Sedimentary System Research And Geological Modeling Of HG Group In WT Gas Field

WT gas field is located in the south of XH sag, East C hina Sea. Lots of research has been done on the study of regional sedimentary phase, but there are also a lot of controversy on it. Sedimentary facies controls the distribution of the sand body, and it is of great significance for the oil and gas exploration and development. Based on the comprehensive analysis of core, logging and seismic data, considering that the system of braid braided river, meandering stream and delta is developed. The sedimentary evo lution model and the 3D geological model was established further.The types of sedimentary facies in the study area was distinguished to braided river, meandering stream and delta depositional system by the comprehensive utilization of the core, logging curve and seismic data in 3D. Four sequences of three were identified in WT gas field and the sequence stratigraphic framework of the gas field was established based on the sequence stratigraphy. Under the guidance that sedimentary facie controls sand body, vertical sedimentary evolution rules and layer development condition was analysed of single well, based on the standard well, the whole distribution pattern of sedimentary system in the study area was established according to the well connection. Due to the different layers’ different depositional environment, specific small layer contrast method was used to different sedimentary reservoir, namely, braided river system by sedimentary interface contrast method, the meandering river system by cycle correlation method, the delta by isochronous correlation. Each sublayer sedimentary microfacies types, which are braid river, beach, river floodplain thin sand, floodplain, beach, abandoned channel, crevasse splay, flood plain, plain distributary channel, underwater distributary river, river mouth bar, far sand bar and sheet sand 13 kinds of sedimentary microfacies types were distinguished by subdividing the horizons. Because of the tectonic movement and the increasing of the lake surface, study area experienced rap id deposition of braided river, meandering river, delta evolution process, and sedimentary evolution model in the study area were analyzed.On the basis of the research on the stratigraphic subdivision and microfacies, the sedimentary models of the study area was established using the method of deterministic modeling by petrel geological modeling software. Then, under the control of phase, the reservoir property model was established by fitting the variable range of different matter source directions. The structural characteristics of the study area, the distribution range of the sand body and the model of the reservoir parameters were clearly characterized in the three-dimensional space, which provides a basis for the further development of gas field.