Petroleum Exploration and Development最新文献

{"title":"Formation mechanism of coal-rock gas accumulation transition zones","authors":"Guoxin LI,&nbsp;Qun ZHAO,&nbsp;Junfeng ZHANG,&nbsp;Dan LIU,&nbsp;Jian SUN,&nbsp;Tianqi ZHOU,&nbsp;Yuhang XIAO","doi":"10.1016/S1876-3804(26)60717-3","DOIUrl":"10.1016/S1876-3804(26)60717-3","url":null,"abstract":"<div><div>Research on hydrocarbon accumulation mechanism in coal-measure whole petroleum systems and coal-rock gas exploration has revealed that coal-rock gas occurs along coal-bearing strata and forms different reservoir types with distinct geological characteristics in different structural regions, and that between primary coal-rock gas reservoirs and residual coal-rock gas reservoirs (i.e., traditional shallow coalbed methane reservoirs), the gas–water relationship in the macroscopic pores and fractures of coal reservoirs gradually evolves in space, forming coal-rock gas accumulation transition zones with prominent features. Taking the coal-rock gas of the Carboniferous Benxi Formation in the central-eastern Ordos Basin, China, as an example, this study constructs the dynamic mechanism and mathematical models for the coal-rock gas accumulation transition zone by considering the dual-medium structure, stress sensitivity, and wettability variation of coal reservoirs. On this basis, the dynamic equilibrium among buoyancy, capillary force and hydrocarbon-generation expansion force is clarified. The results show that, under the geological background of uplift and reworking, the cleat fracture system and porosity–permeability properties of coal reservoirs are fundamental for the formation of the transition zone, the hydrocarbon-generation expansion force of coal rocks is an inherent determinant for the depth of the transition zone, and the spatial variation of coal rank and tectonic reworking intensity control the distribution of the transition zone. Numerical simulation results and practical exploration and development have demonstrated that, at the eastern margin of the Ordos Basin, the transition zone for medium- to high-rank coal-rock gas reservoirs in the Daning–Jixian area in the south is mainly buried at 1 300–1 800 m, while the transition zone for low- to medium-rank coal-rock gas reservoirs in the north occurs at a greater depth of 1 500–2 300 m. Through comprehensive investigation, the coal-rock gas accumulation zones at the eastern margin of the Ordos Basin are examined by hydrocarbon accumulation evolution analysis and spatial distribution prediction. Three continuous hydrocarbon accumulation evolution units are identified, i.e. deep coal-rock gas accumulation zone, coal-rock gas accumulation transition zone, and shallow coalbed methane accumulation zone. The research results deepen the understanding of accumulation mechanism and differential enrichment mechanism of coal-rock gas, and provide a theoretical basis for improving coal-rock gas classification and guiding favorable area evaluation and efficient exploration and development.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"53 3","pages":"Pages 348-365"},"PeriodicalIF":10.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148544632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geologic characteristics, development technologies and prospects of unconventional natural gas in China","authors":"Caineng ZOU,&nbsp;Rongze YU,&nbsp;Dazhong DONG,&nbsp;Xiaowei ZHANG,&nbsp;Yanpeng CHEN,&nbsp;Majia ZHENG,&nbsp;Hanlin LIU,&nbsp;Jinliang GAO","doi":"10.1016/S1876-3804(26)60725-2","DOIUrl":"10.1016/S1876-3804(26)60725-2","url":null,"abstract":"<div><div>Based on China’s latest exploration and development achievements, production performance data of over 7 000 horizontal wells, and the Unconventional Oil &amp; Gas Digital-Intelligent Platform (UOG), and by integrating statistical analysis and machine learning prediction techniques, this study systematically compares four types of unconventional natural gas (tight gas, shale gas, shallow coalbed methane and medium–deep coal-rock gas) in the country, from the aspects of resource characteristics, key technologies, development indicators and prospects. China holds a substantial quantity of unconventional natural gas, especially shale gas and medium–deep coal-rock gas which boast prominent resource advantages and present a large-scale “continuous” spatial distribution. More than 75% of high-quality resources are concentrated in the Ordos and Sichuan basins. A type-adaptive key technical system has been established, incorporating extensive