塔里木盆地顺北地区中新生界断裂构造特征及演化

塔里木盆地顺北地区古生界油气资源非常丰富, 此外在中新生界也发现了良好的油气显示, 揭示出该区中新生界也具有较好的油气勘探潜力。因此, 为了揭示对顺北地区中新生界油气成藏具有关键控制因素的断裂构造特征及其发育机制, 通过对顺北地区最新三维地震资料的精细构造解释, 系统分析了该区中新生界断裂构造的类型、几何学特征及其成因演化。研究表明: 顺北地区中新生界断裂以张性正断层为主, 发育少量逆断层和走滑断层, 该区断裂发育数量众多但单条断裂规模较小、平面上呈杂乱展布且具有明显的分区分层的差异活动特征。与区域动力背景和盆地演化阶段相统一, 顺北地区中新生界断裂演化经历了印支、燕山和喜山期3个阶段多期次伸展-挤压构造旋回, 而且该区所处的构造位置、下伏中二叠统火成岩地层特征及下三叠统柯吐尔组砂泥岩塑性层等对中新生界断裂的形成演化具有重要控制作用。通过对顺北地区连通T₉0~T₅0界面通源断裂的精细刻画, 揭示出在5号断裂带中部和7号断裂带中南部存在两大通源断裂发育区, 上述两地区部分断裂由T₉0界面往上一直断到T₅0界面之上, 对古生界油气向中新生界垂向输导具有建设性作用, 为该区中新生界油气的有利勘探区带。 

Structural characteristics and tectonic evolution of Mesozoic-Cenozoic faults in the Shunbei area,Tarim Basin

Oil and gas resources in the Shunbei area of the Tarim Basin are rich in Paleozoic strata.Recent petroleum exploration indicates that Mesozoic-Cenozoic sedimentary rocks have a good potential in hydrocarbon extraction. In this study, recently acquired 3D seismic surveys were used to systematically analyze fault types, geometrical characteristics, and evolution of Mesozoic-Cenozoic faults in the Shunbei area. The objective is to understand the characteristics and development mechanisms of faults that have the key controlling factors of hydrocarbon accumulation.In the Shunbei area, the dominant faults are tensional normal faults with few thrust faults and strike-slip faults. The district has many small scale, disorderly distributed faults. Combined with the regional setting and basin evolution stage, we suggest that the development of Mesozoic-Cenozoic faults in the Shunbei area experienced three tectonic cycles during the Indosinian, Yanshanian, and Himalayan periods. The structural position, middle Permian igneous rocks, and the sandy mudstone of the Lower Triassic Tongketuer Formation have significant control on fault evolution.Detailed interpretation of faults in the T₉0-T₅0 stratigraphic interval in the Shunbei area shows that the central part of the No.5 fault and south central part of the No.7 fault are two large faults that connect downward to the source rock of the basin. In these two areas, some faults cut upward through T₉0 to T₅0, which is good forvertical migration of hydrocarbon from Paleozoic to Mesozoic-Cenozoic strata and therefore are ideal locations for petroleum exploration.