Petroleum Science最新文献

{"title":"Mechanical differences of laminations and crack propagation mechanism of continental shale","authors":"Yong-Ting Duan ,&nbsp;Cheng-Cheng Zhu ,&nbsp;Pathegama Gamage Ranjith ,&nbsp;Bai-Cun Yang ,&nbsp;Tian-Qiao Mao ,&nbsp;Yu Li","doi":"10.1016/j.petsci.2025.01.006","DOIUrl":"10.1016/j.petsci.2025.01.006","url":null,"abstract":"<div><div>Clarify the mechanical properties of different laminations and the fracture mechanism of continental shale under in-situ stress can provide theoretical basis for more comprehensive evaluation of the fracability of continental shale oil reservoir. The Chang 7₂ continental shale was used to investigate the mechanical properties of laminations and the effect of natural structure on the crack propagation of the shale. The XRD and thin section tests show that the laminations contain two types: bright sandy lamination with void structure and dark muddy lamination with layer structure. The real-time CT uniaxial compression tests were conducted to investigate the differences of mechanical properties between the muddy lamination and sandy lamination. It found that the uniaxial compression strength and elastic modulus of the sandy lamination are higher, forming a simple crack with large opening, and the Poisson's ratio of the muddy lamination is large, forming obvious lateral deformation and more secondary cracks. On this basis, the cuboid-shaped continental shale specimens were tested under true triaxial compression conditions to study the effect of laminations and interface cracks on crack propagation combining AE and CT techniques. It found that nascent cracks connected laminations and interface cracks to form fracture network under appropriate loading condition, tensile cracks developed in sandy lamination and shear cracks occurred in muddy lamination because of deformation dissonance and brittleness index differences, and more secondary cracks formed in muddy lamination with smaller fracture toughness. Moreover, the combination relationships between nascent and natural cracks mainly conclude direct penetration and deflection, which is affected by the filling degree and morphology of interface cracks and the relationship of lamination types. These conclusions show that laminar continental shale is conducive to forming complex fracture network, which can provide a theoretical basis for the proposal of indicators and methods for fracability evaluation.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 4","pages":"Pages 1653-1669"},"PeriodicalIF":6.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143917204","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":"TOC","authors":"","doi":"10.1016/S1995-8226(25)00132-3","DOIUrl":"10.1016/S1995-8226(25)00132-3","url":null,"abstract":"","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 4","pages":"Pages i-ii"},"PeriodicalIF":6.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143917206","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":"Efficient deep-learning-based surrogate model for reservoir production optimization using transfer learning and multi-fidelity data","authors":"Jia-Wei Cui ,&nbsp;Wen-Yue Sun ,&nbsp;Hoonyoung Jeong ,&nbsp;Jun-Rong Liu ,&nbsp;Wen-Xin Zhou","doi":"10.1016/j.petsci.2025.02.014","DOIUrl":"10.1016/j.petsci.2025.02.014","url":null,"abstract":"<div><div>In the realm of subsurface flow simulations, deep-learning-based surrogate models have emerged as a promising alternative to traditional simulation methods, especially in addressing complex optimization problems. However, a significant challenge lies in the necessity of numerous high-fidelity training simulations to construct these deep-learning models, which limits their application to field-scale problems. To overcome this limitation, we introduce a training procedure that leverages transfer learning with multi-fidelity training data to construct surrogate models efficiently. The procedure begins with the pre-training of the surrogate model using a relatively larger amount of data that can be efficiently generated from upscaled coarse-scale models. Subsequently, the model parameters are fine-tuned with a much smaller set of high-fidelity simulation data. For the cases considered in this study, this method leads to about a 75% reduction in total computational cost, in comparison with the traditional training approach, without any sacrifice of prediction accuracy. In addition, a dedicated well-control embedding model is introduced to the traditional U-Net architecture to improve the surrogate model's prediction accuracy, which is shown to be particularly effective when dealing with large-scale reservoir models under time-varying well control parameters. Comprehensive results and analyses are presented for the prediction of well rates, pressure and saturation states of a 3D synthetic reservoir system. Finally, the proposed procedure is applied to a field-scale production optimization problem. The trained surrogate model is shown to provide excellent generalization capabilities during the optimization process, in which the final optimized net-present-value is much higher than those from the training data ranges.