Petroleum Science最新文献

{"title":"Enhancing uniformity of multi-fracture propagation by temporary plugging and diversion fracturing in a horizontal well with multi-cluster perforations","authors":"Xin Chang ,&nbsp;Shi-Long Teng ,&nbsp;Xing-Yi Wang ,&nbsp;Yin-Tong Guo ,&nbsp;Chun-He Yang","doi":"10.1016/j.petsci.2025.05.021","DOIUrl":"10.1016/j.petsci.2025.05.021","url":null,"abstract":"<div><div>Multi-stage and multi-cluster fracturing (MMF) is a crucial technology in unconventional oil and gas development, aiming to enhance production by creating extensive fracture networks. However, achieving uniform expansion of multi-cluster hydraulic fractures (HFs) in MMF remains a significant challenge. Field practice has shown that the use of temporary plugging and diversion fracturing (TPDF) can promote the balanced expansion of multi-cluster HFs. This study conducted TPDF experiments using a true triaxial fracturing simulation system setting a horizontal well completion with multi-cluster jetting perforations to investigate the equilibrium initiation and extension of multi-cluster fractures. The influence of key parameters, including cluster spacing, fracturing fluid viscosity, differential stress, and fracturing fluid injection rate, on fracture initiation and propagation was systematically examined. The results indicate that while close-spaced multi-cluster fracturing significantly increases the number of HFs, it also leads to uneven extension of HFs in their propagation. In contrast, TPDF demonstrates effectiveness in mitigating uneven HF extension, increasing the number of HFs, and creating a larger stimulated reservoir volume, ultimately leading to improved oil and gas well productivity. Moreover, under conditions of high differential stress, the differential stress within the formation exerts a stronger guiding effect in HFs, which are more closely aligned with the minimum principal stress. Low-viscosity fluids facilitate rapid and extensive fracture propagation within the rock formation. High-volume fluid injection, on the other hand, more comprehensively fills the formation. Therefore, employing low-viscosity and high-volume fracturing is advantageous for the initiation and extension of multi-cluster HFs.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3688-3708"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223068","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}

{"title":"An unsupervised intelligent warning model for drilling kick risk based on multi-temporal feature coupling","authors":"De-Tao Zhou ,&nbsp;Zhao-Peng Zhu ,&nbsp;Tao Pan ,&nbsp;Xian-Zhi Song ,&nbsp;Shi-Jie Xiao ,&nbsp;Gen-Sheng Li ,&nbsp;Cheng-Kai Zhang ,&nbsp;Chen-Zhan Zhou ,&nbsp;Zi-Yue Zhang","doi":"10.1016/j.petsci.2025.06.013","DOIUrl":"10.1016/j.petsci.2025.06.013","url":null,"abstract":"<div><div>As oil and gas exploration continues to progress into deeper and unconventional reservoirs, the likelihood of kick risk increases, making kick warning a critical factor in ensuring drilling safety and efficiency. Due to the scarcity of kick samples, traditional supervised models perform poorly, and significant fluctuations in field data lead to high false alarm rates. This study proposes an unsupervised graph autoencoder (GAE)-based kick warning method, which effectively reduces false alarms by eliminating the influence of field engineer operations and incorporating real-time model updates. The method utilizes the GAE model to process time-series data during drilling, accurately identifying kick risk while overcoming challenges related to small sample sizes and missing features. To further reduce false alarms, the weighted dynamic time warping (WDTW) algorithm is introduced to identify fluctuations in logging data caused by field engineer operations during drilling, with real-time updates applied to prevent normal conditions from being misclassified as kick risk. Experimental results show that the GAE-based kick warning method achieves an accuracy of 92.7% and significantly reduces the false alarm rate. The GAE model continues to operate effectively even under conditions of missing features and issues kick warnings 4 min earlier than field engineers, demonstrating its high sensitivity and robustness. After integrating the WDTW algorithm and real-time updates, the false alarm rate is reduced from 17.3% to 5.6%, further improving the accuracy of kick warnings. The proposed method provides an efficient and reliable approach for kick warning in drilling operations, offering strong practical value and technical support for the intelligent management of future drilling operations.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3613-3626"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223294","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}

