Geoenergy Science and Engineering最新文献

{"title":"A review of laboratory hydraulic fracturing experiments on shales","authors":"Rui Li ,&nbsp;Hongyu Zhai ,&nbsp;Changsheng Jiang ,&nbsp;Wei Zhu ,&nbsp;Xiaying Li ,&nbsp;Ziang Wang ,&nbsp;Yibo Wang","doi":"10.1016/j.geoen.2025.214028","DOIUrl":"10.1016/j.geoen.2025.214028","url":null,"abstract":"<div><div>Hydraulic fracturing (HF) experiments on shale are crucial for understanding the changes in shale's physical and mechanical properties, fracture propagation, and the mechanisms of fracture activation induced by fluid injection. This study reviews the evolving methodologies in HF experimental research on shale, analyzing current literature to identify key challenges and research gaps. It highlights significant issues in shale research, including scale-dependent data integration and the real-time monitoring of fracture dynamics. Critical scientific questions, such as the evolution of reservoirs during HF, the dynamic development of fracture networks, and the primary factors controlling induced fracture activation, remain largely unexplored. This paper provides a systematic review of experimental findings related to shale mineral composition, physical and mechanical properties from global shale formations, with a focus on factors governing fracture network development. The study links these findings with laboratory experiments to better understand the mechanisms of fracture activation and the factors influencing shale's mechanical and geophysical responses during HF. Additionally, the paper critically assesses current experimental methodologies and suggests promising future research directions. It also proposes solutions to address existing limitations, with the aim of optimizing shale HF practices and mitigating risks such as induced seismicity, which is crucial for the sustainable development of shale gas resources. The comprehensive analysis presented offers valuable insights for both the scientific community and industry professionals, facilitating the enhancement of shale gas recovery strategies.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"254 ","pages":"Article 214028"},"PeriodicalIF":0.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144262299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"CFD–DEM-based design and evaluation of sand control media with a novel gradient structure for geo-energy development","authors":"Yong Chen ,&nbsp;Chuanliang Yan ,&nbsp;Yuanfang Cheng ,&nbsp;Zhongying Han ,&nbsp;Mingyu Xue ,&nbsp;Jiping Ding ,&nbsp;Jin Sun","doi":"10.1016/j.geoen.2025.214024","DOIUrl":"10.1016/j.geoen.2025.214024","url":null,"abstract":"<div><div>In response to the contradiction between solid phase control and productivity release during geo-energy development, especially for the exploitation of fine silty oil and gas reservoirs, sand control media with a novel gradient structure, which includes a gravel-packed layer and a mechanical screen with an increasing accuracy distribution in the direction of fluid flow, are proposed. Based on the four-way coupling scheme of the discrete element method (DEM) and computational fluid dynamics (CFD), a sand-carrying with sand-retaining numerical model is established to evaluate the effectiveness of the designed structure and analyze its working mechanism from a mesoscopic perspective. The results show that for both the conventional uniformly distributed and novel gradient-distributed gravel-packed layer and standalone screen with the same apparent accuracy, the gradient-structured sand control medium possesses both excellent sand-retention and seepage performance, while these two aspects are usually contradictory for conventional sand control media. The gradient structure alleviates blockage by inhibiting the formation of an external dense accumulative sand body and prolongs the duration of the effective sand control state. In contrast to the substantial and rapid accumulation of mixed-sized particles on the exterior of the uniformly distributed sand control medium, the intercepted particles are predominantly distributed within the gradient-distributed sand control medium. After step-by-step sieving, the particles exhibited a spatial gradient distribution similar to that of the sand control medium structure. This indicates that the blockage of the sand control medium by the particles is weakened by spatial homogenization, which directly leads to an increase in the duration of the effective sand control state. Under the specified simulation conditions, the sand production mass and maximum sand production rate are reduced by more than 50 % through optimization, while improvements in permeability and pressure gradient range between 10 % and 50 %. Finally, recommendations for selecting the appropriate class of sand control media for gradient structures are provided based on reservoir characteristics, suggesting that gravel-packed layers and standalone screens should be utilized to reservoirs with poor permeability and high mud content respectively.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"254 ","pages":"Article 214024"},"PeriodicalIF":0.