环渤中地区新近系控藏模式与高丰度油藏勘探实践

环渤中地区新构造运动强烈,新近系是主要的含油层系.新近系勘探早期集中于凸起区和陡坡带,而斜坡带和凹陷区由于缺乏油气运移条件的系统性研究导致其勘探成效较差.基于前人研究和钻井资料,从分析环渤中地区新近系油气运移路径出发,通过建立"汇聚脊-断层-圈闭(脊-断-圈)"三元控藏模式,明确了受潜山风化壳汇聚脊控制的深层油气的汇聚...

Neogene reservoir-controlling mode and exploration practice of high-abundance oil reservoirs in Bozhong sag and its surrounding area

The neotectonic movement is intensive in Bozhong sag and its surrounding area, and the Neogene is the main oil-bearing set. In the early stage, the exploration of Neogene focused on the uplift area and steep slope area, while the exploration of slope area and sag area was poor due to the lack of systematic study of hydrocarbon migration conditions. Based on previous researches and drilling data, as well as the analysis of Neogene oil and gas migration pathway in Bozhong sag and its surrounding area, this paper establishes a ternary reservoir-controlling mode of “catchment ridge-fault-trap”. This mode clarifies that the hydrocarbon accumulation ability in deep layers controlled by the catchment ridge of weathering crust of buried hill is the prerequisite for the Neogene oil and gas enrichment, and creates an oil accumulation index using traps as the core to quantitatively evaluate the deep hydrocarbon accumulation ability. Moreover, it is clarified that the vertical migration of faults is the key to the formation of Neogene reservoirs. The configuration relationship between faults, catchment ridges, and regional cap rocks determines the vertical migration of faults. When the faulted-contact thickness of the deep cap rocks is less than 220 m, oil and gas can migrate to shallow strata. It is clear that trap is the final link for the formation of Neogene reservoirs, and the configuration relationship between traps and faults controls the lateral migration of shallow oil and gas. The dual faulted sandbody has a strong lateral charging capacity. The ternary reservoir-controlling mode of “catchment ridge-fault-trap” has further enriched the late accumulation theory of the Bohai oilfield, and has shown good application prospects in guiding the discovery of mid-large Neogene oilfields and the exploration of other external-sourced strata.