recovery of tight gas by virtue of “well pattern optimization + low-cost fracturing”, commercial development of shale gas relying on “geological-engineering dual sweet spot evaluation + super fracture network fracturing”, stable production of shallow–medium coalbed methane through “precision drainage and depressurization”, and breakthroughs in pilot technologies such as pressure-controlled development and energy-gathered fracturing for horizontal wells of medium–deep coal-rock gas. The four types of unconventional natural gas vary significantly in development indicators. Tight gas, shale gas and medium–deep coal-rock gas reach peak production 10–30 days after gas breakthrough, showing the characteristics of high initial production followed by rapid decline (with a first-year decline rate of 30%–51%). Specifically, shale gas horizontal wells have the highest average daily production in the first year (7.28×10⁴ m³/d on average) and single-well estimated ultimate recovery (EUR) (8 255×10⁴ m³ on average). Shallow coalbed methane reaches peak production about 240 days after gas breakthrough, presenting a trend of slow rise–gentle decline, with the lowest single-well indicators. At present, the development of unconventional natural gas is faced with four major constraints including complex geology, technical bottlenecks, environmental restrictions and imperfect policies. It is necessary to address the predicament through multi-dimensional coordination in terms of resources, technology, environmental protection and policies.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"53 3","pages":"Pages 480-496"},"PeriodicalIF":10.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148544592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seepage field construction and technical directions for efficient development of shale gas reservoirs: A case study of Fuling shale gas field, Sichuan Basin, China","authors":"Huanquan SUN,&nbsp;Aiwei ZHENG,&nbsp;Jichao FANG,&nbsp;Li LIU,&nbsp;Yaowen LIU,&nbsp;Cheng DAI,&nbsp;Baiyu ZHU,&nbsp;Yongchao WU,&nbsp;Yuling JIANG","doi":"10.1016/S1876-3804(26)60726-4","DOIUrl":"10.1016/S1876-3804(26)60726-4","url":null,"abstract":"<div><div>Based on the post-frac core evaluation results for shale gas reservoirs in the Jiaoshiba block of the Fuling gas field, a simulation method for tensile-shear composite fracture networks in shale and a multi-scale characterization method for residual gas were developed. The types and distribution characteristics of residual shale gas were clarified, and an efficient seepage field with coordinated “artificial well pattern – induced fracture network – natural fracture network” was established. Strategies for residual gas recovery were proposed, and the expected technologies for efficient development of shale gas reservoirs were recommended. The induced fractures in shale exhibit features such as single overall morphology, clustered non-uniform distribution, branching dendritic extension and limited propped area. Residual gas can be classified into four types: gas uncontrolled by well pattern, gas insufficiently swept by inter-well fractures, gas unevenly swept by inter-layer fractures, and gas unswept between clusters. For purpose of residual gas recovery and enhanced gas recovery, an efficient seepage field with coordinated “artificial well pattern – induced fracture network – natural fracture network” can be constructed through drilling infill wells with small well-spacing, sidetracking in old wells, differential trajectory design, and precise fracturing design. Future efficient development of shale gas is expected to be achieved by improving accurate reservoir characterization, advancing coordinated 3D development technologies, iteratively optimizing technologies for enhanced shale gas recovery, and deepening the synergy between conventional and unconventional development methods. These efforts are believed to drive high-quality advancement of the shale gas development technology in China.