塔里木盆地北部石油地质几个问题的讨论

1984年塔里木盆地北部沙参2井获高产油气流之后,投入了大量的物探、钻探等工作。笔者根据近几年在该区所取得的新资料和成果,对以下地质问题进行了讨论。 1.塔北地区的沉积特征:从震旦一二叠纪出现两次大的海侵,即:寒武—奥陶纪及石炭纪;形成了四大沉积旋回,即:震旦系、寒武—奥陶系、志留—泥盆系及石炭一二叠系。震旦—泥盆系满加尔以东为深海槽盆一大陆斜坡相为主;以西则为陆表海相为主。震旦系在东部发育齐全,厚度大,为一套碎屑岩夹火山岩及冰碛岩,上部为碳酸盐岩;其西部下震旦统发育局限,上统分布广泛。 区内古生界具有多时代成油组合,油气资源十分丰富,足寻找古生代油气田最佳地区。 2.沙雅隆起的构造演化:加里东早期开始出现隆起显示,海西期为隆起的发展阶段,海西末期定型;中生代为潜伏隆起状态;新生代呈北倾斜坡。根据隆起的沉积发育和构造特点,可将区内进一步划分为4个次一级构造单元。 3.区内油气圈闭类型有:构造凸起古风化带型、背斜型、地层不整合楔状体型、生物礁—滩型、砂体及断层遮挡型等6种。 根据上述研究结果,塔北是个储量可观的含油气区。

DISCUSSION ON SEVERAL PETRO-GEOLOGICAL PROSLEMSIN THE NORTHERN TARIM BASIN

After we have fulfilled a lot of geophysics-xploration and well-exploration, and obtained high-product oil-gas stream from Shan-2 well in the Northern Tarim Basin (NTB) in 1984, now based on the new infornition and result what we have got in recent years, several petro-eological problem concerned are discussed as follows:1. The sedimentary characteristic of the NTB region: There were two great transgression from Z to P (-0 and C) and four cycles of deposition, were formed, e. i. , Z, G, S-D and C. In the Eide of Manjiaer region, troughike basin of deep oceans-ontinent slope facies is the major form, while in the Whide, the major one is epicontinental ocean facies. In the E of Manjiaer, Z developped perfectly with a huge thickness, and belongs to clastic rock with some volcanic rocks and tillites (in the upper parts there occur carbonates). To the W of Manjiaer, the lower Z developped only locally, but the upper Z distributed widely,Any way, in this region, the Pz had developped some oil-enerating combinations of multiple periods, and the oil-gas resource is quite abundant, Therefore, it is the best region for seeking the Pz oil-gas.2, Evolution of the Shaya uplift:The upliftting made its appearance from early Caledonian. It enteied into the developping stage in the Hercynian period. But its from was fixed in late Hercynian period, and showed as a potential upliftting state in Mesozoic period, its slope trended to the N in Cenozoic. Base on its sedimentary and structural characteristics, there distinguished four kinds of secondary structure unit in the region.3.There are six kinds of types of oil-as trap in the regions namely: The palaeo-eathering zone type of structure upliftting, anticline type, stratal discontinuity wedge type, reef of Lifebed type, sand body and fault trap type, and so on.