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 4","pages":"Pages 1736-1756"},"PeriodicalIF":6.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916701","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":"Insight into the evolution of refractory basic and neutral nitrogen compounds during residue hydrotreating process","authors":"Zhong-Huo Deng,&nbsp;Si-Yang Guo,&nbsp;Xin-Peng Nie,&nbsp;Xin-Heng Cai,&nbsp;Yan-Zi Jia,&nbsp;Wei Han,&nbsp;Li-Shun Dai","doi":"10.1016/j.petsci.2025.02.015","DOIUrl":"10.1016/j.petsci.2025.02.015","url":null,"abstract":"<div><div>A comprehensive insight into the evolution and molecular structure of basic and neutral nitrogen compounds during the residue hydrotreating (RHT) process was gained through ESI(+)/ESI(−) FT-ICR MS analysis of the feedstock and its hydrogenated samples, with hydrodenitrogenation (HDN) ratios of 15.9%–70.1%. This study revealed that carbazoles, characterized by a double bond equivalent (DBE) of 9–11, were the refractory neutral nitrogen compounds during the RHT process. Their recalcitrant nature was primarily due to their low aromaticity and high steric hindrance. Conversely, quinolines (DBEs 7 to 9) were the most abundant basic nitrogen compounds. Through a meticulous analysis of DBE evolution, we revealed the intricate reaction mechanisms of benzocarbazoles and dibenzocarbazoles in residual oil, highlighting the crucial role of quinolines as key intermediates in eliminating these compounds. Interestingly, nitrogen compounds with either low or high carbon numbers (for a given DBE) exhibited higher reactivity than those with medium carbon numbers, which can be attributed to the low steric hindrance resulting from short alkyl chains and more naphthenic-aromatic structures, respectively. After hydrotreatment, the molecular structures of the most refractory or abundant nitrogen compounds could consist of two main types: those with multiple naphthenic-aromatic rings and those with long side chains near the nitrogen atom. This research has revealed nitrogen compounds' evolutionary mechanisms and refractory nature, and the molecular structure of the most resistant or abundant basic and neutral nitrogen compounds, providing a deeper understanding of the HDN process and ultimately paving the way for the rational RHT catalyst design and process development.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 4","pages":"Pages 1787-1801"},"PeriodicalIF":6.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916670","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":"Effective pure qP-wave equation and its numerical implementation in the time-space domain for 3D complicated anisotropic media","authors":"Shi-Gang Xu ,&nbsp;Xing-Guo Huang ,&nbsp;Li Han","doi":"10.1016/j.petsci.2025.02.009","DOIUrl":"10.1016/j.petsci.2025.02.009","url":null,"abstract":"<div><div>Seismic anisotropy has been extensively acknowledged as a crucial element that influences the wave propagation characteristic during wavefield simulation, inversion and imaging. Transversely isotropy (TI) and orthorhombic anisotropy (OA) are two typical categories of anisotropic media in exploration geophysics. In comparison of the elastic wave equations in both TI and OA media, pseudo-acoustic wave equations (PWEs) based on the acoustic assumption can markedly reduce computational cost and complexity. However, the presently available PWEs may experience SV-wave contamination and instability when anisotropic parameters cannot satisfy the approximated condition. Exploiting pure-mode wave equations can effectively resolve the above-mentioned issues and generate pure P-wave events without any artifacts. To further improve the computational accuracy and efficiency, we develop two novel pure qP-wave equations (PPEs) and illustrate the corresponding numerical solutions in the time-space domain for 3D tilted TI (TTI) and tilted OA (TOA) media. First, the rational polynomials are adopted to estimate the exact pure qP-wave dispersion relations, which contain complicated pseudo-differential operators with irrational forms. The polynomial coefficients are produced by applying a linear optimization algorithm to minimize the objective function difference between the expansion formula and the exact one. Then, the developed optimized PPEs are efficiently implemented using the finite-difference (FD) method in the time-space domain by introducing a scalar operator, which can help avoid the problem of spectral-based algorithms and other calculation burdens. Structures of the new equations are concise and corresponding implementation processes are straightforward. Phase velocity analyses indicate that our proposed optimized equations can lead to reliable approximation results. 