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"53 3","pages":"Pages 497-513"},"PeriodicalIF":10.7,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148544593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dolomitization controlled by geological events during the critical tectonic transition of the Tethyan domain: A case study from the Permian Maokou Formation in eastern Sichuan Basin, SW China","authors":"Yanxian ZHU ,&nbsp;Zhiliang HE ,&nbsp;Xiaowen GUO ,&nbsp;Hao ZHANG ,&nbsp;Long LI","doi":"10.1016/S1876-3804(26)60700-8","DOIUrl":"10.1016/S1876-3804(26)60700-8","url":null,"abstract":"<div><div>Focusing on the dolomites within the Permian Maokou Formation in eastern Sichuan Basin, this study integrates petrographic observation, geochemical analysis and in situ U-Pb dating to constrain the timing of dolomitization and trace the sources of dolomitizing fluids, analyze the intrinsic links among geological events during the tectonic transition of the Paleo-Tethys to Neo-Tethys oceans, strike-slip faulting and dolomitization, so as to reveal the dolomitization mechanism of the Maokou Formation. Three types of matrix dolomites occur in the Maokou Formation in eastern Sichuan Basin, with U-Pb ages indicating three dolomitization phases at (260.6 ± 6.8)–(265.1 ± 2.4), (244.0 ± 11.0)–(247.7 ± 6.0), and (220.6 ± 8.5)–(221.4 ± 7.8) Ma, respectively. Geochemical data indicate distinct fluid origins for each phase of dolomitization. Three geological events and the resulting three episodes of faulting during the tectonic transition from Paleo- to Neo-Tethys Ocean are key controlling factors of three phases of dolomitization. Specifically, the Middle Permian Emeishan magmatism activated the Houba-Peng’an-Fengdu strike-slip fault zone and induced thermal anomalies, promoting thermal convection between contemporaneous seawater and the Lower Silurian siltstone aquifer, and initiating the first phase of dolomitization. During the Middle Triassic, oblique closure of the Mianlüe Ocean induced transtensional faulting, and density-driven downward migration of residual evaporitic seawater and brines from evaporates in the Lower–Middle Triassic facilitated the second phase of dolomitization. The Late Triassic continental collision between the South China Block and North China Block induced transpressional faulting, driving the upward migration of brines within the Lower Silurian to mix with residual evaporitic seawater in the Lower–Middle Triassic, thus supplying the magnesium source for the third phase of dolomitization. A strike-slip fault-controlled dolomitization model is established, providing new insights into the formation mechanisms of dolomite reservoirs in the Tethyan domain.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"53 2","pages":"Pages 401-413"},"PeriodicalIF":8.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754151","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":"Experimental study on mechanism of inter-well steam channeling and steam channeling control capability of multicomponent thermal composite system in difficult- to-produce heavy oil reservoirs","authors":"Haitao WANG ,&nbsp;Huanquan SUN ,&nbsp;Yongqiang TANG ,&nbsp;Weiyi PAN ,&nbsp;Zengmin LUN ,&nbsp;Tao MA ,&nbsp;Jiajing CHANG ,&nbsp;Bing ZHOU ,&nbsp;Suobing ZHANG","doi":"10.1016/S1876-3804(26)60706-9","DOIUrl":"10.1016/S1876-3804(26)60706-9","url":null,"abstract":"<div><div>Taking typical difficult-to-produce heavy oil reservoirs as the research object, a multi-scale physical simulation experimental device for heavy oil thermal recovery and corresponding similarity criteria were established. The evolution characteristics of the temperature field and saturation field, as well as the variation patterns of development indices during cyclic steam stimulation, were clarified, and the steam channeling control capability of multicomponent thermal composite system was evaluated. It is found that, during cyclic steam stimulation, steam channeling primarily occurs along the main flow line in the direction of the maximum pressure differential horizontally, while steam channeling appears in the upper part of the reservoir as a result of steam override vertically. High-temperature steam causes the separation of light and heavy components in the heavy oil, with the light components being preferentially produced. The interaction between high-temperature steam and the reservoir induces particle migration and mineral dissolution, accelerating the steam channeling and thus degrading the development performance in later cycles. As the steam temperature increases, the heavy oil in large pores is continuously produced, and the oil displacement efficiency increases significantly. The multicomponent thermal composite flooding systems including the nitrogen foam system, the high-temperature profile control and displacement system, and the thermosetting profile control system all effectively mitigate steam channeling and significantly enhance oil recovery. They rank as the thermosetting profile control system, the high-temperature profile control and displacement system, and the nitrogen foam system, in a descending order of the increase in pressure differential and the enhancement of oil recovery.