鄂尔多斯盆地中部长8成藏主控因素

陕西延长石油(集团)有限责任公司研究院,陕西 西安 710065

鄂尔多斯盆地; 长8致密油; 优质烃源岩; 储层; 成藏主控因素

Main control factors of tight oil reservoir in Chang 8 oil-bearing formation,central part of Ordos Basin
DU Yan-jun,HE Yong-hong,DONG Li-hong,LI Xin-wei,SONG Jian

(search Institute of Shaanxi Yanchang Petroleum(Group)Co.,Ltd., Xi'an 710065,China)

Ordos Basin; Chang 8 tight oil; high-quality source rocks; reservoir; main control factors of reservoir formation

DOI: 10.13800/j.cnki.xakjdxxb.2017.0313

备注

鄂尔多斯盆地陇东地区和新安边地区成功实施了致密油勘探与开发,提交探明石油地质储量近亿吨。近年来在盆地中部和南部地区致密油勘探也取得了重要进展,但成藏条件研究程度依然较低。从长8致密油分布特征、烃源岩特征、沉积储层、源-储配置关系及运移动力等方面,对鄂尔多斯盆地中部长8致密油成藏主控因素进行了探讨。研究认为长8致密油成藏受控于以下地质因素:①优质烃源岩不仅提供了充足的油源,而且还是运移充注动力来源,其分布控制致密油的成藏位置和规模; ②大面积发育的三角洲前缘水下分流河道复合砂体是长8致密油聚集的主要储集场所,广泛致密背景上的局部“甜点”有利于石油的富集与高产; ③长7、长9优质烃源岩与长8段优质储层空间配置关系控制了长8致密油的形成与富集。

A huge progress has been made in tight oil exploration and exploitation activities in the Longdong area and Xinanbian region of Ordos Basin in recent years,where nearly 100 millions geological oil reserves have been confirmed.In recent years,the tight oil exploration in central and southern of the Ordos Basin has made important progress,but inadequate study on accumulation conditions.In this paper,the main controlling factors are discussed from the distribution characteristics,the sedimentary and reservoir characteristics,the source rock characteristics,as well as the source-reservoir collocated relation and migration forces.The results show that:①The high-quality source rocks not only provide enough oil,but also provide power of oil migration and reservoir infill,and the distribution of high-quality source rock controls the location and scale of the tight oil reservoir; ②The large area of the underwater distributary channel composite sand bodies in the delta front are the main accumulation sites of the Chang 8 tight oil,and the partial “dessert” under the wide tight reservoir background is conducive to oil enrichment and high yield of oil; ③The spatial collocated relations between the High-quality sources of Chang 7 and Chang 9 and Chang 8 reservoir control the migration and enrichment of Chang 8 tight oil reservoir.