Petroleum Science最新文献

{"title":"Innovative design of a fully mechanical well deviation measurement system with experimental validation","authors":"Qi-Long Xue,&nbsp;Jun Qu,&nbsp;Jin Wang,&nbsp;Xing-Yu Tan,&nbsp;Chong Wang,&nbsp;Ya-Feng Li","doi":"10.1016/j.petsci.2026.05.028","DOIUrl":"10.1016/j.petsci.2026.05.028","url":null,"abstract":"<div><div>With the advancement of ultra-deep well drilling and dry hot rock energy development, the demand for measurement-while-drilling (MWD) systems has grown increasingly critical. The electronic MWD system is difficult to complete the measurement in the downhole environment above 200 °C. In this study, a novel fully mechanical well deviation measurement system is designed, utilizing a bias structure to sense inclination and translate it into flow-related data. The system leverages the turbineʼs flow sensitivity to determine the well deviation. A mathematical model for well deviation sensing and signal coding was established, and a signal pulse generator capable of reflecting well deviation changes was also built. The fluid simulation of the pulse generator was carried out by using computational fluid dynamics (CFD) simulation software. The stable output state of the pulse generator under different flow rates was calculated. The feasibility of the fully mechanical well deviation measurement system was verified through theoretical calculation and simulation analysis. An experimental system for mechanical well deviation measurement was established, and the performance of mechanical well deviation sensing and measurement was analyzed. A downhole experiment was carried out to verify the reliability of this mechanical well deviation measurement system in achieving mechanical well deviation measurement.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 10","pages":"Pages 6378-6394"},"PeriodicalIF":6.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149095704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Laboratory evaluation of an inorganic gel for conformance control in high-temperature gas reservoirs","authors":"Tao Song,&nbsp;Man-Tian Li,&nbsp;Ying-Ting Zhu,&nbsp;Song Zhang,&nbsp;Fa-Lin Wei,&nbsp;Bin Ding","doi":"10.1016/j.petsci.2026.06.005","DOIUrl":"10.1016/j.petsci.2026.06.005","url":null,"abstract":"<div><div>Water invasion is a widely encountered challenge in deep fractured gas reservoirs. Gel treatment is an effective method for controlling excessive water production, yet existing gel systems cannot fully meet the requirements of long-term, large-volume injection in terms of cost, injectivity, gelation time control, and stability. In this study, a high-temperature, high-salinity-tolerant inorganic gel system based on polyaluminum chloride (PAC) was developed, and the factors influencing gelation time and gel strength were systematically evaluated. The injectivity and plugging performance of the PAC gel were also investigated using sandpack and fracture models. Results indicate that the addition of methyl lactate effectively delays gelation at high temperatures, allowing gelation time at 150 °C to be controlled from a few hours to several days. The PAC gelant can be easily injected into the rock matrix with an injection pressure gradient below 1.2 MPa/m, achieves over 99% plugging efficiency for 1.2 mm open fractures, and delivers a water breakthrough pressure gradient of 2.6 MPa/m. A 50-m long-tube dynamic gelation test further confirmed that the PAC system can gel in open fractures under dynamic conditions, with gelation time effectively regulated at high temperatures. The PAC gel exhibits excellent thermal stability at high temperatures, with only slight syneresis observed at 150 °C over a 200-d stability test. Overall, the PAC inorganic gel system developed in this study addresses the key bottlenecks of traditional gels applied in high-temperature, high-salinity fractured gas reservoirs, provides a low-cost, high-performance solution for water invasion control in gas reservoirs, and lays a solid laboratory foundation for subsequent field pilot tests and large-scale industrial application.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 10","pages":"Pages 6624-6635"},"PeriodicalIF":6.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149095839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unlocking shale oil: Synergistic mechanisms of CO2 extraction enhanced by fractures and surfactants","authors":"Huan Zhang,&nbsp;Ming-Wei Zhao,&nbsp;Hou-Jian Gong,&nbsp;Cai-Li Dai,&nbsp;Ming-Zhe Dong,&nbsp;Xin Li,&nbsp;Zhen-Feng Ma,&nbsp;Zhi-Hao Zhang,&nbsp;Zhong-Zheng Xu,&nbsp;Xin-Jie Xu","doi":"10.1016/j.petsci.2026.06.032","DOIUrl":"10.1016/j.petsci.2026.06.032","url":null,"abstract":"<div><div>The development of unconventional oil and gas resources is currently the primary focus of the petroleum industry. Shale oil has attracted significant attention due to its vast reserves. However, shale oil reservoirs are characterized by low porosity and low permeability, combined with rich organic matter, resulting in low oil recovery. The extraction efficiency of