Petroleum Science最新文献

{"title":"Long-term sustained release of small molecular surfactants using microcapsules","authors":"Shuang Liu ,&nbsp;Ling-Ling Ren ,&nbsp;Zheng Wang ,&nbsp;Jia-Wei Shi ,&nbsp;Chen-Guang Wang ,&nbsp;Jia-Hui Guo ,&nbsp;Lu Zhang ,&nbsp;Hao-Ran Cheng ,&nbsp;Li-Yuan Zhang","doi":"10.1016/j.petsci.2025.11.019","DOIUrl":"10.1016/j.petsci.2025.11.019","url":null,"abstract":"<div><div>The controlled manipulation of surfactant concentration is essential for optimizing performance in numerous industrial applications, such as enhanced oil recovery in oil industry. However, encapsulating surfactants has proven challenging due to their propensity to localize at interfaces. In this study, we use microfluidic technology to fabricate poly (ethylene glycol) diacrylate-based microcapsules for encapsulating small molecular cargoes through finely tuning the relationships among the interfacial tensions of inner, middle and outer phases. These microcapsules show excellent retention by regulating the shell thickness and monomer content, releasing less than 47.2% over 49 d at 20 °C. Upon oil contact, surfactant release is indicated by a contact angle decrease of 7.2° at 20 °C and 21.8° at 50 °C within 48 h. The releases of nonionic Tween 80 and zwitterionic Betaine 1 calculated via surface tension in saline solutions at 80 °C are reduced to as low as 8.2% within 48 h and 1.1% within 8 h. The pressure-induced release reaches 22.7% within 24 h under 15 MPa, significantly exceeding the impacts of temperature and salinity. Notably, even microcapsules with reduced eccentricity still demonstrate sustained-release behavior. Mechanical and degradation tests show that the sustained release is driven by the increase in pore size of the shell due to its gradual degradation. This tunable system offers a versatile platform for encapsulating and controlling the release of surfactants or other sensitive agents, ideal for harsh environmental applications requiring sustained functionality.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 2","pages":"Pages 954-965"},"PeriodicalIF":6.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147330855","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 the effect of nanoemulsion on the EOR in low-permeability, highly waxy oil reservoirs based on NMR displacement experiments","authors":"Rui-Jie Fei ,&nbsp;Ming-Hui Li ,&nbsp;Shuai Yuan ,&nbsp;Chen Cao ,&nbsp;Fu-Jian Zhou ,&nbsp;Er-Dong Yao ,&nbsp;Hao Bai ,&nbsp;Diu-Wei Ding","doi":"10.1016/j.petsci.2025.11.013","DOIUrl":"10.1016/j.petsci.2025.11.013","url":null,"abstract":"<div><div>Wax precipitation damage caused by cold water injection or temperature reduction is very commonly seen in the development of waxy crude oil reservoirs. Various methods for eliminating wax precipitation damage have been studied by many scholars, such as injecting hot water, artificial fracture, and using chemical dewaxing agents. However, the effects of nanoemulsion on wax crystals and enhanced oil recovery (EOR) have not yet been systematically studied. This study used core displacement system based on nuclear magnetic resonance (NMR) to investigate the effect of nanoemulsion on the EOR in low-permeability, waxy oil reservoirs. Some influencing factors such as injection water temperatures, core permeability, fractured/unfractured core, and nanoemulsion concentration conditions have been investigated. Meanwhile, the wax crystal morphology and quantity have been studied before and after using nanoemulsion using a polarizing microscope. The main conclusions are as follows: (1) After injecting 60 °C hot water, the recovery can be increased from 19.36% to 32.82%, which can alleviate wax deposition damage to a certain extent. (2) Enhancing core permeability or using fractured cores can increase the flow capacity of displacement fluid within the core and enhance waxy crude oil recovery. The EOR after improving core permeability is 10.22%, while the EOR of the fractured core is 26.24%. (3) Nanoemulsions can dissolve wax crystals in waxy crude oil and inhibit their formation to achieve EOR. The crude oil recovery at nanoemulsion concentrations of 0.1, 0.5, and 1.0 wt% were 34.84%, 38.24%, and 42.85%, respectively. (4) The use of nanoemulsion can reduce the number, area ratio, and fractal dimension of wax crystals, thereby mitigating wax deposition damage. Using a 1 wt% of nanoemulsion, the area ratio of wax crystals decreased from 47.25% to 16.67%, and the number of wax crystals decreased from 1309 to 496.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 2","pages":"Pages 897-912"},"PeriodicalIF":6.