Abstract
Whether or not the tight oil in the Triassic Yanchang Formation of the Ordos Basin is controlled by structural factors is a controversial issue, the relationship between the structural factors of the strata and the distribution of tight oil is limited to the study of current structures. The traditional view is that structural factors have no obvious control over the formation and distribution of the oil reservoir. Taking the Chang 8 member of the Triassic Yanchang Formation in the Ordos Basin as an example, this paper studies respectively the burial of strata-hydrocarbon generation history of the individual well and the structural evolution history of strata in the basin by using software tools of the Genex burial-hydrocarbon generation history restoration and TemisFlow evolution of stratigraphic structures. It is considered that the hydrocarbon generation period of the source rock of the Triassic Yanchang Formation in the Ordos Basin is from early Middle Jurassic to end of Early Cretaceous. By reconstructing the evolution and structure of the Chang 8 member during the hydrocarbon accumulation period, combined with a comprehensive analysis on the distributional characteristics of the Chang 8 oil reservoir, we found the palaeoslopes and palaeohighs of the Chang 8 reservoir to represent areas in which tight oils were distributed. Palaeo-structural characteristics of the target layer exhibit control over the Chang 8 reservoir. The new theory underlying tight oil exploration, which is based on the recovery of the palaeogeomorphology of the target layer during the hydrocarbon generation period, incorporates the vital roles of key controlling factors over tight oil accumulation, so that the mind-set on tight oil exploration in the Ordos Basin has evolved.
Highlights
The exploration of tight oil in the Ordos Basin has been aimed at the deep water zone
Current studies on the factors controlling tight oil accumulation are mostly based on comprehensive analyses of various geological factors, among which structural factors have gradually attracted the attention of researchers
TemisFlow basin simulation software was used to reconstruct the structure of the target layers of the Chang 8 reservoir and their evolution after the hydrocarbon generation period, comprehensive basin burial-hydrocarbon generation history analysis, in order to reveal the intrinsic coupling between the palaeostructure and evolution of the target layer during the hydrocarbon generation period and the distribution of the oil reservoir
Summary
The exploration of tight oil in the Ordos Basin has been aimed at the deep water zone. Current studies on the factors controlling tight oil accumulation are mostly based on comprehensive analyses of various geological factors, among which structural factors have gradually attracted the attention of researchers. This change reflects the fact that researchers have been focused on discerning the distributions of the high-quality reservoirs and the sweet spots of tight oil reservoirs. What should be emphasized in particular, is that the controlling effect of tectonism on the formation and distribution of the tight oil reservoir in the Triassic Yanchang Formation has increasingly attracted attention of researchers, and the traditional theories applied to this reservoir have gradually changed. Researchers focused on current structural characteristics; based on the traditional mind-set that “the slope in northern Shaanxi is a gentle west-inclined monocline with simple structure, and lacks structural traps such as anticline”, it has been assumed that the formation and distribution of oil reservoirs are dominantly controlled
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
