Petroleum Exploration and Development最新文献

{"title":"Scope, nature, and exploration significance of Ordos Basin during geological historical periods, NW China","authors":"Dengfa HE ,&nbsp;Xiang CHENG ,&nbsp;Guowei ZHANG ,&nbsp;Wenzhi ZHAO ,&nbsp;Zhe ZHAO ,&nbsp;Xinshe LIU ,&nbsp;Hongping BAO ,&nbsp;Liyong FAN ,&nbsp;Song ZOU ,&nbsp;Baize KAI ,&nbsp;Danfeng MAO ,&nbsp;Yanhua XU ,&nbsp;Changyu CHENG","doi":"10.1016/S1876-3804(25)60608-2","DOIUrl":"10.1016/S1876-3804(25)60608-2","url":null,"abstract":"<div><div>Based on the analysis of surface geological survey, exploratory well, gravity-magnetic-electric and seismic data, and through mapping the sedimentary basin and its peripheral orogenic belts together, this paper explores systematically the boundary, distribution, geological structure, and tectonic attributes of the Ordos prototype basin in the geological historical periods. The results show that the Ordos block is bounded to the west by the Engorwusu Fault Zone, to the east by the Taihangshan Mountain Piedmont Fault Zone, to the north by the Solonker–Xilamuron Suture Zone, and to the south by the Shangnan-Danfeng Suture Zone. The Ordos Basin boundary was the plate tectonic boundary during the Middle Proterozoic to Paleozoic, and the intra-continental deformation boundary in the Meso-Cenozoic. The basin survived as a marine cratonic basin covering the entire Ordos block during the Middle Proterozoic to Ordovician, a marine–continental transitional depression basin enclosed by an island arc uplift belt at the plate margin during the Carboniferous to Permian, a unified intra-continental lacustrine depression basin in the Triassic, and an intra-continental cratonic basin circled by a rift system in the Cenozoic. The basin scope has been decreasing till the present. The large, widespread prototype basin controlled the exploration area far beyond the present-day sedimentary basin boundary, with multiple target plays vertically. The Ordos Basin has the characteristics of a whole petroleum (or deposition) system. The Middle Proterozoic wide-rift system as a typical basin under the overlying Phanerozoic basin and the Cambrian–Ordovician passive margin basin and intra-cratonic depression in the deep-sited basin will be the important successions for oil and gas exploration in the coming years.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"52 4","pages":"Pages 855-871"},"PeriodicalIF":8.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903509","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":"Numerical simulation of fracture propagation in deflagration-hydraulic composite fracturing of unconventional reservoirs","authors":"Tiankui GUO ,&nbsp;Haiyang WANG ,&nbsp;Ming CHEN ,&nbsp;Zhanqing QU ,&nbsp;Caili DAI ,&nbsp;Cheng ZHAI ,&nbsp;Jiwei WANG","doi":"10.1016/S1876-3804(25)60619-7","DOIUrl":"10.1016/S1876-3804(25)60619-7","url":null,"abstract":"<div><div>Based on continuum-discontinuum element method, the numerical simulation of fracture propagation during deflagration-hydraulic composite fracturing was constructed by considering deflagration stress impact induced fracture creation, deflagrating gas driven fracture propagation, and hydraulic fracture propagation, exploring the effects of in-situ stress difference, deflagration peak pressure, deflagration pressurization rate, hydraulic fracturing displacement and hydraulic fracturing fluid viscosity on fracture propagation in deflagration-hydraulic composite fracturing. The deflagration-hydraulic composite fracturing combines the advantages of deflagration fracturing in creating complex fractures near wells and the deep penetration of hydraulic fracturing at the far-field region, which can form multiple deep penetrating long fractures with better stimulation effects. With the increase of in-situ stress difference, the stimulated area of deflagration-hydraulic composite fracturing is reduced, and the deflagration-hydraulic composite fracturing is more suitable for reservoirs with small in-situ stress difference. Higher peak pressure and pressurization rate are conducive to increasing the maximum fracture length and burst degree of the deflagration fractures, which in turn increases the stimulated area of deflagration-hydraulic composite fracturing and improves the stimulation effect. Increasing the displacement and viscosity of hydraulic fracturing fluid can enhance the net pressure within the fractures, activate the deflagration fractures, increase the turning radius of the fractures, generate more long fractures, and effectively increase the stimulated reservoir area. The stimulated reservoir area is not completely positively correlated with the hydraulic fracturing displacement and fracturing fluid viscosity, and there is a critical value. When the critical value is exceeded, the stimulated area decreases.