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147417678","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":"The impact of fossil energy technological progress on sectoral implied energy intensity: Evidence from the U.S. shale gas revolution","authors":"Xiang-Yu Kong,&nbsp;Hong Li,&nbsp;Bang-Rui Wu","doi":"10.1016/j.petsci.2025.12.017","DOIUrl":"10.1016/j.petsci.2025.12.017","url":null,"abstract":"<div><div>This paper investigates how sectoral implied energy intensity responds to energy technology progress, using the U.S. shale gas revolution—the most significant energy breakthrough of the 21st century—as a quasi-natural experiment. Using industry-level input-output and trade data, we implement a difference-in-differences (DID) strategy to identify the effects. We find that the shale revolution, on average, increases sectoral implied energy intensity in countries with higher natural gas import demand. The results are robust to alternative specifications, multiple fixed effects, parallel-trend checks, and placebo tests. Mechanism analysis suggests that the rise in implied energy intensity is driven by increased natural gas imports and intensified competition among gas-exporting countries. Heterogeneity analysis further reveals that skill-intensive sectors, transportation, public services, and environmental industries are more responsive to the shale gas technology shock. These findings underscore the spillover effects of the revolution not only on global trade patterns but also on sectoral energy use, highlighting the need for enhanced coordination in energy technology development and energy security strategies.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 2","pages":"Pages 990-997"},"PeriodicalIF":6.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147417680","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":"Changes in the effective absolute permeability of hydrate-bearing sands during isotropic loading and unloading","authors":"Hui-Long Ma ,&nbsp;Xiu-Li Feng ,&nbsp;Le-Le Liu ,&nbsp;An Zhang ,&nbsp;Dong Wang","doi":"10.1016/j.petsci.2025.10.009","DOIUrl":"10.1016/j.petsci.2025.10.009","url":null,"abstract":"<div><div>The effective stress of marine sediments frequently shifts owing to natural or anthropogenic factors, and a broad spectrum of processes fundamentally require accounting for sediment responses to such changes. Marine sediments hosting natural gas hydrates have been regarded as a prospective energy reservoir, and depressurization-driven production efficiency hinges largely on the effective absolute permeability of hydrate-bearing strata. Yet, how this permeability evolves during depressurization remains unresolved, and whether pore-hosted hydrates impede or enhance it remains ambiguous. This study probes the permeability response of hydrate-bearing sands to cyclic loading through isotropic compression/swelling and water flow tests. Results reveal that methane hydrate presence curbs the void-ratio decline yet amplifies the effective-void-ratio reduction during isotropic loading. The effective absolute permeability of hydrate-bearing sands declines with rising hydrate saturation and increasing mean effective stress, and permeability stress sensitivity intensifies at higher hydrate saturations and lower mean effective stresses. The introduced model accurately predicts void-ratio changes during isotropic loading and unloading. Coefficients for strengthening, normal filling, and enhanced filling effects are introduced and quantified to disentangle the positive and negative influences of methane hydrate, with the negative filling effect exceeding the positive strengthening effect by one order of magnitude for quartz sands.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 2","pages":"Pages 998-1013"},"PeriodicalIF":6.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147417835","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 on the phase behavior and minimum miscible pressure of CO2-shale oil in nanopores with confinement effect","authors":"Ying Xiong ,&nbsp;Peng-Fei Chen ,&nbsp;Wan-Fen Pu ,&nbsp;Rui Jiang ,&nbsp;Qin Pang","doi":"10.1016/j.petsci.2025.11.039","DOIUrl":"10.1016/j.petsci.2025.11.039","url":null,"abstract":"<div><div>CO₂ injection is a significant enhanced oil recovery method in shale oil reservoirs and facilitates the mitigation of CO₂ emissions. However, the phase behavior and miscibility process of light shale oil and CO₂ system in shale reservoirs with widely distributed nanopores remain uncertain. Based on the thermodynamic equilibrium theory and the modified Peng-Robinson equation of state (PR-EOS), a confined fluid model considering the effect of nanoconfinement (critical property shift and adsorption) and capillarity was used to study the phase diagram and thermodynamic property of shale oil-CO₂ mixtures. The validity of the fluid model in bulk and in nanopores was verified with the pressure-volume-temperature (PVT) experiments and literature data, respectively. The interfacial tension (IFT) and minimum miscible pressure (MMP) were determined by the Parachor model and IFT vanishing method (VIT), respectively. The effects of pore sizes, temperature and injected gas type and compositions on the IFT and MMP was comprehensively investigated. The result shows that the nanoconfinement effect causes the two-phase region in the phase diagram of reservoir fluids to contract and enhances the ability of CO₂ and light components to enter smaller pores, thus reducing the bubble point pressure, oil density, oil viscosity and IFT of shale oil-CO₂ mixtures in nanopores. The nanoconfinement effect is more pronounced in pore radius of less than 50 nm, with roughly 16% reduction in the MMP of shale oil-CO₂ mixtures. Temperature has a negative effect on the IFT and MMP of shale oil-CO₂ mixtures due to the decreased solubility of CO₂ under high temperature. The miscibility of CO₂ and shale oil is improved by propane (C₃H₈) and ethane (C₂H₆), while decreased by methane (CH₄).