博孜-大北区域断裂活动的差异性及其对油气聚集的指示意义——来自天然地震及数值模拟的启示  

Fault Slip Distribution and Its Implication on Hydrocarbon Accumulation in the Bozi-Dabei Region:Insights from Earthquake and Numerical Simulations

作　　者：王清华[1] 汪伟[2] 吴超[1] 尹宏伟[2] 金江宁[1] 贺婉慧 李志豪[1] WANG Qinghua;WANG Wei;WU Chao;YIN Hongwei;JIN Jiangning;HE Wanhui;LI Zhihao(Research Institute of Petroleum Exploration and Development,Tarim Oilfield Company,PetroChina,Korla 841000,Xinjiang,China;School of Earth Science and Engineering,Nanjing University,Nanjing 210046,Jiangsu,China)

机构地区：[1]中国石油塔里木油田公司勘探开发研究院,新疆库尔勒841000 [2]南京大学地球科学与工程学院,江苏南京210046

出　　处：《大地构造与成矿学》2024年第4期677-689,共13页Geotectonica et Metallogenia

基　　金：国家自然科学基金项目(41972219、41572187、41927802);国家科技重大专项专题项目(2017ZX005008001、2016ZX05003);国家深地专项专题项目(2019YFC0605505);股份重大专项专题项目(2018E-1801);中国博士后科学基金项目(2020M671432)联合资助。

摘　　要：本文针对博孜-大北地区的天然地震活动与分布进行统计分析,结果显示博孜与大北区域的地震分布存在明显差异性。博孜地区的天然地震呈现出山前向盆地方向减少的特征,而大北地区的地震活动主要聚集在靠近盆地的盐下冲断楔前部。通过对博孜-大北区域盐下断裂活动的定量分析和模拟,发现大北地区受到厚盐层沉积的影响,在盐下冲断楔前部区域出现持续的强断裂活动区,形成盐下断裂乱序传播模式;而博孜地区断裂自山前向盆地方向递进传播,其活动性逐渐减弱。研究结果表明,盐下断裂活动和天然地震分布具有良好的相关性,该地区盐下断裂活动的强弱是其天然地震分布的主要控制因素。大北盐下冲断楔前部区域断裂的持续活动导致该区域天然地震高频活动,而博孜区域盐下冲断楔前部区域断裂活动较弱,天然地震活动频率相对较低。区域油气勘探结果显示,地震活动对油气分布具有指示意义。博孜冲断楔前部区域的博孜1构造区具有断裂活动弱、地震频率低、油气藏保存条件好以及整体连片含气等特征,是油气勘探的有利区域。The amount and distribution of earthquakes in the Bozi-Dabei region differed along strike and dip.The number of earthquakes in the Bozi Block decreases toward the piedmont basin and increases in the Dabei Block.The balanced restorations of the two seismic profiles show that the fault propagation in the Dabei Block is disordered,while that in the Bozi Block is sequenced.Displacement analysis of the subsalt fault also shows that the Dabei Block has extremely high fault activity in the front zone near the basin,whereas the fault activity decreases gently from the orogenic toward the basin in the Bozi Block.The numerical simulation suggests that the thicker salt deposition in the front zone of the Dabei Block is the main cause of the different fault activities in the Bozi-Dabei region.The earthquake distribution is well correlated with the subsalt fault activity,which implies that fault activity is the main factor controlling the earthquake distribution.The earthquake frequency was high in the front region of the Dabei Block due to high fault activity,which decreased in the Bozi Block,where fault activity was weak.Hydrocarbon exploration suggests that earthquake distribution can influence hydrocarbon distribution.The Bozi 1 zone could be a beneficial exploration area in this region due to its weak fault activity,low earthquake frequency,well-preserved conditions,and connected reservoirs.

关 键 词：地震分布 断裂活动 数值模拟 盐构造 库车坳陷 

分 类 号：P542[天文地球—构造地质学] P628[天文地球—地质学]