Pub Date : 2025-09-01DOI: 10.1016/j.petsci.2025.05.020
Shu-Xia Li , Bin Xu , Shu-Qian Li , Feng-Hua Zhao , You-Chuan Li , Hong-Fu Sun , Le Lu , Jin-Zhong Liu
Gas derived from the primary cracking of kerogen and the secondary cracking of oil has historically been the focus of petroleum geologists, given its importance as a gas source. The Wenchang A Depression within the Zhu III Sub-basin is the largest gaseous hydrocarbon-rich depression in the Pearl River Mouth Basin (PRMB), and the sources of gaseous hydrocarbons in this depression are a research focus. Mudstones from the Eocene Wenchang Formation contain type I and type II organic matter and are oil-prone, with TOC, S1+S2, and HI values mostly ranging from 1.42% to 3.12%, 9.71 mg/g to 20.61 mg/g, and 410.71 mg/g TOC to 736.17 mg/g TOC, respectively. Data of gaseous hydrocarbon yields and carbon isotopic compositions show that the gaseous hydrocarbons generated from oil-prone mudstones are mainly derived from the secondary cracking of oil, and the plot of δ13C2–δ13C3 versus ln(C2/C3) effectively identified the gas source. To further assess the gas generation processes and the ratio of oil-cracking gas under geological conditions, we reconstructed the history of gaseous hydrocarbon generation in mudstones from the Wenchang Formation in the Wenchang A Depression. Results showed that gaseous hydrocarbon generation began at approximately 33 Ma, a maximum of 69% of total gaseous hydrocarbons (C1–C5) was generated by oil cracking, and total heavy hydrocarbon gases (C2-C5) were mainly generated from oil cracking (65%–81%). This study provides a deeper understanding of the characteristics of gas generated from oil-prone mudstones and is important for gas exploration in the Wenchang Depression.
{"title":"Gas generation from oil-prone mudstones in the Eocene Wenchang A Depression, Pearl River Mouth Basin","authors":"Shu-Xia Li , Bin Xu , Shu-Qian Li , Feng-Hua Zhao , You-Chuan Li , Hong-Fu Sun , Le Lu , Jin-Zhong Liu","doi":"10.1016/j.petsci.2025.05.020","DOIUrl":"10.1016/j.petsci.2025.05.020","url":null,"abstract":"<div><div>Gas derived from the primary cracking of kerogen and the secondary cracking of oil has historically been the focus of petroleum geologists, given its importance as a gas source. The Wenchang A Depression within the Zhu III Sub-basin is the largest gaseous hydrocarbon-rich depression in the Pearl River Mouth Basin (PRMB), and the sources of gaseous hydrocarbons in this depression are a research focus. Mudstones from the Eocene Wenchang Formation contain type I and type II organic matter and are oil-prone, with TOC, S1+S2, and HI values mostly ranging from 1.42% to 3.12%, 9.71 mg/g to 20.61 mg/g, and 410.71 mg/g TOC to 736.17 mg/g TOC, respectively. Data of gaseous hydrocarbon yields and carbon isotopic compositions show that the gaseous hydrocarbons generated from oil-prone mudstones are mainly derived from the secondary cracking of oil, and the plot of <em>δ</em><sup>13</sup>C<sub>2</sub>–<em>δ</em><sup>13</sup>C<sub>3</sub> versus ln(C<sub>2</sub>/C<sub>3</sub>) effectively identified the gas source. To further assess the gas generation processes and the ratio of oil-cracking gas under geological conditions, we reconstructed the history of gaseous hydrocarbon generation in mudstones from the Wenchang Formation in the Wenchang A Depression. Results showed that gaseous hydrocarbon generation began at approximately 33 Ma, a maximum of 69% of total gaseous hydrocarbons (C<sub>1</sub>–C<sub>5</sub>) was generated by oil cracking, and total heavy hydrocarbon gases (C<sub>2</sub>-C<sub>5</sub>) were mainly generated from oil cracking (65%–81%). This study provides a deeper understanding of the characteristics of gas generated from oil-prone mudstones and is important for gas exploration in the Wenchang Depression.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3512-3529"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.1016/j.petsci.2025.07.006
Wei-Wei Teng , Jian-Bo Wang , Jian-Tong Liu , Hong-Kui Ge , Xiao-Di Li , Yuan-Kai Zhang , Ting-Feng Zhao
Mahu Sag, located in Junggar Basin, China, is the largest conglomerate oil reservoir in the world (in this paper, conglomerate generally refers to rocks containing gravel, including pebbly sandstone, sand conglomerate, and conglomerate). The reservoir has the characteristics of low porosity and low permeability and needs hydraulic fracturing. The micromechanical properties and rock fracture characteristics are studied to provide a theoretical basis for hydraulic fracturing treatment. In this study, the mechanical properties, micromechanical properties, fracture characteristics, and micromechanical mechanism of conglomerate are studied experimentally. Assuming that the gravel size is constant, conglomerate with the same cementation type has the following rules: When the gravel content (GC) is ≤ 40%, the rock fracture is controlled by Orowan additional stress, and the strength of miscellaneous foundation is the key factor, forming a single fracture with high tortuosity. When the GC is 40%–65%, the GC and cementation strength are the key factors of rock fracture, resulting in the fracture network around the gravel. When the GC is ≥ 65%, the rock fracture is controlled by Hertz contact stress. The GC is the key factor. Surrounding gravel and passing through gravel cracks are developed, resulting in complex fracture network, but the transformation scale of fracture network is small. Through this study, the fracture morphology and key factors of conglomerate fracture are explored, which can provide reference for hydraulic fracturing.
