Research On Hydrocarbon Accumulation Pattern Of Cenozoic In The Chunguang Block Of The Junggar Basin

Chepaizi uplift is located in the northwest margin of the Junggar basin,and the uplift and Hongche fault belong to the secondary tectonic units of the Western uplift of the Junggar basin.The history of oil and gas exploration for many years shows that the Chunguang block accumulation conditions are favorable,and the complexity of the hydrocarbon accumulation conditions and the difficulty of the selection of exploration targets are also showned.Previous researches on the migration force of the Cenozoic Oil and gas migration in Chunguang block are not comprehensive,and the research on the accumulation pattern is not thorough enough.It is necessary to further study on the Cenozoic accumulation pattern.This paper summarized and absorbed the results of previous studies,according to the existing logging,seismic and geochemical data,with the new oil and gas accumulation theory,focus on oil and gas accumulation elements and analyze the forming process,through the study of hydrocarbon source rock,source reservoir cap combination,oil and gas transportation system,the migration path of oil and gas,clarify the hydrocarbon accumulation process,summarize the hydrocarbon accumulation pattern,lay the foundation for future development.The main idea is to get the following understanding:1)The hydrocarbon source rocks are not developed in the study area itself,and the oil and gas are mainly derived from the Shawan depression Permian and Sikeshu depression Jurassic mudstones and the dark mudstone of the lake facies in the Anji Haihe formation.2)The main pathway system on study area composed of fracture,unconformity and compound pathway system,which the unconformity played a role in communicating oil sources,the fracture is the main channel for the initial and two vertical migration of oil and gas,the compound pathway system mainly controlled the migration path of oil and gas by fracture and unconformity.3)The crude oil in the study area can be divided into 3 types: The crude oil A originates from the Permian source rocks in the Sanwan depression;The crude oil B originates from the Jurassic source rocks in the Sikeshu depression;The crude oil C originates from the Jurassic source rocks in the Sikeshu depression and Anji Haihe formation source rocks.4)Analysis of oil and gas accumulation period;there are two stages of oil and gas filling in crude oil A,the first stage is the late Cretaceous,and the Cretaceous strata are gathered and formed,the second stage is the end of the Neogene,and the Shawan formation strata are gathered and formed;there are two stages of oil and gas filling in crude oil B,the first stage is the end of the Paleogene,and the Anji Haihe formation strata are gathered and formed,the second stage is the end of the Neogene,and the Shawan formation strata are gathered and formed;two stage continuous filling in crude oil C,the first stage is the Jurassic oil and gas filling,The second stage is the Anji Haihe formation oil and gas filling,and the filling time is the end of the Neogene to the present.5)Three types of accumulation patterns developed in the study area.The accumulation pattern of crude oil A is a "multi" type single source one-way transport model in two periods;The accumulation pattern of crude oil B is a anti "Z" type single source one-way transport model in two periods;The accumulation pattern of crude oil C is a anti "Z" type double source one-way transport model in two periods.