The Method of Log and Seismic Combined Modeling Used in the Geosteering Pre-Modeling

In the process of pre-drilling geo-steering modeling, the wells near the horizontal well are used to determine the depth and azimuth of layers to be penetrated. The horizontal structural relief among wells is controlled by the seismic interpretation layer. If there are difference between the depth of seismic interpretation layer and the depth of log interpretation in the well location, predrilling geo-steering model will has great inaccuracy. In order to control the error range, the log and seismic combined ways were used in this paper. Firstly, calibrate the seismic interpretation horizons with log interpretation results. Then according to the subzone depth interpretated in the well, calculate the isopachous body data of subzone using moving average algorithm. Finally, control the horizontal structural relief with the calibrated seismic horizons, and compile the structural map for every geologic subzone to guide the work of geo-steering and improve the accuracy of the horizontal well. This method can control the inaccuracy rang within 2 m by verification with actual data.