{"title":"Study of micromechanical characteristics and failure mechanism of conglomerate reservoirs","authors":"Wei-Wei Teng , Jian-Bo Wang , Jian-Tong Liu , Hong-Kui Ge , Xiao-Di Li , Yuan-Kai Zhang , Ting-Feng Zhao","doi":"10.1016/j.petsci.2025.07.006","DOIUrl":"10.1016/j.petsci.2025.07.006","url":null,"abstract":"<div><div>Mahu Sag, located in Junggar Basin, China, is the largest conglomerate oil reservoir in the world (in this paper, conglomerate generally refers to rocks containing gravel, including pebbly sandstone, sand conglomerate, and conglomerate). The reservoir has the characteristics of low porosity and low permeability and needs hydraulic fracturing. The micromechanical properties and rock fracture characteristics are studied to provide a theoretical basis for hydraulic fracturing treatment. In this study, the mechanical properties, micromechanical properties, fracture characteristics, and micromechanical mechanism of conglomerate are studied experimentally. Assuming that the gravel size is constant, conglomerate with the same cementation type has the following rules: When the gravel content (GC) is ≤ 40%, the rock fracture is controlled by Orowan additional stress, and the strength of miscellaneous foundation is the key factor, forming a single fracture with high tortuosity. When the GC is 40%–65%, the GC and cementation strength are the key factors of rock fracture, resulting in the fracture network around the gravel. When the GC is ≥ 65%, the rock fracture is controlled by Hertz contact stress. The GC is the key factor. Surrounding gravel and passing through gravel cracks are developed, resulting in complex fracture network, but the transformation scale of fracture network is small. Through this study, the fracture morphology and key factors of conglomerate fracture are explored, which can provide reference for hydraulic fracturing.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3709-3728"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.1016/j.petsci.2025.05.025
Ying-He Wu , Shu-Lin Pan , Kai Chen , Yao-Jie Chen , Da-Wei Liu , Zi-Yu Qin , Sheng-Bo Yi , Ze-Yang Liu
Passive source imaging can reconstruct body wave reflections similar to those of active sources through seismic interferometry (SI). It has become a low-cost, environmentally friendly alternative to active source seismic, showing great potential. However, this method faces many challenges in practical applications, including uneven distribution of underground sources and complex survey environments. These situations seriously affect the reconstruction quality of virtual shot records, resulting in unguaranteed imaging results and greatly limiting passive source seismic exploration applications. In addition, the quality of the reconstructed records is directly related to the time length of the noise records, but in practice it is often difficult to obtain long-term, high-quality noise segments containing body wave events. To solve the above problems, we propose a deep learning method for reconstructing passive source virtual shot records and apply it to passive source time-lapse monitoring. This method combines the UNet network and the BiLSTM (Bidirectional Long Short-Term Memory) network for extracting spatial features and temporal features respectively. It introduces the spatial attention mechanism to establish a hybrid SUNet-BiLSTM-Attention (SBA) network for supervised training. Through pre-training and fine-tuning training, the network can accurately reconstruct passive source virtual shot records directly from short-time noisy segments containing body wave events. The experimental results of theoretical data show that the virtual shot records reconstructed by the network have high resolution and signal to noise ratio (SNR), providing high-quality data for subsequent monitoring and imaging. Finally, to further validate the effectiveness of proposed method, we applied it to field data collected from gas storage in northwest China. The reconstruction results of field data effectively improve the quality of virtual records and obtain more reliable time-lapse imaging monitoring results, which have significant practical value.
