Reservoir Characteristics Of The Carboniferous Huanglong Formation In The Longhuichang-Tieshan Area Of ??the Northeastern Sichuan Basin

Northeast of Sichuan basin Longhuichang-Tieshan as the area for research district in this paper,and Carboniferous huanglong group reservoir formation as research object.Using theory of sedimentary rocks Petrology,and storage layer geology,and oil geology,and geochemical for guide,integrated geological,logging,core,and analysis of data and part of earthquake information,combined with previous research achievement,the paper studies on Longhuichang-Tieshan area huanglong group formation's exhibition cloth features,features of sedimentary facies,reservoir features,and reservoir longitudinal,and horizontal exhibition cloth features and the factors which controls the reservoir,eventually pointed out the favourable district that reservoir developed.Generally,huanglong formation of Carboniferous in the study area is divided into three sections and is thicker from North-South to West-East.Strata is comparable between wells.The rocks and logging characteristics between strata under or overlying huanglong group are distinct.According to the characteristics of lithology and electric property,combined with the previous research results the sedimentary environment of huanglong in the study area is tidal flat sedimentary environment on the whole.Tidal flat sedimentary facies can be divided into three sub-phases,and sedimentary environment of the first huanglong period mainly in supratidal,the second huanglong period mainly in the intertidal zone,and the third huanglong period mainly deposited in phases of the subtidal but part of well areas are intertidal sedimentary environment.Water invaded from North East to South WestThe rock types in the study area are mainly the dolomite,particle dolomite,and breccia dolomite.But limestone reservoirs doesn't develop in this area.The reservoir type is about Porous?cracks.Pores are the main storage space,and pore type is mainly grain(dissolved)pore,granular dissolved pore and intergranular(dissolved)pore.Cracks,which played an important role in improving the permeability of the reservoir.Reservoirs in the region is mainly developed in huanlong ?,and most of the reservoir is type ? according to the standard of classification.Reservoir development controlled by micro-facies,multiple-diagenesis and tectonic processes.Advanced sedimentary micro-facies are granular beach and(limestone)dolomite flat.By using the previous research results,we conclude that burial period dolomitization,dissolution on surface and in burial period have crucial effects on reservoir development.According to the distribution of reservoir,superimposed sedimentary facies in the second huanglong period,points out the region that ? class and ? class of reservoirs might develop well.The class ? advantageous area is located west of Tieshan,and east of the Longhuichang and the class ? is located in Longgang 80 well area.