CO₂ is one of the key mechanisms for enhancing oil recovery. In this study, a comprehensive analysis was conducted on the factors influencing the extraction efficiency of CO₂, including CO₂ development parameters, core properties, and fractures. Additionally, the effect of C₄EO₃PO₆ (a polyether surfactant) on enhancing extraction efficiency of CO₂ was evaluated. The results show that the developed micropore and nanopore structure in shale makes oil in micropores, as well as absorbed and adsorbed oil, particularly difficult to mobilize. Under comparable permeability and porosity conditions, the CO₂ extraction recovery for tight sandstone is 2.2 times higher than that for shale, and the mobilization efficiency of free oil is 3.87 times higher than that of absorbed and adsorbed oil. The presence of fractures facilitates the dissolution and diffusion of CO₂ within the rock matrix. After three CO₂ extraction cycles, the extraction recoveries reach 81.6% for the naturally fractured shale core (containing natural fractures) and nearly 100% for both shale block samples and tight sandstone block samples. C₄EO₃PO₆ effectively reduces the interfacial tension and minimum miscibility pressure between CO₂ and shale oil, significantly enhancing the extraction efficiency of CO₂. With the addition of C₄EO₃PO₆, the extraction recovery of the shale core increases by 29.43%, with improvements of 27.25% for oil in micropores and 27.31% for absorbed and adsorbed oil. This work aims to provide an innovative development strategy for enhancing shale oil recovery through CO₂ injection.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 10","pages":"Pages 6636-6652"},"PeriodicalIF":6.4,"publicationDate":"2026-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"149095840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental and simulation of nanofluid-enhanced tubular heating process for waxy crude oil storage tank","authors":"Jian Zhao,&nbsp;Zhen-Dong Yang,&nbsp;Fan Li,&nbsp;Hang Dong,&nbsp;Zhi-Hua Wang","doi":"10.1016/j.petsci.2026.05.006","DOIUrl":"10.1016/j.petsci.2026.05.006","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Traditional tubular heating systems using water as the heat transfer fluid suffer from high energy consumption and uneven heating. This study proposes an innovative approach: employing nanofluids as a novel heat transfer fluid and developing a comprehensive numerical model capable of accurately describing the complex gel-sol transition behavior of waxy crude oil. The model characterizes the temperature-dependent viscosity of waxy crude oil using a hybrid Arrhenius + power law + Herschel-Bulkley model, accounts for phase change latent heat through the apparent heat capacity method, and calculates the thermal conductivity of waxy crude oil in different states using a weighted average method. Focusing on a floating roof tank equipped with a tubular heating system, nanofluids were prepared in-house and an indoor experimental system was constructed. The study investigated the temperature field, flow field, and gel-sol transition behavior of waxy crude oil during the tubular heating process within a small-scale model. Results indicated a relative deviation between experimental and simulation data within 4.61%. The findings demonstrated that CuO-water nanofluid significantly enhanced heating efficiency: it increased the heating rate of crude oil at the model bottom by 32% and at the top by 25%, reduced the thermal lag time by 15%, decreased the radial temperature difference by 1.2 °C, and accelerated the transition of crude oil from gel state through an intermediate state to sol state. Experiments also show that nanofluids exhibit significant heat transfer enhancement for crude oils with different properties, demonstrating good universality. Subsequently, the validated model and algorithm were employed to simulate the heating process in an actual size storage tank using different nanofluids. The simulations revealed the synergistic heat transfer enhancement mechanism of the nanofluid. Benefiting from superior thermal conductivity and a moderate specific heat capacity, it retards its own temperature drop and thins the thermal boundary layer inside the tube (CuO-water nanofluid reduced the thickness by 25%), and enhanced natural convection outside the tubes, achieving synergistic heat transfer enhancement on both sides. CuO-water nanofluid exhibited the best heat transfer enhancement performance. Although it did not alter the macroscopic structure of the temperature field, it increased the average heating rate of the crude oil by 16%, improved heating efficiency by 3.88%, and is projected to reduce heating energy consumption by 3.1% and carbon emissions by 4.9%. Simulations further reveal that optimized heating tube layout combined with nanofluids yields a synergistic enhancement effect, further elevating the overall tank temperature and reducing the low-temperature zone. This study provides not only a validated optimization methodology but also delivers fundamental insights and a theoretical framework for the technological innovation of tank he","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 9","pages":"Pages 5928-5959"},"PeriodicalIF":6.