Carlos A. Garcia , Eilis Rosenbaum , Ali M. Farahani , Elaheh Mehdizadeh , Matthew Grasinger , Richard Spaulding , Igor V. Haljasmaa , John C. Brigham
{"title":"Design optimization and evaluation of wellbore fluid placement processes for zonal isolation incorporating uncertainty","authors":"Carlos A. Garcia , Eilis Rosenbaum , Ali M. Farahani , Elaheh Mehdizadeh , Matthew Grasinger , Richard Spaulding , Igor V. Haljasmaa , John C. Brigham","doi":"10.1016/j.jgsce.2026.205851","DOIUrl":"10.1016/j.jgsce.2026.205851","url":null,"abstract":"<div><div>This paper presents a novel application integrating the lattice Boltzmann method (LBM) with a surrogate model-assisted Monte Carlo approach to assess and optimize wellbore isolation fluid materials and their placement processes incorporating uncertainty. The approach is introduced for the generalized design optimization problem to maximize the reliability of performance of isolation materials, and then focused on the specific case of material and/or process design for multi-layered wellbore plug placement. A novel performance metric is proposed for this example case to quantify the success of a plug placement process. Additionally, the details are presented for the approach to propagate uncertainty through the simulation of such a plug placement process using the LBM and a Gaussian process surrogate model-assisted Monte Carlo method. A cement slurry–bentonite clay gel multi-layered plug placement scenario is used to evaluate the framework numerically. Initially, deterministic cases assess the importance of process variability and applicability of the performance metric, revealing significant and consistently quantified variation in cement slurry placement performance based on pipe eccentricity. Then, the uncertainty propagation method is applied and verified to evaluate plug placement performance with respect to uncertainty in material and process parameters. Results show that the effect of uncertainty depends on both the uncertain parameter itself and the overall combination of material and system parameters considered. Lastly, a set of stochastic design optimization cases are shown, in which bentonite clay gel concentrations are estimated to maximize reliability of performance of the plug placement incorporating different levels of uncertainty. The optimal design is shown to significantly depend on the level of system uncertainty considered, confirming the importance of accurately accounting for the various sources of uncertainty to ensure reliable design of wellbore isolation procedures.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"148 ","pages":"Article 205851"},"PeriodicalIF":5.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081365","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Muhammad M. Alhotan, Mojdeh Delshad, Kamy Sepehrnoori
{"title":"Fluid model validation and impact of parameter tuning on underground hydrogen storage performance","authors":"Muhammad M. Alhotan, Mojdeh Delshad, Kamy Sepehrnoori","doi":"10.1016/j.jgsce.2026.205854","DOIUrl":"10.1016/j.jgsce.2026.205854","url":null,"abstract":"<div><div>This study develops and validates a comprehensive fluid property model for underground hydrogen storage (UHS), focusing on the accurate representation of hydrogen's behavior in subsurface reservoirs. Key fluid properties, including hydrogen density, viscosity, and solubility, are modeled and calibrated using experimental data and regression techniques within CMG WinProp. The Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK) equations of state are evaluated and tuned, with the PR EOS selected for its superior performance in hydrogen containing, multi-component systems. The Jossi–Stiel–Thodos (JST) correlation is calibrated for viscosity, showing that the Yoon-Thodos–Herning-Zipperer (YT-HZ) model significantly outperforms the Lee-Eakin correlation in hydrogen-rich mixtures. Hydrogen solubility is modeled using a Henry's-law-based approach and calibrated across a range of salinities and temperatures. Finally, the impact of tuning on hydrogen storage simulations is evaluated using a closed-boundary 2D reservoir model under saline aquifer and depleted gas reservoir scenarios. Results indicate that solubility tuning has the greatest impact in aquifer scenarios, while EOS tuning has the most pronounced effect in depleted gas scenarios. Overall, the fully tuned model significantly improves simulation accuracy for hydrogen storage in porous media and highlights the importance of rigorous parameter calibration to ensure reliable reservoir performance predictions.