Acta Petrolei Sinica ›› 2017, Vol. 38 ›› Issue (3): 286-296.DOI: 10.7623/syxb201703005

• Petroleum Exploration • Previous Articles     Next Articles

Transformation mechanism of fault and its associated microstructures for different kinds of reservoirs

Jia Ru1,2,3, Fu Xiaofei1,2,3, Meng Lingdong1,2,3, Gong Lei1,2,3, Liu Zhida1,2,3   

  1. 1. CNPC Fault Controlling Reservoir Research Laboratory, Northeast Petroleum University, Heilongjiang Daqing 163318, China;
    2. Accumulation and Development of Unconventional Oil and Gas, State Key Laboratory Cultivation Base Jointly-constructed by Heilongjiang Province and the Ministry of Science and Technology, Northeast Petroleum University, Heilongjiang Daqing 163318, China;
    3. College of Earth Science, Northeast Petroleum University, Heilongjiang Daqing 163318, China
  • Received:2016-08-22 Revised:2017-01-10 Online:2017-03-25 Published:2017-04-07

断裂及其伴生微构造对不同类型储层的改造机理

贾茹1,2,3, 付晓飞1,2,3, 孟令东1,2,3, 巩磊1,2,3, 刘志达1,2,3   

  1. 1. 东北石油大学CNPC断裂控藏研究室 黑龙江大庆 163318;
    2. 东北石油大学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;
    3. 东北石油大学地球科学学院 黑龙江大庆 163318
  • 通讯作者: 付晓飞,男,1973年2月生,1996年获大庆石油学院学士学位,2007年获中国石油勘探开发研究院博士学位,现为东北石油大学教授、博士生导师,主要从事断裂变形、封闭性及流体运移方面的研究工作。Email:fuxiaofei2008@sohu.com
  • 作者简介:贾茹,女,1988年3月生,2007年获东北石油大学学士学位,现为东北石油大学博士研究生,主要从事断裂变形及流体运移方面的研究工作。Email:jiaru_dq@163.com
  • 基金资助:

    国家自然科学基金联合基金项目(No.U1562214)、国家自然科学基金项目 (No.41602129,No.41502138)和国家重大科技专项(2016ZX05054-009) 资助。

Abstract:

Fault zone has a typical binary structure, i.e., fault core and fracture zone. Due to certain differences in the physical properties of fault core, fracture zone and parent rock, the faults have significant different manifestations in low-porosity–non-porosity rocks and high-porosity rocks, thus leading to the reverse transformation effects on reservoir physical properties. It was traditionally considered that all reservoirs were deformed by force to form fractures, but actually deformation zones were developed in high-porosity rocks to reduce the physical properties of reservoirs. Most of petroliferous basins in China are continental basins, where reservoirs and caps are generally sand-mud interbedded formations, affected by rock consolidation degree, clay content, physical properties and other factors. There are six structural types of fault zone in sand-mud interbed formations, including disaggregated type, cataclastic type, phyllosilicate-framework fault rock type, fault-breccia type, fault-gouge type and shale-smearing type. The Putaohua high-porosity reservoir in Daqing Placanticline of Songliao Basin and the tight volcanic reservoirs in Yingcheng Formation of Xujiaweizi Fault Depression are taken as examples to systematically analyze the types of fault associated microstructures and its reverse transformation effects on reservoirs. Through observing the cores from Well X7-20-S632 drilled in the fault zone of Xingshugang Anticline, Daqing Placanticline, it is found that a large number of deformation zones are developed around the fault sliding plane. With an increasing distance from the fault sliding plane, the density of deformation belt is gradually decreased. Research on microstructure characteristics indicates that the deformation zone has lower porosity and permeability than parent rocks. The Yingcheng Formation in Xujiaweizi Fault Depression consists of tight volcanic reservoirs; these reservoirs were deformed to form fractures. The density of associated fractures on both sides of Xuzhong and Xudong Fault is gradually reduced with the increasing distance from faults. Statistics show that the volcanic reservoirs adjacent to the faults had significantly higher porosity than those far away from the faults. According to the distribution law of fault core and fracture zone, an idealized geology model was established to simulate the influence from the development of fault associated microstructures on fluid flow efficiency. The results show that when the deformation zones or fractures in reservoirs are developed to a certain extent, obvious inhibition or transport effects will be made on fluid flow. Therefore, the fault and its associated microstructures have reverse transformation effects on reservoir physical properties.

Key words: fault zone, sand-mud interbedded formation, deformation belt, fracture, fluid flow efficiency

摘要:

断裂带具有典型的二元结构,即断层核和破碎带。由于断层核、破碎带与母岩间的物性具有一定差异,断裂在低-非孔隙性岩石和高孔隙性岩石中的表现形式明显不同,使其对储层物性具有相反的改造作用。传统观点认为,储层受力变形均会形成裂缝,而实际上高孔隙性储层中发育的是变形带,会降低储层的物性。中国含油气盆地多为陆相盆地,储盖层普遍为砂泥互层地层,受岩石固结程度、泥质含量、物性等因素影响,断裂在砂泥互层地层中具有6种断裂带结构类型:解聚型断裂带、碎裂型断裂带、层状硅酸盐-框架断层岩型断裂带、断层角砾岩型断裂带、断层泥型断裂带和涂抹型断裂带。以松辽盆地大庆长垣葡萄花油层高孔隙性储层和徐家围子断陷营城组致密火山岩储层为例,系统剖析断裂伴生微构造类型及其对储层反向改造作用。通过对大庆长垣杏树岗背斜带过断裂带钻探X7-20-S632井的岩心观察,发现断裂滑动面周围伴生大量变形带,且随着距滑动面距离增加,变形带密度越来越小。微观结构特征研究表明,变形带具有比母岩更低的孔渗性。徐家围子断陷营城组为致密的火山岩储层,储层变形后形成裂缝,徐中、徐东断裂两侧伴生裂缝密度随着距断裂距离增加逐渐减小,统计表明,断裂附近火山岩储层较远离断裂储层的孔隙度明显提高。依据断层核、破碎带的分布规律,建立了理想的地质模型,模拟了断裂伴生微构造的发育对流体流动效率的影响。结果表明,当储层中的变形带或裂缝发育达到一定程度时,对流体流动具有明显的阻滞或输导作用,因此,断裂及伴生微构造对储层物性具有反向改造作用。

关键词: 断裂带, 砂泥互层, 变形带, 裂缝, 流体流动效率

CLC Number: