Abstract:

According to oil and gas spatial distribution characteristics of Shang 9-4 trap in Shangjia oilfield, relationship between temporal matching of hydrocarbon accumulation and fault activity, comparison results of crude oil biomarker, it is shown that the crude oil of Putaohua reservoir in Shangjia oilfield was not injected from Fuyu-Yangdachengzi oil layers through the fracture by vertical migration. Based on drilling data, sandbodies of Putaohua oil layer in Shangjia oilfield distributed widely but the thickness was thin. Under the control of faults, the sandbody continuity became poor. Oil from K₂qn¹ source rocks in Sanzhao depression transported laterally into Putaohua layer in Shangjia oilfield through sands connected by fractures. Combination styles of fracture and sandbodies are the key factors to control oil migrate laterally and accumulate in Putaohua layer of Shangjia oilfield.The combination of synthetic faults and sand is favorable for oil and gas for long-distance lateral migration, while the combination of antithetic fault and sand is against to lateral migration but is favorable to form screened traps and accumulate oil. Meanwhile, the spatial distribution of fluid potential field also controls the lateral migration and oil gathering sites in Putaohua reservoir of Shangjia oilfield.

Key words: Shangjia oilfield, Putaohua oil layer, lateral migration, synthetic fault, antithetic fault, petroleum gas