Abstract:

Banghu Syncline is the main source sag in Qianjiang Depression. The source rocks of Eq₃ and Eq₄ around Banghu Syncline has matured and generated oil and gas. Many updip pinch-out traps of lithologic sandstone are developed on the southern and eastern slopes around Banghu Syncline. The permeable sandstones accepted hydrocarbon in a way of surface supply, and oil and gas migration was driven by buoyancy. Hydrocarbon migration and accumulation in these slopes were mainly controlled by three factors. The tectonic framework controlled the migration trends of oil and gas.The hydrocarbon migration paths were controlled by special disposition of permeable sandstone conductor and migration trends.Each lithologic trap corresponding to the convergence area was limited by oil and gas migration path network.The petroliferous property of lithologic trap was controlled by volume of source rocks and hydrocarbon-generating and hydrocarbon-expulsing performances of corresponding source rock. The convergence area was in positive proportion with the petroliferous property of lithologic trap in the same combination of petroleum migration and accumulation. On the basis of prediction technology for hydrocarbon migration path in source sag, the petroliferous property of lithologic trap could be correctively evaluated.

Key words: Qianjiang Depression, source sag, oil-gas migration, lithologic trap, petroliferous property

摘要：

蚌湖向斜是潜江凹陷主要的生油洼陷,潜三、潜四段烃源岩均已成熟生油,向斜东、南斜坡带发育大量砂岩上倾尖灭型岩性圈闭,油气呈面状补给方式进入渗透性砂岩输导体,并在浮力驱动下发生运移。油气的运移和聚集主要受3个因素的控制:①构造格局控制了油气的运移趋势;②渗透性砂岩输导体与运移趋势的空间配套决定了油气运移路径的实际分布;③每个岩性圈闭均有运移路径网络所限定的油气汇聚范围,其源岩体积和生、排烃性能控制了圈闭含油气性。在同一个运聚组合中,油气运聚范围的面积与圈闭含油气性呈正比关系。以生油洼陷内油气运移路径的预测技术为基础,可对岩性圈闭的含油气性作出较为确切地评价。

关键词: 潜江凹陷, 生油洼陷, 油气运移, 岩性圈闭, 含油气性