动态裂缝是特低渗透油藏注水开发中出现的新的开发地质属性  

Dynamic fractures are an emerging new development geological attribute in water-flooding development of ultra-low permeability reservoirs

作　　者：王友净[1] 宋新民[1] 田昌炳[1] 石成方[1] 李佳鸿[1] 惠钢[1] 侯建锋[1] 高春宁[2] 王小军[2] 刘萍[2] 

机构地区：[1]中国石油勘探开发研究院 [2]中国石油长庆油田分公司

出　　处：《石油勘探与开发》2015年第2期222-228,共7页Petroleum Exploration and Development

基　　金：中国石油重大科技专项(2011B-1205);中国石油勘探与生产公司专项"特低渗透油藏水驱提高采收率关键技术"

摘　　要：基于特低渗透油田注水动态特征,提出了动态裂缝概念,探讨其成因机理及对油田开发的影响。动态裂缝是指特低渗透油藏在长期注水过程中,由于注水井近井地带憋压,当井底压力超过岩层破裂、延伸压力,岩石破裂产生的新生裂缝,或原始状态下闭合、充填的天然裂缝被激动、复活所产生的有效裂缝通道。动态裂缝受现今地应力场控制,随着注水量的增长和井底压力的升高,不断向油井方向延展,直至与油井压裂缝连通。位于JA油田同一区块内的L76-60、L88-40密闭取心井组分析表明,动态裂缝改变了特低渗透油藏水驱油渗流特征,加剧了储集层的非均质性,导致剖面动用程度降低,平面上剩余油呈连续或不连续条带状分布在裂缝两侧;动态裂缝的产生、激化延伸与注水压力、注采比以及油、水井改造措施等密切相关。基质孔渗条件可以有效形成基质驱油时,应尽可能减弱高压注水和油、水井改造规模,实现基质驱油。Based on the dynamic characteristics of water-flooding in ultra-low permeability oilfields, the concept of dynamic fracture is proposed and its formation mechanism and impacts on oilfield development are discussed. Dynamic fractures refer to the new-generated fracture channels when bottom hole pressure exceeds rock breakdown pressure and propagation pressure, or the effective fracture channels generated when the originally closed or filled natural fractures are reactivated, due to high pressure in near wellbore area of injection well in a long term water injection of the ultra-low permeability reservoir. Dynamic fractures, controlled by the current stress field, constantly extend toward the direction of the oil well with the rise of the injected water volume and bottom hole pressure, until connecting with the oil well hydraulic fractures. The analysis of the sealed coring well groups L76-60 and L88-40 located in the same block in the JA Oilfield, Changqing Oilfield, NW China shows that the dynamic fractures changed the seepage characteristics of water displacing oil in the ultra-low permeability reservoir, greatly aggravated the reservoir heterogeneity, which led to the reduction of profile producing degree and the distribution of remaining oil on both sides of the fractures in continuous or discontinuous belts. The generation and propagation of dynamic fractures are closely related to water injection pressure, injection-production ratio, oil and water well stimulation measures. When the porosity-permeability condition of the matrix allows effective oil displacement, high pressure water injection or oil and water well stimulation measures should be avoided as far as possible.

关 键 词：动态裂缝 特低渗透油藏 开发地质属性 成因机理 注水波及体积 

分 类 号：TE348[石油与天然气工程—油气田开发工程]