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"52 4","pages":"Pages 1017-1028"},"PeriodicalIF":8.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144902829","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":"Progress in CO2 flooding and storage techniques for lacustrine oil reservoirs and development directions of their large-scale application in China","authors":"Weifeng LYU ,&nbsp;Hailong ZHANG ,&nbsp;Tiyao ZHOU ,&nbsp;Ming GAO ,&nbsp;Deping ZHANG ,&nbsp;Yongzhi YANG ,&nbsp;Ke ZHANG ,&nbsp;Hongwei YU ,&nbsp;Zemin JI ,&nbsp;Wenfeng LYU ,&nbsp;Zhongcheng LI ,&nbsp;Guoqiang SANG","doi":"10.1016/S1876-3804(25)60625-2","DOIUrl":"10.1016/S1876-3804(25)60625-2","url":null,"abstract":"<div><div>Based on the technological demands for significantly enhancing oil recovery and long-term CO₂ sequestration in the lacustrine oil reservoirs of China, this study systematically reviews the progress and practices of CO₂ flooding and storage technologies in recent years. It addresses the key technological needs and challenges faced in scaling up the application of CO₂ flooding and storage to mature, developed oil fields, and analyzes future development directions. During the pilot test phase (2006–2019), continuous development and application practices led to the establishment of the first-generation CO₂ flooding and storage technology system for lacustrine reservoirs. In the industrialization phase (since 2020), significant advances and insights have been achieved in terms of confined phase behavior, storage mechanisms, reservoir engineering, sweep control, engineering process and storage monitoring, enabling the maturation of the second-generation CO₂ flooding and storage theories and technologies to effectively support the demonstration projects of Carbon Capture, Utilization and Storage (CCUS). To overcome key technical issues such as low miscibility, difficulty in gas channeling control, high process requirements, limited application scenarios, and coordination challenges in CO₂ flooding and storage, and to support the large-scale application of CCUS, it is necessary to strengthen research on key technologies for establishing the third-generation CO₂ flooding and storage technological system incorporating miscibility enhancement and transformation, comprehensive regulation for sweep enhancement, whole-process engineering techniques and equipment, long-term storage monitoring safety, and synergistic optimization of flooding and storage.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"52 4","pages":"Pages 1086-1101"},"PeriodicalIF":8.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903516","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":"Fracture propagation of deflagration fracturing in deep shale multi-branch wells","authors":"Haiyan ZHU ,&nbsp;Enbo WANG ,&nbsp;Kai TANG ,&nbsp;Xiangyi YI ,&nbsp;Peng ZHAO ,&nbsp;Qin LI ,&nbsp;Jianqiao ZHU ,&nbsp;Dezhao XU ,&nbsp;Ying DENG","doi":"10.1016/S1876-3804(25)60623-9","DOIUrl":"10.1016/S1876-3804(25)60623-9","url":null,"abstract":"<div><div>Based on the finite element-discrete element numerical method, a numerical model of fracture propagation in deflagration fracturing was established by considering the impact of stress wave, quasi-static pressure of explosive gas, and reflection of stress wave. The model was validated against the results of physical experiments. Taking the shale reservoirs of Silurian Longmaxi Formation in Luzhou area of the Sichuan Basin as an example, the effects of in-situ stress difference, natural fracture parameters, branch wellbore spacing, delay detonation time, and angle between branch wellbore and main wellbore on fracture propagation were identified. The results show that the fracture propagation morphology in deflagration fracturing is less affected by the in-situ stress difference when it is 5–15 MPa, and the tendency of fracture intersection between branch wellbores is significantly weakened when the in-situ stress difference reaches 20 MPa. The increase of natural fracture length promotes the fracture propagation along the natural fracture direction, while the increase of volumetric natural fracture density and angle limits the fracture propagation area and reduces the probability of fracture intersection between branch wells. The larger the branch wellbore spacing, the less probability of the fracture intersection between branch wells, allowing for the fracture propagation in multiple directions. Increasing the delay detonation time decreases the fracture spacing between branch wellbores. When the angle between the branch wellbore and the main wellbore is 45° and 90°, there is a tendency of fracture intersection between branch wellbores.