Evaluating the Production Potential of the Reservoirs with Seismic Attributes and Inversion analysis by 3D seismic and well logs data of NIM Exploration Block, Pakistan

Abstract

Seismic surveying is categorically the most significant geophysical exploration technique, mainly because to its ability to identify both large- and small-scale subsurface structures. Since the early 1900s, seismic technology has been used to measure water depths, find icebergs, and used for exploration of oil and gas reserves. The primary purpose of this study is to explore the hydrocarbon resource potential of the sandstone reservoir using petrophysics, making cross plots with the help of elastic parameters, estimation of Gross Rock Volume (GRV), applying seismic attributes and inversion algorithms. Using well logs and seismic data, in the present study petrophysics and GRV are applied to the B-Sand, which is part of the Lower Goru Formation. Well log cross-plots are used to define the sand body and determine whether a particular interval of sandstone in a formation is filled with hydrocarbon or water. According to the petrophysical analysis, the reservoir has high porosity and contains a sizable quantity of hydrocarbon, but it is filled with water. Some of the rock properties cross-plotted together show a linear relationship and do not differentiate easily regarding lithology, while the other the cross-plots shows that the reservoir is predominantly sand with very few traces of shale. Investigating further by applying the GRV and Original Gas In Place (OGIP) in B-Sand reveals that Dars West-01 as compared to Jumman Shah-01 holds not only a significant amount of hydrocarbon but is also less saturated with water. Determining lithology variation and presence of hydrocarbon potential in the form of Gas concentration is determined by using the RAI, TE and RMS attributes. The B-Sand reservoir offers good hydrocarbon possibilities, according to the results of the seismic attribute analysis, and may be further investigated for future opportunities. Three different seismic inversion methods band limited impedance, sparse spike and model-based inversion have been used in this study to approximate the reservoir properties using 3D seismic and well logs. According to our findings, as compared to the sparse-spike inversion approach, model-based and band-limited post-stack seismic inversion delivers more accurate assessments and returns detailed spatial variations for acoustic impedance and porosity. When the inversion algorithm results are compared to the data from well logs and petrophysical analysis then our conclusions are confirmed. The methods utilized in this investigation showed the characteristics of the B-Sand formation in NIM exploration block, Sindh, Pakistan. Validation of these estimates DRSML QAU x | P a g e using petrophysics, cross plots, seismic attributes, and inversion analysis demonstrates that these analysis forecasts the gas resource potential in the study region. In addition, the current effort helps in estimating the reservoir property by employing an enhanced integrated geophysical approach to predict hydrocarbon bearing zones in reservoirs. The methodologies employed in this research can be used to other geographical regions with geological features like Pakistan for a better understanding and characterization of gas reserves