3D synthetic examples demonstrate that our proposed FD-based PPEs can produce accurate and stable P-wave responses, and effectively describe the wavefield features in complicated TTI and TOA media.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 4","pages":"Pages 1534-1547"},"PeriodicalIF":6.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916790","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":"Microscopic oil occurrence in the Permian alkaline lacustrine shales: Fengcheng formation, Mahu Sag, Junggar basin","authors":"Jia-Hao Lv ,&nbsp;Tao Hu ,&nbsp;Wang Zhang ,&nbsp;Fu-Jie Jiang ,&nbsp;Jing Xue ,&nbsp;Chen-Xi Zhang ,&nbsp;Zhen-Guo Qi ,&nbsp;Ren-Da Huang ,&nbsp;Mei-Ling Hu ,&nbsp;Shu Jiang","doi":"10.1016/j.petsci.2025.01.005","DOIUrl":"10.1016/j.petsci.2025.01.005","url":null,"abstract":"<div><div>Alkaline lacustrine shale is highly heterogeneous, and the complex relationship between the organic-inorganic porosity network and hydrocarbon occurrence restricts the effectiveness of shale oil exploration and development. Herein, we investigated the Fengcheng Formation (P₁f) in Mahu Sag. This study integrated geochemistry, Soxhlet extraction, scanning electron microscopy, gas adsorption, and nuclear magnetic resonance T₁-T₂ spectroscopy to elucidate the microscopic oil occurrence mechanisms in shales. Results indicate the presence of felsic shale, dolomitic shale, lime shale, and mixed shale within the P₁f. Matrix pores and microfractures associated with inorganic minerals are the predominant pore types in P₁f. Adsorbed oil primarily resides on the surfaces of organic matter and clay minerals, while free oil predominantly occupies inorganic pores and microfractures with larger pore sizes. Variations exist in the quantity and distribution of shale oil accumulation across different scales, where free oil and adsorbed oil are governed by dominant pores with diameters exceeding 10 nm and ineffective pores with diameters below 10 nm, respectively. Shale oil occurrence characteristics are influenced by organic matter, pore structure, and mineral composition. Felsic shale exhibits a high abundance of dominant pores, possesses the highest oil content, predominantly harbors free oil within these dominant pores, and demonstrates good mobility. Fluid occurrence in dolomitic shale and lime shale is intricate, with low oil content and a free oil to adsorbed oil ratio of 1:1. Mixed shale exhibits elevated clay mineral content and a scarcity of dominant pores. Moreover, ineffective pores contain increased bound water, resulting in medium oil content and limited mobility predominantly due to adsorption. Presently, shale oil mainly occurs in the dominant pores with a diameter larger than 10 nm in a free state. During the exploration and development of alkaline lacustrine shale oil resources, emphasis should be placed on identifying sweet spots within the felsic shale characterized by dominant pores.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 4","pages":"Pages 1407-1427"},"PeriodicalIF":6.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143917209","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":"Ball-sealer transport characteristics and plugging performance in vertical wells","authors":"Ying Liu ,&nbsp;Hai Qu ,&nbsp;Mao Sheng ,&nbsp;Hai-Zhu Wang ,&nbsp;Ting-Xue Jiang ,&nbsp;Shi Wang","doi":"10.1016/j.petsci.2025.01.002","DOIUrl":"10.1016/j.petsci.2025.01.002","url":null,"abstract":"<div><div>Ball-sealer plugging is a cost-effective method for hydraulic fracturing in vertical wells, yet the transport and plugging behavior of ball sealers remains poorly understood. This paper investigates ball-sealer plugging using both experimental and numerical approaches. A coupled computational fluid dynamics (CFD) and discrete element method (DEM) model simulates ball transport under field conditions, validated by experiments in inclined pipes. Results show that plugging performance improves with a higher flow rate ratio of the perforation, allowing effective plugging even when the ball is far from the target perforation. There exists a threshold distance between the ball and