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"52 4","pages":"Pages 1064-1073"},"PeriodicalIF":8.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144902832","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":"Fracture propagation and fatigue damage mechanisms in pulse hydraulic fracturing of deep coal","authors":"Ruiyue YANG,&nbsp;Meiquan LU,&nbsp;Ao LI,&nbsp;Haojin CHENG,&nbsp;Meiyang JING,&nbsp;Zhongwei HUANG,&nbsp;Gensheng LI","doi":"10.1016/S1876-3804(25)60624-0","DOIUrl":"10.1016/S1876-3804(25)60624-0","url":null,"abstract":"<div><div>By integrating laboratory physical modeling experiments with machine learning-based analysis of dominant factors, this study explored the feasibility of pulse hydraulic fracturing (PHF) in deep coal rocks and revealed the fracture propagation patterns and the mechanisms of pulsating loading in the process. The results show that PHF induces fatigue damage in coal matrix, significantly reducing breakdown pressure and increasing fracture network volume. Lower vertical stress differential coefficient (less than 0.31), lower peak pressure ratio (less than 0.9), higher horizontal stress differential coefficient (greater than 0.13), higher pulse amplitude ratio (greater than or equal to 0.5) and higher pulse frequency (greater than or equal to 3 Hz) effectively decrease the breakdown pressure. Conversely, higher vertical stress differential coefficient (greater than or equal to 0.31), higher pulse amplitude ratio (greater than or equal to 0.5), lower horizontal stress differential coefficient (less than or equal to 0.13), lower peak pressure ratio (less than 0.9), and lower pulse frequency (less than 3 Hz) promote the formation of a complex fracture network. Vertical stress and peak pressure are the most critical geological and engineering parameters affecting the stimulation effectiveness of PHF. The dominant mechanism varies with coal rank due to differences in geomechanical characteristics and natural fracture development. Low-rank coal primarily exhibits matrix strength degradation. High-rank coal mainly involves the activation of natural fractures and bedding planes. Medium-rank coal shows a coexistence of matrix strength degradation and micro-fracture connectivity. The PHF forms complex fracture networks through the dual mechanism of matrix strength degradation and fracture network connectivity enhancement.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"52 4","pages":"Pages 1074-1085"},"PeriodicalIF":8.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144902833","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":"Natural gas types and coal-rock gas classification in the whole petroleum system of coal measures","authors":"Junfeng ZHANG ,&nbsp;Guoxin LI ,&nbsp;Chengzao JIA ,&nbsp;Qun ZHAO","doi":"10.1016/S1876-3804(25)60611-2","DOIUrl":"10.1016/S1876-3804(25)60611-2","url":null,"abstract":"<div><div>There are various types of natural gas resources in coal measures, making them major targets for natural gas exploration and development in China. In view of the particularity of the whole petroleum system of coal measures and the reservoir-forming evolution of natural gas in coal, this study reveals the formation, enrichment characteristics and distribution laws of coal-rock gas by systematically reviewing the main types and geological characteristics of natural gas in the whole petroleum system of coal measures. First, natural gas in the whole petroleum system of coal measures is divided into two types, conventional gas and unconventional gas, according to its occurrence characteristics and accumulation mechanism, and into six types, distal detrital rock gas, special rock gas, distal/proximal tight sandstone gas, inner-source tight sandstone gas, shale gas, and coal-rock gas, according to its source and reservoir lithology. The natural gas present in coal-rock reservoirs is collectively referred to as coal-rock gas. Existing data indicate significant