Research On The Sequence Stratigraphy Of Jurassic And Cretaceous In The Southern Margin Of Hashan

The Hashan area at the northwestern margin of Junggar basin is a complex tectonicbelt, in the southern margin of which mainly exit the Mesozoic strata, and the Jurassic andCretaceous is the key oil and gas exploration horizon of Western New Prospect ResearchCenter, Shengli Oilfield Company,SINOPEC.Based on sequence stratigraphy theory andintegrated information about geology, well logging and seismic data, through determiningJurassic and Cretaceous sequence stratigraphy division method in the research area andbuilding up isochronous sequence stratigraphic framework and clearing about the maincontrolling factors of sequence stratigraphy and favorable sand body development pattern,the paper ultimately predicts the advantageous exploration block combining try oil andlogging data interpretation.Jurassic in the southern margin of Hashan is divided into a secondary sequence JSS1,which includs four tertiary sequence JSQ1,JSQ2,JSQ3,JSQ4. JSQ1and JSQ3developlowstand system, transgressive system tract and highstand systems tract,and JSQ2dose notdevelop lowstand system tract,and the highstand system tracts of JSQ4is lack in theresearch area.Cretaceous can be divided into a sequence KSQ1,which includes QingshuiheFormation for transgressive system tract and Hutubihe Formation for highstand systemtract,and lowstand system tract is lack in the research area.Through building up the sequence stratigraphy frame of Jurassic and Cretaceous in thesouthern margin of Hashan,and combining distributing feature of the sequence units,Iconclude that the characteristics of Jurassic sequences and filling mode is mainly controlledby tectonic activity.and subsidence,rate of source recharge and palaeotopography,and theCretaceous is mainly controlled by tectonic subsidence and lake level variation.Through researching the development rule of single well sand body and even well sand body in the sequence stratigraphy framework, I conclude that J1b and J2x developt thicklayer of favorable sand body, whose distribution range is larger and connectivity is good,and J1b can be divided into three sand group and J2x group can be divided into two sandgroup. At last, combined with testing for oil and logging data interpretation and favorablesand body plane exhibition cloth characteristics, I think Jurassic in the southern margin ofHashan has three favorable exploration blocks,and J1b has two favorable exploration blocksthat are mainly located in west area of Hashan and Xiazijie area and J2x has one favorableexploration block that is mainly located in the near of heavy size well area in front ofHashan.