东濮凹陷方里集构造带油气来源及成藏期

通过精细油源对比、气源对比，明确了渤海湾盆地东濮凹陷方里集构造带的油气来源；基于流体包裹体的光性特征和均一温度，结合埋藏史确立了油气成藏时间及期次，恢复了油气成藏过程。油源对比结果表明，沙三段原油和烃源岩地球化学指标相近，具有自生自储特征，沙二段和沙三段天然气以煤成气为主，为断层输导成藏。沙三段油包裹体荧光下呈蓝色,盐水包裹体均一温度峰值为130 ℃~140 ℃，原油成藏期为明化镇组晚期—平原组中期(距今1~3 Ma)。根据山西组—本溪组煤系烃源岩的热演化史，煤成气的成藏期为东营组时期，早于原油的成藏时间。油气成藏过程恢复表明:在东营组中期至东营组剥蚀期间，煤成气通过断层输导，形成沙二段气藏和沙三段早期气藏；在明化镇组晚期—平原组中期，沙三段烃源岩生成的原油就近充注于沙三段气藏中，形成了沙三段油气藏。方里集构造带具有“双源两期”的成藏特征。

Hydrocarbon Sources and Reservoir Forming Stages in Fangliji Tectonic Belt of Dongpu Depression,China

Hydrocarbon sources and reservoir forming stages in Fangliji tectonic belt of Dongpu depression, Bohai Bay Basin were studied by fine oil and gas source contrasts; combined with the characteristics of microscopic fluorescence and homogenization temperatures of fluid inclusions and buried history, the reservoir forming periods and stages were discussed, and the hydrocarbon forming process was reconstructed. The oil and gas source contrasts show that the crude oil and hydrocarbon source rocks in Sha 3 member are similar; and have characteristics of self-generating and self-preserving; the gas in Sha 3 member is main coal bed gas, and is fault migration reservoir. The fluorescence of oil inclusion is blue, and the peak of homogenization temperatures of saline inclusions is 130 ℃-140 ℃; the crude oil forming stages are late Minghuazhen period and middle Pingyuan period(1-3 Ma before nowadays). According to the thermal evolution history of coal-bearing hydrocarbon source rocks in Dongying Formation-Benxi Formation, the reservoir-forming stage of coal bed gas is Dongying period, which is earlier than that of the crude oil. The reconstruction of hydrocarbon reservoir forming process shows that the coal bed gas transforms by fault, and the gas reservoirs form in Sha 2 member and the early Sha 3 member; the rude oil formed by the hydrocarbon source rocks in Sha 3 member fills into Sha 3 member gas reservoir in late Minghuazhen and middle Pingyuan periods. Fangliji tectonic belt has the characteristics of “double sources and two stages”.