通过后期构造成岩作用研究高渗透碳酸盐岩变形带的成因机制

Due to the complicated mechanism and roles for fluid, deformation band comes into notice in the geotechnical engineering and petroleum geology research. Except for the focus on the low permeability deformation band in sandstone, the origin of high permeability deformation band and its late remodificaion mechanism are unclear so far. On the basis of the methods of structural diagenesis, this project intends to study the mechanism of high permeability deformation band in carbonate by the reconstruction effect of structure-diagenesis after the deformation band initiation, which taking the lower Palaeozoic of Tarim basin as an example. First, it is need to identify and classify different types and characteristics of the deformation bands of high permeability by outcrop combined with borehole data. Then with the petrology and geochemitry date, having the single factor multi-factors analysis of structrual diagenesis mainly on dissolution and fracturing roles, and their interaction to study the effect and mode of structual diagenesis to high permeability carbonate deformation band. In addition, studying the internal particles redeformation and fracture development pattern by the rock mechanics experiments in the condition of different stress and characteristics of deformation bands. So it is key to study the comprehensive reconstruction of structral diagenesis to carbonate deformation band, and clarify special mechanism of high permeability in carbonate deformation band. It is of great significance to reveal the evolution of late structural diagenesis to deformation band, and provide theorey and method for the carbonate reservoir heterogeneity research.

变形带复杂多样，其成因与作用在岩土工程与油气地质研究中引起关注。目前研究重点是碎屑岩中低渗透变形带，高渗透变形带形成机理及其后期改造作用尚不清楚。本项目拟以塔里木盆地下古生界为例，通过构造成岩作用的研究方法与思路，从变形带形成后构造-成岩改造作用的角度研究碳酸盐岩中高渗透变形带成因机制。在识别高渗透变形带、明确分类特征的基础上，通过高渗透变形带与围岩的岩矿、流-岩作用对比分析，开展以溶蚀、裂缝作用为主的构造-成岩作用单因素及多因素综合分析，剖析碳酸盐岩变形带产生高渗透的建设性构造-成岩作用方式及其作用模式。设计不同应力、不同特征变形带的岩石力学实验，对比解析变形带内部颗粒再变形方式及其破裂发育过程。通过综合探讨碳酸盐岩变形带的构造成岩改造作用，阐明高渗透碳酸盐岩变形带的特殊机理。该研究对揭示变形带后期构造成岩作用改造机制具有重要意义，为碳酸盐岩储层非均质性研究提供理论基础与评价思路。

高渗透碳酸盐岩断裂带的成因机理复杂多样，与油气关系密切。本项目通过露头与井下构造建模、模拟实验与测试分析，研究酸盐岩变形带的分类特征及其对储层的影响作用、断层破碎带的构造成岩作用、高渗透碳酸盐岩破碎带成因及其演化。结果表明：（1）碳酸盐岩中变形带发育程度远低于碎屑岩；目前实验还未能实现重现碳酸盐岩变形带的形成过程；碳酸盐岩变形带对储层渗透率影响不大；（2）实验揭示了走滑带贯穿连通过程；走滑破碎带的宽度与位移具有较好的幂指数关系，压扭叠覆区长度与宽度呈正相关关系；雁列断裂的长度增长速度呈约2 倍于深度增长速度线性增长，而与主位移带夹角随深度呈二次函数变小；（3）判识塔里木盆地碳酸盐岩断裂带多期构造-成岩作用，明确长期裂缝的开启的控制因素，提出断层破碎带多期胶结形成的硬化作用形成的外向生长模式；揭示碳酸盐岩断层破碎带构造成岩演化的差异；（4）发现长度-位移2阶段快速生长模式，叠覆区的生长出现4阶段阶梯状生长模式，揭示了断裂连接生长的机制；提出"X" 共轭二面角生长的主要机制；提出断层破碎带宽度与构造高差的定量预测模型；提出井下断层破碎带宽度判识的组合地质方法，提出利用碳酸盐岩断层破碎带地震刻画的方法；探讨碳酸盐岩断层破碎带宽度存在异常的高值生长的机制。本研究为碳酸盐岩断层破碎带的成因机制及其预测提供了新的思路与方法，以及可供借鉴的成果认识。断层破碎带的定量解析方法与研究成果在油气、涵洞桥梁工程等方面具有广泛的应用前景，并在塔里木盆地油气勘探与开发中得到应用。