Abstract
Based on the studies of sedimentary facies, oil-source correlation, formation pressure structure, homogenization temperature of fluid inclusions, etc., the oil and gas accumulation model and main controlling factors in lower Yanchang Formation in Wuqi-Dibian area have been discussed. It is believed that two sets of source rocks, C7 and C9, are developed in study area, and hydrocarbon produced from layers of C8 and C9 is mainly from C7 source rock, followed by C9, according to oil-source correlation; hydrocarbon-generating pressurization of C7 source rock is the main driving force for the downward migration of oil. The high value area formed by the low value of overpressure difference between C7 and C8 is the main hydrocarbon accumulation area; deltaic front subaqueous distributary channel and mouth bar in lower Yanchang formation are the main accumulation spaces due to their good porosity and permeability; besides, C8 reservoir shows the characteristics of “episodic filling and continuous accumulation,” and they both are the undersource reservoir-forming combination; it is believed that the distribution of oil reservoir in Triassic series is controlled by the factors of “near source, low pressure, superior facies.”
Highlights
Ordos Basin is a cratonic hydrocarbon-bearing basin with polycyclic sedimentary, and it is the second largest sedimentary basin in China due to its prolific hydrocarbon resources [1,2,3]
Commercial oil flow has been obtained through the lower reservoir group combination prospecting within the structural belt of Shaanbei slope and Tianhuan depression in Ordos Basin, such as reservoirs of Xifeng, Jiyuan, Wuqi, and Dingbian, among which the main production layer is the Chang8 (C8) reservoir group
Accumulation mechanism and controlling factors of reservoir groups in lower Yanchang formation will be discussed in this paper through the study of geochemical characteristics, pressure structure characteristics, and of reservoir forming characteristics and model
Summary
Ordos Basin is a cratonic hydrocarbon-bearing basin with polycyclic sedimentary, and it is the second largest sedimentary basin in China due to its prolific hydrocarbon resources [1,2,3]. Commercial oil flow has been obtained through the lower reservoir group combination prospecting within the structural belt of Shaanbei slope and Tianhuan depression in Ordos Basin, such as reservoirs of Xifeng, Jiyuan, Wuqi, and Dingbian, among which the main production layer is the Chang (C8) reservoir group. The previous research was mainly focused on the sedimentary facies and reservoir characteristics of lower Yanchang formation [4,5,6], and migration and accumulation mechanism of oil and gas was not studied thoroughly. Accumulation mechanism and controlling factors of reservoir groups in lower Yanchang formation will be discussed in this paper through the study of geochemical characteristics, pressure structure characteristics, and of reservoir forming characteristics and model. The further understanding of reservoir-forming mechanism of lower combination in lower Yanchang formation would help to improve reservoirforming theory of Yanchang formation and guide the future oil and gas exploration in lower combination fields
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
