巴楚—麦盖提下古生界不整合特征与油气的关系

Lower Paleozoic Unconformity Characteristics and the Relation with Hydrocarbon in Bachu- Maigaiti

不整合是控制碳酸盐岩岩溶储层发育的重要因素之一,尤其对表生岩溶储层的影响更为明显。巴楚—麦盖提地区下古生界碳酸盐岩在其漫长的地质演化过程中,经历了加里东中期第一幕、加里东晚期第三幕和海西早期构造运动,发育了3个大型不整合面,分别为中下奥陶统顶不整合面T47、志留系底不整合面T07和上泥盆统底不整合面T06。按不整合的分布样式可划分为4种类型。3个重要不整合面对巴楚—麦盖提地区奥陶系地层造成不同程度的剥蚀和溶蚀,形成了广泛的风化壳岩溶储层,这对该地区油气运移和有效圈闭的形成有着重要的影响。

The palaeogeomorphology is one of the important factors controlling carbonate karst reservoir develop- ment, especially more impact on the supergene karst reservoir. Lower Paleozoic carbonate rocks in Bachu - Maigaiti region has long geological evolution experienced three times tectonic movement which are the first act of middle Cal- edonian. The third act of late Caledonian, and early Hercynian , has developed three large unconformity surface, respectively, the top of the middle and lower Ordovieian unconformity T4, the bottom of Silurian unconformity To and the bottom of upper Devonian unconformity T~. According to the distribution pattern of unconformity, it can be divided into four types. Three important unconformity face in Bachu - Maigaiti region causes varying degrees of ero- sion and corrosion in Ordovician stratum, and forms a wide range of weathering crust karst reservoir, has crucial in- fluence on the regional oil and gas storage and transportation and effective tral3 formation.