the perforation under specific conditions. The closer the ball is to the wellbore wall, the higher the likelihood of successful plugging. Low-density balls can enhance plugging performance to some extent. At high flow rates, ball inertia along the wellbore axis increases, reducing the ball's ability to redirect and weakening plugging performance. Ball interactions also affect their positioning and plugging success. In vertical wells with multiple clusters, prioritizing higher flow rates to the first fracturing cluster optimizes overall plugging performance and minimizes excessive plugging in lower, under-stimulated clusters. These findings offer valuable insights for optimizing ball-sealer deployment in well completions, improving operational outcomes.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 4","pages":"Pages 1686-1698"},"PeriodicalIF":6.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916777","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":"Enlightenment of geochemistry for ultra-deep petroleum accumulation: Coupling of secondary processes and filling events","authors":"Rong-Zhen Qiao ,&nbsp;Mei-Jun Li ,&nbsp;Dong-Lin Zhang ,&nbsp;Hong Xiao","doi":"10.1016/j.petsci.2025.02.019","DOIUrl":"10.1016/j.petsci.2025.02.019","url":null,"abstract":"<div><div>Light oil and gas reservoirs are abundant in the Ordovician marine carbonate reservoir in Shunbei Oilfield, Tarim Basin. This presents a compelling geological puzzle, as ultra-deep reservoirs undergo intense alteration and complex petroleum accumulation processes. A comprehensive suite of geochemical analyses, including molecular components, carbon isotope composition, homogenization temperature of saline inclusions, and burial-thermal history of single wells, was conducted to elucidate the genesis of these ancient reservoirs. Three petroleum filling events have been identified in the study area: Late Caledonian, Hercynian-Indosinian, and Himalayan, through analysis of homogenization temperatures of brine inclusions and burial-thermal histories. Additionally, the oil in the study area has undergone significant alteration processes such as biodegradation, thermal alteration, mixing, evaporative fractionation, and gas invasion. This study particularly emphasizes the influential role of Himalayan gas filling-induced evaporation fractionation and gas invasion in shaping the present petroleum phase distribution. Furthermore, analysis of light hydrocarbon and diamondoid parameters indicates the oil within the study area is at a high maturity stage, with equivalent vitrinite reflectance values ranging from 1.48% to 1.99%. Additionally, the analysis of light hydrocarbons, aromatics, and thiadiamondoids indicates that TSR should occur in reservoirs near the gypsum-salt layers in the Cambrian. The existence of the Cambrian petroleum system in the study area is strongly confirmed when considering the analysis results of natural gas type (oil cracking gas), evaporative fractionation, and gas invasion. Permian local thermal anomalies notably emerge as a significant factor contributing to the destruction of biomarkers in oil. For oil not subject to transient, abnormal thermal events, biomarker reliability extends to at least 190 °C. In conclusion, examining the special formation mechanisms and conditions of various secondary processes can offer valuable insights for reconstructing the history of petroleum accumulation in ultra-deep reservoirs. This research provides a scientific foundation for advancing our knowledge of petroleum systems and underscores the importance of hydrocarbon geochemistry in unraveling ultra-deep, complex geological phenomena.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 4","pages":"Pages 1465-1484"},"PeriodicalIF":6.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916786","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":"Multidisciplinary insights into the origin of natural gas from hydrocarbon generation and charging history of Permian dolomite reservoir in Sichuan Basin","authors":"Yan-Xian Zhu ,&nbsp;Zhi-Liang He ,&nbsp;Xiao-Wen Guo ,&nbsp;Long Li ,&nbsp;Kamaldeen O.L. Omosanya ,&nbsp;Jian Gao ,&nbsp;Ze Tao ,&nbsp;Xue-Song Lu","doi":"10.1016/j.petsci.2025.02.004","DOIUrl":"10.1016/j.petsci.2025.02.004","url":null,"abstract":"<div><div>Understanding the origin of natural gas in deep and ultra-deep reservoirs with multiple potential source rocks remains challenging due to the complex thermal evolution of hydrocarbons at high temperatures and multi-stage accumulation processes. This study investigates the origin of natural gas in deep hydrothermal dolomite reservoirs of the Maokou Formation, eastern Sichuan Basin, using