{"title":"Accurate reconstruction method of virtual shot records in passive source time-lapse monitoring based on SBA network","authors":"Ying-He Wu , Shu-Lin Pan , Kai Chen , Yao-Jie Chen , Da-Wei Liu , Zi-Yu Qin , Sheng-Bo Yi , Ze-Yang Liu","doi":"10.1016/j.petsci.2025.05.025","DOIUrl":"10.1016/j.petsci.2025.05.025","url":null,"abstract":"<div><div>Passive source imaging can reconstruct body wave reflections similar to those of active sources through seismic interferometry (SI). It has become a low-cost, environmentally friendly alternative to active source seismic, showing great potential. However, this method faces many challenges in practical applications, including uneven distribution of underground sources and complex survey environments. These situations seriously affect the reconstruction quality of virtual shot records, resulting in unguaranteed imaging results and greatly limiting passive source seismic exploration applications. In addition, the quality of the reconstructed records is directly related to the time length of the noise records, but in practice it is often difficult to obtain long-term, high-quality noise segments containing body wave events. To solve the above problems, we propose a deep learning method for reconstructing passive source virtual shot records and apply it to passive source time-lapse monitoring. This method combines the UNet network and the BiLSTM (Bidirectional Long Short-Term Memory) network for extracting spatial features and temporal features respectively. It introduces the spatial attention mechanism to establish a hybrid SUNet-BiLSTM-Attention (SBA) network for supervised training. Through pre-training and fine-tuning training, the network can accurately reconstruct passive source virtual shot records directly from short-time noisy segments containing body wave events. The experimental results of theoretical data show that the virtual shot records reconstructed by the network have high resolution and signal to noise ratio (SNR), providing high-quality data for subsequent monitoring and imaging. Finally, to further validate the effectiveness of proposed method, we applied it to field data collected from gas storage in northwest China. The reconstruction results of field data effectively improve the quality of virtual records and obtain more reliable time-lapse imaging monitoring results, which have significant practical value.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3548-3564"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.1016/j.petsci.2025.07.002
Dan Bao , Si-Yuan Liu , Yan-Jie Yang , Yu-Tong Sang , Zhi-Peng Miao , Hua Li , Biao Wang , Tao-Song Liang , Peng Zhang
Lost circulation of drilling fluid is an international engineering problem during drilling. Aiming at the problems of the first-time lost circulation control success rate and poor adaptability of traditional lost circulation materials, a new self-healing lost circulation material based on dynamic disulfide bonds was prepared and named CKSH. In this paper, the particle size of self-healing lost circulation material was from 0.1 to 5 mm. The structure was analyzed by modern characterization means, and the drilling fluid compatibility, self-healing performance were evaluated. The self-healing and bridging-filling-sealing mechanism of CKSH were revealed. The results showed that the healing rate of CKSH could reach 100% after 12 h over 70 °C. It showed good compatibility with drilling fluid, with no effect on rheology or filtration loss. It could be stably suspended in drilling fluid, and the temperature resistance reached 140 °C. Healing by self-healing lost circulation materials of different particle size, the pressure bearing capacity of plugging zone were over 12 MPa for fracture opening of 1–5 mm. It could play a synergistic role with traditional lost circulation materials by chemical bonding, and the repeated loss caused by physical plugging was avoided. The research results of this paper can improve the bridging plugging bearing pressure strength and the first-time lost circulation control success rate, which is of great significance for improving drilling efficiency and reducing non-productive time.
