Sequence Stratigraphy And Depositional System Of The Member One And Two Of Dongying Formation In The Middle Of Liaozhong Depression

Taking high precision sequence stratigraphy and earthquake sedimentology,tectonic stratigraphic,basin analysis and simulation theory as the guide,on the basis of studying seismic profiles and logging fine interpretation,core observation and computer simulation Seismic profiles and logging fine interpretation,core observation and computer simulation combined,establish the sequence stratigraphic framework of the region of interest,identify the sedimentary facies in the region of interest, clarify the distribution and evolution of the sedimentary system within each sequence,reveal the control function of the paleostructure and the lake-level change.So predict sandbody space distribution effectively.In order to establish isochronal stratigraphic framework of dongying formation,We analyze the single well,framework profile and well tie profile of the central of Liaozhong depression,carry on the stratigraphic classification strata of dongying formation on the basis of Combining with core,logging and seismic profiles of.We divide Dongying formation into as a complete second-grade sequence,corresponding Oligocene strata.According to local existing unconformity and their corresponding conformity,divide dongying formation into three third-grade sequences Sqd1, Sqd2, Sqd3.And in third-grade sequences internal tracking easy to track and recognition of the reliction interface,and carry on the level 4 stratigraphic classification,among them Sqd1 and Sqd2 are the intended interval of the research. We divide Sqd2 formation into d2-1?d2-2 two fourth-grade sequences.Combining logging curve shape, core,and seismic facies comprehensive analysis, recognition mainly sand scattered system and sedimentary system type of the study area.Differentiate braided delta system, mild or vertical far source river delta system, sublacustrine fan system, littoral and shallow lake- beach dam system, deep lake shale depositional facies types,clarify the structure of the sedimentary facies in the major depositional systems tractsand the distribution of stratigraphic framework.Analyze the control factors of the development and distribution of the sedimentary system in the stratigraphy - systems tracts,find that the lake-level change,tectonic activities ,source supply all control the development of sequence in different degrees.The lake-level change is the direct reason of controlling sequence interface formation;tectonic activities,especially tectonic subsidence role, fundamentally control the development of the high level sequences.According to the different structural position,we divide the region of interest into six different zones,and analyze its oil accumulation conditions respectively,identify the main controling accumulation factors,and combine the sedimentary system distribution.Finaly put the different zones exploration prospects.