Regular Pattern Of The Enrichment Of Chang8 Reservoir In Wu Qi-ding Bian Region

WuQi-DingBian region is located in the middle of the Ordos basin. Chang 8 is one of the most important oil layers that have been discovered recently in this area. This article comprehensively combined multiple theories and methods of petroleum geology, including sequence stratigraphy, geochemistry, sedimentology and reservoir dynamics, to give a systematical study on the Chang 8 reservoir founded in WuQi-DingBian region. Mainly focused on its distribution characteristics, structural characteristics, sedimentary reservoir characteristics, the main control factors of reservoir and the regular pattern of rich oil, this paper figured out the main factors controlling the Chang 8 oil layer reservoir-forming and got the following conclusion: the enrichment of the oil reservoir in this region is not only affected by the distribution of the hydrocarbon source rock, but the hydrocarbon trap condition and the migration condition are also the key for the reservoir-forming: 1. The developed hydrocarbon source rocks provide sufficient oil source condition for the Chang 8 layer oil reservoir-forming while controlling the range of it;2. The water distributary channel, mouth bar and distal bar formed in delta front have poor lateral connectivity and longitudinally can be superimposed contiguously, providing abundant reservoir for oil and gas enrichment and favorable zones for the formation of lithological and physical traps;3. The Chang 8 reservoir in this area is formed above and stored below, in which case the driving force to promote the oil and gas migration is the excess pressure and the orientation is the low pressure funnel area near the high pressure area. This paper gave a clear vision about the Chang 8 reservoir’s exploration potential and regular pattern of the enrichment in the WuQi-Ding Bian region.