{"title":"Bayesian AVO inversion of fluid and anisotropy parameters in VTI media using IADR-Gibbs algorithm","authors":"Ying-Hao Zuo ,&nbsp;Zhao-Yun Zong ,&nbsp;Xing-Yao Yin ,&nbsp;Kun Li ,&nbsp;Ya-Ming Yang ,&nbsp;Si Wu","doi":"10.1016/j.petsci.2025.05.006","DOIUrl":"10.1016/j.petsci.2025.05.006","url":null,"abstract":"<div><div>Fluid identification and anisotropic parameters characterization are crucial for shale reservoir exploration and development. However, the anisotropic reflection coefficient equation, based on the transverse isotropy with a vertical axis of symmetry (VTI) medium assumption, involves numerous parameters to be inverted. This complexity reduces its stability and impacts the accuracy of seismic amplitude variation with offset (AVO) inversion results. In this study, a novel anisotropic equation that includes the fluid term and Thomsen anisotropic parameters is rewritten, which reduces the equation's dimensionality and increases its stability. Additionally, the traditional Markov Chain Monte Carlo (MCMC) inversion algorithm exhibits a high rejection rate for random samples and relies on known parameter distributions such as the Gaussian distribution, limiting the algorithm's convergence and sample randomness. To address these limitations and evaluate the uncertainty of AVO inversion, the IADR-Gibbs algorithm is proposed, which incorporates the Independent Adaptive Delayed Rejection (IADR) algorithm with the Gibbs sampling algorithm. Grounded in Bayesian theory, the new algorithm introduces support points to construct a proposal distribution of non-parametric distribution and reselects the rejected samples according to the Delayed Rejection (DR) strategy. Rejected samples are then added to the support points to update the proposal distribution function adaptively. The equation rewriting method and the IADR-Gibbs algorithm improve the accuracy and robustness of AVO inversion. The effectiveness and applicability of the proposed method are validated through synthetic gather tests and practical data applications.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3565-3582"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223567","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}

{"title":"Experimental study of dehydration performance of re-crosslinkable preformed particle gel during extruding through an open fracture","authors":"Shu-Da Zhao ,&nbsp;Baojun Bai ,&nbsp;Thomas Schuman","doi":"10.1016/j.petsci.2025.06.010","DOIUrl":"10.1016/j.petsci.2025.06.010","url":null,"abstract":"<div><div>Re-crosslinkable preformed particle gel (RPPG) has been considered to be one of the most promising gels for dealing with fracture and void space conduit (VSC) conformance problems. However, the dehydration of RPPG during its propagation in the fracture-type features and its effect on gel properties remains unclear. This paper investigates the dehydration behavior during RPPG propagating in an open fracture using matrix-free fracture model. Then the results were verified using real fractured sandstone core model. Moreover, the gel properties after extruding a fracture were studied in detail including gel dehydration and gel strength. Results reveal that the RPPG properties changed significantly with increasing propagation distance, which correlated with the gel injection rate. At high gel injection rates, the dehydration and gel strength (<span><math><mrow><msup><mi>G</mi><mo>′</mo></msup></mrow></math></span>) decrease with increasing propagation distance.</div><div>In contrast, the opposite result was found at low injection rates. Based on the study of the different gel injection rates, it is found that dehydration time is another key factor affecting dehydration behavior. Results also indicate that the fracture width affects gel dehydration at different locations. Dehydration was more pronounced at narrow fractures but only in the inlet section, while in the outlet section, RPPG contains more water than the initial condition. This study has profound implications for field applications. It provides new insights into the transport of RPPG in fractures and helps field engineers to optimize the gel injection operations.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3760-3769"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223153","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}

