塔里木盆地塔河油田加里东期古岩溶特征及其意义

塔河油田位于塔里木盆地北部沙雅隆起阿克库勒凸起,是迄今为止我国已发现的最大的碳酸盐岩油气藏。勘探实践表明,塔河油田主力油层奥陶系油藏储集空间以碳酸盐岩岩溶孔、洞、缝为主,因此岩溶作用及其发育程度对奥陶系碳酸盐岩岩溶缝洞型储集体的发育及油气成藏必然具有重要的控制作用。多种资料表明,本区除发育海西期岩溶外,还存在加里东期岩溶。原岩性质、断裂、裂缝发育强度、古地貌形态、古气候、古水系是控制岩溶发育的因素,其中古地貌形态、断裂裂缝发育强度是主要的控制因素。加里东期岩溶对该区奥陶系碳酸盐岩缝洞系统的形成具有重要作用,对上奥陶统桑塔木组覆盖区之下的中—下奥陶统一间房组、鹰山组和上奥陶统良里塔格组碳酸盐岩的油气勘探具有重要意义,从而扩大了该区的油气勘探前景。 

CHARACTERISTICS AND SIGNIFICANCE OF THE CALEDONIAN KARST IN THE TAHE OIL FIELD, THE TARIM BASIN

The Tahe oil field is located in the Akekule uplift in the north of Tarim basin. It is the biggest carbonate hydrocarbon reservoir found in the Tarim basin up to now, and the biggest in China. According to exploration, the Ordovician reservoir, as the main reservoir bed in Tahe oil field, is mainly composed of hole, cave and aperture. Karst development consequentially controls the development of carbonate aperture-cave reservoir and reservoir formation. Kinds of data indicate that, there is Caledonian, besides Hercynian karst in the Tahe oil field. Study findings indicate that, native rock characteristics, development of rupture and fissure, ancient physiognomy, climate and water system control karst development, among which ancient physiognomy and development of rupture and fissure are the main factors. The Caledonian karst plays an important role in the development of rupture and fissure system of Ordovician carbonate rock, and is important to the exploration of middle Ordovician Yijianfang Formation, middle-low Ordovi-clan Yinshan Formation and upper Ordovician Lianglitage Formation covered by the upper Ordovician San-gtamu Formation, consequentially enlarging the exploration foreground in this area.