Research On Sedimentary Characteristics Of Tongbomiao Group In Northern Area Of Wuerxun Hollow

The sand body is well developed in the TongBoMiao Formation of Northern Area of WuErxun Hollow and maybe becomes effective reservoir spaces.So it is necessary to study its depositional features.Based on the features of cores,according to the theories and methods of the sequence stratigraphy and sedimentology as well as the data of core, seismic,well logging, the author deeply studies the sequence stratigraphic framework and sedimentary facies types of the TongBoMiao formation in the northern area. The author combines the research results of previous studies with the initial research above,and predicts the favorable reservoir facies.In northern area, T3 and T4 which are the top and bottom interface of TongBoMiao group are larger regional unconformitysurfaces in the block sag. Combining the well logging with seismic, we achieve the unification of the drilling stratification and the seismic interface. We divide the TongBoMiao formation into one three-order sequence, four fouth-order sequences.In the light of lithology ,depositional structures ,log facies and sesmic facies,the papers summarize sedimentary facies characteristics of the TongBoMiao formation in the area. The area mainly deposits Fan-delta and lacustrine, partly volcanic facies.Using source,sesmic attribute and distribution of the strata,based on the analysis of single well facies and the correlation of cross sections, this paper studys sedimentary system in each four-order sequence.Finally, considering the research above and the factor of oil generation, storage, cap rock, trap comprehensively, we point out the favorable reservoir facies.