Petroleum SciencePub Date : 2025-06-01DOI: 10.1016/j.petsci.2025.03.037
Chao-Fan Zhu , Tian-Le Zhang , Jun-Fan Pan , Yan-Wei Li , James J. Sheng , Dong Ge , Rui Jia , Wei Guo
{"title":"Evolution of the 3D pore structure of organic-rich shale with temperature based on micro-nano CT","authors":"Chao-Fan Zhu , Tian-Le Zhang , Jun-Fan Pan , Yan-Wei Li , James J. Sheng , Dong Ge , Rui Jia , Wei Guo","doi":"10.1016/j.petsci.2025.03.037","DOIUrl":"10.1016/j.petsci.2025.03.037","url":null,"abstract":"<div><div>Organic-rich shale is a significant potential source of oil and gas that requires development through in situ conversion technology. However, the evolution patterns of the internal three-dimensional (3D) pore structure and kerogen distribution at high temperatures are not well understood, making it difficult to microscopically explain the evolution of the flow conductivity in organic-rich shale at high temperatures. This study utilizes high-resolution X-ray computed tomography (micro-nano CT) to obtain the distribution of pores, kerogen, and inorganic matter at different temperatures. Combined with the pyrolysis results for the rock, the evolution of the pore structure at various temperatures is quantitatively analyzed. Based on three-phase segmentation technology, a model of kerogen distribution in organic-rich shale is established by dividing the kerogen into clustered kerogen and dispersed kerogen stored in the inorganic matter and the pores into inorganic pores and organic pores within the kerogen skeleton.</div><div>The results show that the inorganic pores in organic-rich shale evolve through three stages as the temperature increases: kerogen pyrolysis (200–400 °C), clay mineral decomposition (400–600 °C), and carbonate mineral decomposition (600–800 °C). The inorganic pores porosity sequentially increases from 3% to 11.4%, 13.1%, and 15.4%, and the roughness and connectivity of the inorganic pores gradually increase during this process. When the pyrolysis temperature reaches 400 °C, the volume of clustered kerogen decreases from 25% to 12.5%. During this process, the relative density of kerogen decreases from 9.5 g/cm<sup>3</sup> in its original state to 5.4 g/cm<sup>3</sup>, while the kerogen skeleton density increases from 1.15 g/cm<sup>3</sup> in its original state to 1.54 g/cm<sup>3</sup>. Correspondingly, 7%–8% of organic pores develop within the clustered kerogen, accounting for approximately 50% of the volume of clustered kerogen. In addition, approximately 30% of the kerogen in organic-rich shale exists in the form of dispersed kerogen within inorganic matter, and its variation trend is similar to that of clustered kerogen, rapidly decreasing from 200 to 400 °C and stabilizing above 400 °C. The results of this study provide an essential microscopic theoretical basis for the industrial development of organic-rich shale resources.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 6","pages":"Pages 2339-2352"},"PeriodicalIF":6.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572803","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}
Petroleum SciencePub Date : 2025-06-01DOI: 10.1016/j.petsci.2025.03.039
Tong-Jie Sheng , Jing-Tao Zhao , Su-Ping Peng , Zong-Nan Chen , Jie Yang
{"title":"Diffraction classification imaging using coordinate attention enhanced DenseNet","authors":"Tong-Jie Sheng , Jing-Tao Zhao , Su-Ping Peng , Zong-Nan Chen , Jie Yang","doi":"10.1016/j.petsci.2025.03.039","DOIUrl":"10.1016/j.petsci.2025.03.039","url":null,"abstract":"<div><div>In oil and gas exploration, small-scale karst cavities and faults are important targets. The former often serve as reservoir space for carbonate reservoirs, while the latter often provide migration pathways for oil and gas. Due to these differences, the classification and identification of karst cavities and faults are of great significance for reservoir development. Traditional seismic attributes and diffraction imaging techniques can effectively identify discontinuities in seismic images, but these techniques do not distinguish whether these discontinuities are karst cavities, faults, or other structures. It poses a challenge for seismic interpretation to accurately locate and classify karst cavities or faults within the seismic attribute maps and diffraction imaging profiles. In seismic data, the scattering waves are associated with small-scale scatters like karst cavities, while diffracted waves are seismic responses from discontinuous structures such as faults, reflector edges and fractures. In order to achieve classification and identification of small-scale karst cavities and faults in seismic images, we propose a diffraction classification