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"53 2","pages":"Pages 489-500"},"PeriodicalIF":8.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754292","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":"Components and stable carbon isotopic fractionation mechanisms of over-mature coal-derived gas in the Daji gas field, Ordos Basin, NW China","authors":"Jun LI ,&nbsp;Jingzhou ZHAO ,&nbsp;Xiaoqing SHANG ,&nbsp;Fengyin XU ,&nbsp;Yixin ZHANG ,&nbsp;Jiachen LI ,&nbsp;Xiao YANG ,&nbsp;Chengzhuo YUAN ,&nbsp;Yujiao REN ,&nbsp;Chuang ER ,&nbsp;Guoping LYU ,&nbsp;Yue ZHANG ,&nbsp;Chenlong GAO","doi":"10.1016/S1876-3804(26)60699-4","DOIUrl":"10.1016/S1876-3804(26)60699-4","url":null,"abstract":"<div><div>Based on the natural gas composition and stable carbon isotope data from the Upper Paleozoic tight sandstone gas in the Daji gas field, Ordos Basin, and through a comparative analysis of the geochemical characteristics of typical overmature coal-derived gases in China and the world, this study clarified the geochemical features and the origins of stable carbon isotopic anomalies of overmature coal-derived gas, and revealed the components of overmature coal-derived gas and the mechanisms of stable carbon isotopic fractionation and their geological implications. The research shows that the Upper Paleozoic tight gas in the Daji gas field is dominated by methane, and its stable carbon isotopic compositions exhibit a large-scale full reverse sequence, suggesting that it was primarily originated from a mixture of kerogen, crude oil, and wet gas cracking gases during the over-mature stage of coal-measure source rocks. Vertically, with the thick limestone of the Permian Taiyuan Formation as a boundary, two gas-bearing systems are delineated in the upper and lower sections with gas respectively supplied by the source rocks of the second member of Permian Shanxi Formation and the Carboniferous Benxi Formation, which exhibit significant differences in migration and accumulation patterns and exploration directions. A three-stage evolution pathway for the stable carbon isotopic composition sequence in overmature coal-derived gas is proposed. This full reverse sequence is not only controlled by the mixed-source genesis effects during the overmature stage, but also influenced by the migration fractionation effects resulting from the preferential diffusion of natural gas generated at this stage. Both factors have, to some extent, enhanced the abundance of coal-derived gas resources in the area, although the enrichment effects of natural gas differ across the various gas-bearing systems.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"53 2","pages":"Pages 386-400"},"PeriodicalIF":8.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754146","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":"Reservoir types and reservoir-forming differentiation of onlap-type carbonate-evaporite paragenetic assemblages: A case study of the second member of the Ordovician Majiagou Formation in the central-eastern Ordos Basin, NW China","authors":"Jiansheng DU ,&nbsp;Ying XIONG ,&nbsp;Junfeng REN ,&nbsp;Shoukang ZHONG ,&nbsp;Liubin WEI ,&nbsp;Zhou YU ,&nbsp;Wenjie CAI ,&nbsp;Jingkang YONG ,&nbsp;Xiucheng TAN ,&nbsp;Ling LI","doi":"10.1016/S1876-3804(26)60703-3","DOIUrl":"10.1016/S1876-3804(26)60703-3","url":null,"abstract":"<div><div>Based on drilling core, thin section, physical property and logging data, taking the second member of the Ordovician Majiagou Formation (Ma 2 Member) in the Ordos Basin as an example, this paper discusses the reservoir types, distribution and forming mechanisms of the carbonate-evaporite paragenetic system. The results are obtained in three aspects. First, the Ma 2 Member was deposited in an onlapping pattern toward the Central Paleouplift and is in unconformable contact with the underlying Cambrian around the paleouplift. From the paleouplift to the eastern depression, sedimentary environments such as tidal flat, grain shoal and lagoon, as well as five types of carbonate-evaporite paragenetic sequences, developed in turn. Second, dolomicrite, silt-crystalline dolomite and grain dolomite reservoirs are developed in the Ma 2 Member. According to sedimentary and diagenetic differences, they are further subdivided into four types of reservoir rocks, including mottled silt-crystalline dolomite, grain dolomite, burrow-bearing micritic (silt-crystalline) dolomite, and