Seismic Prediction Of Coal Bearing Strata In ShaQu Area

Shaqu coal mine is located in the middle of Hedong Coalfield,and mine collapse column is well developed. It is also found that there are a number of faults and folds. Along with the further exploration and development, it is urgent to study the coal seams of the tectonic, fracture, lithology and coal seam gas rich in order to achieve efficient production of coal mine and to ensure the sustainable development of coal and coal seam gas development.Under the constraint of drilling and logging data, firstly, we calibrate the well to the 3D seismic work area in order to obtain a reasonable time depth relationship, and identify the horizon. We use the method of seismic coherence analysis and stratigraphic dip scanning means for the fault interpretation. Besides, this paper predicts the fault less than 5m and the mine collapse column by making full use of seismic attribute, explaining a total of 44 faults and improving the interpretation accuracy of small faults and collapse column.In order to get more accurate interpretation of the area, we inverse the wave impedance and velocity of the objective area based on the log and seismic joint inversion method. This method established the basis for the interpretation of lithology and physical.In this paper, the data is sorted out, and the lithology intersection chart is plotted in order to confirm the range of the coal bearing strata impedance distribution and the threshold value. The thickness of coal seam is estimated by setting the threshold value directly on the impedance data, and the prediction map of the thickness of the coal seam is obtained. The comparison between the thickness map of inversion and the thickness map of well drilling is conducted to verify the accuracy of the coal seam thickness prediction and the accuracy of the seismic inversion.For the prediction lithology of the top and bottom of the coal seam, the paper adopts the method of comprehensive analysis of various attributes. In this paper,we predict the coal seam roof and floor lithology by extracting the mean square root amplitude, impedance and instantaneous frequency attribution value. Finally, it is found that the impedance has the best effect, and the second is the instantaneous frequency, and the root mean square amplitude is the worst.In addition, we also predict the water content of the formation. The paper made regression analysis to many kinds of attributes with resistivity, but the result is not ideal. Finally, the neural network inversion method is used to calculate the apparent resistivity, and the prediction results are in good agreement with the drilling. The water area is predicted and analyzed by the plane distribution map of resistivity.At the end of this paper, the volume method is used to predict the coal bed gas resources, and the Langmuir equation is used to calculate the gas content of the coal. The total resource is 42.14(×108m~3).