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A prediction method for safe mud density of natural gas hydrate reservoirs under temperature-pressure dual control","authors":"Lin Dong,&nbsp;Neng-You Wu,&nbsp;Ke Ke,&nbsp;Li-Lin Li,&nbsp;Yong-Chao Zhang,&nbsp;Yan-Long Li","doi":"10.1016/j.petsci.2026.04.012","DOIUrl":"10.1016/j.petsci.2026.04.012","url":null,"abstract":"<div><div>Wellbore instability is one of the most encountered issues during hydrate exploration, which correlates with mud density and temperature. However, current studies ignore the effect of mud temperature on safe mud density windows, leading it fails to meet requirements of sufficient drilling in hydrate reservoirs. Herein, we propose a new model to predict safe mud density windows by introducing temperature-pressure dual control, which is more accurate and applicable for hydrate reservoirs. Collapse pressure equivalent density decreases 6.19% while fracture pressure equivalent density increases 4.52% with hydrate saturation rising from 0 to 50% under normal conditions. Hydrate formation can narrow the safe mud density window significantly. Equivalent density of collapse pressure presents temperature sensitivity, especially mud temperature ranging from 287.9 to 289.3 K. Hydrate dissociation can narrow the safe mud density window by ∼27% on average with hydrate saturation of 50%, which will be magnified with increasing intermediate principal stress. On this basis, an integrated control system involving temperature-pressure dual control is established to deal with potential drilling risks of multi-layer hydrate reservoirs. This work provides new insights into safe mud density windows dependent on temperature and presents design principles for sufficient drilling in natural gas hydrate reservoirs.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 9","pages":"Pages 5561-5571"},"PeriodicalIF":6.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"OFC","authors":"","doi":"10.1016/S1995-8226(26)00535-2","DOIUrl":"10.1016/S1995-8226(26)00535-2","url":null,"abstract":"","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 9","pages":"Page OFC"},"PeriodicalIF":6.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"UAV-based pipeline leakage detection via acoustics with owl auditory-inspired OPEI representation","authors":"Ying-Han Ma,&nbsp;Hong Zhao","doi":"10.1016/j.petsci.2026.07.024","DOIUrl":"10.1016/j.petsci.2026.07.024","url":null,"abstract":"<div><div>To address the low sensitivity of visual UAV inspection in leakage detection for above-ground natural gas pipelines, an acoustic detection method inspired by the owl auditory mechanism was developed. An innovative oscillatory positional encoding imaging (OPEI) technique was proposed, through which one-dimensional acoustic signals were converted into two-dimensional image representations incorporating time-domain, frequency-domain, and amplitude information. Recognition accuracy of 97.38% for OPEI images on the testing dataset was achieved by the EfficientNetV2 cascade model. The results demonstrated that the biomimetic design enhanced acoustic signal sensitivity and enabled fine-grained recognition of pipeline leakage apertures (1/5/10 mm). This study proposes a novel acoustic signal processing method, providing a theoretical foundation for ensuring the reliability and safety of natural gas pipeline transportation.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 9","pages":"Pages 5908-5913"},"PeriodicalIF":6.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A knowledge-guided multi-task learning method for drill cuttings analysis","authors":"Li Hou,&nbsp;Xin Li,&nbsp;Wei-Zhi Tian,&nbsp;Qian-Xiao Su,&nbsp;Rui-Qi Huang,&nbsp;Ming-Hui Song,&nbsp;Peng Du,&nbsp;Yi-Li Ren","doi":"10.1016/j.petsci.2026.05.037","DOIUrl":"10.1016/j.petsci.2026.05.037","url":null,"abstract":"<div><div>Drill cuttings serve as a fundamental source of geological information in oil and gas exploration and development. However, traditional analysis remains largely manual, resulting in low efficiency and high subjectivity. While recent studies have introduced artificial intelligence, most focus on single-attribute tasks and purely on data-driven approaches, often neglecting geological domain knowledge. This highly limits model generalization and interpretability in real-world applications. To address these challenges, we propose a multi-attribute intelligent identification model based on multi-task learning, which integrates geological prior knowledge and introduces a novel collaboration classifier to enhance the comprehensiveness, robustness, and interpretability of drill cuttings analysis. Specifically, the model constructs structured inter-attribute correlations as prior knowledge and employs a collaboration classifier designed based on the law of total probability, enabling collaborative modeling and cross-attribute information exchange. These innovations significantly improve recognition performance across multiple attribute dimensions. Experimental results demonstrate that the proposed model achieves a mean accuracy of 93.90% and a mean F1-score of 93.08% in identifying cuttings attributes including color, shape, and grain type. These results validate the effectiveness of the structured prior-guided collaborative modeling strategy and highlight its potential for complex multi-attribute analysis tasks in petroleum geology.