{"title":"Preparation and performance of high temperature resistant and high strength self-healing lost circulation material in the drilling industry","authors":"Dan Bao , Si-Yuan Liu , Yan-Jie Yang , Yu-Tong Sang , Zhi-Peng Miao , Hua Li , Biao Wang , Tao-Song Liang , Peng Zhang","doi":"10.1016/j.petsci.2025.07.002","DOIUrl":"10.1016/j.petsci.2025.07.002","url":null,"abstract":"<div><div>Lost circulation of drilling fluid is an international engineering problem during drilling. Aiming at the problems of the first-time lost circulation control success rate and poor adaptability of traditional lost circulation materials, a new self-healing lost circulation material based on dynamic disulfide bonds was prepared and named CKSH. In this paper, the particle size of self-healing lost circulation material was from 0.1 to 5 mm. The structure was analyzed by modern characterization means, and the drilling fluid compatibility, self-healing performance were evaluated. The self-healing and bridging-filling-sealing mechanism of CKSH were revealed. The results showed that the healing rate of CKSH could reach 100% after 12 h over 70 °C. It showed good compatibility with drilling fluid, with no effect on rheology or filtration loss. It could be stably suspended in drilling fluid, and the temperature resistance reached 140 °C. Healing by self-healing lost circulation materials of different particle size, the pressure bearing capacity of plugging zone were over 12 MPa for fracture opening of 1–5 mm. It could play a synergistic role with traditional lost circulation materials by chemical bonding, and the repeated loss caused by physical plugging was avoided. The research results of this paper can improve the bridging plugging bearing pressure strength and the first-time lost circulation control success rate, which is of great significance for improving drilling efficiency and reducing non-productive time.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3655-3670"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223159","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.1016/j.petsci.2025.07.010
Zhao-Wen Hu , Yi-Qun Zhang , Jin-Shan Wang , Xin-Yu Wang , Yu Qin , Ya Liu
Lost circulation critically jeopardizes drilling safety and efficiency, and remains an unresolved challenge in oil and gas engineering. In this paper, by utilizing the self-developed dynamic plugging apparatus and synthetic cores containing large-scale fractures, experimental research on the circulation plugging of different materials was conducted. Based on the D90 rule and fracture mechanical aperture model, we analyze the location of plugging layer under dynamic plugging mechanism. By setting different parameters of fracture width and injection pressure, the laws of cyclic plugging time, pressure bearing capacity and plugging layers formation were investigated. The results show that the comprehensive analysis of particle size and fracture aperture provides an accurate judgment of the entrance-plugging phenomenon. The bridging of solid materials in the leakage channel is a gradual process, and the formation of a stable plug requires 2–3 plug-leakage cycles. The first and second cyclic plugging time was positively correlated with the fracture width. Different scales of fractures were successfully plugged with the bearing pressure greater than 6 MPa, but there were significant differences in the composition of the plugging layer. The experimental results can effectively prove that the utilized plugging agent is effective and provides an effective reference for dynamic plugging operation.
{"title":"Experimental study of a circulation agent dynamic plugging for multi-scale natural fractures","authors":"Zhao-Wen Hu , Yi-Qun Zhang , Jin-Shan Wang , Xin-Yu Wang , Yu Qin , Ya Liu","doi":"10.1016/j.petsci.2025.07.010","DOIUrl":"10.1016/j.petsci.2025.07.010","url":null,"abstract":"<div><div>Lost circulation critically jeopardizes drilling safety and efficiency, and remains an unresolved challenge in oil and gas engineering. In this paper, by utilizing the self-developed dynamic plugging apparatus and synthetic cores containing large-scale fractures, experimental research on the circulation plugging of different materials was conducted. Based on the D90 rule and fracture mechanical aperture model, we analyze the location of plugging layer under dynamic plugging mechanism. By setting different parameters of fracture width and injection pressure, the laws of cyclic plugging time, pressure bearing capacity and plugging layers formation were investigated. The results show that the comprehensive analysis of particle size and fracture aperture provides an accurate judgment of the entrance-plugging phenomenon. The bridging of solid materials in the leakage channel is a gradual process, and the formation of a stable plug requires 2–3 plug-leakage cycles. The first and second cyclic plugging time was positively correlated with the fracture width. Different scales of fractures were successfully plugged with the bearing pressure greater than 6 MPa, but there were significant differences in the composition of the plugging layer. The experimental results can effectively prove that the utilized plugging agent is effective and provides an effective reference for dynamic plugging operation.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3641-3654"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223552","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.1016/j.petsci.2025.03.033
