--> --> Poststack, Prestack and Joint Inversion of P- and S-Wave Data at Postle Field, Oklahoma
[First Hit]

AAPG Annual Convention and Exhibition

Datapages, Inc.Print this page

Poststack, Prestack and Joint Previous HitInversionNext Hit of P- and S-Wave Previous HitDataNext Hit at Postle Field, Oklahoma

Abstract

Postle Field in Panhandle Oklahoma is undergoing CO2 flooding and it is important to understand the characteristics of the Morrow A sandstone reservoir for successful flood management. Prestack P- and S-wave amplitude versus angle (AVA) Previous HitinversionNext Hit and joint P- and S-wave Previous HitinversionNext Hit provide density estimates along with the P- and S-impedance for better characterization of the Morrow A sandstone. We will discuss the poststack, prestack and joint Previous HitinversionNext Hit Previous HitmethodsNext Hit applied to the Postle field Previous HitdataNext Hit. Fluid substitution Previous HitmodelingNext Hit is done to prepare the logs for seismic Previous HitdataNext Hit Previous HitinversionNext Hit by replacing the original fluid properties when the well was logged with those present during seismic Previous HitdataNext Hit acquisition. The single link existing between well Previous HitdataNext Hit and seismic Previous HitdataNext Hit is the wavelet, therefore, it should be carefully estimated. The well to seismic calibration is divided into two main stages: the first one uses seismic Previous HitdataNext Hit only and evaluates a preliminary zero-phase wavelet whose amplitude spectrum is representative of the signal in the seismic Previous HitdataNext Hit. The second main stage tries to globally conciliate the seismic Previous HitdataNext Hit and the well Previous HitdataNext Hit to derive a unique wavelet for the whole field. This two stage analysis is performed for all P, SV and SH stacks. After performing poststack and prestack P- and S-wave Previous HitinversionNext Hit, the joint P- and S-wave Previous HitinversionNext Hit is performed in a way that the density, P- and S-impedance can be interpreted in the same PP time. The SS to PP time correspondence is achieved using a warping method which minimizes the difference between the S-impedance obtained from prestack P Previous HitinversionNext Hit in PP time and the S-impedance obtained from prestack S Previous HitinversionNext Hit transformed in PP time using initial Vs/Vp model. One way of analyzing the results is by visually comparing the bandpass filtered well logs and bandpass filtered Previous HitinversionNext Hit results. Another way of finding the quality of Previous HitinversionNext Hit results is to high-cut filter the logs to Previous HitinversionNext Hit bandwidth and cross correlate it with the Previous HitinversionNext Hit results. Cross correlation of seismic Previous HitinversionNext Hit results with well log Previous HitdataNext Hit and visual comparison of inverted volumes show that the P-impedance is well estimated from prestack Previous HitinversionNext Hit of P Previous HitdataNext Hit and the S-impedance and density are well estimated from prestack Previous HitinversionNext Hit of SV Previous HitdataNext Hit.