Sequence Characteristics Of Dlianhe Formation Inm Three-Dimensional Area Of Fangzheng Depression

Paleogene Dalianhe Formation is the major exploration interval of Fangzheng depression, nowadays only three levels was divided according to the sequence of Dalianhe Formation and neither one common realization was agreed, so it's very urgent to begin to have the research on the character of the sequence of the Dalianhe Formation. Through the sequence dividition to the drilling and well logging, in combine with Synthetic seismograms, Seismic calibration etc.methods, we can set up the Isochronous sequence stratigraphic framework in the zone of 3D project. Then in the basic of indentification in drilling, well logging, seismic etc. Phase marks In the sequence stratigraphic framework. Spatial and temporal distribution of depositional systems and thecontrolling factors was analyzed, the favorable direction of oil and gas exploration was indicated.Fangzheng rift zone Dalianhe group 3D sequence boundaries and at all levels of sequence was normally divided, Paleogene Darien River Formation was divided to three Third-order sequence, six Base level cycle unit. According to the comparasion to the Sequence Stratigraphy of main wells and seismic profile, relative Sequence stratigraphic framework was built, the characters of sequence stratigraphy was analyzed.Through Description of a large number of core observation, well logging and logging data, combine seismic data, we can draw an conclusion that in the stratum of Paleogene Darien River Formation, three kinds of sedimentary types was made, Lacustrine, Fan-delta and bottom fan. Lacustrine can be divided to Shallow lake facies and Semi-deep lake-deep lake; Fan delta can be divided to three Subphases: Fan delta plain, Fan-delta front and Fan delta. Lake fan facies can be divided to 3 subphases: Inner fan, middle fan and outer fan.Through the research on the Stratigraphic isochronous depositional system within the framework, Fangzheng rift with more knowledge of source characteristics was suggested. We indicated that in different geological period the main origin direction was not the same. Sedimentary facies distribution law and Favorable, reservoir and seal assemblage was clear, Sand and oil and gas distribution was discussed, according to the Spatial and temporal distribution of depositional systems and the analysis of reservation condition, favorable exploration zone was indicated.