Abstract：It is very hard to identify carbonate cavern reservoirs by conventional methods because of their strong longitudinal and transverse heterogeneity.According to the bead-like seismic reflection response, the seismic energy gradient estimation based on least-square fitting is concluded in the paper.The estimation procedure is as follows：① Selecting or assigning a estimated direction, and defining the estimated radius;② Taking the target as the centre, confirming sample points along the estimated direction in the range of estimated radius, and variants x are made from the sequence number, the variants y are from the amplitudes of all the sample points;③ Applying linear ftt on by least squares to obtain the intercept and gradient.④ Taking the arithmetic product of the intercept and gradient from the linear ftt as the seismic energy gradient of the targets.Comparing with others, this method is more stable, and obtains more obvious energy variation of the bead-like seismic reflection.Applications have shown the efficiency and accuracy of carbonate fracture-cave abnormal body identification by the seismic energy gradient estimation based on least-square fitting.
