Geismic Facies And Sedimentary Facies Study In Sungang-Xiaermen Area Of Biyang Sag

In order to study the sedimentary characteristics in Sungang-Xiaermen area of Biyang sag, based on the high-precision3D seismic data of80km2and logging data of61wells, the seismic facies and the sedimentary facies in the Ⅰ～Ⅶ sand groups of He3member are studied. Based on the depth data of the top and bottom boundaries of each the sand groups, the residual stratum thickness charts are obtained. The residual stratum thickness charts are combined with the seismic event contacting relationship in seismic profiles to analyse the ancient landform. Using the conventional seismic phase identification method and the waveform classification seismic facies analysis method of Kohonen neural network, the7sets of sand groups in the study area is used to identify the seismic facies. By the study, four typical seismic facies are identified, including imbricate progradatio、oblique foreset facies、sphenoid foreset facies and sub-paralleling sheet facies. Combined with seismic attributes of amplitude、frequency、 horizon-correlation、waveform classification、etc, the four typical seismic facies are divided into different blocks, which provide a reference for classification of sedimentary subfacies. Analysing the single well facies of key wells in the study area. And the connecting-well profiles are made to analyse the source direction and the evolutionary regularity of delta. Finally, combined with seismic facies and logging facies, the sedimentary facies distribution of Sungang-Xiaermen area are obtained. the following three types of sedimentary facies are developed in the Ⅰ～Ⅶ sand groups of He3member in the study area,braided river delta, fan delta and lake sediment. In the northern study area, there are vast braideddelta front subfacies in the He3member.And in the southern study area, there are two small leafy sand bodies of fan delta front in the He3member.