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"148 ","pages":"Article 205854"},"PeriodicalIF":5.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146190216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Impact of underground coal thermal treatment on the structural framework and compositional transformations in bituminous coal: Opportunities for enhanced CO2 geo-storage","authors":"Manikandan Ramu , Vinoth Srinivasan , Rohit Pandey , T.N. Singh","doi":"10.1016/j.jgsce.2026.205847","DOIUrl":"10.1016/j.jgsce.2026.205847","url":null,"abstract":"<div><div>Underground coal thermal treatment (UCTT) allied with CO<sub>2</sub> geo-storage offers promising opportunities for advancing clean coal technologies. However, temperature-driven changes in coal composition and microstructure can influence hydrocarbon migration and CO<sub>2</sub> storage potential. Therefore, this study investigates the pyrolysis behaviour of bituminous coal from India's Jharia coalfield. XRD, FTIR, and LRS were utilized to detect macromolecular changes, while LPGA was used to infer changes in pore characteristics and volume fractal dimensions of the coal. The result concluded that heating coal around 300 °C induced significant macromolecular and pore structural transformations. Aromatization drives carbon crystalline reorganization, directing the development of a modified pore network. The compositional changes are characterized by an enrichment of aromatic functionalities and a decrease in non-aromatic groups. As the heating continues, constricted pores diminished while slit-shaped pores became dominant, enabling higher gas flow through the modified pore network. Furthermore, the coalescence of micropores was found to increase surface area and pore volume within meso- and macropores, with mesopores in 2–8 nm exhibiting the greatest structural complexity. This suggests that mesopores play a dominant role in enhancing the overall surface area and pore volume within the coal matrix. These structural transformations are anticipated to improve gas diffusion through the coal. However, the diminished proportion of micropores can significantly reduce the coal's CO<sub>2</sub> adsorption. Despite this reduction, pyrolyzed coal remains an effective carbon sink compared to other sedimentary lithotypes, due to its higher total surface area, pore connectivity, and increased aromatic functionalities. Consequently, the finding reaffirms that heating at 400–500 °C represents the optimal range for UCTT, simultaneously maximizing hydrocarbon recovery and facilitating CO<sub>2</sub> storage in resulting coal char. Overall, this study provides insights into the effect of UCTT on coal's macromolecular and pore characteristics, influencing adsorption and diffusion factors critical for hydrocarbon extraction and CO<sub>2</sub> storage in unmineable coal seams.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"148 ","pages":"Article 205847"},"PeriodicalIF":5.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146045208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elaheh Arjomand , Jeremie Dautriat , Lingping Zeng , Stephen Banks , James Kear , Cameron Huddleston-Holmes
{"title":"Stimulating shale creep as a strategy for long-term well integrity during decommissioning","authors":"Elaheh Arjomand , Jeremie Dautriat , Lingping Zeng , Stephen Banks , James Kear , Cameron Huddleston-Holmes","doi":"10.1016/j.jgsce.2026.205852","DOIUrl":"10.1016/j.jgsce.2026.205852","url":null,"abstract":"<div><div>This study explores the potential of shale as a barrier for well decommissioning, focusing on its creep behavior and mineral transformations under various chemical conditions. Advanced mineralogical analyses and multi-stage triaxial creep tests were conducted on dry samples and those saturated with synthetic brine and Na<sub>2</sub>SiO<sub>3</sub> solution. Geochemical modeling revealed that Na<sub>2</sub>SiO<sub>3</sub> promotes quartz dissolution and albite precipitation, altering the shale's structure. In contrast, the synthetic brine scenario produced relatively minor mineral changes; the increased strain relative to the dry baseline is therefore interpreted as consistent with physico-chemical effects of saturation and clay–fluid interactions rather than substantial dissolution or precipitation. Empirical and analytical creep models were applied to predict long-term deformation, demonstrating their applicability for extrapolating time-dependent shale behaviour beyond laboratory test durations. This research highlights the role of chemical stimulation in enhancing creep deformation and improving shale's effectiveness as a sealing barrier, contributing to long-term well integrity.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"148 ","pages":"Article 205852"},"PeriodicalIF":5.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yanpeng Xu , Wenbin Jin , Zhi Li , Manzhou Di , Lei Zhang , Zhihong Wan , Weimei Liu , Tangding Zhong
