塔里木盆地玛扎塔格断裂带构造特征及其油气地质意义

Structural Characteristics and Petroleum Geological Significances of Mazhatage Fault Belt in Tarim Basin

根据最新地震资料精细解释成果,建立塔里木盆地玛扎塔格断裂带断裂发育模式,并对断裂活动时代和构造演化过程展开分析。玛扎塔格断裂带具有明显的分层构造特征,同时又具有分段差异性:深层铲式逆冲断裂主要发育在断裂带中、西段,走滑-逆冲断裂沿断裂走向自西向东转换为走滑-逆冲断裂;浅层铲式逆冲断裂各构造段均有发育。断裂带主要经历了4个构造变形阶段:晚奥陶世—泥盆纪铲式逆冲断裂、二叠纪末—三叠纪继承活动性铲式逆冲断裂、古近纪末逆冲-走滑断裂(或走滑-逆冲断裂)、上新世末—全新世浅层铲式逆冲断裂。玛扎塔格断裂带在晚奥陶世—泥盆纪和二叠纪末—三叠纪向下滑脱于中寒武统,对烃源岩和储层的沟通作用有限,且对古油气藏具有破坏作用;古近纪末期演化为巴楚隆起的南侧边界断裂,成为天然气运移的有利通道,断裂带中、西段形成较好的断垒构造圈闭,与喜马拉雅期主成藏期具有良好的时空配置关系。

Based on the latest elaborations of seismic data,the fault development model,active stages and tectonic evolution of Mazhatage fault belt in Tarim Basin were discussed in terms of unconformities,strata thickness and syntectonic strata.Mazhatage fault belt has clear layered and segmentation characteristics.Deep listric thrust fault mainly lies in the western and middle sections,thrusting strike-slip faults gradually change into strike-slip thrust fault from the west to the east,and the shallow listric thrust develops in the whole fault belt.The study area has experienced four deformation stages and four fault systems,the Late Ordovician-Devonian listric thrust fault,the Permian-Triassic inherited active listric thrust fault,and the Late Paleogene thrusting strike-slip thrust fault（or strike-slip thrust fault）and the Late Pliocene-Holocenethrust fault have been recognized.Mazhatage fault belt,which is an accompanied fault of Hetian palaeohigh in Upper Ordovician-Devonian and Permian-Triassic,provides limited communications between the source rock and reservoir,and could damage paleo-oil-gas reservoirs.Then,it evolves into a boundary fault on the south side of Bachu uplift in Late Paleogene,becoming a favorable channel for natural gas transportation;and a good structural trap is formed in the middle and west sections of the fault,showing agood spatial-temporal relationship with the main accumulation period during the Himalayan.