银额盆地哈日凹陷油气成藏条件研究及有利区带预测

哈日凹陷是银额盆地中北部苏红图坳陷的一个次级构造单元,该区勘探程度低,勘探效果不理想,本文综合分析其油源、储集层、盖层、圈闭等成藏条件。结果表明：下白垩统及二叠系地层均有烃源岩发育,但二叠系地层烃源岩丰度较差,目前尚未发现有效烃源岩,从有机质类型、丰度及成熟度多方面考虑,苏红图组烃源岩较好,为油气勘探重点潜力层系,银根组和巴音戈壁组为次重点潜力层系,平面上湖盆中心烃源岩发育程度最好；下白垩统储集层主要为下白垩统滨浅湖砂坝、三角洲砂体以及近岸水下扇砂体；盖层条件整体较好,同烃源岩特征一样,越向烃源岩发育程度最好的湖盆中心区域,盖层条件越好,越向凹陷边缘盖层条件越差；圈闭主要有构造圈闭和岩性圈闭,构造圈闭中又以断块和断鼻圈闭为主。油气显示指示着苏红图组为哈日凹陷的主要目的层,其次为巴音戈壁组,建立油气成藏模式,叠合成藏要素,预测苏红图组有利勘探区,有利区主要分布在延哈参1井西部的两个陡坡带上,叠合面积为23.9km2。

Research on Petroleum Geological Conditions and Prediction of Favorable Exploration Zone in Hari Sag of Yingen-Ejinaqi Basin

Hari sag, oen of secondary structure units in Suhongtu depression in the north central of Yingen-Ejinaqi basin, sees lower level of exploration and unacceptable result of exploration. Depending on comprehensive analysis of its petroleum geological conditions - oil source, reservoir, cap rock, traps, it shows that hydrocarbon source rocks occurs in the layers of Lower Cretaceous and Permian mudstone, but Permian hydrocarbon source rocks is poor in the abundance.It has not yet found effective source rocks. Considering the organic type, abundance and maturity, Suhongtu source rocks is better for oil and gas exploration focused on potential strata, and the layers of yingen and Bayingebi are the second layer system. The degree of development of hydrocarbon source rocks is the best in the center of lake. Reservoirs of the lower Cretaceous are mainly shallow lake sand bar, sand delta and nearshore subaqueous fan sand body. Capping overall condition is good, with the same characteristics of hydrocarbon source rocks. The more the degree of development of hydrocarbon source rocks in the basin center area best, seal condition better, more depressed edge to seal condition worse. Traps are mainly structural traps and lithologic traps, structural traps are mainly fault block and broken nose traps. Oil and gas shows indicates the main target group of the hari sag is Suhongtu depression, followed Bayingebi, based on the establishment of hydrocarbon accumulation mode and elements of reservoir superimposition, the favorable exploration areas of Suhongtu group are predicted, they lies in the western steep belts of YHC1 well, coving the overlapping area is 23.9km2.