{"title":"The microscopic mechanism of the inhibitory effect of high molecular weight polyacrylamide on gas adsorption-desorption characteristics of coal","authors":"Yanpeng Xu , Wenbin Jin , Zhi Li , Manzhou Di , Lei Zhang , Zhihong Wan , Weimei Liu , Tangding Zhong","doi":"10.1016/j.jgsce.2026.205837","DOIUrl":"10.1016/j.jgsce.2026.205837","url":null,"abstract":"<div><div>This study addresses the problem of extensive gas emissions caused by coal fragmentation during coal seam extraction. By integrating laboratory experiments with molecular dynamics simulations, it investigates how polyacrylamide (PAM) improves the wettability of coal and suppresses gas adsorption and desorption. Systematic measurements of the viscosity, surface tension, and contact angle of PAM solutions with different concentrations show that PAM significantly reduces the coal–water interfacial tension and contact angle by 18.69 % and 38.01 %, respectively, with the optimal wettability enhancement observed at a concentration of 0.2 %. Coal samples treated with PAM exhibit markedly improved wettability compared with raw coal and water-treated coal. Methane adsorption–desorption experiments further demonstrate that both the gas adsorption and desorption capacities of PAM-treated coal are lower than those of raw and water-treated coal. Microstructural characterizations (low-temperature nitrogen adsorption and FTIR) reveal the mechanism through which PAM acts: physically blocking coal pores, enhancing the competitive adsorption of water molecules against methane, and forming stable hydrogen-bond structures on the coal surface, thereby increasing the energy barrier for methane desorption. Molecular dynamics simulations indicate that more water molecules penetrate the coal–water interface in the coal–PAM system, confirming improved wettability. Diffusion coefficient simulations show that, under the same pressure, the diffusion coefficients follow the order: coal–water system > coal–PAM system > raw coal system; while within the same system, the diffusion coefficients decrease with decreasing pressure, following the sequence: 2.0 MPa >1.5 MPa >1.0 MPa >0.5 MPa. Finally, a PAM-based integrated technology scheme for gas and dust control in coal mines is proposed, providing essential theoretical support and practical guidance for gas hazard mitigation.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"147 ","pages":"Article 205837"},"PeriodicalIF":5.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Changpu Liu , Liuyang Yang , Shuyu Zhou , Huimin Yu , Hang Li , Dalei Zhang , Jie Geng , Zhiyuan Wang , Haiming Fan
{"title":"Thermodynamic and kinetic mechanisms governing passive film formation and corrosion product evolution on L80-13Cr stainless steel in high-temperature and highly mineralized CO2 environments","authors":"Changpu Liu , Liuyang Yang , Shuyu Zhou , Huimin Yu , Hang Li , Dalei Zhang , Jie Geng , Zhiyuan Wang , Haiming Fan","doi":"10.1016/j.jgsce.2026.205853","DOIUrl":"10.1016/j.jgsce.2026.205853","url":null,"abstract":"<div><div>This study investigates the corrosion mechanisms of L80-13Cr stainless steel (SS) in highly mineralized produced water from oil and gas fields. The formation, evolution, and interaction of passive films and corrosion products under the effect of turbulent flow at 150 °C and 2 MPa <em>P</em><sub>CO2</sub> were systematically investigated. The results show that the average corrosion rate (<em>v</em><sub>corr</sub>) is higher under turbulent flow than under static conditions. Under static conditions, the outer Cr<sub>2</sub>O<sub>3</sub> passive film transformed into FeCr<sub>2</sub>O<sub>4</sub>, while the inner layer evolved from Cr<sub>2</sub>O<sub>3</sub> and Fe<sub>2</sub>O<sub>3</sub> into a mixed carbonate deposit of CaCO<sub>3</sub> and Fe<sub>x</sub>Ca<sub>y</sub>CO<sub>3</sub> (x + y = 1). In contrast, turbulent flow increased the mass transfer of corrosive ions, promoting early nucleation and growth of Fe<sub>x</sub>Ca<sub>y</sub>CO<sub>3</sub> mixed carbonates in both layers while delaying FeCr<sub>2</sub>O<sub>4</sub> spinel formation. The mixed carbonate deposits increased layer thickness by filling cracks in the passive film and accumulating at the film/substrate interface, enhancing the long-term corrosion resistance of L80-13Cr SS. This study offers new insights into the corrosion mechanisms of L80-13Cr SS in high-temperature, high-pressure (HTHP), highly mineralized CO<sub>2</sub> environments, with implications for materials selection in aggressive oil and gas field applications.