下扬子黄桥地区龙潭组流体包裹体特征与油气成藏期次

下扬子黄桥地区上二叠统龙潭组储层中共发育2期流体包裹体:Ⅰ期主要发育在石英颗粒成岩次生加大早中期,主要沿颗粒加大边内侧微裂隙呈带状或线状分布;Ⅱ期主要发育在石英颗粒成岩次生加大期后,主要沿切穿多个石英颗粒及其加大边的微裂隙呈线状/带状分布。包裹体均一温度分布区间75~120℃,主要集中在75~85℃,结合热—埋藏史、生排烃史分析,龙潭组烃源岩在白垩纪末期进入主生烃期,流体充注主要为侏罗纪(188~160Ma)和晚白垩世至古近纪(60~43Ma),认为该区龙潭组油藏形成于白垩纪末期。 

Characteristics of fluid inclusions and timing of hydrocarbon accumulation in Longtan reservoirs in Huangqiao region, Lower Yangtze Basin

In the Longtan Formation of the Upper Permian in Huangqiao region of the Lower Yangtze Basin, there are 2 stages of fluid inclusion. The fluid inclusions of stage Ⅰ mainly generated during the early-middle period of quartz overgrowth, and generally located along micro-fractures within a linear zone. The fluid inclusions of stage Ⅱ mainly generated after quartz overgrowth, and distributed along micro-fractures which cut through quartz overgrowth. The homogenization temperature of fluid inclusions was 75-120℃, and the peak was 75-85℃. Analyses of geothermal evolution, burial history and hydrocarbon generation-expulsion history revealed that the main hydrocarbon generation period of the Longtan Formation source rocks was in Cretaceous, and oil charging mainly occurred in Jurassic (188-160 Ma) and from the Late Cretaceous to Paleocene (60-43 Ma). The Longtan reservoir mainly formed at the end of Cretaceous.