Analysis Of Sequence Stratigraphy And Favorable Zone Prediction Of Baiyinchagan Depression

Baiyinchagan Depression located in the west of Chuanjing Depression in Erlian basin ,which is a mesozonic-cenozonic half-graban resting on paleozonic base and extensd nearly east-westward.Based on stratigraphic sequence theory and analysis of seismic section.well-log and core rocks, the framework of sequence stratigraphy is built.The strata of bayianhua group can be divided into 5 third-order sequences,sequence .sequence I and sequence II were ' associated with Aershan formation .sequence HI was associated with Tenggeer formation.sequence IV and V were associated with Duhongmu formation.The features of these sequences arerbefore sequence I deposited during the rapid subsidence of the depression, the range of the sediment is limited .sequence II is the first series of source and reservoir rocks of the depression.there are regional unconformity at the bottom of the sequence III.the rock type are variety.this sequence is evaluated as good source rock, sequence IV is associated with the first section of Duhongmu formation, thick mudstone at the bottom and thethick single sandston are the main rock type.this sequence are evaluated as good source rock and reservoir.sequence V associated with the second and the third section of Duhongmu .which is mainly mudstone and can be regional capping rocks.On the basis of the framework of chronostratigraphic sequence and the analysis of well-log,seismic section,the paper studied types and the distribution of sedimentary facies.three types of sediment can be identified: braided river delta systems mainly formed on the south slope.little-sized turbidit fan mainly formed in the middle deep area and dan delta mainly formed on the north slope of the depression.Through identifying the special seismic faciesin the seismic lines of Baiyinchagan depress ion.formed the sedimentary facies distribution charts of the five sequences .At last ,through analyzing the assemblage of source .reservoir, and capping rocks.favorable zone is finally predicted.