Xiao-Tong Xu , Lian-Bo Zeng , Shao-Qun Dong , Hai-Ming Li , Jian-Zhong Liu , Chun-Qiu Ji
High-quality reservoirs with sufficient physical properties of ultra-deep tight gas reservoirs in the Lower Cretaceous Bashijiqike Formation exhibit significant relationship with gas production across the Dabei Gas Field. Clarifying the characteristics, controlling factors, evolution and distribution of the high-quality reservoirs is important for the deployment of "sweet spots". An integrated approach of petrography, SEM, cathode luminescence, XRD, physical property, NMR experiment, well logs and 3D pre-stack depth migration data was carried out. This study examined the sedimentation, diagenesis, tectonism, gypsum-rock and overpressure to reveal the formation and distribution of the high-quality reservoirs. The sandstones are very fine-to coarse-grained lithic arkose. The variation in detrital grains texture and mineralogical composition affects diagenetic evolution, pore structure and gas-bearing characteristic. Three diagenetic facies (diagenetic facies A to C) are classified. Different diagenetic facies underwent different evolution of reservoir quality. The medium–fine to medium-grained lithic arkose (diagenetic facies A) underwent medium vertical compaction, tectonic compression and cementation, and exhibited relatively porous, which makes partial primary pores preserved with the occurrence and persistence of overpressure. Conversely, the very fine to fine-grained and mud gravel-rich medium-grained lithic arkose (diagenetic facies B) and diagenetic facies C appeared premature densification by strong compaction and tight carbonate cementation, respectively, which makes them free from overpressure effects. Natural fractures increased the permeability by several orders of magnitude. Gypsum-rock weakened the vertical compaction and tectonic compression, and delayed cementation, promoted and preserved overpressure. With the injection of internal high alkaline fluids, anhydrite/dolomite cements/veins and dissolution of siliceous developed. Diagenetic facies A exhibited sufficient physical properties and gas volume, making it the high-quality reservoir in tight gas sandstone. Diagenetic facies B and C mainly were used as barriers for hydrocarbon charging. Diagenetic facies A was mainly distributed in the middle-lower part of distributary channel or the middle-upper part of mouth bar. This distribution model provides guidance for exploration in ultra-deep tight sandstone gas reservoir.
{"title":"The characteristics and controlling factors of high-quality reservoirs of ultra-deep tight sandstone: A case study of the Dabei Gas Field, Tarim Basin, China","authors":"Xiao-Tong Xu , Lian-Bo Zeng , Shao-Qun Dong , Hai-Ming Li , Jian-Zhong Liu , Chun-Qiu Ji","doi":"10.1016/j.petsci.2025.03.033","DOIUrl":"10.1016/j.petsci.2025.03.033","url":null,"abstract":"<div><div>High-quality reservoirs with sufficient physical properties of ultra-deep tight gas reservoirs in the Lower Cretaceous Bashijiqike Formation exhibit significant relationship with gas production across the Dabei Gas Field. Clarifying the characteristics, controlling factors, evolution and distribution of the high-quality reservoirs is important for the deployment of \"sweet spots\". An integrated approach of petrography, SEM, cathode luminescence, XRD, physical property, NMR experiment, well logs and 3D pre-stack depth migration data was carried out. This study examined the sedimentation, diagenesis, tectonism, gypsum-rock and overpressure to reveal the formation and distribution of the high-quality reservoirs. The sandstones are very fine-to coarse-grained lithic arkose. The variation in detrital grains texture and mineralogical composition affects diagenetic evolution, pore structure and gas-bearing characteristic. Three diagenetic facies (diagenetic facies A to C) are classified. Different diagenetic facies underwent different evolution of reservoir quality. The medium–fine to medium-grained lithic arkose (diagenetic facies A) underwent medium vertical compaction, tectonic compression and cementation, and exhibited relatively porous, which makes partial primary pores preserved with the occurrence and persistence of overpressure. Conversely, the very fine to fine-grained and mud gravel-rich medium-grained lithic arkose (diagenetic facies B) and diagenetic facies C appeared premature densification by strong compaction and tight carbonate cementation, respectively, which makes them free from overpressure effects. Natural fractures increased the permeability by several orders of magnitude. Gypsum-rock weakened the vertical compaction and tectonic compression, and delayed cementation, promoted and preserved overpressure. With the injection of internal high alkaline fluids, anhydrite/dolomite cements/veins and dissolution of siliceous developed. Diagenetic facies A exhibited sufficient physical properties and gas volume, making it the high-quality reservoir in tight gas sandstone. Diagenetic facies B and C mainly were used as barriers for hydrocarbon charging. Diagenetic facies A was mainly distributed in the middle-lower part of distributary channel or the middle-upper part of mouth bar. This distribution model provides guidance for exploration in ultra-deep tight sandstone gas reservoir.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3473-3496"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223158","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.1016/j.petsci.2025.07.004
