塔里木盆地古隆起演化特征及油气勘探

The Evolution Characteristics of Palaeo-Uplifts in Tarim Basin and Its Exploration Directions for Oil and Gas

在构造解析方法结合区域构造背景分析的基础上,探讨塔里木盆地古隆起构造演化及勘探方向。发现塔里木盆地古隆起经历多期构造运动与变迁,主要有前寒武纪基底隆起雏形期、早奥陶世末期古隆起形成期、奥陶纪末期古隆起定型期、志留纪-泥盆纪古隆起改造期、二叠纪末古隆起调整期、中生代古隆起差异沉降期6个阶段的构造活动,形成了以下古生代碳酸盐岩为主的塔中、塔北、塔西南等三大古隆起,古隆起构造演化具有阶段性、继承性与迁移性。古生代形成的古隆起控制了台盆区油气的分布,多旋回构造运动与多期成藏配置形成多层系含油的复式成藏格局,古隆起斜坡区是大油气田的主要勘探方向。古隆起形成演化分析表明麦盖提斜坡区发育喜山晚期才沉没的塔西南早古生代大型古隆起,石炭系泥岩盖层与奥陶系碳酸盐岩古岩溶储层形成优质储盖组合,具有海西期成油、喜山期注气的油气成藏史,是台盆区继塔北、塔中古隆起大油气田之后的有利勘探接替领域。

Based on the structure interpretation and the analysis of regional tectonic setting controlling on oil, it indicates that multi-cycle tectonic movement and migration of palaeo-uplifts had occurred in Tarim basin. It includes six stages of evolution： the commence of basement lift in the Precambrian, the formation before the end of Early Ordoviclan, completion before the end of Ordovician, modification during Silurian-Devonian, local regulation during the end of Permian, tectonic station during Mesozoic. The evolution of palaeo-uplift was characterized by multiple epoches, inheritance, migration and modification and formed three large Palaeozoic palaeo-uplifts which were dominated by the lower Palaeozoic carbonate, including the central uplift, the northern uplift and the southwestern uplift. The uplifts forming in the Palaeozoic controlled the hydrocarbon distribution in the platform-basin region. The polycyclic tectonic movements together with three stages of hydrocarbon migration and accumulations, resulted in the vertical overlap of the producing layer, reservoir rock, multi-phase and multi-type of oil reservoir, and then formed a complex petroleum accumulation zone in the palaeo-uplifts. The slopes of the Palaeozoic uplifts are the main exploration orientations in Tarim basin. The Paleao-uplifts evolution analysis showed that there exists a large Palaeozoic uplift which submerged in the late Himalayan in Migaiti slope, southwestern Tarim basin. The Ordovician karst reservoir and the Carboniferous mud cap rock formed a high-quality reservoir-cap assemblage in the uplift with the Hercynian hydrocarbon and oil accumulation and the Himalayan gas accumulation. Thus, the southwestern uplift is a potential exploration domain after the discovery of the big oil/gas fields in the uplift in the north and centrel of Tarim basin.