Three-dimensional Geological Modeling Of The Neogene ?-? Oil Group In The Footwall Of The No. 2 Fault In Gaskule Oilfield

Guided by the theories of sequence stratigraphy,seismic stratigraphy,tectonic geology,sedimentary petrology,mathematical geology and other disciplines,this paper makes full use of the data of coring,seismic and logging in the work area to complete a series of basic geological interpretations such as sequence framework establishment,seismic structural interpretation and sedimentary microfacies analysis,then establish an accurate three-dimensional geological model of ?-? oil formation of N1-N21 Reservoir in Gaskule Oilfield by using deterministic and stochastic modeling methods.The main achievements are as follows:In this paper,applying marker layer method,index bed method,sedimentary cycle method and slice method,the Neogene ?-? oil formation in the footwall of fault ? is compared and the stratigraphic framework is re-established.Oil group ? is divided into sixteen sub-layers,oil group ? into 20 sub-layers and oil group ? into 20 sub-layers,altogether into 56 sub-layers,this is how to lay the foundation for the follow-up work.With the support of logging technology,three-dimensional seismic data,this paper used synthetic seismograms to calibrate seismic horizons,established variable velocity fields of each layer in the work area,and carried out structural mapping in order to study the structural and fault characteristics of the target section and to provide data support for three-dimensional geological modeling.The study reckons that the footwall of Gaskule Oilfield is a nose-like structure with a nearly north-south direction,which is mainly controlled by the ? fault and cut by several faults at the same time.Considering tectonic and sedimentary background of the working area,the paper concludes that braided river delta front deposits are developed in ?-? oil formation.Combining with sedimentary facies markers such as geological facies and logging facies,the?-? oil formation is further subdivided into many sedimentary microfacies such as underwater distributary channel,and the plane distribution characteristics and vertical variation rules of sedimentary microfacies are summarized.Finally,the sedimentary facies pattern of the work area is established.According to the structure and fault data obtained from three-dimensional seismic structural interpretation,the structural model of the work area is established;According to the results of sedimentary facies analysis,the sedimentary facies model is established by using deterministic modeling method;Porosity model,permeability model and oil saturation model are obtained by using phase-controlled Gauss stochastic simulation algorithm and variable function control.Finally,the volume method is used to calculate the geological reserves of each reservoir group.The geological reserves of ?-? oil group are 493.00 × 104t,whose relative error with actual reserves is 1.8%.With relatively high fitting degree,this paper provides a credible geological model for the further research and development of Gaskule Oilfield.