Research On 3D Geological Modeling Of Coal Reservoir Based On Joint Well-seismic Constraints

Coal reservoirs in China are greatly affected by tectonic activities and their geological conditions are complex,which makes coal bed methane reservoirs generally characterized by high heterogeneity.As a geological phenomenon of coal reservoirs,the heterogeneity of coal reservoirs has obvious spatial characteristics,showing high-level heterogeneity,planar heterogeneity and intra-layer heterogeneity.This paper provides a new idea and technology for the quantitative characterization of coal bed methane reservoirs by conducting three-dimensional geological modeling of coal reservoirs,and provides a basis for numerical simulation of coal bed methane reservoirs and prediction of favorable areas.According to the principle of high-resolution sequence stratigraphy,according to the various sedimentary characteristics of the drilling core in the study area,log characteristics analysis and various sedimentary facies signs,combined with the regional sedimentary background,the delta is identified in the Taiyuan Formation of the Sijiazhuang mining area.There are three types of sedimentary facies on the barrier coast and carbonate tidal flat,five subphases and nine microfacies.By comparing the drilling core,sedimentary facies type definition and logging curve response characteristics of the study area,the Taiyuan Formation of the study area is divided into five third-order sequences,and the sequence stratigraphic framework of the coal reservoir in the study area is established.Aiming at the thin thickness of coal seam,the spectral bluening frequency-raising technique and the colored inversion method are used to improve the original seismic data,which effectively improves the resolution of seismic data and assists in the identification and precision of No.9 and No.15 coal seams.track.By performing the layer calibration,the reflected wave layer formed by the No.9 coal seam and the No.15 coal seam was identified.By extracting variance,chaos and ants,the effective identification and interpretation of faults and collapse columns in coal seams are realized by comprehensive application of seismic data processing and attribute extraction.Analysis of various reservoir modeling methods,because the original sedimentation controls the macroscopic heterogeneity of the reservoir,the alternating of phases is the basic factor limiting the nature of the reservoir,so the deterministic geostatistical interpolation needs to be combined with the stochastic simulation.In the attribute simulation,the stochastic modeling method can better reflect the heterogeneity of the coal seam.Through the fine structure interpretation and logging interpretation,the paper firstly establishes the fault model and the layer model of the study area,and then establishes the structural model of the Taiyuan coal seam in the study area through the planar grid design and the longitudinal small layer splitting.Then,using the stochastic modeling method,the lithofacies modeling of the Taiyuan Formation in the study area is carried out.Based on the comprehensive modeling,the ash model and vitrinite of the coal reservoir are established by using the sequential Gaussian simulation algorithm controlled by the phase model.The reflectivity model studies the physical distribution of coal reservoir ash and vitrinite reflectivity in three dimensions.