英买力—牙哈地区碳酸盐岩潜山的油气成藏模式

Hydrocarbon Accumulation Pattern of Carbonate Buried Hills int he Yingmaili-Yaha Area

英买力—牙哈地区碳酸盐岩潜山成藏条件优越,其南北两侧存在满加尔凹陷海相和库车坳陷陆相两套油气源,发育中上奥陶统泥岩和卡普沙良群泥岩两套区域性盖层。碳酸盐岩储集空间主要为溶蚀孔洞和裂缝,储层发育控制着潜山油气分布,缝洞体的横向展布特征决定着油气成藏模式。与轮南地区潜山储层相比,研究区潜山储层横向非均质性相对更强,溶蚀孔洞级别相对较小,潜山成藏模式更为复杂。英买力—牙哈地区潜山油气藏表现为底水块状特征,缝洞储集体内部不同部位可因"连通管效应"或者油气驱替过程受缝洞系统大小影响,致使潜山油气水界面高低不统一。

Yingmaili-Yaha buried hills are of abundant petroleum resources and good petroleum geologic conditions. The hydrocarbon was dirived from the Manjiaer sag marine facies in the south of the buried hill and the Kuqa depression terrestrial facies in the north. Two regional caprocks, the Middle-to Upper-Ordovician nmdstone and the Cretaceous Kapushaliang Group mudstone play the most important roles in formation of hydrocarbon reservoir. The oil-gas distribution in the buried bill is chiefly controlled by reservoir space which is mainly featured by cavities and cracks. The hydrocarbon accumulation pattern is controlled by the lateral distribution characteristics of these cavities and cracks. The hydrocarbon accumulation pattern in the Yingmaili- Yaha buried hills is more complex because the reservoir has more lateral heterogeneity and less pore space and continuity, as compared with the Lunnan buried hill. Generally speaking, these buried hill pools are characterized by massive oil accumulation and bottom water. The oil-gas-water interfaces have different depths due to the connected tube effect in different parts of fracture and cave reservoirs and the displacement process of oil and gas controlled by the reservoir space size.