Exploration of tight oil resources based on stratigraphic paleo-tectonics during hydrocarbon generation in the Ordos Basin, China

Gao Shengli,Yang Jinxia

doi:10.1007/s12517-019-4546-2

Abstract

For many years, oil resource exploration has emphasized the current structural characteristics of potential oil-bearing formations. The traditional view of the Ordos Basin has been that the slope in northern Shaanxi is a gentle westward-dipping monocline that lacks structural traps, such as anticlines. Therefore, it was assumed that structural factors could exert no control over the formation and distribution of the oil reservoirs in the Yanchang Formation. By modeling the evolution and structure of a target layer in the Chang-8 reservoir during its hydrocarbon accumulation period, combined with a comprehensive analysis of the distributional characteristics of the Chang-8 oil reservoir, we found a strong link between paleo-slopes and paleo-highs in the target layer and the modern distribution of tight oils. The paleo-structural characteristics of the target layer clearly exhibit control over the Chang-8 reservoir. We have proposed a new understanding and method for tight oil exploration, which is based on the recovery of the paleo-geomorphology of the target layer during the hydrocarbon generation period. It incorporates a number of key controls over tight oil accumulation and represents an evolution in the mindset suggested for tight oil exploration in the Ordos Basin.

Highlights

Until recently, researchers have focused on the present-day tectonic features of the Ordos Basin, believing that the NorthShaanxi Slope is a gentle westward monocline that features a simple structure and a lack of structural traps for hydrocarbons, such as anticlines
Chang-8 reservoir during its hydrocarbon accumulation period, combined with a comprehensive analysis of the distributional characteristics of the Chang-8 oil reservoir, we found a strong link between paleo-slopes and paleo-highs in the target layer and the modern distribution of tight oils
This demonstrates the importance of paleo-tectonic characteristics during the hydrocarbon generation period in determining the distribution of oil reservoirs

Summary

Introduction

Researchers have focused on the present-day tectonic features of the Ordos Basin, believing that the NorthShaanxi Slope is a gentle westward monocline that features a simple structure and a lack of structural traps for hydrocarbons, such as anticlines. Researchers have focused on the present-day tectonic features of the Ordos Basin, believing that the North. The formation and distribution of reservoirs in the Yanchang Formation are generally considered to be controlled by sedimentary facies, while tectonics and other factors have little effect on the formation and distribution of reservoirs (Yang et al 2007; Yang et al 2013b). University, Xi’an 710119, Shaanxi, China amplitude, nose-shaped uplift structures—have been recognized as important controls on the formation and enrichment of Triassic reservoirs (Zhao et al 2006). Ordos Basin, the discovery of the Chang-6 reservoir in the Huaqing Area has forced researchers to acknowledge the controlling influence of structural factors (e.g., the lake basin bottom configuration) on reservoirs. According to conventional exploration theory, this area is a Bforbidden zone^ for the exploration of tight oil resources

Methods

Results

Discussion

Conclusion