Zhi-Cai Zhang , Jia-Kun Wu , Chao Wang , Zhi-Qiang Hou , Yao Tang , Hao Li , Jiao Yang , Jun Gao , Yi-Kan Yang , Yang-Bin Liu , Xiao-Ping Ouyang , Hai-Kuo Wang
With the global oil and gas industry increasingly targeting ultra-deep well development, the demand for wear resistance in polycrystalline diamond compact (PDC) bits is increasing. However, further improvement of the mechanical properties of PDC incurs prohibitively elevated costs and stringent technological challenges. Here, we present a two-stage high-pressure infiltration (HPI) methodology involving cobalt removal pretreatment followed by lubricant infiltration. The successful infiltration of lubricants into diamond micropores has been systematically verified, and the effects of lubricant phase composition, infiltration pressure, and temperature on infiltration depth have been thoroughly investigated. Fractal dimension analysis characterizes the pore structure of cobalt-removed diamonds, revealing a strong correlation between the fractal dimension and friction coefficient reduction. Tribological testing confirms the formation of lubricating films at friction interfaces, achieving a 71.5% reduction in the coefficient of friction for lubricant-containing diamond materials. This straightforward strategy opens a gate to developing the next generation of self-lubricating diamond materials.
{"title":"High-pressure driven lubricant infiltrated porous diamond for the preparation of self-lubricating diamond tools","authors":"Zhi-Cai Zhang , Jia-Kun Wu , Chao Wang , Zhi-Qiang Hou , Yao Tang , Hao Li , Jiao Yang , Jun Gao , Yi-Kan Yang , Yang-Bin Liu , Xiao-Ping Ouyang , Hai-Kuo Wang","doi":"10.1016/j.petsci.2025.07.004","DOIUrl":"10.1016/j.petsci.2025.07.004","url":null,"abstract":"<div><div>With the global oil and gas industry increasingly targeting ultra-deep well development, the demand for wear resistance in polycrystalline diamond compact (PDC) bits is increasing. However, further improvement of the mechanical properties of PDC incurs prohibitively elevated costs and stringent technological challenges. Here, we present a two-stage high-pressure infiltration (HPI) methodology involving cobalt removal pretreatment followed by lubricant infiltration. The successful infiltration of lubricants into diamond micropores has been systematically verified, and the effects of lubricant phase composition, infiltration pressure, and temperature on infiltration depth have been thoroughly investigated. Fractal dimension analysis characterizes the pore structure of cobalt-removed diamonds, revealing a strong correlation between the fractal dimension and friction coefficient reduction. Tribological testing confirms the formation of lubricating films at friction interfaces, achieving a 71.5% reduction in the coefficient of friction for lubricant-containing diamond materials. This straightforward strategy opens a gate to developing the next generation of self-lubricating diamond materials.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3627-3640"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.1016/j.petsci.2025.08.023
Xian-Chao Du , Xiang Liu , Qian-Yun Liu , Bing Wang
This study systematically investigated the catalytic gasification of two distinct petroleum coke (PC) using magnesium-based tailings (MT) as the catalyst. The research objectives focused on comparative analysis of gasification reactivities and elucidation of carbon microstructure evolution during PC gasification. Experimental results demonstrate that PC-B (derived from Liaohe Oilfields delayed coking) exhibited significantly higher gasification activity than PC-A (from Karamay Oilfields delayed coking), with aromatic C–H content and polycondensation index showing stronger correlations with reactivity than graphitization parameters. Notably, the MT catalyst exhibited material-dependent catalytic behaviors during gasification. MT catalyst enhanced structural ordering in PC-B by: (i) developing denser aromatic carbon layers, (ii) improving microcrystalline alignment, and (iii) elevating graphitization degree. These structural modifications contrasted sharply with PC-A’s response, where MT introduction generated active MgO species in the ash phase, boosting gasification reactivity. Conversely, in PC-B ash systems, MgO preferentially reacted with Al2O3 to form inert MgAl2O4 spinel, effectively deactivating the catalyst. Kinetic investigations validated the shrinking core model (SCM) as the dominant mechanism, with calculated activation energies of 172.12 kJ/mol (PC-A + 5% MT) and 137.19 kJ/mol (PC-B + 5% MT).
