Applied Research For Three-dimensional Geological Modeling And Fracture Prediction

Gas reservoir in Wubaiti blocks in carboniferous huanglong group was found in Sep1989, brought into production test in Dec1992,draw up the overall field development plan in1995and finished it in2001. Under the background of transgression and the co-constraints by sedimentary, diagenetic and tectonic movements developed the fractured-porous gas reservoir. Gas reservoir which controlled by the tectonic movement developed multi-thrust faults of west-dipping and multilevel fault terrace with southward down-dip gradually which contorted the fold structure that made the poor connectivity between layers. For the gas reservoir, well production have development the mid and later stage with contradictions increasingly in the plane, interlayers and inner layers. With the fine description for gas reservoir and the three-dimensional stochastic modeling to reflect the gas reservoir geological features and to identify the favorable reservoir zone and fracture development zone, it’s good for the further understanding of the gas reservoir characteristics and potential production, also provide the basis rule for further exploration and development. In response to these problems, we carried out the following main research work:(1) With the evaluation and analysis by regional geological background and reservoir characteristic for gas reservoir, we can conclude that, Huanglong group can be subdivided into three members based on the petrographic characteristics:C2hl1、C2hl2and C2hl3, gas reservoirs are mainly developed in C2hl2, first member is for sabkha deposition, second member is for open-limited Marine deposit and third member is for open marine carbonate deposits. The study area showed the reservoir properties is medium to low porosity, low matrix permeability cores, low water saturation and the reservoir heterogeneity is serious.(2) By comprehensive using the seismic, drilling, logging and dynamic production data and combining previous research results for deposition, reservoir and well logging to establish the three-dimensional geological modeling, The model is consisted with geological structure model, effective reservoir facies model, net thickness ratio, porosity, permeability and other properties parameter model. Based on testing the attribute parameter and verifying the reliability and accuracy of geological model, it can determine the application effect of three-dimensional geological modeling.(3) By using3-D seismic data to analysis the effects for how the different ant tracking attributes influents the final track results, it can optimized the attribute parameter settings for gas reservoir:Ants seeds is7, ant track deviation is2, ant step size is4, illegal steps allowed is1, legal steps required is3and stop criteria is10%.(4) By using3-D seismic data and Ant Tracking, it can gained the the ant tracking property. Establishment a three dimensional crack model in the study area with the technology of extracting the crack automatically, it can predict the fracture parameters’s reliability and verify the application effect for fracture prediction.