【摘要】 目的查明陕北地区延长组长7沉积环境及古地理演化,进而寻找有利砂体及石油聚集区。方法采用野外观察与室内研究相结合的方法对长7沉积相进行专项研究。结果研究区发育三角洲相和湖泊相,三角洲前缘及深湖浊积岩发育。在古地理演化过程中,长73湖盆达到鼎盛,浅湖区及深湖区分布范围均最大,沉积了广泛分布的张家滩油页岩;三角洲砂体不太发育,浊积岩零星分布;从长73—72—长71,湖岸线及深湖线均向湖内收缩,三角洲前缘砂体及浊积砂体逐渐发育。结论发育良好的油页岩为延长组主要的烃源岩,而三角洲及浊积岩砂体可以作为好的储层。更多还原

【Abstract】 Aim To ascertain depositional system of Yanchang formation Chang 7 in Shanbei Area and furthermore probe favorable sand body and high-yield oil area. Methods Combined research methods of field exploration and indoor analysis are adopted,sedimentary facies of Chang 7 are studied as special item. Results Delta and lake facies are recognized. Furthermore,the sub-facies and micro-facies are recognized,delta front and turbidite in deep lake are bothdeveloped well. During the paleo-geography evolution of Chang 7,lake basin is at its best during Chang 73,shallow lake and deep lake are both at its best,resulting to Zhangjiatan shale broadly distributed,delta sandstone developed not well and turbidite distributed scattered; From Chang 73,Chang 72 to Chang 71,lakeshore line and deep lake line are both moved toward lake center,but sandstones sedimented by delta front and turbidite gradually developed better. Conclusion The well developed oil shale can be as good hydrocarbon source rock and sandstones formed by delta front and turbidite can be good reservoir.更多还原