AVO Forward Modeling Of Coalbed And Seismic Prediction Of The Basic Parameters In Coal Reservoir

Based on the AVO forward theory in coal bed, this paper studied the the stronganisotropy of coal bed and the effective medium model (EDA medium model). Coalgeological model was established according to theory of fractured media elasticconstants model and seismic wave propagation in anisotropic media. With this model, itdiscussed the characteristic of seismic wave propagation and deduced the exact P-andconverted S-wave reflection coefficient equation. Substituting the actual geologicalparameters into the exact equation, the results showed that the fracture factors, waveletfrequency and thickness of the coalbed had different effects on the reflection coefficient.In addition, with the basis of the actual seismic data from Guqiao mining area and themethod of3D seismic prediction, the coal reservoir parameters were predicted in thestudy area. Full three-dimensional seismic interpretation method was used tointerpretated the depth of coalseam, fracture structure and the coal thickness. Thelithologic characteristics of coalseam roof and floor were obtained using post-stackinversion. The AVO attributes were used to predict the distribution of coal porosity. Theresearch result had important directive significance to coalbed methane enrichmentprediction.