高孔隙性岩石中变形带成因机制及对流体流动的影响

发布时间：2018-03-16 00:25

本文选题：高孔隙性岩石　切入点：变形带　出处：《东北石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：低-非孔隙性岩石和高孔隙性岩石对受力变形的响应特征不同。低-非孔隙性岩石变形主要发生破裂作用,形成的具有明显不连续性的构造,如裂缝、节理等。高孔隙性岩石变形发生颗粒流作用、碎裂作用及混合和涂抹作用,形成的亚地震构造类型为变形带。变形带是指发育在高孔隙性的岩石中,在局部压实作用、膨胀作用和(或)剪切作用下,由于颗粒滑动、旋转和破碎形成的带状构造,具有低孔隙度、低渗透率的特征。在不同应力状态下,变形带的类型、特征及成因存在差异。为了明确变形带的成因机制及其对流体流动的影响,本文以柴达木盆地油砂山构造带野外露头区和冀中坳陷束鹿凹陷西曹固构造带钻井取心岩心中发育的变形带为重点研究对象,通过分析其宏观、微观及物性特征,明确变形带类型。利用应力状态分析和q-p图解定量分析变形带的成因机制。采取数值模型的方法探讨变形带对流体流动的影响。研究结果表明:高孔隙性岩石在应力的作用下,由于孔隙空间的存在,导致颗粒发生变形:(1)由于颗粒的重排(颗粒流作用)导致压实、膨胀或等体积的应变;(2)颗粒接触点处高应力作用下发生颗粒破裂、破碎(碎裂作用),促进剪切作用。根据其运动学特征,可将变形带分为膨胀带、膨胀型剪切带、剪切带、压实型剪切带、剪切增强型压实带和压实带。当有效平均应力较小时,在拉应力的作用下形成膨胀型变形带,随着平均应力的增大,由于压应力的作用,形成压实型变形带。若存在差应力,发生剪切作用,形成剪切型变形带。在差应力和有效平均应力的共同作用下,形成膨胀型剪切带、压实型剪切带或剪切增强型压实带。油砂山构造带中的变形带为碎裂带,形成于挤压环境中,由于差应力较小,有效平均应力较大,发育成分散式的压实型剪切带,孔隙度同母岩相比发生明显的降低,渗透率降低1-2个数量级,对流体流动没有明显的影响。西曹固构造带的变形带也为碎裂带,但形成于拉张环境,由于差应力较大,有效平均应力相对小,发育为集中式的剪切带,孔隙度发生了明显的降低,渗透率降低2-3个数量级,对流体的流动起到明显的阻碍作用。
[Abstract]:The response characteristics of low-porosity rock and high-porosity rock to stress deformation are different. The deformation of low-porosity rock is mainly caused by fracture, resulting in a structure with obvious discontinuity, such as fracture. The deformation of high porosity rock is characterized by grain flow, fragmentation, mixing and smearing, and the subseismic tectonic type is deformation zone. The deformation zone refers to the local compaction of high porosity rock. Under dilation and / or shearing, the zonal structure formed by particle sliding, rotation and fragmentation has the characteristics of low porosity and low permeability. In order to clarify the genetic mechanism of the deformation zone and its influence on fluid flow, In this paper, the deformation zone developed in the core of drilling coring rock in the west Caogu structural belt of the Shoulu depression and the outcrop area of the Yeshaishan structural belt in the Qaidam Basin are taken as the main research objects. The macroscopic, microcosmic and physical properties of the deformed zone are analyzed through the analysis of its macroscopic, microscopic and physical properties. By means of stress state analysis and q-p diagram, the formation mechanism of deformation zone is analyzed. The influence of deformation zone on fluid flow is studied by numerical model. The results show that the high porosity rock is affected by stress. Due to the existence of the pore space, the particle is deformed. (1) due to the rearrangement of the particle (particle flow action) resulting in compaction, expansion or strain of equal volume, the particle breaks under the action of high stress at the contact point of the particle. According to its kinematic characteristics, the deformed zone can be divided into expansion zone, expansive shear zone, shear zone, compacted shear zone, shear-enhanced compaction zone and compaction zone. When the effective average stress is small, Under the action of tensile stress, an expansive deformation zone is formed. With the increase of average stress, a compacted deformation zone is formed due to the effect of compressive stress. If there is a differential stress, shear action occurs. Forming shear-type deformation zone. Under the action of differential stress and effective average stress, the expansive shear zone, compacted shear zone or shear-enhanced compaction zone are formed. As the difference stress is small and the effective average stress is large, the distributed compacted shear zone is developed, the porosity is obviously reduced compared with the parent rock, and the permeability is reduced by 1-2 orders of magnitude. There is no obvious effect on fluid flow. The deformation zone of the Western Caogu tectonic belt is also a fracture zone, but formed in the tensile environment. Due to the large differential stress, the effective average stress is relatively small and developed into a concentrated shear zone. The porosity is obviously reduced and the permeability is reduced by 2-3 orders of magnitude, which hinders the flow of fluid obviously.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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