断裂在纯净砂岩中的变形机制及断裂带内部结构  

Fault Deformation Mechanisms and Internal Structure Characteristics of Fault Zone in Pure Sandstone

作　　者：付晓飞[1,2] 肖建华[1,2] 孟令东[1,2] 

机构地区：[1]东北石油大学CNPC断裂控藏实验室,黑龙江大庆163318 [2]非常规油气成藏与开发省部共建国家重点实验室培育基地,黑龙江大庆163318

出　　处：《吉林大学学报（地球科学版）》2014年第1期25-37,共13页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(41072163);黑龙江省普通高等学校新世纪人才支持计划项目(1251-NCET-015)

摘　　要：以纯净砂岩为对象，考虑了影响断裂变形的主要因素，包括成岩阶段、孔隙度、温度和围压，系统剖析了不同性质砂岩的断裂变形机制、微构造特征及形成断裂带的内部结构，对研究砂岩内断裂封闭性具有重要的指导意义。研究表明：纯净的砂岩在未固结半固结成岩阶段发生断裂，变形机制为颗粒边界摩擦滑动，导致颗粒旋转和滚动，即为颗粒流，形成的微构造为解聚带，孔渗性同母岩比没有明显降低，断裂带尽管具有断层核和破碎带二分结构，但渗透率比母岩高，为流体垂向运移的通道；在固结成岩阶段（孔隙度大于15％）发生断裂，变形机制为碎裂作用，颗粒边界摩擦滑动导致颗粒旋转，即为碎裂流，形成的微构造为碎裂带，渗透率同母岩比一般降低1～3个数量级，形成侧向有一定封闭能力、垂向渗透的断裂带；固结阶段（孔隙度小于15％）发生断裂，开始由于破裂作用，形成断层角砾岩，伴随着碎裂流发生，形成碎裂岩，因此早期形成高渗透断裂带，后期断层逐渐封闭。固结成岩的砂岩在抬升过程发生断裂，变形机制为破裂作用，形成无内聚力的角砾岩，为高渗透断裂带。在不同成岩阶段发生变形，形成多类型变形构造的叠加，对于一条晚期形成的断层而言，由于不同深度变形机制及微构造类型不同，导致油气选择性充注，碎裂带和压溶胶结碎裂带阻止油气向高孔隙度砂岩中充注，解聚带会成为油气运移的通道，裂缝有利于油气优先充注。因此，高孔隙性砂岩中孔隙度较低的储集层由于碎裂带不发育常常含油气性最好，而低孔隙性砂岩由于裂缝产生含油气性较好。With sandstone as the object of this article , taking into account the main factors influencing the fracture deformation , including the stage of diagenesis ,porosity , temperature and confining pressure ,we analyse systematiclly the fracture deformation mechanism of the different nature＆amp;nbsp;of sandstone ,the micro-structural characteristics and the formation of internal structure of fault zone .It is of great significance on the study of fault sealing in the sandstone .Studies have shown that fracture of pure sandstone occurs in non-consolidated to semi-consolidated of diagenetic stage . Deformation mechanism of grain boundary frictional sliding ,called‘particulate flow ’ ,results in particle rotating and rolling .And the formed micro-structure is Disaggregation band ,without significant decrease in porosity and permeability comparing with parent rock .Though fault zone being consist of fault nuclear and damage zone ,it is the fluid channel for vertical migration with higher permeability than parent rock . The fracture develops in the consolidation of diagenesis stage （porosity is greater than 15% ） which deformation mechanism is cataclasis .The cataclasis flow involves particle rotating and cataclasis between grains .And the formed micro-structure is cataclastic band ,with 1 to 3 orders of magnitude decrease in porosity and permeability comparing with parent rock . And formed fault zone is lateral sealing and vertical penetration .The fracture developed in consolidation stage （porosity less than 15% ） ,due to rupturing in the early stage ,forms fault breccia ,then forms cataclastic rock ,accompanying with the occurrence of cataclastic flow . T hus ,fault zone is high permeability in the early stage and then fault gradually closed .The deformation mechanisms of consolidation sandstone is cataclasis during the uplift process .It forms incoherent breccia and fault zone of a highly permeability . In different diagenetic stages ,it formed overlay of multiple type deformation structures . For a sec

关 键 词：砂岩 变形机制 颗粒流 碎裂流 解聚带 碎裂带 断裂带结构 

分 类 号：P618.13[天文地球—矿床学]