imaging method which classifies diffracted and scattered waves in the azimuth-dip angle image matrix using a modified DenseNet. We introduce a coordinate attention module into DenseNet, enabling more precise extraction of dynamic and azimuthal features of diffracted and scattered waves in the azimuth-dip angle image matrix. Leveraging these extracted features, the modified DenseNet can produce reliable probabilities for diffracted/scattered waves, achieving high-accuracy automatic classification of cavities and faults based on diffraction imaging. The proposed method achieves 96% classification accuracy on the synthetic dataset. The field data experiment demonstrates that the proposed method can accurately classify small-scale faults and scatterers, further enhancing the resolution of diffraction imaging in complex geologic structures, and contributing to the localization of karstic fracture-cavern reservoirs.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 6","pages":"Pages 2353-2383"},"PeriodicalIF":6.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572804","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}
Petroleum SciencePub Date : 2025-06-01DOI: 10.1016/j.petsci.2025.04.019
Xiao-Xiao Lv , Wen-Rui Jin , Xin Zhang
{"title":"A dual-scale failure evaluation method for Carbon-glass hybrid Fiber sucker rod and their joints under complex loads","authors":"Xiao-Xiao Lv , Wen-Rui Jin , Xin Zhang","doi":"10.1016/j.petsci.2025.04.019","DOIUrl":"10.1016/j.petsci.2025.04.019","url":null,"abstract":"<div><div>A hybrid fiber-reinforced polymer (HFRP) continuous sucker rod, comprising a carbon fiber-reinforced polymer (CFRP) core layer, a glass fiber-reinforced polymer (GFRP) winding layer, and a GFRP coating layer (CFRP:GFRP = 2:3), has been developed and widely used in oilfield extraction due to its lower specific gravity, enhanced corrosion resistance, and superior strength. However, HFRP rod joints and their adjacent sections are prone to multi-mode failures, including fracture, debonding, and cracking. Due to the complexity of joint structure and the coupling of tension, bending, and torsion, the failure mechanism is unclear. To address this issue, a dual-scale failure assessment methodology for HFRP rods was proposed, utilizing both macro and meso finite element models (FEM). This methodology was validated through tensile and bending experiments, which yielded critical loads for the φ22 mm HFRP rod: a tensile load of 340.2 kN, a torque of 132.3 N m, and a bending moment of 1192.4 N m. Additionally, a comprehensive FEM of the joint was established, which identified potential failure points at the necking of the rotary joint, resin adhesive and the HFRP rod cross-section at the first groove tip. These failure modes closely matched the experimental observations. Furthermore, the simulation results show that stress concentration at the joint reduced the tensile, bending, and torsional strengths of the HFRP rod to 61%, 12%, and 82% of their original values, respectively. The effects of bending moments and torque on the tensile strength of HFRP rods were subsequently explored, leading to the development of an equivalent fatigue assessment method for HFRP rod joints. This method, based on the fatigue characteristics of HFRP rods and joint components, reveals that the primary cause of joint failure is the susceptibility of both the joint and the HFRP rod to bending moments and torque induced by dynamic buckling of the sucker rod string (SRS). Using this method, the fatigue ultimate axial force of the φ22 mm HFRP joint was determined to be 91.5 kN, with corresponding fatigue ultimate torque and bending moment under an axial force of 62.4 kN being 89.3 N m and 71.5 N m, respectively. Finally, a design method incorporating a concentrated weighting strategy for HFRP-steel mixed rods was proposed to enhance their service life, and its effectiveness was demonstrated through on-site testing.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 6","pages":"Pages 2570-2591"},"PeriodicalIF":6.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572904","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}
Petroleum SciencePub Date : 2025-06-01DOI: 10.1016/j.petsci.2025.04.011
Yi-Wei Zhang , Jia-Nan Li , Zhi-Qiang He , Ling Chen , Cong Li , Da Guo , Ding-Ming Wang , Xin Fang , He-Ping Xie