differences in the geological characteristics of coal-rock gas exploration and development between shallow and deep layers in the same area, with the transition depth boundary generally 1 500–2 000 m. Based on the current understanding of coal-rock gas and respecting the historical usage conventions of coalbed methane terminology, coal-rock gas can be divided into deep coal-rock gas and shallow coalbed methane according to burial depth. Second, according to the research concept of “full-process reservoir formation” in the theory of the whole petroleum system of coal measures, based on the formation and evolution of typical coal-rock gas reservoirs, coal-rock gas is further divided into four types: primary coal-rock gas, regenerated coal-rock gas, residual coal-rock gas, and bio coal-rock gas. The first two belong to deep coal-rock gas, while the latter two belong to shallow coal-rock gas. Third, research on the coal-rock gas reservoir formation and evolution shows that shallow coal-rock gas is mainly residual coal-rock gas or bio coal-rock gas formed after geological transformation of primary coal-rock gas, with the reservoir characteristics such as low reservoir pressure, low gas saturation, adsorbed gas in dominance, and gas production by drainage and depressurization, while deep coal-rock gas is mainly primary coal-rock gas and regenerated coal-rock gas, with the reservoir characteristics such as high reservoir pressure, high gas saturation, abundant free gas, and no or little water. In particular, the primary coal-rock gas is wide in distribution, large in resource quantity, and good in reservoir quality, making it the most favorable type of coal-rock gas for exploration and development.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"52 4","pages":"Pages 894-906"},"PeriodicalIF":8.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903512","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":"Tectonic deformation and its petroleum geological significance of continental margin necking zone in deepwater area of Pearl River Mouth Basin, South China Sea","authors":"Guangrong PENG ,&nbsp;Guofu CAI ,&nbsp;Hongbo LI ,&nbsp;Lili ZHANG ,&nbsp;Xuhong XIANG ,&nbsp;Jinyun ZHENG ,&nbsp;Baojun LIU","doi":"10.1016/S1876-3804(25)60614-8","DOIUrl":"10.1016/S1876-3804(25)60614-8","url":null,"abstract":"<div><div>Based on a set of high-resolution 3D seismic data from the northern continental margin of the South China Sea, the lithospheric structure, thinning mechanisms and related syn-rift tectonic deformation response processes in the crustal necking zone in the deepwater area of the Pearl River Mouth Basin were systematically analyzed, and the petroleum geological significance was discussed. The necking zone investigated in the study is located in the Baiyun Sag and Kaiping Sag in the deepwater area of the Pearl River Mouth Basin. These areas show extreme crustal thinned geometries of central thinning and flank thickening, characterized by multi-level and multi-dipping detachment fault systems. The necking zone exhibits pronounced lateral heterogeneity in structural architectures, which can be classified into four types of thinned crustal architectures, i.e. the wedge-shaped extremely thinned crustal architecture in the Baiyun Main Sub-sag, dumbbell-shaped moderately thinned crustal architecture in the Baiyun West Sub-sag, box-shaped weakly thinned crustal architecture in eastern Baiyun Sag, and metamorphic core complex weakly thinned crustal architecture in the Kaiping Sag. This shows great variations in the degree and style of crustal thinning, types of detachment faults, distribution of syn-rift sedimentary sequences, and intensity of magmatism. The thinning of the necking zone is controlled by the heterogeneous rheological stratification of lithosphere, intensity of mantle-derived magmatism, and deformation modes of detachment faults. The syn-rift tectonic deformation of the necking zone evolved through three phases, i.e. uniform stretching during the early Wenchang Formation deposition period, necking during the late Wenchang Formation deposition period, and hyperextension during the Enping Formation deposition period. The crustal thinning extent and architectural differentiation in these phases were primarily controlled by three distinct mechanisms, i.e. the pure shear deformation activation of pre-existing thrust faults, the simple shear deformation of crust-mantle and inter-crust detachment faults, and differential coupling of lower