gypsum-mold-pore-bearing dolomicrite. Among them, grain dolomite reservoirs have superior physical properties and high development frequency, representing the high-quality reservoirs in the study area. Vertically, the reservoirs are mainly developed in the middle and upper parts of high-frequency cycles; laterally, they show a pattern of distribution along sags and around structural highs (“along sags and around highs”), characterized by multi-stage superposition and lateral migration. Third, based on the understanding of the sedimentary geomorphic pattern and onlap sedimentary filling model, combined with the lithology, lithofacies distribution and evolution of reservoir rocks, and considering the penecontemporaneous dissolution and dolomitization under high-frequency periodic sea-level cycles, a four-element reservoir-controlling differentiation model of slope geomorphology, particle shoal, dissolution and dolomitization (“slope–shoal–dissolution–dolomitization”) has been established.. The research results can provide a basis for evaluating the exploration potential of hydrocarbon replacement areas in the deep Ma 2 Member of the basin.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"53 2","pages":"Pages 444-459"},"PeriodicalIF":8.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754152","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":"Connotation, key issues, and future development of the new-generation volume stimulation technology","authors":"Yun XU ,&nbsp;Dingwei WENG ,&nbsp;Zeyuan MA ,&nbsp;Deqi LI ,&nbsp;Bo CAI ,&nbsp;Ming CHEN ,&nbsp;Xinbin YI ,&nbsp;Haifeng FU ,&nbsp;Zhanwei YANG ,&nbsp;Shuai LI ,&nbsp;Hao JIANG","doi":"10.1016/S1876-3804(26)60708-2","DOIUrl":"10.1016/S1876-3804(26)60708-2","url":null,"abstract":"<div><div>This paper systematically reviews the development history and generational characteristics of multi-stage fracturing technology in horizontal wells and defines the connotation and essence of the new-generation volume stimulation technology, as represented by eXtreme Limited Entry (XLE). The research indicates that classical fracturing theory remains the cornerstone for optimizing stimulation designs. Optimization based on fracture units is fundamental for achieving “perfect fracturing”, while “proppant loading intensity” serves merely as a statistical parameter and therefore cannot be used to evaluate fracturing effectiveness. Consequently, expanding the stimulated volume is identified as the key to achieving optimal stimulation results. Regarding limited entry perforation strategies, the study clarifies that all clusters initiation can be achieved when the total perforation friction exceeds the horizontal in-situ stress difference among clusters. Furthermore, XLE requires a total perforation friction greater than 10 MPa, superimposed on the treating pressure at wellhead after all clusters initiation, to ensure even fluid distribution across all fractures. Based on the characteristics of “fracture swarms” observed in cores from hydraulic fracturing test sites (HFTS), it is revealed that creating a single principal fracture is critical for effective fracture propagation. Drawing on the rheological characteristics of proppant settling in slickwater and learnings from North American HFTSs, three novel viewpoints on modern fracturing are proposed: Slickwater fracturing relies on velocity for proppant transport, and subsequently injected proppant travels the furthest, suggesting that “CounterProp” is the future direction of fracturing technology; High-viscosity slickwater struggles to achieve effective proppant transport; The proppant settling mode determines that the dynamic fracture width during the treatment is effectively equal to the propped fracture width. Finally, the technical connotation and implementation pathway for “whole-domain propped” treatment are presented, and a future development vision for Autonomous Intelligent Fracturing (AIF) is proposed.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"53 2","pages":"Pages 512-533"},"PeriodicalIF":8.