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"147 ","pages":"Article 205853"},"PeriodicalIF":5.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038356","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Exploring high-pressure CO2/CH4 separation performance with CALF-20: A Zn-based MOF","authors":"Sandeep Kumar , Sejin Park , Sungyeop Jung , Hyunchul Oh","doi":"10.1016/j.jgsce.2026.205850","DOIUrl":"10.1016/j.jgsce.2026.205850","url":null,"abstract":"<div><div>Natural gas separation, particularly the removal of CO<sub>2</sub> from CH<sub>4</sub>, is critical for industrial applications to enhance methane purity, prevent pipeline corrosion, and meet processing and transport specifications. Industrial natural gas separation typically operates at high pressures to enhance separation efficiency and meet processing requirements. Metal-organic frameworks (MOFs), with their tunable pore structures, are promising candidates for this task. In this study, we investigate the high-efficiency separation of natural gas, specifically CO<sub>2</sub>/CH<sub>4</sub>, at high pressures using CALF-20, a zinc-based MOF. The CO<sub>2</sub> uptake (4.76 mmol/g, 17.31 wt%) is significantly higher than that of CH<sub>4</sub> (2.33 mmol/g, 3.6 wt%), resulting in a high IAST selectivity of 394.57 at 298 K and 25 bar. The dynamic breakthrough experiment further confirmed the excellent separation performance for natural gas. For CO<sub>2</sub>/CH<sub>4</sub> mixtures, the breakthrough experiments revealed CO<sub>2</sub> uptakes of 2.36 mmol/g for the 1:1 feed and 2.44 mmol/g for the 2:8 feed, highlighting the material's strong and selective CO<sub>2</sub> adsorption performance.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"147 ","pages":"Article 205850"},"PeriodicalIF":5.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038353","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Junfang Zhang , Mohammad Sayyafzadeh , Regina Sander , Michael Camilleri
{"title":"Investigating competitive CO2/H2 sorption in coal through laboratory core flooding experiments and molecular dynamics modelling","authors":"Junfang Zhang , Mohammad Sayyafzadeh , Regina Sander , Michael Camilleri","doi":"10.1016/j.jgsce.2025.205832","DOIUrl":"10.1016/j.jgsce.2025.205832","url":null,"abstract":"<div><div>The contrasting affinities of low absorbing H<sub>2</sub> and strongly absorbing CO<sub>2</sub> in coal are central to a nascent concept for simultaneous H<sub>2</sub> purification and CO<sub>2</sub> storage in depleted coalbed methane reservoirs. We perform experimental studies as well as molecular dynamics (MD) simulations to examine the underlying mechanisms driving the strong preferential adsorption of CO<sub>2</sub> over H<sub>2</sub> in a H<sub>2</sub>/CO<sub>2</sub>-coal system.</div><div>MD simulations were performed at 308.5 K (35 °C) and pressures up to 45 MPa to investigate pure and mixed-gas adsorption behavior of CO<sub>2</sub> and H<sub>2</sub> on a bituminous coal model. The results confirm strong preferential adsorption of CO<sub>2</sub> over H<sub>2</sub> across the entire pressure range. In addition, H<sub>2</sub> adsorption is strongly suppressed compared to the uptake predicted by its pure-gas isotherm, indicating deviation from ideal competitive adsorption. In contrast, CO<sub>2</sub> adsorption in the mixture closely follows its pure-gas isotherm, suggesting minimal interference from H<sub>2</sub>. Observations from a laboratory coreflooding test and from H<sub>2</sub> sorption experiments, performed at 35 °C and 24 MPa, are qualitatively consistent with the MD simulation results. H<sub>2</sub> adsorption is suppressed by up to 80 % in the presence of CO<sub>2</sub>, while CO<sub>2</sub> uptake remains largely unaffected. The findings from this study strongly support the potential use of coal seams for selective hydrogen purification and CO<sub>2</sub> storage.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"147 ","pages":"Article 205832"},"PeriodicalIF":5.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940946","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qi Yu , Danqing Liu , Sen Yang , Yuan Feng , Zexing Zhang , Hong Kou , Yilian Li