{"title":"In-situ temperature-pressure preserved coring for onshore deep oil and gas exploration: research on the design principles and mechanical properties of the temperature-preserved core chamber","authors":"Yi-Wei Zhang , Jia-Nan Li , Zhi-Qiang He , Ling Chen , Cong Li , Da Guo , Ding-Ming Wang , Xin Fang , He-Ping Xie","doi":"10.1016/j.petsci.2025.04.011","DOIUrl":"10.1016/j.petsci.2025.04.011","url":null,"abstract":"<div><div>A novel temperature-preserved core chamber designed for depths exceeding 5000 m has been developed to enhance the scientific understanding of deep oil and gas reservoirs. This temperature-preserved core chamber employs an innovative vacuum layer for temperature preservation and is compatible with a temperature-pressure preserved coring system. The design principles and key parameters of the temperature-preserved core chamber were determined through static analysis. Numerical simulations assessed the mechanical properties of 70, 85, and 100 MPa core chambers under conditions of 120–150 °C. The results demonstrate that the temperature-preserved core chambers withstand the applied stresses without plastic deformation, and the vacuum layer maintains its integrity under these conditions. A 70 MPa class core chamber prototype was manufactured, and system integration tests were performed on a self-developed in-situ coring platform. The system demonstrated stable operation at 70 MPa for 120 min, with pressure fluctuations within 5%. Additionally, the integrated system operated without interference, enabling the successful extraction of cores with a 50 mm diameter. These findings provide valuable theoretical guidance and design recommendations for advancing oil and gas in-situ temperature-pressure preserved coring technologies in high-temperature and high-pressure environments.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 6","pages":"Pages 2438-2456"},"PeriodicalIF":6.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572575","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}
Petroleum SciencePub Date : 2025-06-01DOI: 10.1016/j.petsci.2025.05.022
Wen-Bin He , Ji-Lin Fan , Qiong Zhang , Ya Jin , Wei Yuan , Quan-Wen Zhang
{"title":"Thin layer identification using a theoretical X-ray logging while drilling (LWD) density imaging tool","authors":"Wen-Bin He , Ji-Lin Fan , Qiong Zhang , Ya Jin , Wei Yuan , Quan-Wen Zhang","doi":"10.1016/j.petsci.2025.05.022","DOIUrl":"10.1016/j.petsci.2025.05.022","url":null,"abstract":"<div><div>With the increasing demand for oil exploration and subsurface resource development, density imaging plays an increasingly important role in identifying thin layers. However, conventional density imaging tools are limited by poor vertical resolution and therefore suffer from errors in accurately estimating the thickness and relative dip angle of thin layers. This affects the accurate evaluation of thin layer oil and gas reserves. To address this issue, this study evaluates the feasibility of employing novel methods based on advanced tool design. First, an electronically controllable X-ray source is selected to replace the traditional Cs-137 source, aiming to improve the tool's vertical resolution while reducing the radioactive risks commonly associated with chemical sources. Simulation results show that the X-ray tool provides sufficient depth of investigation with better vertical resolution while maintaining the same level of measurement sensitivity. Once the tool design is established, Fisher's optimal segmentation method is improved to enhance the estimation of thin layer thickness and relative dip angle. This is completed by transforming identifying thin layer interface into a mathematical clustering problem. The thin layer interface is fitted using the nonlinear least squares method, which enables the calculation of its parameters. The results demonstrate a 38.5% reduction in RMSE (<em>root mean square error</em>) for thin layer thickness and a 33.7% reduction in RMSE for relative dip angle, demonstrating the superior performance of enhanced X-ray tool in thin layer identification. This study provides a new perspective on the design of density imaging tools and assessment of thin layer, which can help in future thin layer hydrocarbon reserves evaluation and development decisions.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 6","pages":"Pages 2403-2413"},"PeriodicalIF":6.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572573","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}
Petroleum SciencePub Date : 2025-06-01DOI: 10.1016/j.petsci.2025.04.002
Yun Zhao , Xiao-Tao Wen , Chun-Lan Xie , Bo Li , Chen-Long Li , Xiao Pan , Xi-Yan Zhou