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144241823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact-water interaction effects on mechanical and energy characteristics of granite during uniaxial compression","authors":"Kang Peng ,&nbsp;Xu Liu ,&nbsp;Mao Jing ,&nbsp;Tao Wu ,&nbsp;Kun Luo ,&nbsp;Song Luo","doi":"10.1016/j.geoen.2025.214033","DOIUrl":"10.1016/j.geoen.2025.214033","url":null,"abstract":"<div><div>The broken rock zone resulting from blasting disturbances is more susceptible to destabilization due to groundwater erosion. To investigate the impact-water interaction effects on the mechanical and energy characteristics of rock, triaxial dynamic impact tests and water saturation tests were first conducted on a granite to prepare impact-damaged specimens (IDSs) and impact-damaged water-saturated specimens (IDWSs), and then a series of static uniaxial compression tests were undertaken on the IDSs and IDWSs. The results show that, with the increasing number of cyclic impacts, the stress thresholds of IDSs and IDWSs first increase and then decrease, and the proportion of the unstable microfracture development stage increases. This trend is more pronounced in IDWSs. Compared to those of IDSs, the total strain energy, elastic strain energy, and dissipation strain energy of IDWSs are significantly reduced, showing an initial increase followed by a decrease with the increasing number of cyclic impacts. For both IDSs and IDWSs, the rockburst proneness first decreases then increases with an increase in the number of cyclic impacts, and water saturation weakens the rockburst proneness of IDSs. The findings of this study can provide a theoretical basis for the support of engineering surrounding rock under blasting disturbance and saturation conditions.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"254 ","pages":"Article 214033"},"PeriodicalIF":0.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144253678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluation of comprehensive acid fracturing performance of a new environmentally friendly acid for high-temperature carbonate reservoirs","authors":"Juan Du ,&nbsp;Jinlong Li ,&nbsp;Jinming Liu ,&nbsp;Pingli Liu ,&nbsp;Gang Xiong ,&nbsp;Pengfei Chen ,&nbsp;Yaochen Li ,&nbsp;Wenhao Tian ,&nbsp;Zixuan Zuo","doi":"10.1016/j.geoen.2025.214020","DOIUrl":"10.1016/j.geoen.2025.214020","url":null,"abstract":"<div><div>Geothermal energy and oil and gas remain the primary underground energy sources, with acid fracturing playing a crucial role in their extraction by cleaning wellbores, enhancing reservoir permeability, preventing mineral deposition, and extending well longevity. By improving production rates and reducing operational costs, acid fracturing significantly enhances oilfield development efficiency and economic viability. However, conventional hydrochloric acid (HCl) has a limited effective reaction distance, while gelled acid and other retarded acids exhibit poor non-uniform etching characteristics, struggle to maintain conductivity, and tend to generate substantial amounts of CO₂. In response to the growing emphasis on carbon capture, utilization, and storage (CCUS) technologies, chelating agents have emerged as a novel class of retarded acids with increasing applications in oilfields. Chelating acids not only demonstrate excellent retardation properties but also indirectly contribute to CO₂ emission reduction. Despite their potential, comprehensive evaluation methods for chelating acids remain limited. In this study, the acid fracturing performance of a newly developed environmentally friendly retarded acid was systematically assessed through dissolution experiments, acid-rock reaction rate measurements, and acid-etched fracture conductivity tests. Additionally, 3D laser scanning was employed to analyze fracture etching morphology, and the least squares method was used to quantify surface roughness as an indicator of rock etching characteristics. Scanning electron microscopy (SEM) was utilized to examine the microstructural changes of the etched rock surface. The results indicate that G acid exhibits an exceptionally low reaction rate and a negative reaction order, meaning its reactivity increases as its concentration decreases—distinct from conventional acids. Conductivity tests revealed that HCl, whether used alone or in alternating injection, induces significant etching on rock surfaces, whereas G acid demonstrates weak etching capability. Surface roughness was found to correlate with etching effectiveness and can serve as an indicator for evaluating fracture conductivity. Post-etching microstructural analysis showed that acid dissolution renders the rock structure more porous, facilitating subsequent reactions between G acid and the rock matrix. Additionally, due to the presence of polymers in gelled acid, a thin film forms on the rock surface during acid flow, which partially inhibits the reaction between G acid and the rock. Notably, alternating injection of G acid and HCl exhibited a synergistic effect, enhancing both the overall etching intensity of HCl and the non-uniform etching characteristics of the acid system.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"254 ","pages":"Article 214020"},"PeriodicalIF":0.