Nanjing Branch of Geology Research Institute, Jiangsu Bureau of Petroleum Exploration, P.O.Box 4608,Yaohuamen, Nanjing City, Jiangsu Province, Postcode:210046
Abstract：A new formula for estimating velocity parameters is advanced in the ligth of velocity analysis principle in quadrants.Velocity elliptic formula involves three parameters:velocity v,azimuth ψ and dip angle a;therefore,we need to divide one 3-D CDP bin into more than three quadrants then use three quadrant velocities to solve for v,ψ and a.To improve velocity accuracy,we use the velocities in each quadrant to respectively estimate the fitting errors between theoretical and real time-distance curves in a certain perturbation scope.The velocity corresponding to the minimum fitting error serves as the central velocity in a quadrant that is then used to get final 3-D velocity parameters.The method produces accurate velocity efficiently.