crustal flow and ductile domes with main detachment faults. The hydrocarbon accumulation and enrichment in the necking zone exhibit marked spatial heterogeneity. Four distinct crustal thinned architecture-hydrocarbon accumulation models were identified in this study. The hydrocarbon accumulations in the shallow part exhibit significant correlations with their deep crustal thinned architectures. The unique lithospheric structure and deformation process predominantly control the favorable hydrocarbon accumulation zones with excellent source-fault-ridge-sand configurations, which is critical to reservoir-forming. The most promising exploration targets are mainly identified on the uplift zones and their seaward-dipping flanks associated with the middle and lower crustal domes. This research provides additional ","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"52 4","pages":"Pages 937-951"},"PeriodicalIF":8.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903449","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":"Key parameters and evaluation methods for large-scale production of lacustrine shale oil","authors":"Lichun KUANG ,&nbsp;Songtao WU ,&nbsp;Haoting XING ,&nbsp;Kunyu WU ,&nbsp;Yue SHEN ,&nbsp;Zhenlin WANG","doi":"10.1016/S1876-3804(25)60610-0","DOIUrl":"10.1016/S1876-3804(25)60610-0","url":null,"abstract":"<div><div>Based on the analysis of typical lacustrine shale oil zones in China and their geological characteristics, this study elucidates the fundamental differences between the enrichment patterns of shale oil sweet spots and conventional oil and gas. The key parameters and evaluation methods for assessing the large-scale production potential of lacustrine shale oil are proposed. The results show that shale oil is a petroleum resource that exists in organic-rich shale formations, in other words, it is preserved in its source bed, following a different process of generation–accumulation–enrichment from conventional oil and gas. Thus, the concept of “reservoir” seems to be inapplicable to shale oil. In China, lacustrine shale oil is distributed widely, but the geological characteristics and sweet spots enrichment patterns of shale oil vary significantly in lacustrine basins where the water environment and the tectonic evolution and diagenetic transformation frameworks are distinct. The core of the evaluation of lacustrine shale oil is “sweet spot volume”. The key factors for evaluating the large-scale production of continental shale oil are the oil storage capacity, oil-bearing capacity and oil producing capacity. The key parameters for evaluating these capacities are total porosity, oil content, and free oil content, respectively. It is recommended to determine the total porosity of shale by combining helium porosity measurement with nuclear magnetic resonance (NMR) method, the oil content of key layers by using organic solvent extraction, NMR method and high pressure mercury intrusion methods, and the free oil content by using NMR fluid distribution secondary spectral stripping decomposition and logging. The research results contribute supplemental insights on continental shale oil deliverability in China, and provide a scientific basis for the rapid exploration and large-scale production of lacustrine shale oil.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"52 4","pages":"Pages 883-893"},"PeriodicalIF":8.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903511","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":"Differential accumulation characteristics and production of coalbed methane/coal-rock gas: A case study of the No. 8 coal seam of the Carboniferous Benxi Formation in the Daji block, Ordos Basin, NW China","authors":"Lihong ZHOU ,&nbsp;Yong LI ,&nbsp;Rong DING ,&nbsp;Xianyue XIONG ,&nbsp;Wei HOU ,&nbsp;Yongzhou LI ,&nbsp;Hui MA ,&nbsp;Haijiao FU ,&nbsp;Yi DU ,&nbsp;Weiqi ZHANG ,&nbsp;Zhitong ZHU ,&nbsp;Zhuangsen WANG","doi":"10.1016/S1876-3804(25)60609-4","DOIUrl":"10.1016/S1876-3804(25)60609-4","url":null,"abstract":"<div><div>Based on the coalbed methane (CBM)/coal-rock gas (CRG) geological, geophysical, and experimental testing data from the Daji block in the Ordos Basin, the coal-forming and hydrocarbon generation &amp; accumulation characteristics across different zones were dissected, and the key factors controlling the differential CBM/CRG enrichment were identified. The No. 8 coal seam of the Carboniferous Benxi Formation in the Daji block is 8–10 m thick, typically overlain by