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144470266","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress-induced borehole deformation mechanism of self-rotating waterjets drilling under true triaxial stress conditions","authors":"Xiangjie Liu ,&nbsp;Zhaolong Ge ,&nbsp;Zhe Zhou ,&nbsp;Yilong Tang ,&nbsp;Di Zhang","doi":"10.1016/j.geoen.2025.214021","DOIUrl":"10.1016/j.geoen.2025.214021","url":null,"abstract":"<div><div>Hydraulic jet drilling (HJD) technology is an economically effective means of developing geothermal and unconventional natural gas. However, its successful implementation in deep reservoirs is significantly affected by geo-stress and faces the risk of borehole deformation and collapse. Therefore, in order to study the drilling characteristics and stress-induced borehole deformation mechanism of HJD in deep stress fields, a self-rotating multi-nozzle water jet (SMWJ) bit was used for drilling experiments under true triaxial stress conditions. The geometric characteristics of the borehole were analyzed using Computed Tomography (CT). The results indicate that under the influence of triaxial stress, the geometric dimensions of the borehole decrease compared to the unloaded state. The minimum inscribed diameter, drillable depth, and erosion depth of the borehole are reduced by a maximum of 41.3 %, 51.6 %, and 52.4 %, respectively. The vertical plane stress difference has a significant impact on the geometric shape of the borehole section. Under large stress differences, the borehole exhibits an elliptical geometric shape and occurs breakouts along the major axis. The horizontal stress difference mainly affects the drillable depth and erosion depth of the borehole. The direction of the higher stress concentration zones induces the deformation of the borehole.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"254 ","pages":"Article 214021"},"PeriodicalIF":0.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144513922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of reservoir dynamic evolution and well production with CO2-enhanced coalbed methane recovery using a multi-lateral horizontal well","authors":"Zhonghui Wang ,&nbsp;Shoujian Peng ,&nbsp;Jiang Xu ,&nbsp;Li Jia ,&nbsp;Liang Cheng ,&nbsp;Qingfeng Xu ,&nbsp;Chenyang Chang","doi":"10.1016/j.geoen.2025.214029","DOIUrl":"10.1016/j.geoen.2025.214029","url":null,"abstract":"<div><div>CO₂-enhanced coalbed methane (CO₂-ECBM) can improve CBM recovery efficiency while realizing CO₂ sequestration capacity. However, the outputs of different CBM production wells and the main control factors are unknown. CO₂-ECBM engineering with multi-lateral horizontal wells was used to construct large-scale physical experiments under conventional CBM recovery and different CO₂ injection pressures. The reservoir pressure during conventional CBM recovery decreased with time, whereas with the CO₂-ECBM process it decreased, then increased, and finally achieved a dynamic balance. In the early stage of displacement, CH₄ desorption caused reservoir temperature to decrease, the continuous injection of CO₂ into reservoir increased the temperature. The recovery rate of CH₄ is 93.18 % under the 2.5 MPa injection pressure, which is higher than that of 89.60 % under the 2.0 MPa injection pressure and 75.17 % under conventional CBM recovery. During the CO₂-ECBM process, CO₂ from production well Ⅰ, closest to injection well, breaks through first, making its CH₄ recovery less than that of production wells II and III. The higher the CO₂ injection pressure, the more CH₄ was extracted from production well Ⅰ, and the less CH₄ was extracted from production well Ⅲ, farthest from injection well. Thus, to optimize the CO₂-ECBM injection process, the closest production well should be closed first, the greater the CO₂ injection pressure, the later the shut-in time for production well I, whereas for production well III, the shut-in time will be earlier.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"254 ","pages":"Article 214029"},"PeriodicalIF":0.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144241819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Productivity analysis of cyclic supercritical multi-thermal fluid stimulation based on a novel relative permeability measurement method","authors":"Mingda Dong,&nbsp;Yu Gao,&nbsp;Jinmei Peng,&nbsp;Wende Yan,&nbsp;Yingzhong Yuan,&nbsp;Jingang Fu,&nbsp;Lu Zhang,&nbsp;Zhilin Qi,&nbsp;Jie Tian,&nbsp;Xiao Ling,&nbsp;Anfeng Xiao","doi":"10.1016/j.geoen.2025.214023","DOIUrl":"10.1016/j.geoen.2025.214023","url":null,"abstract":"<div><div>Supercritical multic-thermal fluid (SCMTF) is an innovative and eco-friendly medium for thermal heavy oil recovery. However, due to limitations in experimental conditions and methods, the seepage characteristics of SCMTF remain unclear, complicating productivity analysis. This study proposes a high-temperature and high-pressure steady-state method to measure the relative permeability of SCMTF and obtains three-phase oil relative permeability at different temperatures using the Stone-II model. By integrating heat diffusion model with pseudo-steady-state seepage theory, a cyclic SCMTF stimulation productivity model is established. The model incorporates the individual effects of scH₂O, scCO₂, and scN₂ on reservoir, as well as override phenomena induced by the layered system. After validation, the model was applied to analyze the impacts of production dynamics and injection parameters on productivity. The results reveal that the oil relative permeability curve undergoes dramatic changes under supercritical conditions, with the oil flow region in the isoperms expanding from 38.86 % to 54.59 %. Neglecting the abrupt change in relative permeability or the non-isothermal characteristics of hot regions results in underestimated production. Increasing temperature, molar ratio of scN₂/scCO₂ to scH₂O, and injection volume all contribute to production. With the cycle number increases, the impact of dramatic changes in relative permeability on production gradually diminishes. This study provides valuable insights into the seepage characteristics and productivity analysis of SCMTF injection in heavy oil reservoirs.