陕北地区延长组长10油层组成藏特征

Characteristics of hydrocarbon pooling in Chang-10 interval of the Yanchang Fm in the northern Shaanxi province

李士祥 刘显阳 韩天佑 黄锦绣 焦军

Li Shixiang Liu Xianyang Han Tianyou Huang Jinxiu Jiao Jun

采用地质与地球化学相结合的方法,通过对长10原油、长7烃源岩和长9烃源岩地球化学特征对比分析,并结合长10储层流体包裹体与长7烃源岩供烃层位储层流体包裹体均一温度分布特征差异性分析,对长10油层组油源进行综合判识。在此基础上,结合沉积及储层特征,对长10油藏的控制因素进行分析。研究结果表明,长9烃源岩为长10油藏的主力烃源岩,长7烃源岩也有贡献,但作用有限。长10油藏的形成受源岩条件、沉积、成岩和微构造等多种因素的影响,成藏条件较为复杂。长9烃源岩的范围及发育程度控制着长10油藏的分布,有利的沉积相带、成岩相带和长9暗色泥岩的过剩压力高值区,为油藏发育的有利目标区。长10油藏受构造和岩性的双重控制,主要发育构造-岩性油藏、砂岩上倾方向尖灭性油藏和上倾方向岩性致密遮挡油藏3种类型。

Oil-source correlation is performed in Chang-10 interval of the Yanchang Fm through comparative analysis of the geochemical characteristics of Chang-10 crude oil,Chang-7 and Chang 9 source rocks,as well as difference analysis of fluid inclusions homogenization temperature distribution between Chang-10 reservoir and other reservoirs with hydrocarbons from Chang 7 source rocks.Moreover,the factors controlling hydrocarbon pooling in Chang-10 are also identified based on sedimentary and reservoir characteristics.The result shows that the Chang-9 is the major source rocks for the Chang-10 oil reservoir,to which the Chang-7 also contributed limited hydrocarbons.The formation of the Chang-10 oil reservoir was controlled by various factors such as quality,deposition,diagenesis and micro-structure of source rocks.The distribution of the Chang-10 oil reservoir was controlled by the distribution and development of the Chang-9 source rocks.Favorable sedimentary facies belts,diagenetic facies zones and high overpressure zones of the Chang-9 dark mudstone are the favorable target areas for discovering oil reservoirs.The Chang-10 oil reservoir is controlled by both structure and lithology.Three main reservoir types are identified,including structural-lithological reservoir,up-dip pinch-out sandstone reservoir and up-dip tight layer sealing reservoir.

10.11743/ogg20110508