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754288","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":"Dynamic conditions and processes of three-dimensional accumulation of Sinian-Permian natural gas in Penglai gas area, central Sichuan Basin, SW China","authors":"Bing LUO ,&nbsp;Benjian ZHANG ,&nbsp;Gang ZHOU ,&nbsp;Luya WU ,&nbsp;Wei YAN ,&nbsp;Baoshou ZHANG ,&nbsp;Xihua ZHANG ,&nbsp;Yuan ZHONG ,&nbsp;Kui MA ,&nbsp;Xiaorong LUO ,&nbsp;Yishu LI","doi":"10.1016/S1876-3804(26)60695-7","DOIUrl":"10.1016/S1876-3804(26)60695-7","url":null,"abstract":"<div><div>Considering the complexities of gas-water relationships in the gas reservoirs, unclear natural gas distribution and difficult exploration expansion of the Sinian–Permian natural gas in the Penglai gas area of the central Sichuan Basin, this study investigates the gas source, charging processes and enrichment patterns of gas reservoirs based on reservoir characterization, natural gas geochemical analysis, reservoir testing, well logging-seismic data interpretation, as well as basin modeling and dynamic analysis. The results are obtained in three aspects. First, four sets of highly efficient source rocks are developed beneath the salt of the Triassic Jialingjiang Formation, dominated by the Cambrian source rocks. The reservoirs exhibit strong heterogeneity, with six sets of effective reservoirs being isolated from each other yet dynamically connected. Multi-stage strike-slip fault-related fault-fracture-cavity-unconformity systems constitute the hydrocarbon migration network. Second, overpressure generated by hydrocarbon generation in the Cambrian source rocks drove bidirectional hydrocarbon expulsion from the source kitchen. Multiple sources, including cracked gas from paleo-oil reservoirs and residual hydrocarbons within source rocks, contributed to the hydrocarbon supply. The Sinian–Permian system underwent multiple dynamic hydrocarbon accumulation processes, resulting in the formation of extensive “sweet spots” within multi-layered heterogeneous reservoirs, which were subsequently modified by late-stage gas adjustments to their current form. Third, a three-dimensional accumulation model for deep marine natural gas is established, with multi-source hydrocarbon supply, three-dimensional migration, multi-stage accumulation, dynamic adjustment and lithology-controlled distribution. Large-scale reservoirs within positive structural settings, late-stage structurally stable areas, and slope structures are identified as favorable plays for gas exploration.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"53 2","pages":"Pages 327-342"},"PeriodicalIF":8.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754313","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":"Thermo-mechanical damage mechanisms of heterogeneous granite under plasma jet","authors":"Yancong HAN ,&nbsp;Chao ZHENG ,&nbsp;Yonghong LIU ,&nbsp;Wenhao ZHAO ,&nbsp;Yuming LIU ,&nbsp;Ningrui XU","doi":"10.1016/S1876-3804(26)60711-2","DOIUrl":"10.1016/S1876-3804(26)60711-2","url":null,"abstract":"<div><div>This study establishes a one-way finite element method-discrete element method (FEM-DEM) coupling numerical framework to dynamically simulate the thermal damage and crack evolution of heterogeneous granite under plasma jet, and to identify the thermo-mechanical cracking mechanisms. The finite element method is used to build a Gaussian rotating conical heat source to compute the transient temperature field. The temperature is then mapped onto a heterogeneous DEM model reconstructed from real mineral grain boundaries. The model incorporates temperature-dependent bond strength degradation and temperature-threshold-triggered fracture criterion to capture the crack evolution process. Validation against experiments shows errors of less than 7% for temperature, 6% for pit morphology, and 11% for crack inclination, suggesting the reliability and accuracy of the model. Simulation reveals the crack evolution in three stages: crack initiation, rapid propagation and stable extension. The dominance of tensile failure and presence of significantly more cracks within grain than at grain boundary indicate that intragranular cracking driven by thermal strain mismatch is the primary pattern of plasma thermal cracking. When the plasma current exceeds 200 A, the damage factor increases sharply and nonlinearly, indicating the existence of a current threshold where the rate of thermal stress accumulation exceeds the rate of stress relaxation. Higher initial rock temperature intensifies thermal damage and shifts the failure mode from tensile-dominated to tensile-shear composite, while confining pressure suppresses axial crack propagation but exacerbates the near-surface thermal spalling effect.</div></div>","PeriodicalId":67426,"journal":{"name":"Petroleum Exploration and Development","volume":"53 2","pages":"Pages 561-574"},"PeriodicalIF":8.0,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147754315","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}