Research On The Reservoir Characteristics Of Jialingjiang Formation Of The Triassic In Tongnanba Area

Tongnanba area is the largest exploration block of Sinopec in the Northeast of sichuan basin,and it is the second largest belt in Sichuan basin. Recent years it has become a hot petrochemical exploration area.So far, it haven't pay enough attention to Jialingjiang formation, the research on reservoir dolomitization and dissolution process is not deep enough,and the reservoir development controlling factors of Jialingjiang formation is not being comprehensive understanded.Therefore,it has important theoretical and practical significance for finding favorable areas in next exploration.This paper is based on previous research,using modern carbonate sedimentation reservoir geology and sequence stratigraphy theory, and this paper research the equence stratigraphy and sedimentary facies by the observation of outcrops, drilling cores and thin sections, combined with well logs and seismic data.On this basis, this paper research the rock characteristics, reservoir properties,pore structure and content of diagenetic evolution by the analysis of test data of physical properties, mercury, relative permeability,cathode luminescence, isotopic, electron microprobe, evaluat the reservoir by above results, and predict the favorable area.The result showed that this formation has low porosity and permeability,but some areas and sections are good regional and local level,which may constitute middle-hole,middle perm eability type and fissure-hole reservoir,and the secend section of Jialingjiang formation is bese,it can be evaluated toⅡ,Ⅲtype reservoir.The Jialingjiang formation main lithology is dolomite, anhydrite, salt and limestone.The reservoir lithology is psammatic dolomite, oolitic dolomite.The sedimentary facies of Jialingjiang formation is open platform-restricted platform. The main diagenesis is complex such as cementation, dolomitization, late dissolution, gypsification and degypsification. Early dissolution,dolomitization and fracture created by late tectonic movement are benefit to the reservoir,but multiple cementation and compaction are harmful to the reservoir.Dissolution pore and mold hole are the main pore types of Jialingjiang formation in this area. Account 90% of the total porosity, the Jia2 are poor physical property (the porosity are 0-4percent,the permeability are main 0.01-1×10-3μm2) has poor correlation of porosity and permeability which means that the reservoir has strong heterogeneity. TheⅠ-Ⅱtype reservoir will be found in Jia2 and Jia4 in the north of Tongnanba area,it is fissure-porous type reservoir;Ⅱ-Ⅲtype reservoir is found in the upper of Jia2 in the middle and west of Tongnanba area,it is rich of fissure,and it is fissure-porous type reservoir; IV types reservoirs distribute in all section of this formation are fissure types reservoirs with orizintial in the middle and the south of Tongnanba area.At last,the paper predict that the favorable block of Jia2 is in Heichiliang area,Heba area and the north in of Tongnanba area.