{"title":"Micro-structure alteration of gas-bearing shale induced by CO2-O2-water-rock reactions: Experiments vs. numerical simulation","authors":"Qi Yu , Danqing Liu , Sen Yang , Yuan Feng , Zexing Zhang , Hong Kou , Yilian Li","doi":"10.1016/j.jgsce.2026.205849","DOIUrl":"10.1016/j.jgsce.2026.205849","url":null,"abstract":"<div><div>O<sub>2</sub> is a reactive oxidizing impurity commonly produced in the CO<sub>2</sub> oxyfuel combustion capture process. The direct injection of CO<sub>2</sub> containing O<sub>2</sub> impurities into gas-bearing shale and coal seams rich in reducing components, including pyrite and organic matter, is expected to further improve matrix permeability, promote natural gas production, and reduce CO<sub>2</sub> purification costs. To explore the alteration effect of O<sub>2</sub> on the microstructure and permeability of gas-bearing shale, we studied geochemical reactions between impure CO<sub>2</sub> containing 5 % and 10 % O<sub>2</sub>, water, and different gas-bearing shales collected from Yichang, China. The alteration of shale micro-structure response to different reactions was investigated via chemical analysis, characterization techniques and numerical simulation. The uncertainty of O<sub>2</sub> fraction, mineral composition, temperature and pressure was also explored numerically. Results indicated that the presence of O<sub>2</sub> in CO<sub>2</sub> can significantly promote carbonate dissolution in shale by enhancing groundwater acidification via pyrite oxidation. The process increased the mesopores and macropores generation in shale and exposed the organic pores in the 0–10 nm range. The porosity enhancement was predicted to increase by about 8.3–12.8 % after 1 year of reaction at 10–30 MPa and 60–120 °C with numerical modeling. The optimal O<sub>2</sub> fraction in the CO<sub>2</sub> stream of about 2.5 % was also determined. The research results can provide theoretical support for the feasibility assessment of geological storage and utilization of non-pure CO<sub>2</sub>, and offer new ideas for the efficient and economic exploitation of shale gas and coalbed methane.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"147 ","pages":"Article 205849"},"PeriodicalIF":5.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146038354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yi Zhang , Changyu Fan , Dewen Qin , Xiaopei Wang , Bo Jiang
{"title":"Deep-learning-based prediction of mutant formation pore pressure: A case study from the Xihu Sag in the East China sea","authors":"Yi Zhang , Changyu Fan , Dewen Qin , Xiaopei Wang , Bo Jiang","doi":"10.1016/j.jgsce.2026.205846","DOIUrl":"10.1016/j.jgsce.2026.205846","url":null,"abstract":"<div><div>Accurate formation pore pressure prediction is essential for hydrocarbon exploration and development. Extensive exploration practices have demonstrated that subsurface formation pore pressure often exhibits nonlinear abrupt variations. Taking the Xihu Sag in the East China Sea as a case, mutant formation pore pressure (MFPP) is highly prevalent in Paleogene adjacent wells and formations, resulting in frequent drilling incidents within this sag. However, field researchers face challenges in predicting these pressure anomalies using analogy-based methods, which depend on data from nearby wells and formations. Conventional prediction approaches (e.g., Eaton’s and Bowers’ method) are constrained by linear assumptions and regional empirical parameter dependency, leading to significant errors in MFPP prediction. Typically, these methods yield prediction errors of approximately 5 % in simple, gradual pressure intervals, while errors can fluctuate between 5 % and 20 % in complex pressure mutation intervals. To address these limitations and capture the underlying nonlinear relationships, deep learning methods have proven particularly advantageous. This study employed a deep learning approach to construct a model that correlates well-log lithology parameters with pore pressure. A hybrid neural network architecture called CNN-LSTM-ATTENTION was created by merging the benefits of several networks, innovating the model structure. Through 5-fold cross-validation, this architecture demonstrated its suitability for MFPP prediction. With an average accuracy of 96.7 % in blind testing, the results suggest that this model performs exceptionally well predicting the MFPP. It greatly improves the MFPP’s prediction accuracy compared to traditional pressure prediction methods. Meanwhile, it validates the feasibility of deep learning algorithms in addressing the challenges associated with MFPP.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"147 ","pages":"Article 205846"},"PeriodicalIF":5.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145940948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}