页岩水化作用对支撑剂嵌入影响实验研究  

Experimental Study on the Influence of Shale Hydration on Proppant Embedment

作　　者：潘林华 王海波[1] 贺甲元[1] 田永敏[2] 李小龙 PAN Lin-hua;WANG Hai-bo;HE Jia-yuan;TIAN Yong-min;LI Xiao-long(Exploration Production Research Institute, SINOPEC, Beijing 100089, China;Zhongyuan Oilfield Company, SINOPEC, Puyang 457000, China)

机构地区：[1]中国石油化工股份有限公司石油勘探开发研究院,北京100089 [2]中国石油化工股份有限公司中原油田分公司,濮阳457000

出　　处：《科学技术与工程》2022年第13期5228-5235,共8页Science Technology and Engineering

基　　金：中国博士后科学基金(2019M660935)。

摘　　要：页岩压裂改造过程中大量压裂液进入储层后滞留于孔隙或微裂隙中,滞留的流体与页岩发生复杂的物理-化学作用,会改变储层物性和力学性能,加剧压裂裂缝的支撑剂嵌入程度,从而影响压裂裂缝的导流能力。采用页岩自渗吸测试与支撑剂嵌入实验测试,明确了页岩自渗吸量变化特征以及吸水软化对支撑剂嵌入程度的影响。通过实验研究发现:页岩储层的自渗吸量与黏土矿物含量呈正相关,黏土矿物含量越高,单位体积页岩自渗吸量越大。滑溜水中的助排剂和防水锁剂能降低页岩与压裂液的表界面张力与毛细管力,导致页岩自渗吸量降低。页岩弹性模量越小,相同闭合应力条件支撑剂嵌入深度越大。页岩吸水导致弹性模量和强度降低,支撑剂嵌入深度大幅度提升。支撑剂嵌入深度与闭合压力线性相关,吸水后页岩的支撑剂嵌入深度与闭合应力关系的斜率大幅度提升。地应力对支撑剂嵌入的影响作用明显,围压增加,支撑剂嵌入深度大幅度降低,以期为页岩压裂效果评价和压后产能评估提供参考和理论支撑。During the shale fracturing,large amount of fracturing fluid entered into reservoir and stayed on the porosity and micro-fractures.The physical properties and mechanical properties of the shale reservoir were changed and the proppant embedded degree was exacerbated because of complex physical and chemical interactions between the trapped fluid and shale mineral composition.The increase of proppant embedment would lead to a significant reduction in the propped fracture conductivity.A series of experiments such as spontaneous imbibition experiments and proppant embedment experiments were conducted.The characteristics of the change in water self-absorption,the effect of water self-absorption softening on proppant embedment magnitude were cleared.The results of experiments are shown as follow.Shale clay minerals have a positive correlation with the magnitude of water self-absorption.The greater the clay mineral content,the greater the water absorption per unit volume of shale.The cleanup additive and water lock prevention agent in the slick water can reduce the surface interfacial tension and capillary force between shale and fracturing fluid,resulting in a decrease in the water absorption per unit volume.The proppant embedment increases at the same closing stress with the elastic modulus decrease.The water absorption and hydration would cause the elastic modulus and strength decrease,and the amount of proppant embedment is greatly increases.The proppant embedment magnitude is linearly related to the closing pressure,and the linear equation slope is greatly increased after water absorption.Geo-stress has a significant effect on proppant embedding,the confining pressure increases,and the amount of proppant embedding is greatly reduced.The research results can provide reference and theoretical support for the evaluation of shale fracturing effect and productivity evaluation after hydraulic fracture.

关 键 词：页岩 水力压裂 自渗吸 水化 支撑剂嵌入 

分 类 号：TE357[石油与天然气工程—油气田开发工程]