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"254 ","pages":"Article 214023"},"PeriodicalIF":0.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144253676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Stress-strain and creep behaviors of marine overconsolidated hydrate-bearing sediments","authors":"Lei Wang ,&nbsp;Zhiheng Liu ,&nbsp;Xianjie Yan ,&nbsp;Zhaoran Wu ,&nbsp;Zaixing Liu ,&nbsp;Shihui Ma ,&nbsp;Yanghui Li","doi":"10.1016/j.geoen.2025.214036","DOIUrl":"10.1016/j.geoen.2025.214036","url":null,"abstract":"<div><div>Natural gas hydrate (NGH) reservoirs are currently discovered in an overconsolidated state across numerous regions worldwide. NGH exploitation can result in the release of overconsolidation pressure within these reservoir, subsequently exacerbating creep deformation. These alterations can adversely affect the efficiency and safety of NGH extraction. Therefore, it is imperative to investigate the creep behaviors of overconsolidated hydrate-bearing sediments (OHBSs). Based on this, this paper obtains the stress-strain and creep curves of OHBSs through a series of triaxial shear and creep experiments, and compares the strength and creep behaviors of OHBSs under various overconsolidation ratios (OCRs) and hydrate saturations. The findings demonstrated that the failure strength of hydrate-free samples remained unaffected by increasing the OCR. However, the failure strength of hydrate-bearing samples exhibited an increment with a corresponding rise in OCR. For creep characteristics of OHBSs, under similar failure strengths and at a constant creep stress ratio, creep deformation and creep rate diminish with an increase in the OCR when hydrate saturation remains constant. Conversely, when the OCR is held constant, they decrease as hydrate saturation increases. However, when there is a significant difference in failure strength at different OCRs or hydrate saturations, creep deformation and creep rate are only governed by the creep stress at the same creep stress ratio. The determination of stress-strain and creep characteristics not only contributes to a deeper understanding of the short-term and long-term mechanical behaviors of OHBSs, but also holds significant importance for promoting the safe extraction of NGH resource.</div></div>","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"254 ","pages":"Article 214036"},"PeriodicalIF":0.0,"publicationDate":"2025-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144253677","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of caprock complexity on carbon dioxide plume behaviour and storage security in the Bunter Sandstone Formation","authors":"Ali Alsayah ,&nbsp;Sean P. Rigby","doi":"10.1016/j.geoen.2025.214011","DOIUrl":"10.1016/j.geoen.2025.214011","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Carbon capture and storage (CCS) is expected to play a vital role in achieving greenhouse gas reduction targets. The lower Triassic Bunter Sandstone Formation in the UK Southern North Sea is considered one of the most promising CO&lt;sub&gt;2&lt;/sub&gt; storage sites. The Bunter Sandstone reservoir is structurally complex, featuring shale inter-layers, fractures, and, in particular, vertical and horizontal variations in the structure of overlying caprocks within the potential storage zone. This study demonstrated the need to include all of this complexity in a model of a ‘Bunter-like’ storage site.&lt;/div&gt;&lt;div&gt;Due to the lack of detailed geological information on Bunter, four different plausible scenarios (Cases 1–4) were developed to evaluate the impact of CO&lt;sub&gt;2&lt;/sub&gt; storage on the integrity of the complex caprock structure. The study simulated the injection of 34.2 million tons of supercritical CO&lt;sub&gt;2&lt;/sub&gt; at a rate of 0.683 million tons per year over 50 years, followed by a 950-year shut-in period (no injection) to monitor the long-term behaviour and migration of the injected CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/div&gt;&lt;div&gt;The study findings indicate that the use of an oversimplified caprock model, which assumed only a single impermeable caprock layer and no CO&lt;sub&gt;2&lt;/sub&gt; leakage, would give rise to misleading conclusions about CO&lt;sub&gt;2&lt;/sub&gt; plume migration. When comparing CO&lt;sub&gt;2&lt;/sub&gt; plume migration between scenarios with either a multi-layered, variegated caprock, versus just a single caprock, it was found that 20 % of the injected CO&lt;sub&gt;2&lt;/sub&gt; leaked in the former, while no leakage was observed through the latter. Further, the presence of a chimney-like structure, within a multi-layered caprock, facilitated lateral CO&lt;sub&gt;2&lt;/sub&gt; plume movement due to advection forces, unlike with a single, uniform caprock.