辽河盆地兴隆台潜山变质岩-火山岩油藏烃类注入史及其成藏模式

HYDROCARBON CHARGING HISTORY AND POOL-FORMING MODEL OF THE ARCHEOZOIC-MESOZOIC METAMORPHIC-VOLCANIC RESERVOIRS,XINGLONGTAI BURIED HILL, LIAOHE BASIN

流体包裹体分析在石油地质学中的主要用途之一是利用成岩矿物包裹体资料进行油气运移路径、注入时间和方向的推测、计算与判断。兴隆台潜山油藏烃类包裹体均一化温度整体上呈单峰正态或不对称单峰分布,其主要形成温度为80～100℃,反映各样品具有相近的烃类包裹体形成过程。部分井的双峰温度特征暗示存在2次烃类注入期。储层烃类充注时间距今3～35Ma,可分为2个主要的充注期:距今27～35Ma和3～24Ma,以前者注入作用更强烈。潜山内部油气是由东向西注入的。成藏分为3个阶段:a)沙三段沉积晚期,形成的少量油气进入已逐步发育并定型的圈闭中,沙三末期的短暂抬升导致已聚集成藏的油气遭受一定的氧化形成黑色沥青;b)沙二段、沙一段—东营组沉积期为潜山主要油气聚集期;c)晚第三纪以来的生烃强度较弱。潜山上覆沙四段及沙三段泥岩为良好的封盖层,使油藏得以保存。

One of the uses of fluid inclusion enclaves analysis in petroleum geology is to utilize inclusion enclaves in diagenic minerals in inferring hydrocarbon migration path, calculating injection time and determin-ing injection direction. The patterns of homogeneous temperature of hydrocarbon inclusion enclaves in the Xinglongtai reservoir, as a whole, are characterized by normal unimodal or asymmetric unimodal distributions, and the major peak temperatures range from 80 ℃ to 100 ℃, which reflect that, the hydrocarbon inclusion enclaves in different samples are of the similar formation process. In addition, inclusion homogeneous temperatures in a few wells display a bimodal distribution pattern, which may imply that, there exist at least 2 stages of inclusion formation. Studies on the burial-heat evolution history shows that, hydrocarbon injection period in the Xinglongtai reservoir is 3-35 Ma ago, which can be divided into 2 major stages: 27-35 Ma and 3-24 Ma, and the former is the main hydrocarbon injection stage. Researches also show that, the direction of hydrocarbon injection is from the east to the west. There are 3 pool-forming stages: a)A small amount of hydrocarbon migrates into the embryonic trap in the late Es^3, after which the temporary uplift in the end of Es^3 results in oxidation for part of the hydrocarbon in the incipient reservoir, forming black asphalt; b)The Es^2-Ed stage is the major hydrocarbon accumulation period; c)Hydrocarbon gene-(ration) intensity is relatively weak since the late Tertiary. Hydrocarbon in the reservoir is preserved, which is attributed to the excellent mudstone cap of the overlying Es^(3+4).