</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 2","pages":"Pages 777-790"},"PeriodicalIF":6.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147417833","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":"A more efficient subsidy policy for CO2 enhanced oil recovery: Insights from a vertically integrated business model","authors":"Liang-Yu Xia ,&nbsp;Yao Wu ,&nbsp;Yue-Mei Zhang","doi":"10.1016/j.petsci.2025.11.040","DOIUrl":"10.1016/j.petsci.2025.11.040","url":null,"abstract":"<div><div>Although carbon dioxide enhanced oil recovery (CO₂-EOR) is a technically and economically viable option within carbon capture, utilization, and storage (CCUS), its transition from demonstration to commercial application still requires subsidies. Existing research mainly focuses on carbon capture, overlooking the impact of stakeholder interest distribution and subsidy demand differences across the industrial chain. To address this issue, we first investigated the factors influencing subsidy requirements for CO₂-EOR projects under a vertically integrated business model. Utilizing the dynamic feedback relationships among these factors, we developed a system dynamics model to assess subsidy demand. Considering CO₂-EOR decision flexibility, we used real options analysis to evaluate the value of flexible decisions. Simulation identified three key factors for subsidy stratification: capture method, reservoir depth, and oil displacement efficiency. By calculating from the economic break-even point, we defined subsidy thresholds and developed a graded scheme linked to crude oil prices, considering their impact on policy effectiveness. Using the subsidy intensity of Section 45Q tax credit as a reference for simulation, the results indicate that when crude oil prices reach a certain level, the subsidy demand for projects can drop to zero. Differentiated subsidies reduced the amount required to achieve the same policy objectives by 25%, significantly enhancing policy efficiency.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 2","pages":"Pages 979-989"},"PeriodicalIF":6.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147417681","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":"A novel NMR methodology for the quantitative characterization of solid organic matter in shale oil","authors":"Chen-Yu Xu ,&nbsp;Ran-Hong Xie ,&nbsp;Jiang-Feng Guo ,&nbsp;Xiang-Yu Wang ,&nbsp;Li-Zhi Xiao ,&nbsp;Guo-Wen Jin ,&nbsp;Bo-Chuan Jin ,&nbsp;Xiao-Long Ju","doi":"10.1016/j.petsci.2025.11.009","DOIUrl":"10.1016/j.petsci.2025.11.009","url":null,"abstract":"<div><div>Continental shale oil reservoirs in China, particularly those of low to medium maturity, contain a high proportion of untransformed solid organic matter (SOM). The SOM plays a critical role as a potential oil and gas resource. Nuclear magnetic resonance (NMR) is a powerful technique for the evaluation of shale oil reservoirs. However, it is challenging for conventional <em>T</em>₁-<em>T</em>₂ measurement methods to fully capture signals from ultra-short relaxation components such as SOM, due to the measurement deficiency caused by NMR instruments. To this end, the free induction decay (FID) and inversion recovery FID (IR-FID) pulse sequences are introduced, and two novel methods are proposed for quantitative characterization of SOM. The first method, Method I, employs the signal amplitude difference between <em>T</em>₂^∗ and <em>T</em>₁-<em>T</em>₂ spectra to obtain the SOM content. The second, Method II, directly quantifies the SOM signal from the <em>T</em>₁-<em>T</em>₂^∗ spectrum. A novel parameter, the ratio of <em>T</em>₁/<em>T</em>₂^∗ to <em>T</em>₁/<em>T</em>₂, is also proposed to refine the identification of SOM in the <em>T</em>₁-<em>T</em>₂ spectrum. The effectiveness of the proposed methods is validated by strong correlations with four geochemical parameters indicative of SOM content. The results from Method I show significantly improved correlations with all four geochemical parameters compared to the conventional <em>T</em>₁-<em>T</em>₂ method. The results from Method II show excellent correlations with parameters from step-by-step (SBS) Rock-Eval pyrolysis, reaching coefficients of determination (<em>R</em>²) as high as 0.8958 and 0.8828. This method also shows strong numerical consistency with the geochemical parameters, specifically with (<em>S</em>_1–2b + <em>S</em>_2-1+<em>S</em>_2-2). Method II is therefore highly suitable for quantitatively evaluating the total solid hydrogen content, including solid petroleum hydrocarbons, bitumen, and kerogen. This work achieves, for the first time, the precise quantification of SOM at the core scale, providing a high-precision, large-scale, and non-destructive approach for evaluating the resource potential of shale oil reservoirs.