塔里木西南地区含油气系统特征

CHARACTERISTICS AND APPRAISAL OF OIL,GAS-BEARING SYSTEM IN SOUTHWESTERN

根据对塔里木西南坳陷可能的烃源岩有机地球化学的分析、评价及已知油气藏和重要油气显示点的油(气)岩的对比结果,该区存在着6套现实的烃源岩:(1)下寒武统暗色泥岩及碳酸盐岩;(2)奥陶系的碳酸盐岩和暗色泥岩;(3)石炭系碳酸盐岩和暗色泥页岩;(4)下二叠统暗色泥页岩(5)中下侏罗统的暗色泥岩;(6)上白垩—古近系的碳酸盐岩及暗色泥岩.这几套烃源岩除白垩—古近系有待落实外,其它各套烃源岩均已形成油气显示或工业油气流.综合评价结果最为有利的含油气系统是寒武系,其次为石炭系,根据2个含油气系统的地理分布看,前者主要分布于巴楚隆起及麦盖提斜坡上倾部,后者主要分布于山前坳陷.

The analysis and appraisal of organic geochemistry of potential hydrocarbon source rocks, and correlative result of the known oil-gas pools and key localities with oil-gas indication in southwestern Tarim depression reveal the existence of 6 sets of practical hydrocarbon source rocks. They are 1) Dark-colored mudstone and carbonate rocks of the Lower Cambrian, 2) carbonate rocks and dark-colored mudstone of the Ordovician, 3) carbonate rocks and dark-colored mudstone-shale of the Carboniferous, 4) dark-colored mudstone-shale of the Lower Permian, 5) Dark-colored mudstone of the Lower-Middle Jurassic, and 6) carbonate rocks and dark mudstone of the Upper CretaceousLower Tertiary. All hydrocarbon source rocks except Cretaceous-Paleogene ones in need of further check have either oil-gas indication or industrial oil-gas flow. The appraisal shows that the Cambrian is the most favorable oil,gas-bearing system, followed by the Carboniferous. The former is mainly distributed at Bachu uplift and Maigaiti slope, and the latter mainly at foreland depressions.