渤中凹陷北部中生界顶面断层破碎带量化研究

渤中凹陷是渤海海域最大的生烃凹陷,环渤中凹陷北部潜山带是目前重要的油气勘探区带。渤中凹陷北部中生界以火成岩为主,裂缝对火成岩储层的形成具有重要影响。利用地震方差属性值量化断层破碎带,建立断层破碎带宽度与断层斜距之间的数量关系,构建方差属性值等值线图的方式,结合前人研究的图版和薄片资料,对渤中凹陷北部中生界顶面断层破碎带进行量化、验证和分析。结果显示:研究区内的断层均有多个断层核,断层系统复杂,断层破碎带宽度由几百米至几千米不等,断层破碎带对中生界火山岩影响作用显著;断层破碎带的影响程度与距断层的距离呈负相关,即距离断层越远,影响程度越弱,方差属性值越小;利用地震方差属性值量化断层破碎带的结果与相关研究的图版规律、薄片资料的显示结果契合度高,对断层破碎带的量化研究具有较高的可行性。

Quantitative Study on the Uppermost Mesozoic Fault Damage Zones in Northern Bozhong Sag

The Bozhong sag is the largest hydrocarbon-generating sag in the Bohai Sea, and the buried hill belt in the northern part of the sag is an important exploration target. The local Mesozoic geology is mainly dominated by igneous rocks, and fractures are important to the formation of igneous reservoirs. Here, we quantified the fault damage zones by using the seismic variance attribute value, established the quantitative relationship between the width and the fault slant distance, and established a contour map of the variance attribute value. Combined with published chart and thin section data, the fault damage zones at the uppermost Mesozoic sequence in the northern Bozhong sag are quantified, verified and analyzed. The results show that the local faults have multiple fault cores, and that the fault systems are complex. The width of the fault damage zones varies from several hundred meters to several kilometers. The fault damage zones have obvious influence on the Mesozoic volcanic rocks, and the degree of influence correlates negatively with the distance from the fault. The quantitative results of fault damage zones based on seismic variance attribute value is in good agreement with the layout pattern of related research and the thin section analysis results in the study area, which demonstrate high feasibility for the quantitative study of fault damage zones.