| Based on the theory of sequence stratigraphy、sedimentary petrology、petroleum geology and other related subjects,this paper uses comprehensive methods of Stratigraphic comparison、sequence analysis and sedimentary facies analysis to contribute the sequence stratigraphic framework、identify the type of sedimentary facies and predict the favorable area of the Shahejie group in Sanhecun formation,also combining the core logging data、survey/drilling data、seismic data and the regional geological background.The main layer of this paper is the first、second and third section of Shahejie group.Because this area lack terrain slope and it’s difficult to identify the first lake surface,so the third-order sequences of this area can only be divided into two system tracts,which contains transgressive system tract(TST)and high system tract(HST).This paper combines the third and the second section of Shahejie group in Sanhecun formation as a third-order sequence which can be divided into two system tracts,and make the first section as a beginning of a new sequence.In this paper,there are six subsequence sets—three in transgressive system tract,two in high system tract and one in the first section.The sediments are mainly provided by ChenJiaZhuang salient in south,as well as a little from the bottom of sequence in north;the sedimentary type of the third and second section is fan delta which is rich in provenance and gravel,mainly locating in south land,while in the north land located a small number of underwater alluvial fan.The sedimentary type of the first section is salt lake.The favorable exploration area is located in the structural high part where the seismic amplitude is strong and the lithology in front of the fan delta thins out.Based on this,there are totally seven favorable targets in sand group one and sand group two which is in the lower part of the third section in Shahejie formation,and the total area is4.92km~2,with the total geological reserves of about 21.87 million tons. |
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