Estimation of acoustic-impedance model by using model-based seismic inversion on the Ghar Member of Asmari Formation in an oil field in southwestern Iran

Abstract

Raw seismic data show the subsurface reflectors among the rock layers, while the acoustic-impedance section shows the layers. Therefore, acoustic impedance is closer to reality and more accurate than the raw seismic section. Also, acoustic-impedance sections are convertible to other reservoir characteristic sections such as porosity and permeatability, which provide data about these mentioned characteristics. Seismic inversion can be used as a reliable method for quantitative estimation of reservoir properties and to obtain quantified values of acoustic impedance from seismic data, well-logging data, and interpreted horizons. The primary aim of this research is to provide a reservoir acoustic-impedance model in one of the oil fields in southwestern Iran. Six 2D seismic sections obtained in the form of poststack seismic data and the results of the analysis of well logs obtained from two wells (A-1 and A-12) were interpreted in the study area. According to the results, the model-based inversion of seismic data, which is highly dependent on the initial model, produced good results compared to other methods. Regarding the results of inversion sections, it is recognized that the acoustic impedance of the reservoir and two well locations show small values, confirming good-quality reservoir on the Ghar Formation. Eventually, with the study of the obtained acoustic-impedance model, it is recognized that the lowest value of acoustic impedance in the region was related to the common-depth point of the 3370 location, so it can be used for future study.