&lt;/div&gt;&lt;div&gt;In a scenario with both shale inter-layers in the reservoir and a chimney in the caprock, while, during the post-injection period, fracture re-activation was observed in the upper inter-layer near the chimney zone in both multi-layer and single caprocks, this occurred significantly earlier for the former compared to the latter. The presence of a chimney in the caprock led to significant localised downward CO&lt;sub&gt;2&lt;/sub&gt;-rich brine fingering in the reservoir below, caused by gravitational instability and heterogeneity in petrophysical properties, due to leakage through the chimney.&lt;/div&gt;&lt;div&gt;Calcite minerals significantly influenced caprock porosity across all Cases studied, while halite changes within sub-layers varied between multi-layer and single caprocks. Over the 1000-year simulation period, most of the injected CO&lt;sub&gt;2&lt;/sub&gt; remained in the supercritical phase, followed by dissolved CO&lt;sub&gt;2&lt;/sub&gt;, hysteresis trapping, and finally, mineralisation. The long-term spreading behaviour of the leaked fraction of the plume is very different for multi-layer, as opposed to single, caprocks.&lt;/div&gt;&lt;div&gt;This study demonstrated the importance o","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"254 ","pages":"Article 214011"},"PeriodicalIF":0.0,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144241822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on wellbore stability considering rock matrix and weak plane of porous shale subjected to polyaxial compression and different time-domain poroelastic solutions","authors":"Jiajia Gao ,&nbsp;Gengchen Bian ,&nbsp;Hai Lin ,&nbsp;Binqi Zhang ,&nbsp;Zhe Wang ,&nbsp;Fuzhi Chen ,&nbsp;Weidong Yang","doi":"10.1016/j.geoen.2025.213986","DOIUrl":"10.1016/j.geoen.2025.213986","url":null,"abstract":"&lt;div&gt;&lt;div&gt;Deep hydrocarbon exploration of shale gas and oil resources meets weak planes (bedding, micro-fractures) with strong anisotropic strength compared to the rock matrix and the time-dependent borehole collapse during the drilling operation. These two factors consist of the internal control factor of frequent wellbore instability and seriously restrict the improvement of drilling quality and efficiency. Based on the fundamental theory of elastic mechanics, this work derives the weak plane strength criterion under polyaxial compression (three-dimensional stress), and the Mogi-Coulomb strength criterion is also introduced to evaluate the failure of the rock matrix. Primarily, one derives a strength expression depending on the dip angle and direction to assess the failure characteristics of the weak plane and reformulates the Mogi-Coulomb criterion to obtain the strength expression of the rock matrix in terms of intermediate and minimum principal stress loadings. These two strength expressions are expected to guide the experiment design and study the strength variation of laminated rock developed weak plane when the stress loading magnitude and direction are applied under polyaxial compression. Besides, to avoid the inversion operation after the Laplace transformation to the isotropic poroelastic solutions, one provides analytical poroelastic solutions for arbitrarily inclined boreholes, including five-time domains related to instantaneous, modified instantaneous, short-time, long-time, and time-independent elastic ones. Thus, the variation of the equivalent density of collapse pressure is analyzed considering the new strength criterion for the weak plane and different time-domain poroelastic solutions drilled through the shale formation. The apparent influence of intermediate principal stress on the rock matrix and weak plane shows that the strength of the rock matrix increases first and then decreases with the increasing intermediate principal stress. The strength of the weak plane does not change with the increasing intermediate principal stress where the applied direction of intermediate principal stress parallels the plane of the weak plane structure. Given intermediate principal stress, the failure angle range of the weak plane gradually increases with the increasing dip direction angle of the weak plane. Given a weak plane occurrence and the intermediate principal stress, the apparent strength of the rock increases with the increase of the minimum principal stress. The equivalent density magnitude of collapse pressure is arranged in descending order when short-time, modified instantaneous, long-time, instantaneous, and elastic solutions are adopted. Severe wellbore instability occurs at a larger angle between the wellbore axis line and the normal line of the weak plane. Studying the influence of three-dimensional stress on the strength of the weak plane and rock matrix is conducive to improving the prediction accuracy of collapse pressu","PeriodicalId":100578,"journal":{"name":"Geoenergy Science and Engineering","volume":"254 ","pages":"Article 213986"},"PeriodicalIF":0.0,"publicationDate":"2025-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144230348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}