limestone. The primary hydrocarbon generation phase occurred during the Early Cretaceous. Based on the differences in tectonic evolution and CRG occurrence, and with the maximum vitrinite reflectance of 2.0% and burial depth of 1 800 m as boundaries, the study area is divided into deeply buried and deeply preserved, deeply buried and shallowly preserved, and shallowly buried and shallowly preserved zones. The deeply buried and deeply preserved zone contains gas content of 22–35 m³/t, adsorbed gas saturation of 95%–100%, and formation water with total dissolved solid (TDS) higher than 50 000 mg/L. This zone features structural stability and strong sealing capacity, with high gas production rates. The deeply buried and shallowly preserved zone contains gas content of 16–20 m³/t, adsorbed gas saturation of 80%–95%, and formation water with TDS of 5 000–50 000 mg/L. This zone exhibits localized structural modification and hydrodynamic sealing, with moderate gas production rate. The shallowly buried and shallowly preserved zone contains gas content of 8–16 m³/t, adsorbed gas saturation of 50%–70%, and formation water with TDS lower than 5 000 mg/L. This zone experienced intense uplift, resulting in poor sealing and secondary alteration of the primary gas reservoir, with partial adsorbed gas loss, and low gas production rate. A depositional unification and structural divergence model is proposed, that is, although coal seams across the basin experienced broadly similar depositional and tectonic histories, differences in tectonic intensity have led to spatial heterogeneity in the maximum burial depth (i.e., thermal maturity of coal) and current burial depth and occurrence of CRG (i.e., gas content and occurrence state). The research results provide valuable guidance for advancing the theoretical understanding of CBM/CRG enrichment and for improving exploration and development practices.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"52 4","pages":"Pages 872-882"},"PeriodicalIF":8.0,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144903510","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 clay coating on sandstone reservoir quality: A multiphase-field investigation by numerical simulation","authors":"Akash KUMAR ,&nbsp;Michael SPÄTH ,&nbsp;Nishant PRAJAPATI ,&nbsp;Benjamin BUSCH ,&nbsp;Daniel SCHNEIDER ,&nbsp;Christoph HILGERS ,&nbsp;Britta NESTLER","doi":"10.1016/S1876-3804(25)60598-2","DOIUrl":"10.1016/S1876-3804(25)60598-2","url":null,"abstract":"<div><div>The presence of clay coatings on the surfaces of quartz grains can play a pivotal role in determining the porosity and permeability of sandstone reservoirs, thus directly impacting their reservoir quality. This study employs a multiphase-field model of syntaxial quartz cementation to explore the effects of clay coatings on quartz cement volumes, porosity, permeability, and their interrelations in sandstone formations. To generate various patterns of clay coatings on quartz grains within three-dimensional (3D) digital sandstone grain packs, a pre-processing toolchain is developed. Through numerical simulation experiments involving syntaxial overgrowth cementation on both single crystals and multigrain packs, the main coating parameters controlling quartz cement volume are elucidated. Such parameters include the growth of exposed pyramidal faces, lateral encasement, coating coverage, and coating pattern, etc. The coating pattern has a remarkable impact on cementation, with the layered coatings corresponding to fast cement growth rates. The coating coverage is positively correlated with the porosity and permeability of sandstone. The cement growth rate of quartz crystals is the lowest in the vertical orientation, and in the middle to late stages of evolution, it is faster in the diagonal orientation than in the horizontal orientation. Through comparing the simulated results of dynamic evolution process with the actual features, it is found that the simulated coating patterns after 20 d and 40 d show clear similarities with natural samples, proving the validity of the proposed three-dimensional numerical modeling of coatings. The methodology and findings presented contribute to improved reservoir characterization and predictive modeling of sandstone formations.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"52 3","pages":"Pages 715-730"},"PeriodicalIF":7.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144491476","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}