Sedimentary Diagenetic Facies Model Of The Faulted Basin Under The Influence Of Volcano

The Anan Sag is located in the eastern part of the Manite Depression in the Erlian Basin.It is a typical Early Cretaceous inherited faulted basin.The A-3member was accompanied by strong volcanic activity during the sedimentary period.Faults,volcanoes and sedimentation have created unique sedimentary and diagenetic characteristics and strong physical differences in the third member.However,predecessors mostly studied its impact on reservoirs unilaterally from the perspective of sedimentation or diagenesis.Research on the combination of sedimentation and diagenesis is urgently needed to provide reference for similar basins in China and even eastern Asia.Aiming at the volcanic conglomerate of the third member of the A third member of the Anan Depression,based on core,microscope and scanning electron microscope observations,the characteristics of rock and sedimentology were determined,the types,stages and sequences of diagenesis were divided,and the characteristics of fractured volcanoes and sedimentation in the study area were combined to extract The key factors affecting diagenesis are to clarify the types of sedimentary diagenetic facies and their inter-distribution rules,and construct the development model of dominant reservoir sedimentary facies.The following main results have been realized:(1)The volcanic conglomerate reservoir of the third member of the A3 member of the Anan Sag is dominated by secondary pores.In addition to the standard type of diagenesis,devitrification alteration of unstable volcanic material and diagenetic shrinkage of volcanic ash alteration products have also developed,Thermal fluid characteristics authigenic mineral cementation and tectonic stress.The diagenesis stage is mainly in the mid-diagenesis B stage,which has undergone mechanical compaction-the first stage dissolution-nontonite cementation-chalcedony autogenous quartz and calcite cementation-kaolinite cementation-quartz enlargement and second stage nontonite cementation-The second stage of dissolution-illite cementation.(2)Analyzed the influence of fault depression,sedimentation and volcanism on diagenesis,which is mainly reflected in the contribution to the internal primary pores of the reservoir and the transformation of the external diagenetic environment;the division standard of sedimentary diagenetic facies was established and divided Six typical sedimentary diagenetic facies,of which the strong dissolution-residual intergranular pore porous facies in the fan delta front underwater distributary channel and the braided channel strong dissolution-residual intergranular pore porous facies in the nearshore underwater fan fan are the main ones Advantageous reserves.(3)The distribution of sedimentary diagenetic facies of the third member of the A3 member in the Anan Sag was explained,and the development model of the dominant reservoir sedimentary diagenetic facies was constructed,that is,near the fault location,the surface atmosphere fresh water and low-carbon organic acids discharged from argillaceous source rocks were mixed Penetrating into the reservoir with relatively well-sorted and relatively well-developed residual intergranular pores,it strongly dissolves easily soluble materials such as calcite cement,feldspar and intermediate-acid volcanic rock fragments,forming a large number of secondary pores,making the storage properties better.