泥岩涂抹形成的地质条件及有效封闭机理

The main purpose of this paper is to systematic research effects of the formation and development of shale smearing such as rock phase, buried uplift environment, lithological types ( shale content), thickness, throw( deformation rate and fault types ), deformation mechanism, smearing material, the strength of surrounding rock and the style of faults reactivity. While we need to find out the key geological factors which control of shale smearing formation and evolution at different stages and different buried into rock uplift environment, and put forward to judge the developmental quantitative standard of shale smear. Also critical parameters of the continuity of shale smea and evaluation of the vertical sealing of faults should be determined. For sand mud interbed, multiple activities of faults will lead to early continuous shale smear damage forming of Mixture of sand and mud in the fault zone. Through the measured rock clay content and multi parameter calculation results, we can preferably or proposed fault argillaceous content calculation parameters. At the same time, we will analysis of the relationship of shale content in fault zone, fault support pressure and closed maximum hydrocarbon column height, and establish the quantitative evaluation method of the lateral seal of faults.

本文以海拉尔盆地和松辽盆地周边露头及典型区块为对象，以物理模拟实验为手段，通过对比泥岩涂抹发育和不发育的断裂，系统研究成岩阶段、埋藏抬升环境、岩性（泥质含量）、厚度、断距、变形机制（变形速率和断层性质）、涂抹物质与围岩的强度差异、断裂再活动方式对泥岩涂抹形成演化的影响，确定在不同成岩阶段和不同埋藏抬升环境下控制泥岩涂抹形成和演化的关键地质因素，提出判断泥岩涂抹是否发育的定量标准，厘定泥岩涂抹保持连续性临界的参数值及断层垂向封闭性判别方法，分析泥岩涂抹连续性对油气保存的影响。对于砂-泥互层地层而言，断裂多期活动将导致早期连续泥岩涂抹的破坏，形成砂-泥混合型断裂带填充物，通过实测围岩泥质含量与多参数计算结果的对比，便可以优选或提出断裂带泥质含量计算参数。同时，分析断裂带中泥质含量、断层支撑压力差与封闭最大烃柱高度之间的定量关系，建立断层侧向封闭性定量评价方法。

不同埋深及成岩条件下，断裂错断砂泥互层地层时变形机制不同，形成的断裂带内部结构也不同，封闭机理也不同。本文以不同埋深、不同成岩阶段的涂抹型断裂带为重点解剖对象，以野外露头、物理模拟实验、数值模拟为手段，明确了涂抹型断裂带形成的地质条件及封闭机理。确定了相对能干性差异是断层分段生长的必要条件，明确了定性以及定量判别相对能干性差异的方法，分别为断裂作用的宏观、微观变形机制及特征，三轴压缩物理参数测试，回弹仪测试回弹值，破坏前应变量测试。清楚了断层分段生长的三种几何排列方式分别为：拉张型叠覆区、挤压型弯曲带、中立型叠覆区。证实了拉张型叠覆区的断层分段生长方式是泥岩涂抹发育以及连续性保持的有利条件。以野外露头及物理模拟实验结合国内外大量文献调研，重点研究不同固结程度的涂抹型断裂带内部结构。在浅埋未固结的软沉积物中，砂泥岩地层发生能干性反转，发生断裂作用时形成砂岩涂抹型剪切带；随着埋深以及成岩程度的增加，泥岩相对能干性逐渐降低，当断裂错断地层时，逐渐由砂岩涂抹向泥岩涂抹型断裂带演化，中间经历砂泥岩层共同贡献断裂带的混合涂抹阶段。本文在分析不同变形机制的基础上，探索不同成岩阶段涂抹型断裂带内部结构及涂抹型断裂带连续性的定量判别方法，有效指导油气勘探。