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 2","pages":"Pages 680-691"},"PeriodicalIF":6.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147418367","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":"Mechanism and influencing factors of electroosmosis-driven residual water drainage in soft coal seams during coalbed methane recovery","authors":"Jun-Qing Guo ,&nbsp;Peng-Hui Liu ,&nbsp;De-Zhi Sun ,&nbsp;Chun-Sheng Lu ,&nbsp;Yu-Qing Wang ,&nbsp;Wei Li","doi":"10.1016/j.petsci.2025.10.021","DOIUrl":"10.1016/j.petsci.2025.10.021","url":null,"abstract":"<div><div>Soft coal seams with low porosity are prone to water-blocking during mid to late stages of coalbed methane production, reducing gas recovery. To address this, an electroosmosis-driven drainage strategy was proposed in this paper, based on the charged properties of soft coal in water. Three coal ranks (anthracite, coking coal, and long-flame coal) were tested using a custom electroosmotic drainage device. Electrical properties were characterized, and the effects of potential gradients on drainage were analyzed. Fluorescent particle tracing and Fourier-transform infrared spectroscopy were used to explore residual water migration. It is shown that electroosmosis can significantly enhance drainage across all coal ranks. For coking and long-flame coals, drainage increases with voltage before stabilizing; anthracite exhibits peaked at 4 V/cm. The fluorescent tracing reveals water coalescence and migration. Long-flame coal shows best, linked to optimal higher hydroxyl content and electronegativity. Electroosmotic force, governed by pH, hydroxyl content, and field strength, enables directional water transport. Finally, an engineering design is suggested to reduce water-blocking and enhance coalbed methane recovery.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 2","pages":"Pages 791-803"},"PeriodicalIF":6.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147417834","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":"A machine learning method for evaluating shale gas production based on the TCN-PgInformer model","authors":"Hao-Yu Zhang ,&nbsp;Wen-Sheng Wu ,&nbsp;Zhang-Xin Chen ,&nbsp;Benjieming Liu","doi":"10.1016/j.petsci.2025.11.022","DOIUrl":"10.1016/j.petsci.2025.11.022","url":null,"abstract":"<div><div>Since shale gas is a valuable energy resource, effective planning for its extraction and utilization depends on precise forecasting of gas well production. Conventional models need long computation time, a wide range of geological and fluid data, and suffer from unstable predictions. To develop a low-cost, intelligent, and reliable forecast system for shale gas production, a hybrid Temporal Convolutional Network-Policy Gradient Informer (TCN-PgInformer) model was constructed for multivariate production prediction research. This model is based on the Informer model of its own unique self-attention mechanism, which lowers the temporal complexity of conventional self-attention technique while increasing the model’s accuracy. Meanwhile, to completely avoid the gradient vanishing problem, the dilated convolutions of TCN structure are employed to extract the long-term dependency relationships. Ultimately, a policy gradient (Pg) algorithm is introduced to enhance the parameter training speed. The results indicate that the daily gas production may be accurately predicted by TCN-PgInformer model. A detailed performance comparison was carried out among TCN-PgInformer, CNN, GRU and CNN-LSTM models in the literature. The comparison demonstrates that the suggested TCN-PgInformer model outperforms existing techniques. For four different gas production stages, the MAPE/RMSE error of other models is 2–12 times higher than that of the TCN-PgInformer model, while the <em>R</em>² accuracy of TCN-PgInformer model can be as high as 1 time higher than other models. Therefore, the designed model has excellent applicability, which offers reference and guidance for shale gas development.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 2","pages":"Pages 643-655"},"PeriodicalIF":6.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147418371","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":"OFC","authors":"","doi":"10.1016/S1995-8226(26)00058-0","DOIUrl":"10.1016/S1995-8226(26)00058-0","url":null,"abstract":"","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"23 2","pages":"Page OFC"},"PeriodicalIF":6.1,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147417947","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}