{"title":"Investigation into the characteristics of magnesite tailings-catalyzed gasification of petroleum coke","authors":"Xian-Chao Du , Xiang Liu , Qian-Yun Liu , Bing Wang","doi":"10.1016/j.petsci.2025.08.023","DOIUrl":"10.1016/j.petsci.2025.08.023","url":null,"abstract":"<div><div>This study systematically investigated the catalytic gasification of two distinct petroleum coke (PC) using magnesium-based tailings (MT) as the catalyst. The research objectives focused on comparative analysis of gasification reactivities and elucidation of carbon microstructure evolution during PC gasification. Experimental results demonstrate that PC-B (derived from Liaohe Oilfields delayed coking) exhibited significantly higher gasification activity than PC-A (from Karamay Oilfields delayed coking), with aromatic C–H content and polycondensation index showing stronger correlations with reactivity than graphitization parameters. Notably, the MT catalyst exhibited material-dependent catalytic behaviors during gasification. MT catalyst enhanced structural ordering in PC-B by: (i) developing denser aromatic carbon layers, (ii) improving microcrystalline alignment, and (iii) elevating graphitization degree. These structural modifications contrasted sharply with PC-A’s response, where MT introduction generated active MgO species in the ash phase, boosting gasification reactivity. Conversely, in PC-B ash systems, MgO preferentially reacted with Al<sub>2</sub>O<sub>3</sub> to form inert MgAl<sub>2</sub>O<sub>4</sub> spinel, effectively deactivating the catalyst. Kinetic investigations validated the shrinking core model (SCM) as the dominant mechanism, with calculated activation energies of 172.12 kJ/mol (PC-A + 5% MT) and 137.19 kJ/mol (PC-B + 5% MT).</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3830-3842"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In multiphase pumps transporting gas-liquid two-phase flows, the high-speed rotation of the impeller induces complex deformations in bubble shapes within the flow domain, making the prediction of gas-liquid two-phase drag forces highly challenging in numerical simulations. To achieve precise prediction of the drag forces on irregular bubbles within multiphase pumps, this study modifies the existing bubble drag force model and applies the revised model to the prediction of gas-liquid two-phase flow within multiphase pumps. The research findings indicate that the modified drag force model significantly enhances the accuracy of predicting flow characteristics within the pump, particularly under high gas volume fraction conditions. The simulation results for gas phase distribution and vorticity exhibit strong agreement with experimental data. The modified drag model better captures the accumulation of the gas phase at the suction side of the impeller outlet. It also accurately predicts the vortex characteristics induced by bubble backflow from the trailing edges of the diffuser. Additionally, the adjustment of the drag coefficient enhances the model’s ability to represent local flow field characteristics, thereby optimizing the performance simulation methods of multiphase pumps. Compared to traditional drag force models, the modified model reduces prediction errors in head and efficiency by 36.4% and 27.5%, respectively. These results provide important theoretical foundations and model support for improving the accuracy of gas-liquid two-phase flow simulations and optimizing the design of multiphase pumps under high gas volume fraction conditions.
