Comprehensive Evaluation Of Carboniferous Carbonate Reservoirs In Bajiaochang Block

Guided by Structural geology,Reservoir geology,Sedimentary rocks and sedimentary facies,Mineral petrology,combined with the previous research results in Bajiaochang area,making full use of the drilling data,core data,logging data,kinds of test and analysis data,using the multidisciplinary and multiple comprehensive research methods,the reservoir classification and comprehensive evaluation have been done in the Carboniferous Huanglong group reservoir in this paper.The Carboniferous sedimentary is controlled by the fourth transgression,and influenced by the Caledonian movement of late silurian system and the Hercynian movement of Carboniferous period,which made the Carboniferous Huanglong group become a residual layer between the Silurian System Hanjiadian group and the Permian system Liangshan group,and developed a suit of carbonate deposits.The Huanglong group can be divided into 3 segments,which is C2hl1?C2hl2 and U2hl3.According to the marks of the sedimentology,sedimentary petrography and the logging facies,the Huanglong group mainly developed the Carbonate tidal flat facies.The C2hl1?C2hl2 and C2hl3 are corresponding to the tidal flat,tidal flat and tidal flat facies,and further divided into eight microfacies.Through the analysis and research,the carboniferous Huanglong group is the fracture-pore reservoir.The holes are mainly intergranular(dissolved)holes,intercrystal(dissolved)holes,and the fractures are mainly low angle and small fractures,which are the main seepage channels.The C2hl1 mainly develop grain limestone and plaster gypsum,the average porosity is 1.4%,and the fracture development is the worst.The C2hl2 mainly develop grain dolostone,the average porosity is 5.5%,and the fracture development is the best.The C2hl3 mainly develop grain dolostone,the average porosity is 1.8%,and the fracture development is poor.According to the standard of the sedimentary characteristics,physical characteristics,electrical characteristics,the fracture development situation and the reservoir effective thickness,the reservoir is classified into four types,which is ?,?,? and ?type.Among them.The most widely distributed reservoir type is the ? type.Among them,the C2hl1 doesn't have reservoir distribution.The C2hl1 is the main reservoir distribution layer,which is the only distributed layer of the ? type reservior and the mainly distributed layer of the ?and ? type reservior.The C2hl3 distributes a small amount of ?Hand ? type reservior.In terms of reservoir distribution area,the most advantageous reservoir development areas are Bajiaochang structure high point in the middle of the study area and the south high point of Bajiaochang structure in the southeast of the study area.