiple wide and short fractures,which is conducive to proppant migration to form high-diversion channels,while low-viscosity and low-displacement fracturing will form multiple narrow and long cracks affecting the proppant migration and fracturing effect.With the increase of the sand ratio,the fracture height becomes larger and the length becomes smaller.At this time,the distribution concentration of proppant in the fracture increases,and the width of the fracture in the distal fracture becomes smaller.The blocked flow of fluid and proppant in the fracture will cause sand plugging.With the increase of cluster spacing,the stress shadow effect between fractures decreases,and each fracture is more likely to expand independently.When the cluster spacing decreases,the expansion of the middle fracture is inhibited and the fracture is stable,and the seam width becomes smaller.The research results can provide theoretical guidance for the optimal design of multi-cluster fracturing in horizontal wells.

关 键 词：水力压裂 水平井 位移不连续法 数值模拟 

分 类 号：TE3[石油与天然气工程—油气田开发工程] O242[理学—计算数学]