hydrocarbon inclusion analysis, radiometric U-Pb dating of calcite cements, maturity modeling of potential source rocks, and constraints on reactivation periods of the nearby No. 15 Fault System. Results indicate an oil charging event at approximately 246.9 Ma, followed by two episodes of gas charging at 222.4 Ma and 175.2 Ma. Furthermore, the oil and gas charging events occurred synchronously with activities of the No. 15 Fault System, suggesting that its reactivation induced episodic hydrocarbon migration. Maturity modeling indicates that during the oil charging period, source rocks in the Qiongzhusi, Wufeng-Longmaxi, and first member of the Maokou formations reached the stages of dry gas generation, significant oil generation, and the threshold of oil generation, respectively. During the subsequent two-episode gas charging periods, the Qiongzhusi and Wufeng-Longmaxi formations progressed to dry and wet gas generation stages, respectively, while the first member of the Maokou Formation attained the oil generation stage. The hydrocarbon charging time and maturity history of potential source rocks indicate that: 1) oil in hydrothermal dolomite reservoirs predominantly originated from the Wufeng-Longmaxi Formation at approximately 246.9 Ma; 2) during the subsequent gas charging episodes, the Wufeng-Longmaxi Formation could contribute wet gas, while the Qiongzhusi Formation likely supplied cracking gas from kerogen and residual liquid hydrocarbon; 3) all oil in the hydrothermal dolomite reservoirs underwent thermal cracking to gas at approximately 110 Ma. This study indicates that gas pools in (ultra-)deep carbonate reservoirs of the Sichuan Basin have mixed genetic origins, with contributions from multiple sources. The multidisciplinary approach, combining direct dating of hydrocarbon charge events and simulation of hydrocarbon generation, proves robust and effective in identifying the origin of natural gas in (ultra-)deep reservoirs.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 4","pages":"Pages 1428-1445"},"PeriodicalIF":6.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916869","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":"Quantitative insight into fracture distribution during supercritical CO2 fracturing in tight sandstone formation","authors":"Bing Yang ,&nbsp;Hai Huang ,&nbsp;Qian-Qian Ren ,&nbsp;Hai-Zhu Wang ,&nbsp;Bin Wang ,&nbsp;Jun Ni ,&nbsp;Yong Zheng ,&nbsp;Wen-Tong Zhang","doi":"10.1016/j.petsci.2025.02.006","DOIUrl":"10.1016/j.petsci.2025.02.006","url":null,"abstract":"<div><div>Supercritical CO₂ (SC-CO₂) fracturing stands out a promising waterless stimulation technique in the development of unconventional resources. While numerous studies have delved into the induced-fracture mechanism of SC-CO₂, the small scale of rock samples and synthetic materials used in many studies have limited a comprehensive understanding of fracture propagation in unconventional formations. In this study, cubic tight sandstone samples with dimensions of 300 mm were employed to conduct SC-CO₂ fracturing experiments under true-triaxial stress conditions. The spatial morphology and quantitative attributes of fracture induced by water and SC-CO₂ fracturing were compared, while the impact of in-situ stress on fracture propagation was also investigated. The results indicate that the SC-CO₂ fracturing takes approximately ten times longer than water fracturing. Furthermore, under identical stress condition, the breakdown pressure (BP) for SC-CO₂ fracturing is nearly 25% lower than that for water fracturing. A quantitative analysis of fracture morphology reveals that water fracturing typically produces relatively simple fracture pattern, with the primary fracture distribution predominantly controlled by bedding planes. In contrast, SC-CO₂ fracturing results in a more complex fracture morphology. As the differential of horizontal principal stress increases, the BP for SC-CO₂ fractured rock exhibits a downward trend, and the induced fracture morphology becomes more simplified. Moreover, the presence of abnormal in-situ stress leads to a further increase in the BP for SC-CO₂ fracturing, simultaneously enhancing the development of a more conductive fracture network. These findings provide critical insights into the efficiency and behavior of SC-CO₂ fracturing in comparison to traditional water-based fracturing, offering valuable implication for its potential applications in unconventional reservoirs.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 4","pages":"Pages 1670-1685"},"PeriodicalIF":6.0,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143916947","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}