2D3C Seismic Prediction Of Coalbed Methane Reservoir In Heshun Block

In recent years, as unconventional energy such as coalbed methane exploration is developing rapidly. Problems to be solved have become more and more complex, such as coal seam thickness, roof and bottom, fracture development and reservoir physical property. Single conventional p-wave exploration technology is difficult to meet small structures interpretation, lithology and gas-bearing prediction in coal field. Advanced seismic exploration technology is urgent in coalbed methane reservoir. The multiwave, multi-component seismic technology has gained more and more attention, obtained lots of successful application in the area of oil and gas exploration. Compared with the conventional p-wave exploration technology, multi-component seismic technology has a lot of advantages in reservoir precise description.Qinshui Basin is a secondary tectonic unit with a basement of Paleozoic in North China platform, which is characterized by a large, near north-south compound syncline. Four 2D3 C seismic survey lines have been arranged in Heshun block which is located in the eastern margin of northern Qinshui coalfield. The aim is to find out the development of underground structure, predict the property, lithology and gas-bearing ability of coal reservoir and evaluate the applicability of three component seismic technology. The major prospecting strata is 15# coalbed which is located in lower Taiyuan Formation. As minable coal seam in the region, mudstone and sandy mudstone fill in the bottom and top beds.The thickness of 15# coalbed mainly between 5.10 and 6.07 meters.Combined with geology, logging, drilling and 2D3 C seismic data, horizon and structure interpretation has conducted. Comparison of different structures on PP- and PS-wave sections is the main focus. Small faults and collapse columns are identified by PP-wave sections with PS-wave. The imaging and interpretation of conventional p-wave are similar with three component p-wave. On the basis of horizon interpretation, p- and s-wave impedance, velocity and density data are acquired by multi-wave post-stack joint inversion.Porosity and permeability prediction are performed based on inversion results and the relation between porosity and permeability derived from logging data. The porosity of 15# coalbed mainly concentrates on 5% approximately, while the permeability is between 0.01 and 0.5m D. Because propagation characteristic of p-wave is different from that of s-wave, inversion parameters such as velocity ratio and poisson’s ratio are used to predict lithology and gas-bearing ability. Estimated results of the thickness and gas content of 15# coalbed are close to well log interpretation and borehole data. Multi-component seismic technology has achieved good application on structure interpretation and reservoir evaluation by multi-wave inversion parameters in the region.