{"title":"Coaly source rock evaluation using well logs: The Jurassic Kezilenuer Formation in Kuqa Depression, Tarim Basin, China","authors":"Fei Zhao ,&nbsp;Jin Lai ,&nbsp;Zong-Li Xia ,&nbsp;Zhong-Rui Wang ,&nbsp;Ling Li ,&nbsp;Bin Wang ,&nbsp;Lu Xiao ,&nbsp;Yang Su ,&nbsp;Gui-Wen Wang","doi":"10.1016/j.petsci.2025.05.029","DOIUrl":"10.1016/j.petsci.2025.05.029","url":null,"abstract":"<div><div>Coaly source rocks have attracted considerable attention for their significant hydrocarbon generation potential in recent years. However, limited study is performed on utilizing geochemical data and well log data to evaluate coaly hydrocarbon source rocks. In this study, geochemical data and well log data are selected from two key wells to conduct an evaluation of coaly hydrocarbon source rocks of Jurassic Kezilenuer Formation in Kuqa Depression of Tarim Basin. Initially, analysis was focused on geochemical parameters to assess organic matter type, source rock quality, and hydrocarbon generation potential. Lithology types of source rocks include mudstone, carbonaceous mudstone and coal. The predominant organic matter type identified was Type III and Type II₂, indicating a favorable hydrocarbon generation potential. Well log data are integrated to predict total organic carbon (TOC) content, and the results indicate that multiple regression method is effective in predicting TOC of carbonaceous mudstone and coal. However, the ΔlgR method exhibited limited predictive capability for mudstone source rock. Additionally, machine learning methods including multilayer perceptron neural network (MLP), random forest (RF), and extreme gradient boosting (XGBoost) techniques are employed to predict TOC of mudstone source rock. The XGBoost performs best in TOC prediction with correlation coefficient (<em>R</em>²) of 0.9517, indicating a close agreement between measured and predicted TOC values. This study provides a reliable prediction method of coaly hydrocarbon source rocks through machine learning methods, and will provide guidance for resource assessment.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3599-3612"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223554","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}

{"title":"Chemometric differentiation of oil families in the Mahu sag, Junggar Basin, NW China","authors":"Hang-Xin Cai ,&nbsp;Jun Jin ,&nbsp;Er-Ting Li ,&nbsp;Zhong-Da Zhang ,&nbsp;Shuang Yu ,&nbsp;Chang-Chun Pan","doi":"10.1016/j.petsci.2025.05.024","DOIUrl":"10.1016/j.petsci.2025.05.024","url":null,"abstract":"<div><div>Most oil reservoirs that were found in the Junggar Basin are located in the Mahu sag and neighboring areas. Oil sources and classifications remain unresolved in this region. Oil source assessment can be partially inconsistent on the basis of different molecular and isotopic parameters. In the present study, classifications for the 92 studied oils from the Mahu sag and neighboring areas were performed using chemometric analysis, e.g., hierarchical cluster analysis (HCA) and principal component analysis (PCA) on the basis of integration of sixteen facies parameters. These parameters consist of isotope reversal index (RI), <em>δ</em>¹³C of <em>n</em>-C₂₅, Ph/<em>n</em>-C₁₈, β-carotane/<em>n</em>-C₂₁, six terpane ratios of Ts/C₂₃ tricyclic terpanes, Ts/(C₂₈+C₂₉ tricyclic terpanes), C₂₉ Ts/C₂₃ tricyclic terpanes, C₂₉Ts/(C₂₈+C₂₉ tricyclic terpanes), C₃₀ diahopane/C₂₃ tricyclic terpane and C₃₀ diahopane/(C₂₈+C₂₉ tricyclic terpanes), and six ratios of polynuclear aromatic hydrocarbons (PAH) including trimethylnaphthalenes (TMNs)/(TMNs + phenanthrene (Phen)), tetramethylnaphthalenes (TeMNs)/(TeMNs + Phen), TMNs/(TMNs + methylphenanthrenes (MPs)), TeMNs/(TeMNs + MPs), TMNs/(TMNs + chrysene (Ch)) and TeMNs/(TeMNs + Ch). These sixteen parameters are mainly influenced by source facies and less influenced by maturity as demonstrated in the crossplots of these sixteen parameters versus concentrations of C₃₀ hopane. Oil classifications are more reliable and convenient using chemometric analysis (HCA and PCA) integrating the sixteen facies parameters, compared with using crossplots of two parameters or star charts of several parameters. The 92 oils are classified into three groups using HCA and PCA, i.e., Group I, II and III. Group I and II oils are derived from source rocks within the Lower Permian Fengcheng Formation (P₁<em>f</em>) and Middle Permian Lower Wuerhe Formation (P₂<em>w</em>), respectively. Group III oils are mixtures of Group I and II oils. Group I consists of fifty oils mainly located at the northeastern and central areas of the Mahu sag with only three oils at the southwestern area of the Mahu sag. Group II consists of fourteen oils at the southwestern area of the Mahu sag. Group III consists of twenty-eight oils located at the southwestern and central areas of the Mahu sag. Locations of Group I, II and III oils reflect the distributions of effective source rocks containing oil-prone Type I/II kerogen within the Fengcheng (P₁<em>f</em>) and Lower Wuerhe formations (P₂<em>w</em>).</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3530-3547"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223152","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}