{"title":"Modification of the bubble drag force model and prediction of gas-liquid two-phase flow dynamics in blade-type multiphase pumps","authors":"Yu-Qing Zhang , Guang-Tai Shi , Man-Qi Tang , Ye-Xiang Xiao , Hai-Gang Wen , Zong-Liu Huang","doi":"10.1016/j.petsci.2025.08.015","DOIUrl":"10.1016/j.petsci.2025.08.015","url":null,"abstract":"<div><div>In multiphase pumps transporting gas-liquid two-phase flows, the high-speed rotation of the impeller induces complex deformations in bubble shapes within the flow domain, making the prediction of gas-liquid two-phase drag forces highly challenging in numerical simulations. To achieve precise prediction of the drag forces on irregular bubbles within multiphase pumps, this study modifies the existing bubble drag force model and applies the revised model to the prediction of gas-liquid two-phase flow within multiphase pumps. The research findings indicate that the modified drag force model significantly enhances the accuracy of predicting flow characteristics within the pump, particularly under high gas volume fraction conditions. The simulation results for gas phase distribution and vorticity exhibit strong agreement with experimental data. The modified drag model better captures the accumulation of the gas phase at the suction side of the impeller outlet. It also accurately predicts the vortex characteristics induced by bubble backflow from the trailing edges of the diffuser. Additionally, the adjustment of the drag coefficient enhances the model’s ability to represent local flow field characteristics, thereby optimizing the performance simulation methods of multiphase pumps. Compared to traditional drag force models, the modified model reduces prediction errors in head and efficiency by 36.4% and 27.5%, respectively. These results provide important theoretical foundations and model support for improving the accuracy of gas-liquid two-phase flow simulations and optimizing the design of multiphase pumps under high gas volume fraction conditions.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3770-3786"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-09-01DOI: 10.1016/j.petsci.2025.08.016
Feng Chen , Hong-Lin Lu , Zhi-Hu Liu , Wen-Chang Wang , Ya Liu , Wei Wang , Qin-Feng Di
Recent advancements in drilling technology have driven substantial progress in cuttings removal tool development, particularly for addressing borehole cleaning challenges in highly deviated directional critical factors in operational safety and efficiency improvement. Despite these innovations, two fundamental challenges persist: an incomplete understanding of mechanistic cuttings removal processes and an insufficient methodological framework for optimal tool installation. Studying the installation positions and assessing the effects of two cuttings removal are essential steps to advance the application of such tools. This investigation was initiated with a comprehensive analysis of particle settling dynamics and migration behaviors in annular wellbore spaces. Building upon Moore's terminal settling velocity equation, a modified model was developed to characterize the transport patterns of cuttings. Through model integration, the precise positioning of the efficient Vortex Cuttings Removal Tool (VCRT) was determined at 188 m from the bit. Subsequently, Computational Fluid Dynamics (CFD) numerical simulation was employed to reveal distinct annular flow field characteristics between VCRT and conventional drilling tools. Field validation in Well Z401X demonstrated a strong correlation between empirical measurements and simulated predictions, with pressure drop deviations of 6.25% and rotational speed variances limited to 7.50%. Analytical results confirmed VCRT's superior performance, exhibited 36.43% reductions in cuttings accumulation at the wellbore's lower quadrant compared to conventional drilling tools. The application of VCRT accelerated cuttings migration velocity in the annular space, significantly increasing the volume of returned onsite cuttings. Friction resistance decreased by approximately 35.90%, indicating higher cuttings removal efficiency than conventional drilling tools.
{"title":"Method for determining the installation interval of vortexing cuttings removal tool and its mechanism","authors":"Feng Chen , Hong-Lin Lu , Zhi-Hu Liu , Wen-Chang Wang , Ya Liu , Wei Wang , Qin-Feng Di","doi":"10.1016/j.petsci.2025.08.016","DOIUrl":"10.1016/j.petsci.2025.08.016","url":null,"abstract":"<div><div>Recent advancements in drilling technology have driven substantial progress in cuttings removal tool development, particularly for addressing borehole cleaning challenges in highly deviated directional critical factors in operational safety and efficiency improvement. Despite these innovations, two fundamental challenges persist: an incomplete understanding of mechanistic cuttings removal processes and an insufficient methodological framework for optimal tool installation. Studying the installation positions and assessing the effects of two cuttings removal are essential steps to advance the application of such tools. This investigation was initiated with a comprehensive analysis of particle settling dynamics and migration behaviors in annular wellbore spaces. Building upon Moore's terminal settling velocity equation, a modified model was developed to characterize the transport patterns of cuttings. Through model integration, the precise positioning of the efficient Vortex Cuttings Removal Tool (VCRT) was determined at 188 m from the bit. Subsequently, Computational Fluid Dynamics (CFD) numerical simulation was employed to reveal distinct annular flow field characteristics between VCRT and conventional drilling tools. Field validation in Well Z401X demonstrated a strong correlation between empirical measurements and simulated predictions, with pressure drop deviations of 6.25% and rotational speed variances limited to 7.50%. Analytical results confirmed VCRT's superior performance, exhibited 36.43% reductions in cuttings accumulation at the wellbore's lower quadrant compared to conventional drilling tools. The application of VCRT accelerated cuttings migration velocity in the annular space, significantly increasing the volume of returned onsite cuttings. Friction resistance decreased by approximately 35.90%, indicating higher cuttings removal efficiency than conventional drilling tools.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3787-3802"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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