{"title":"Simultaneous seismic inversion of effective stress parameter, fluid bulk modulus, and fracture density in TTI media","authors":"Yun Zhao , Xiao-Tao Wen , Chun-Lan Xie , Bo Li , Chen-Long Li , Xiao Pan , Xi-Yan Zhou","doi":"10.1016/j.petsci.2025.04.002","DOIUrl":"10.1016/j.petsci.2025.04.002","url":null,"abstract":"<div><div>Predictions of fluid distribution, stress field, and natural fracture are essential for exploiting unconventional shale gas reservoirs. Given the high likelihood of tilted fractures in subsurface formations, this study focuses on simultaneous seismic inversion to estimate fluid bulk modulus, effective stress parameter, and fracture density in the tilted transversely isotropic (TTI) medium. In this article, a novel PP-wave reflection coefficient approximation equation is first derived based on the constructed TTI stiffness matrix incorporating fracture density, effective stress parameter, and fluid bulk modulus. The high accuracy of the proposed equation has been demonstrated using an anisotropic two-layer model. Furthermore, a stepwise seismic inversion strategy with the L<sub><em>P</em></sub> quasi-norm sparsity constraint is implemented to obtain the anisotropic and isotropic parameters. Three synthetic model tests with varying signal-to-noise ratios (SNRs) confirm the method's feasibility and noise robustness. Ultimately, the proposed method is applied to a 3D fractured shale gas reservoir in the Sichuan Basin, China. The results have effectively characterized shale gas distribution, stress fields, and tilted natural fractures, with validation from geological structures, well logs, and microseismic events. These findings can provide valuable guidance for hydraulic fracturing development, enabling more reliable predictions of reservoir heterogeneity and completion quality.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 6","pages":"Pages 2384-2402"},"PeriodicalIF":6.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572801","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}
Petroleum SciencePub Date : 2025-06-01DOI: 10.1016/j.petsci.2025.03.013
Qi Jing , Zi-Yu Fan , Rui Zhou , Yun-Tao Li
{"title":"The influence mechanism of liquid sedimentary layers in urban underground spaces on the characteristics of natural gas explosions and damage risk","authors":"Qi Jing , Zi-Yu Fan , Rui Zhou , Yun-Tao Li","doi":"10.1016/j.petsci.2025.03.013","DOIUrl":"10.1016/j.petsci.2025.03.013","url":null,"abstract":"<div><div>Gas explosions are a frequent hazard in underground confined spaces in the process of urban development. Liquid sedimentary layers, commonly present in these environments, have not been sufficiently studied in terms of their impact on explosion dynamics. This study aims to investigate how gas-liquid two-phase environments in confined underground spaces affect the explosion characteristics of natural gas. To achieve this, experiments are conducted to examine the propagation of natural gas explosions in water and diesel layers, focusing on the influence of liquid properties and the liquid fullness degree (<em>L</em><sub>x</sub>) on explosion behavior. The results indicate that the presence of a liquid layer after the initial ignition stage significantly attenuates both the peak overpressure and the rise speed of pressure, in comparison to the natural gas conditions. During the subsequent explosive reaction, the evaporation and combustion of the diesel surface resulted in a distinct double-peak pressure rise profile in the diesel layer, with the second peak notably exceeding the first peak. Under conditions with a liquid sedimentary layer, the flame propagation velocities range from 6.53 to 34.1 m/s, while the overpressure peaks vary between 0.157 and 0.255 MPa. The explosion duration in both the water and diesel layer environments is approximately twice as long as that of the natural gas explosion, although the underlying mechanisms differ. In the diesel layer, the prolonged explosion time is attributed to the evaporation and combustion of the diesel, while in the water layer, the flame propagation velocity is significantly reduced. Under the experimental conditions, the maximum explosion energy reached 7.15 × 10<sup>6</sup> J, corresponding to a TNT equivalent of 1.7. The peak overpressure surpassed the threshold for human fatality as defined by overpressure standards, posing a potential risk of damage to large steel-frame structures. The explosion shockwave in diesel layer conditions (<em>L</em><sub>d</sub> = 0%, 5%, 7.5%, 12.5%) and water layer (<em>L</em><sub>w</sub> = 12.5%) conditions is observed to be sufficient to damage earthquake-resistant reinforced concrete. This study investigates the impact of sediment layer thickness and composition on gas explosions, and evaluates the associated explosion energy to assess human injuries and structural damage in underground environments. The findings of this study provide a scientific reference for urban underground safety.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 6","pages":"Pages 2619-2629"},"PeriodicalIF":6.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572810","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}
