Comparative Study Of Shale Oil Forming Conditions In Bohai Bay Basin And The Typical Basin Of North America

As an important unconventional oil and gas resources,shale oil has become a hot spot in oil and gas exploration and an alternative energy in recent years.The successful development of the North American shale oil vastly changed the world energy structure,it sure that has a profound impact on the international crude oil prices.Although Chinese continental shale oil resources are rich,the research of exploration and exploitation still in low levels.In order to learn from North America's successful experience to promote the exploration and development of terrestrial shale oil in China.On the basis researchs of shale oil forming conditions in the Ek₂ of the Cangdong sag in Bohai Bay basin,three main shale reservoirs in North Amercia,such as Williston basin Bakken formation,Fort Worth basin Barnett formation and Gulf of Mexico basin Eagle Ford formation,have been investigated for contrastively analyzing in the field of characteristics of basic geological,organic geochemical,petrological,shale oil reservoir and shale-oil reservoirs,etc.At the same time finding similarities and differences to lay the foundation of chinese shale oil forming conditions and concentration regularity.Bohai Wan basin Cangdong sag is a rifted basin in Eocene,the tectonic evolution history is complicates and quite different from shale oil basins in North America which tectonic setting is relatively stable.Compared with the three shales in North America,the average of TOC in Ek₂ shale of Cangdong sag is lower,but genetic potential is higher,organic matter type is given priority to I and?₁.On the whole the Ek₂ shale is immature-unripened,and has obvious hydrocarbon expulsion in Miocene.Until now,it has strong material foundations and good conditions of hydrocarbon generation for forming the shale oil.The brittleness mineral content in the Ek₂ shale is lower than in North America.Content of clay minerals is similar to North America,it gives priority to Mixed-layer illite/smectite.The Ek₂ shows stronger heterogeneity and complexer lithology,it also has more lithofacies which change quickly in vertical direction.That is diaadvantage for fracturing as a whole.High organic carbon phases is the dolomitic shale and sand shale,but compared with North America,the TOC of high organic facies is lower.The main pore types of Ek₂ shale in Cangdong sag are intercrystalline pores and organic pores.Since the pore size distribution range of Ek₂ shale is bigger than North American shales,it is conducive for large oil molecules to flow in the pores.Shale oil reservoirs,both in the Ek₂ shale and the three shales in North America,are low porosity and low permeability reservoirs,whose performance is good.But the reservoir type is also different,like the Ek₂ is Hybrid Shale.