{"title":"Influence of electric and flow field characteristics on the cleaning of fillers for FCCS electrostatic separation","authors":"Wei-Wei Xu ,&nbsp;Can Yang ,&nbsp;Wei-Lin Yu ,&nbsp;Zhao-Zeng Liu ,&nbsp;Qiang Li","doi":"10.1016/j.petsci.2025.06.015","DOIUrl":"10.1016/j.petsci.2025.06.015","url":null,"abstract":"<div><div>Filler cleaning is a challenge that affects the efficient separation of FCCS particles by electrostatic methods and limits the utilization of the oil slurry. Two filler cleaning methods are proposed in this paper, the flushing desorption method and the electrostatic desorption method, where desorption is achieved by respectively applying a flow field or an electric field to the fillers immersed in a cleaning solution (ethyl acetate). Also, the “rough particle-smooth plane” contact model between particles and filler was established, and the particle force model was established by analyzing the movement of particles in the process of cleaning. Furthermore, combining the established contact model and force model, the detachment model of particles was proposed. In this model, the dimensionless number <em>λ</em> is used to discriminate the attachment state of particles whose validity was verified by experiments. The experimental results showed that the cleaning efficiency of flushing desorption method and electrostatic desorption method increase with the increase of flow rate and voltage, which reached 50.5% and 61.4% at 0.1 m/s and 14 kV.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3843-3853"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223557","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}

{"title":"Deep feature learning for anomaly detection in gas well deliquification using plunger lift: A novel CNN-based approach","authors":"Qi-Xin Liu ,&nbsp;Jian-Jun Zhu ,&nbsp;Hai-Bo Wang ,&nbsp;Shuo Chen ,&nbsp;Hao-Yu Wang ,&nbsp;Nan Li ,&nbsp;Rui-Zhi Zhong ,&nbsp;Yu-Jun Liu ,&nbsp;Hai-Wen Zhu","doi":"10.1016/j.petsci.2025.08.017","DOIUrl":"10.1016/j.petsci.2025.08.017","url":null,"abstract":"<div><div>Timely anomaly detection is critical for optimizing gas production in plunger lift systems, where equipment failures and operational issues can cause significant disruptions. This paper introduces a two-dimensional convolutional neural network (2D-CNN) model designed to diagnose abnormal operating conditions in gas wells utilizing plunger lift technology. The model was trained using an extensive dataset comprising casing and tubing pressure measurements gathered from multiple wells experiencing both normal and anomalous operations. Input data underwent a rigorous preprocessing pipeline involving cleaning, ratio calculation, window segmentation, and matrix transformation. Employing separate pre-training and transfer learning methods, the model's efficacy was validated through stringent testing on new, previously unseen field data. Results demonstrate the model's acceptable performance and strong diagnostic capabilities on this novel data from various wells within the operational block. This confirms its potential to fulfill practical field requirements by offering guidance for adjusting production systems in plunger lift-assisted wells. Ultimately, this data-driven, automated diagnostic approach provides valuable theoretical insights and technical support for sustaining gas well production rates.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 9","pages":"Pages 3803-3816"},"PeriodicalIF":6.1,"publicationDate":"2025-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223568","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}

{"title":"Gas generation from oil-prone mudstones in the Eocene Wenchang A Depression, Pearl River Mouth Basin","authors":"Shu-Xia Li ,&nbsp;Bin Xu ,&nbsp;Shu-Qian Li ,&nbsp;Feng-Hua Zhao ,&nbsp;You-Chuan Li ,&nbsp;Hong-Fu Sun ,&nbsp;Le Lu ,&nbsp;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>¹³C₂–<em>δ</em>¹³C₃ 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.</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}

{"title":"Study of micromechanical characteristics and failure mechanism of conglomerate reservoirs","authors":"Wei-Wei Teng ,&nbsp;Jian-Bo Wang ,&nbsp;Jian-Tong Liu ,&nbsp;Hong-Kui Ge ,&nbsp;Xiao-Di Li ,&nbsp;Yuan-Kai Zhang ,&nbsp;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}