The Study Of Tectonic Evolution And Condition Of Oil-gas Reservoir Generation In Suibin Depression

The data of geologic section in the field ,well drilling, geophysics and analysis and test of geochemistry were deeply studied through the systematical collection of formation ,structure,sediment and the material of petroleum geology to study tectonic evolvement and condition of oil-gas reservoir generation in Suibin depression.The structural contour maps of major structural layer in Suibin depression are renewed through integrating the renewed interprete of the data of old seismic section with the new data.Based on it ,the structure and sedimentary facies were restudied .The conclusion can be drawn that there are 2 sags and 3 uplift in Suibin depression, the depression evaluation have 5 stages,which include rift stage in Late Jurassic,depression stage in early and middle stage of Early Cretaceous, compaction and return in middle and late stage of Early Cretaceous, tensional rift in late stage of Early Cretaceous and compaction and invertion in late Cretaceous.Some faults control the structure and deposition of depression ,such as JIANGBIN ,PUBEI,JUNCHUAN, SONG1-SONG2 faults and so on. The thickness of dark mudstone of Chengzihe formation is predicted to study the characteristic of source rock by the use of well-drilling ,sedimentary facies and data of the analysis and assay.It can be known that the distribution of dark mudstone is wide ,the organic matter is abundant,the type of which is mainly Typeâ…¢, organic evolvement exent is from high to higher,generates primarily gas and secondly oil.The peak of oil drain is at the end of Muling formation sediment.The peak of gas drain is at the end of Baoquanling formation sediment. The sandstone thickness of Chengzihe formation is predicted to study the reservoir condition by the use of well-drilling and sedimentary facies data.It can be known that the distribution of sandstone is wide ,the physical characteristic is weak ,the type is belong to lower porosity and lower permeability .The thickness of mudstone caprock is predicted to study the caprock condition by the use of well-drilling ,well-logging and sedimentary facies data . It can be known that the distribution of mudstone is wide,which is in all over the depression .The caprock sealing ability of Chengzihe formation in Suibin depression is synthetically evaluated and the result shows the best district is located in the west .The evaluation parameter of gas- transporting ability of sandstone is defined and calculated to study the characteristic of oil-gas transportion and migration of Chengzihe formation .It can be known that the highest efficiency area is located in the east of Suibin depression.The locomotivity and resistance data of oil-gas migration are calculated to study the path of oil-gas migration of Chengzihe formation .The result shows that oil-gas migrates from the Xinfang sag in the north and the Nandalinzi sag in the south to the high point surrounding .Eight parameter which are used as the trap evaluating parameter of oil potential are chosen to evaluated the oil potential of trap of Chengzihe formation .The grades of trap are classified according to the influencing exent . The result shows that Trap 3 and Trap 13 are the best trap. Based on the evaluating result of source rock ,reservoir rock ,caprock, migration and traps ,the favorable district of oil-gas reservoir generation and distribution of Chengzihe formation in Suibin depression is predicted .The result shows that oil favorable district is mainly located in Xinfang sag,Nandalinzi sag, and the major area of Paoxiao uplift ,secondly located in the west edge of North slope area, which has big area,that gas favorable district is mainly located in Xinfang sag, Paoxiao uplift and the major area of Nandalinzi sag ,secondly located in Fuxing slope and Zhongfutun uplift ,which has big area .On basis of the evaluating result of oil-gas favorable district and traps ,it shows that Trap 3 is the drilling target.