苏北盆地油气田的形成与分布特征

FORMATION AND DISTRIBUTION OF OIL AND GAS FIELDS IN SUBEI BASIN

苏北南黄海盆地与渤海湾盆地之间以鲁苏隆起相隔 ,对称分布于郯庐断裂两侧。研究表明 ,由于两盆地所处的区域构造背景不同 ,致使其盆地演化、成烃演化、资源丰度和油气田规模差异很大。壳幔结构的同相性、晚始新世至渐新世 18Ma的沉积间断、有机质演化程度低、断裂活动改造强烈等是形成苏北盆地小、碎、贫、散含油气特征的主要因素。苏北盆地与渤海湾盆地存在的成藏条件差异及其分布规律表明 ,苏北盆地缺乏形成巨型、大型油气田的条件 ,其勘探对象应该以中小型油气田为主 ,这已经被 2 5年的勘探实践所证实。深部烃源有形成较大规模气田的条件 。

Subei\|South Huanghai basin and Bohaiwan basin are distributed symmetrically on two sides on Tanlu fault and separated by Lusu uplift. The basin evolution, hydrocarbon formation, resource abundance, oil and gas field scale of two basins are different since they are located on different tectonic setting. The in\|phase of crust\|mantle architecture, the hiatus of 18 Ma from later Eocene to Oligocene, the lower evolution of organic matter, the strong reformation of fault activities etc. resulted in the formation of the oil and gas\|bearing with special characteristics of small, fragmental, poor, scattered in Subei basin. The differences of reservoir formation conditions and distribution of Subei basin and Bohaiwan basin demonstrate that Subei basin is short of the conditions to form large oil and gas fields. The exploration objects should predominately be medial\|small oil and gas fields, which has been verified by exploration in 25 years. The hydrocarbon from deep source rocks is of condition to form bigger gas fields.