A New Calculating Method of the Curvature to Predicting the Reservoir Fractures

Fracture density and Fracture orientation have some relationship with the curvature of structure surface. Generally, the greater the curvature value is, the more fractures develop. So it is an important method to predict the distribution of natural fractures by using the structural surface curvature. First, we obtain the grid data of altitude data from the seismic structure contour map, and make a fitting surface in each adjacent grid nodes. Then we deduce the formula to calculate the curvature in any direction from the fitting surface,. It is an improved calculating method which is different from using the simplified formula to obtain the maximum principal curvature and Gaussian curvature as before. In this way, we can predict the fracture zone through curvature analysis. Through analyzing the curvature of Qikou18-1 oil field and the fracture zone predicted by using this method, the results show that the curvature has a good relationship with the fractures distribution.