Reservoir Quality Prediction of Gas-Bearing Carbonate Sediments in the Qadirpur Field: Insights from Advanced Machine Learning Approaches of SOM and Cluster Analysis

Abstract

The detailed reservoir characterization was examined for the Central Indus Basin (CIB), Pakistan, across Qadirpur Field Eocene rock units. Various petrophysical parameters were analyzed with the integration of various cross-plots, complex water saturation, shale volume, effective porosity, total porosity, hydrocarbon saturation, neutron porosity and sonic concepts, gas effects, and lithology. In total, 8–14% of high effective porosity and 45–62% of hydrocarbon saturation are superbly found in the reservoirs of the Eocene. The Sui Upper Limestone is one of the poorest reservoirs among all these reservoirs. However, this reservoir has few intervals of rich hydrocarbons with highly effective porosity values. The shale volume ranges from 30 to 43%. The reservoir is filled with effective and total porosities along with secondary porosities. Fracture–vuggy, chalky, and intracrystalline reservoirs are the main contributors of porosity. The reservoirs produce hydrocarbon without water and gas-emitting carbonates with an irreducible water saturation rate of 38–55%. In order to evaluate lithotypes, including axial changes in reservoir characterization, self-organizing maps, isoparametersetric maps of the petrophysical parameters, and litho-saturation cross-plots were constructed. Estimating the petrophysical parameters of gas wells and understanding reservoir prospects were both feasible with the methods employed in this study, and could be applied in the Central Indus Basin and anywhere else with comparable basins.

CO2 Storage Behavior in Nanopores: Implications for CO2 Sequestration in Ultra-Tight Geological Formations

“…The origin for the adsorption phase is the accumulation of CO 2 molecules in the vicinity of nanopore surface; therefore, the adsorption phase density is much greater than the bulk phase density. As reported, the adsorption methane density could reach 2–7 times the bulk density, and the magnitude continues to rise by intensifying molecule–surface interactions. ,,, Hence, from theoretical perspective, ultra-tight formations possess the advantage over traditional geological sites on storing more CO 2 due to the presence of the adsorption phase. Currently, related research on CO 2 sequestration in ultra-tight formations is heat; however, microscopic characterization on CO 2 behavior inside nanopores, ,,− like quantified description of adsorption phase density and thickness as well as the magnitude on CO 2 storage quantity the nanopores could improve over macropores, remains a challenging knowledge gap. ,,− Effective evaluation on CO 2 sequestration in ultra-tight formations cannot be accomplished favorably until figuring out the nanoconfined CO 2 behavior and its comprehensive relevant sensitivity analysis.…”

“…As reported, the adsorption methane density could reach 2−7 times the bulk density, and the magnitude continues to rise by intensifying molecule−surface interactions. 8,9,49,50 Hence, from theoretical perspective, ultra-tight formations possess the advantage over traditional geological sites on storing more CO 2 due to the presence of the adsorption phase. Currently, related research on CO 2 sequestration in ultra-tight formations is heat; however, microscopic characterization on CO 2 behavior inside nanopores, 10,11,51−53 like quantified description of adsorption phase density and thickness as well as the magnitude on CO 2 storage quantity the nanopores could improve over macropores, remains a challenging knowledge gap.…”

Surface-Molecule Interaction Strength on CO2 Adsorption Capacity in Nanopores: Implications to Advance CO2 Sequestration Performance

“…The inherent mechanism behind this phenomenon is that the molecule–surface interaction strength is far greater than the intermolecular interaction strength. As reported, thickness of the adsorption phase CO 2 ranges from 0.4–0.8 nm, nearly 1–2 times the CO 2 molecular diameter. ,,, From the theoretical angle, the origin for the formation of the adsorption phase is the molecule–surface interactions. Therefore, manipulating molecule–surface interaction strength, like modifying the surface compositions, adding specified atoms on the surface, or reducing the distance between surface and molecules, is capable of varying CO 2 behavior in nanopores. , As for the CO 2 geological sequestration, we always pursue the purpose of advancing the storage capacity of the found geological site.…”

“…As reported, thickness of the adsorption phase CO 2 ranges from 0.4−0.8 nm, nearly 1−2 times the CO 2 molecular diameter. 16,17,64,65 From the theoretical angle, the origin for the formation of the adsorption phase is the molecule−surface interactions. Therefore, manipulating molecule−surface interaction strength, like modifying the surface compositions, adding specified atoms on the surface, or reducing the distance between surface and molecules, is capable of varying CO 2 behavior in nanopores.…”

Gas–Liquid Flow Pattern and Hydrate Risk in Wellbore during the Deep-Water Gas-Well Cleanup Process

“…The liquid gas ratio is significantly higher than other test conditions, and the gas–liquid flow pattern is more variable. Clarifying the flow characteristics of gas–liquid fluid in the wellbore during well cleanup stage is very important for studying the safety guarantee of deep-water wellbore flow and ensuring the gas well testing safety. − …”