塔里木盆地麦盖提斜坡玉北地区奥陶系油气输导体系与成藏期

Hydrocarbon Accumulation Period and Its Carrier Systems in Ordovician Reservoir of Yubei Area,Markit Slope Tarim Basin

对玉北地区输导体系进行研究，分析其油气运聚过程，研究结果表明，玉北地区油气基本输导介质主要分为：断层、不整合、输导层，其中玉北中部地区输导能力较强，而玉北东部地区的输导能力较差．对玉北地区奥陶系3口井25块样品的有机和无机包裹体进行了分析，分析结果表明，玉北地区奥陶系油藏主要发生了两期成藏：第1期发生在海西晚期262～252Ma期间，主要为发黄色荧光的低成熟油充注；第2期发生喜山晚期12．5～0Ma，主要为发蓝白色荧光的高成熟度油充注．玉北地区奥陶系油藏有效烃源岩为下寒武统和上寒武统一下奥陶统两套烃源岩，且发育储盖组合为：下石炭统巴楚组泥岩、泥灰岩盖层与中-下奥陶统风化岩溶型储层组成的不连续层间组合．

Three types of basic carrier systems are identified for of Ordovieian reservoir in Yubei area, Southwest Tarim Basin, analyzing the hydrocarbon migration and accumulation process which are known as fault type, unconformity type and carrier layer type, where the carrier ability is strong in the Middle Part of Yubei area but weak in the Eastern Part. The organic and inorganic fluid inclusion analyses of 25 Ordovician samples from 3 wells in Yubei area indicate that there were two phases of hydrocarbon charging in Ordovician. In the period from 262 Ma to 252 Ma before present （in Late Hercynian）, low-mature oil with yellow fluorescence was charged. In the second period from 12. 5 Ma to 0 Ma before present （in Late Himalayan）, high- maturity oil with blue-white fluorescence was charged. Two groups of hydrocarbon source rocks, namely, the Lower Cambrian source rock and the Upper Cambrian-Lower Ordovician source rock, are developed in Yubei area. The cover is the mudstone and marl of Lower Carboniferous Bachu Formation Strata. The reservoir is the karst weathering of Lower-Middle Ordovician Strata. The cover and reservoir are composed of discontinuous interlayer combinations.