Geological And Geochemical Characteristics Of Tight Oil-source Rocks In Eastern China

As the oil and gas exploration and development moving into further stage,regular oil and gas resources can barely meet the demands of fast-growing economy;the unconventional oil and gas will be the next target of exploration,with tight oil being a crucial part of it.This essay will take Jizhong Depression,Songliao Basin,Liaohe River Bohai Sea Basin and Liaohe River Depression in southern China as main research target,to compare the typical sedimentary structures;and focus on the discussion of source rocks characteristics in oil field and the distribution of its reservoirs as well as the Geological-geochemical factors of its formation.The following conclusion can be summarized from the research:The tight oil-source rocks in eastern China has a variety in organic matter;they are also in the proper stage of thermal evaluation.The good-quality source rocks provide a solid base to produce tight oil while delivering regular oil and gas resources.The quality level of source rocks here is above the average;it's in a good condition of forming concentrated tight oil resources.There is deposition of lacustrine dark mudstone and marl in Bohai Harbor basin Jizhong depression and Shulu sag lower segments of Es₃;the source stones are above average,with a variety of type II₁,type III organic matter.The source stones are ripe and easy to deliver oil,conducting the tight oil resources stored in Es₃ mudstones;belongs to typical“source and storage combined”tight oil resources.The tight oil resources in Bohai harbor basin Liaohe depression mainly located in Western sag and Damintun sag.West downwrap Es₃ develops into the fan-delta and lacustrine deposits system;the source stones are in good shape,mainly type II and III kerogen;in the layers from bottom up type II₁ turns into type III kerogen,they are all in their ripe stage.Es₄ stage deposition turns into salty lake silled basin environment system,there is high volume organic matters in the source rocks with a good quality.Es₄ stage deposition are mainly type I and type II₁,in a ripe condition with rich organic matters.The tight oil storage in Soliao Basin are mainly located at Qingshan segment 1,majorly wide-distributed dark mudstone with rich type I and II₁ organic matters in ripe to post-ripe condition;it is a great base for the formation of tight oil.With the comparison of each oil filed,it can be confirmed that a relatively stable construction background and rick depression-slope deposition system are the best base for tight oil concentration.Good quality source rocks are the physical base,it will provide tight oil the forming space it needed.Source-storage configuration is a critical factor for tight oil concentration,while the Hydrocarbon booster provides the power for oil and gas transfer.