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 9","pages":"Pages 5624-5635"},"PeriodicalIF":6.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A rock physics modeling for hydrate–gas and gas–water mixing in marine sediments","authors":"Jin Qian,&nbsp;Xiu-Juan Wang,&nbsp;Zhen Liu,&nbsp;Qiao-Qiao Wang,&nbsp;Jia-Peng Jin,&nbsp;Neng-You Wu","doi":"10.1016/j.petsci.2026.03.064","DOIUrl":"10.1016/j.petsci.2026.03.064","url":null,"abstract":"<div><div>In 2017 and 2020, China successfully performed two hydrate production tests near Sites GMGS3-W17 and GMGS6-SH2 in the northern South China Sea. Two tests revealed that large amounts of free gas are enriched below the bottom simulating reflection (BSR). However, hydrate saturations at this depth derived from chlorinity data and a pressure core range from 27% to 41%. Well log data in this interval are characterized by low P-wave velocity and high resistivity. Therefore, resistivity-derived hydrate saturations are much higher than P-wave velocity-derived values. This discrepancy occurs because free gas would induce a sharp decrease in P-wave velocity. Currently, the gas–water mixing model is commonly employed to resolve this discrepancy. To improve accuracy, we develop a novel rock physics model of multiphase mixing coexistence including solid phase, hydrate–gas phase, and gas–water phase. The model is applicable to both isotropic and anisotropic hydrate reservoirs. To validate its accuracy, the model and well log data are utilized to predict saturations at six sites worldwide where hydrates and free gas coexist. The predicted hydrate and gas saturations are consistent with those derived from pressure cores and chlorinity data. This suggests that the model can be robustly used for quantitative characterization of hydrate when coexisting with free gas. Therefore, our model will provide an accurate method for the resource predictions of hydrate and free gas in such coexisting sediments, especially those below the conventional BSR. It will also facilitate the understanding of the fluid distributions in such a complex three-phase coexistence system in nature.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 9","pages":"Pages 5400-5417"},"PeriodicalIF":6.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wettability-aware phase-field micro-continuum modeling of two-phase carbonate acidizing with residual CO2","authors":"Qi-Gui Wang,&nbsp;Cheng-Yong Li,&nbsp;Yin Feng,&nbsp;Run-Hua Zhu,&nbsp;Ya-Qi Li,&nbsp;Yi Liu,&nbsp;Dan-Ni Tang,&nbsp;Yang Zeng","doi":"10.1016/j.petsci.2026.04.024","DOIUrl":"10.1016/j.petsci.2026.04.024","url":null,"abstract":"<div><div>Following pre-CO₂ fracturing of carbonate reservoirs, residual CO₂ remaining in and remobilized from the wellbore-fracture system may introduce multiphase-flow and interfacial effects that are often neglected in conventional acidizing models. In this study, we develop a pore-scale micro-continuum framework that couples the Darcy-Brinkman-Stokes equations with a wettability-aware phase-field formulation. A key feature of the model is an implicit wetting scheme that allows the contact angle to evolve consistently with the receding fluid–solid interface during mineral dissolution, thereby addressing the moving contact-line problem. The simulations show that the CO₂ phase fundamentally reshapes acid migration and dissolution patterns through two competing mechanisms: flow diversion, whereby CO₂ clusters redirect acid into non-preferential pores, and bubble shielding, whereby adhered CO₂ shields reactive mineral surfaces. As a result, CO₂-bearing systems exhibit compact dissolution patterns and fluctuating permeability evolution driven by the competition between capillary trapping and pore enlargement. Surface wettability is further identified as a primary control factor: strongly water-wet conditions facilitate CO₂ mobilization, whereas wettability reversal promotes inlet blockage. In addition, parametric analysis reveals a nonlinear trade-off between acid concentration and injection rate. Specifically, increasing acid concentration under high-velocity injection aggravates live-acid bypass and reduces acid-utilization efficiency. These results provide mechanistic insight into gas-liquid-rock interactions and offer a physically grounded basis for optimizing acidizing strategies in carbonate reservoirs after pre-CO₂ fracturing.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 9","pages":"Pages 6004-6023"},"PeriodicalIF":6.4,"publicationDate":"2026-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148859444","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}