Hydrocarbon Accumulation Characteristics And Hydrocarbon Filling Capacity Of Typical Buried Hills In Jizhong Depression

There are abundant oil and gas resources and great exploration potential in the buried hill of Jizhong Depression in Bohai bay basin,it is important to study the mechanism of hydrocarbon accumulation in buried hill and establish a formula to evaluate it.Based on the research of the distribution of oil and gas accumulation and geological background,the types of buried hills in Jizhong depression are divided,and the differences of accumulation mechanisms are compared.For different source-storage docking type buried hills,through the preferred evaluation parameters,the oil and gas charge quantitative evaluation was carried out.Based on the previous research results,compare the formation conditions of the buried hill oil and gas reservoirs in the Jizhong depression.Based on the secondary structural belt of the buried hill reservoir distribution,the buried hill reservoirs in Jizhong depression are divided into three types according to the location of the buried hill distribution: high,medium and low.Both sides of the high buried hill are adjacent to the Paleogene hydrocarbon generating depressions,and the hydrocarbon supply conditions are superior.The middle buried hill usually has a one-way hydrocarbon supply and the source rock has a long distance with the buried hill,so the hydrocarbon supply condition is poor.The overlying carboniferous Permian makes the weathering time of the buried hill shorter and the reservoir conditions poorer.The low buried hill is located under the Paleogene source rock strata,which has good hydrocarbon supply conditions and superior preservation conditions due to its deep burial.The typical oil and gas reservoirs of three types of buried hills were selected and dissected from the oil and gas source,sealing characteristics,transform framework and accumulation time.Represented by the oil and gas reservoirs in the buried hill of Ren qiu and the buried hill of Yang shuiwu,the accumulation mode of the high buried hill is mostly distributed in the central uplift belt.Taking Su qiao buried hill as the representative,the accumulation mode of the middle buried hill is mostly distributed in the slope zone,which has the characteristics of "lateral oil source and complex transmission".The accumulation patterns of the low buried hill are mostly distributed in the sag belt.Niudong 1 buried hill is a typical representative of the low buried hill.Select the hydrocarbon generation intensity of source rock,physical property of buried hill reservoir,weathering and leaching time,hydrocarbon supply mode of buried hill,types of reservoir and sealing rock combination,structural evolution configuration and height of hydrocarbon supply window of buried hill as the parameters for evaluation of hydrocarbon filling capacity of buried hill.The quantitative evaluation formula of oil and gas filling capacity of buried hill was established,and the evaluation parameters were classified and assigned to calculate.The calculation results of oil and gas filling capacity of typical buried hill in Jizhong depression show that the oil and gas filling capacity of the three types of buried hill reservoirs are obviously different,among which the high buried hill has the strongest filling capacity,the low buried hill has the second and the middle buried hill has the weakest.