碳酸盐岩张性断层断裂带结构及水—岩相互作用特征

发布时间：2018-06-27 22:40

本文选题：碳酸盐岩 + 张性断层　；参考：《中国石油大学(华东)》2015年硕士论文

【摘要】：断裂是野外广泛存在的一种构造样式,其内部结构特征及其对油气运聚控制作用受到了广泛关注。碳酸盐岩是野外常见的岩石类型之一,野外露头表明碳酸盐岩内发育的张性断层存在巨大的差异,造成这种差异的影响因素有哪些,断裂内部的流体活动及由此造成的水-岩相互作用特征如何。针对以上问题,本文在野外大量断层观察描述的基础上,对碳酸盐岩内发育的张性断层的断裂带结构及其影响因素进行了分析,结合断裂带样品的分析测试和模拟实验,探讨了碳酸盐岩断裂带内部水-岩相互作用特征。本文对山东新泰、沂水等地碳酸盐岩内出露的60余条正断层进行考察,对26条断裂带结构清楚的张性正断层进行了详细的描述,从平面和剖面的角度直观的分析了断裂带的宏观结构特征,发现碳酸盐岩张性断层断裂带内部结构具有典型的二元特征:断层核和破碎带,但不同断层的断裂带结构存在差异,造成这种差异的主要原因有断距、单层岩层厚度以及岩石的胶结程度和埋深等。断距由小到大,断层核由不发育到不连续发育到连续发育,断层核宽度和断距之间存在1:10~1:100的关系,断裂带宽度与断距之间存在10:1~100:1的关系。岩层厚度小于断距的情况下,裂缝发育;岩层厚度大于断距时,裂缝不发育;在同一断裂中,岩层厚度越小,裂缝发育越密集且裂缝发育带宽度越大,岩层厚度越大,裂缝发育越少且裂缝发育带宽度越小。通过对各结构单元样品的光学显微镜下分析,结合资料调研,探讨了断裂带内部不同结构单元微观特征及物性特征,为断裂带的封堵和连通提供理论基础。本文对断裂带内部充填的方解石脉体中发育的流体包裹体进行了冰点测试及均一温度测试,对岩石薄片进行了阴极发光测试,初步划分了断裂带内部流体活动期次,确定了流体的性质及特征;结合方解石脉的碳、氧同位素特征进一步确定了成脉流体来源及成脉成岩环境。断裂带内部水-岩相互作用极为发育,本文通过实验模拟了不同温、压条件下的碳酸盐岩的水-岩相互作用,发现在不同的温、压条件下断裂带内部水-岩相互作用中溶蚀作用和沉淀作用同时发生。随着温度和压力的升高溶蚀作用越强烈,从溶蚀坑逐渐演变为溶蚀条带及溶蚀晶锥。沉淀作用在温、压升高的过程中沉淀物先减少后增加,析出矿物晶体从半自形晶-他形晶向自形晶演变。溶蚀作用和沉淀作用共同控制着断裂带的封堵和连通性,结合前人的研究成果分析了断裂带的垂向运移及侧向封堵机理,并探讨了不同断裂带结构与油气运聚的关系。
[Abstract]:Fault is a widely existing structural style in the field, and its internal structural characteristics and its controlling effect on oil and gas migration and accumulation have been paid more and more attention. Carbonate rock is one of the common rock types in the field. The outcrop in the field shows that there are great differences in the tensile faults developed in carbonate rocks, and what are the influencing factors for this difference. What are the characteristics of fluid activity and the resulting water-rock interaction in the fault. In view of the above problems, on the basis of a large number of fault observation and description in the field, this paper analyzes the fault zone structure and its influencing factors of the tensional fault developed in carbonate rock, and combines with the analysis, test and simulation experiment of the fault zone sample. The characteristics of water-rock interaction in carbonate fault zone are discussed. In this paper, more than 60 normal faults in carbonate rocks in Xintai and Yishui, Shandong Province are investigated, and 26 extensional normal faults with clear structure are described in detail. The macroscopic structural characteristics of the fault zone are analyzed intuitively from the angle of plane and section. It is found that the internal structure of the carbonate extensional fault zone has typical binary characteristics: the fault nucleus and the broken zone, but the structure of different fault zones is different. The main reasons for this difference are offset, single layer thickness, cementation degree and depth of rock. The fault distance is from small to large, the fault nucleus develops from discontinuity to continuous development, the relationship between the width of the fault nucleus and the fault distance is 1: 10 / 100, and the relationship between the width of the fault zone and the fault distance is 10: 1: 100: 1. If the thickness of rock layer is smaller than the distance of fracture, the fracture develops; when the thickness of rock layer is greater than the distance of fracture, the fracture does not develop; in the same fault, the smaller the thickness of rock layer is, the denser the fracture development is and the wider the fracture development zone is, the greater the thickness of rock layer is, The less fracture develops and the smaller the width of fracture development zone is. The microscopic and physical characteristics of different structural elements in the fault zone are discussed by analyzing the samples of each structural unit under optical microscope and combining with the investigation of data, which provides a theoretical basis for sealing and connectivity of the fault zone. In this paper, the freezing point and homogenization temperature of fluid inclusions developed in calcite veins filled in the fault zone were measured, and the cathodoluminescence tests were carried out on the rock flakes, and the fluid activity stages in the fault zone were preliminarily divided. The properties and characteristics of the fluid are determined, and the source of the fluid and the diagenetic environment of the vein are further determined according to the carbon and oxygen isotope characteristics of the calcite vein. The water-rock interaction in the fault zone is extremely developed. In this paper, the water-rock interaction of carbonate rocks under different temperature and pressure conditions is simulated experimentally, and it is found that the water rock interaction is at different temperatures. Dissolution and precipitation occur simultaneously in the water-rock interaction in the fault zone under compressive conditions. With the increase of temperature and pressure, the dissolution becomes stronger, from the corrosion pit to the dissolution strip and the dissolution crystal cone. In the process of increasing temperature and pressure, the precipitate first decreases and then increases, and the precipitated mineral crystal evolves from hemiautomorphism to eutectic. Dissolution and precipitation jointly control the plugging and connectivity of the fault zone. The vertical migration and lateral sealing mechanism of the fault zone are analyzed based on the previous research results, and the relationship between the structure of different fault zones and the migration and accumulation of oil and gas is discussed.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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