Petroleum SciencePub Date : 2025-06-01DOI: 10.1016/j.petsci.2025.04.003
Ning Huang , Jin-Sheng Sun , Jing-Ping Liu , Kai-He Lv , Xue-Fei Deng , Hai-Jiang Yi
{"title":"Research on small molecule wetting agent for drilling fluids applied in Antarctic drilling engineering","authors":"Ning Huang , Jin-Sheng Sun , Jing-Ping Liu , Kai-He Lv , Xue-Fei Deng , Hai-Jiang Yi","doi":"10.1016/j.petsci.2025.04.003","DOIUrl":"10.1016/j.petsci.2025.04.003","url":null,"abstract":"<div><div>Antarctica contains numerous scientific mysteries, and the Antarctic ice sheet and its underlying bedrock contain important information about the geological structure of Antarctica and the evolutionary history of the ice sheet. In order to obtain the focus of these scientific explorations, the Antarctic drilling engineering is constantly developing. The drilling fluid performance directly determines the success or failure of drilling engineering. In order to enhance the poor performance for drilling fluids due to poor dispersion stability and easy settling of organoclay at ultra-low temperatures, the small-molecule wetting agent (HSR) for drilling fluid suitable for Antarctica was prepared by oleic acid, diethanolamine and benzoic acid as raw materials. Its chemical structure, properties and action mechanism were investigated by various experimental methods. The experimental results showed that 2% HSR could improve the colloidal rate for drilling fluid from 6.4% to 84.8%, and the increase rate of yield point was up to 167%. Meanwhile, it also made the drilling fluid excellent in shear dilution and thixotropy. In addition, 2% HSR could increase the density from 0.872 to 0.884 g/cm<sup>3</sup> at −55 °C. And the drilling fluid with 2% HSR had a good thermal conductivity of 0.1458 W/(m·K) at −55 °C. This study gives a new direction for the research of drilling fluid treatment agents suitable for the Antarctic region, which will provide strong support for the scientific exploration of the Antarctic region.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 6","pages":"Pages 2465-2477"},"PeriodicalIF":6.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572897","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}
Petroleum SciencePub Date : 2025-06-01DOI: 10.1016/j.petsci.2025.04.029
Yang Wang , Shi-Long Yang , Hang Xie , Yu Jiang , Shi-Qing Cheng , Jia Zhang
{"title":"Dynamic characterization of viscoelasticity during polymer flooding: A two-phase numerical well test model and field study","authors":"Yang Wang , Shi-Long Yang , Hang Xie , Yu Jiang , Shi-Qing Cheng , Jia Zhang","doi":"10.1016/j.petsci.2025.04.029","DOIUrl":"10.1016/j.petsci.2025.04.029","url":null,"abstract":"<div><div>Polymer flooding is an important means of improving oil recovery and is widely used in Daqing, Xinjiang, and Shengli oilfields, China. Different from conventional injection media such as water and gas, viscoelastic polymer solutions exhibit non-Newtonian and nonlinear flow behavior including shear thinning and shear thickening, polymer convection, diffusion, adsorption, retention, inaccessible pore volume, and reduced effective permeability. However, available well test model of polymer flooding wells generally simplifies these characteristics on pressure transient response, which may lead to inaccurate results. This work proposes a novel two-phase numerical well test model to better describe the polymer viscoelasticity and nonlinear flow behavior. Different influence factors that related to near-well blockage during polymer flooding process, including the degree of blockage (inner zone permeability), the extent of blockage (composite radius), and polymer flooding front radius are explored to investigate these impacts on bottom hole pressure responses. Results show that polymer viscoelasticity has a significant impact on the transitional flow segment of type curves, and the effects of near-well formation blockage and polymer concentration distribution on well test curves are very similar. Thus, to accurately interpret the degree of near-well blockage in injection wells, it is essential to first eliminate the influence of polymer viscoelasticity. Finally, a field case is comprehensively analyzed and discussed to illustrate the applicability of the proposed model.</div></div>","PeriodicalId":19938,"journal":{"name":"Petroleum Science","volume":"22 6","pages":"Pages 2493-2501"},"PeriodicalIF":6.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572898","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}