Rock Mechanics Bulletin最新文献

{"title":"Analytical prediction for time-dependent interaction of a circular tunnel excavated in strain-softening rock mass","authors":"Chen Xu ,&nbsp;Sheng Wang ,&nbsp;Caichu Xia","doi":"10.1016/j.rockmb.2024.100127","DOIUrl":"10.1016/j.rockmb.2024.100127","url":null,"abstract":"<div><p>Viscoelastic plastic solutions for tunnel excavation in strain-softening rock mass and tunnel-rock interaction are proposed based on the Mohr-Coulomb and the Generalized Zhang-Zhu (GZZ) strength criterion considering stress path. The solutions are verified by numerical simulations, results show that the theoretical solutions are close to the simulated data. The evolutions of rock stresses, strains, displacements and support pressure were investigated and the influences of residual strength parameter, support stiffness, support timing, initial support pressure and viscosity coefficient on the rock deformation and the support pressure are discussed by proposed solution. It is found that strain-softening results in large deformation and high support pressure, with stiffer support and a larger viscosity coefficient contributing to even greater support pressure. Ductile support is recommended at the first stage to release the energy and reduce the support pressure by allowing a relatively large deformation. The support pressure, especially the additional support pressure at the second stage will be much smaller if a higher initial support pressure is applied at the first stage. This can not only control the displacement rate of surrounding rock and improve the tunnel stability at the first stage by exerting sufficient support pressure immediately after tunnel excavation, but also greatly reduce the pressure acted on permanent support and improve the structure stability at the second stage. Therefore, to avoid the instability of support structure, ductile support, which could not only deform continuously but also provide sufficient high support pressure, is recommended at the first stage.</p></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"3 3","pages":"Article 100127"},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S277323042400026X/pdfft?md5=1b13304fd26efac4101bdd25522d028f&pid=1-s2.0-S277323042400026X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140757002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simultaneously improving ROP and maintaining wellbore stability in shale gas well: A case study of Luzhou shale gas reservoirs","authors":"Yaoran Wei ,&nbsp;Yongcun Feng ,&nbsp;Zhenlai Tan ,&nbsp;Tianyu Yang ,&nbsp;Shuang Yan ,&nbsp;Xiaorong Li ,&nbsp;Jingen Deng","doi":"10.1016/j.rockmb.2024.100124","DOIUrl":"10.1016/j.rockmb.2024.100124","url":null,"abstract":"<div><p>The ROP (rate of penetration) within the horizontal section of shale gas wells in the Luzhou oil field is low, seriously delaying the exploration and development process. It is proved that reducing mud density mitigates the bottom-hole differential pressure (<span><math><mrow><mo>Δ</mo><mi>P</mi></mrow></math></span>) and increases the ROP during overbalanced drilling. However, wellbore collapse may occur when wellbore pressure is excessively low. It is urgent to ascertain the optimal equilibrium point between improving ROP and maintaining wellbore stability. The safe mud weight window and the lower limit of mud density in the horizontal section of the Luzhou block are predicted using the piecewise fitting method based on conventional logging data. Then, the accuracy of the collapse pressure prediction was verified using the distinct element method (DEM), and the effect of wellbore pressure, in-situ stress, rock cohesion, and natural fracture density on borehole collapse was investigated. Finally, a fitting model of <span><math><mrow><mo>Δ</mo><mi>P</mi></mrow></math></span> and ROP of the horizontal section in the Luzhou block is established to predict ROP promotion potential after mud density reduction. The field application of this approach, demonstrated in 8 horizontal wells in the Luzhou block, effectively validates the efficiency of reducing mud density for ROP improvement. This study provides a useful method for simultaneously improving ROP and maintaining wellbore stability and offers significant insights for petroleum engineers in the design of drilling parameters.</p></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"3 3","pages":"Article 100124"},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773230424000234/pdfft?md5=844561005278af9e7bfb7156fc770767&pid=1-s2.0-S2773230424000234-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140400841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Rockburst prediction using artificial intelligence techniques: A review","authors":"Yu Zhang ,&nbsp;Kongyi Fang ,&nbsp;Manchao He ,&nbsp;Dongqiao Liu ,&nbsp;Junchao Wang ,&nbsp;Zhengjia Guo","doi":"10.1016/j.rockmb.2024.100129","DOIUrl":"10.1016/j.rockmb.2024.100129","url":null,"abstract":"<div><p>Rockburst is a phenomenon where sudden, catastrophic failure of the rock mass occurs in underground deep regions or areas with high tectonic stress during the excavation process. Rockburst disasters endanger the safety of people's lives and property, national energy security, and social interests, so it is very important to accurately predict rockburst. Traditional rockburst prediction has not been able to find an effective prediction method, and the study of the rockburst mechanism is facing a dilemma. With the development of artificial intelligence (AI) techniques in recent years, more and more experts and scholars have begun to introduce AI techniques into the study of the rockburst mechanism. In previous research, several scholars have attempted to summarize the application of AI techniques in rockburst prediction. However, these studies either are not specifically focused on reviews of the application of AI techniques in rockburst prediction, or they do not provide a comprehensive overview. Drawing on the advantages of extensive interdisciplinary research and a deep understanding of AI techniques, this paper conducts a comprehensive review of rockburst prediction methods leveraging AI techniques. Firstly, pertinent definitions of rockburst and its associated hazards are introduced. Subsequently, the applications of both traditional prediction methods and those rooted in AI techniques for rockburst prediction are summarized, with emphasis placed on the respective advantages and disadvantages of each approach. Finally, the strengths and weaknesses of prediction methods leveraging AI are summarized, alongside forecasting future research trends to address existing challenges, while simultaneously proposing directions for improvement to advance the field and meet emerging demands effectively.</p></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"3 3","pages":"Article 100129"},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773230424000283/pdfft?md5=3fed92d63f57375ee0c4dda28a65a7be&pid=1-s2.0-S2773230424000283-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141055390","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying perforation locations for hydraulic fracturing treatment in deep and tight sandstone gas reservoirs","authors":"Kaiming Xia ,&nbsp;Weihua Wang ,&nbsp;Yufeng Cui","doi":"10.1016/j.rockmb.2024.100131","DOIUrl":"10.1016/j.rockmb.2024.100131","url":null,"abstract":"<div><p>Fracture initiation has been a challenging issue for fracturing deep and tight gas reservoirs, which generally requires a high breakdown pressure for hydraulic fracturing treatment. In this situation, fluid injections frequently have to terminate at the very beginning. Toward predicting and solving this issue, a novel fracturing system for deep and tight sandstone gas reservoirs was developed. The key components of the fracturing system and some criterion will be introduced, which can be used to optimize the ideal perforation locations along the landing part and select the right perforation strategy accordingly. The main components of the fracturing system include: (1) evaluating the log-based diagenetic rock typing and flow index; (2) 1D mechanical earth model; (3) calculating the breakdown pressure envelope along the well trajectory of the landing part; (4) calculating the optimal perforation directions along the landing part; (5) select the first set of perforation locations based on the log-based diagenetic rock typing and flow index; (6) narrowing down the first set of perforation locations to a second set of perforation locations based on the breakdown pressure envelope; (7) determining a perforation strategy based on breakdown pressure envelope and wellhead pressure safety limit in the second set of perforation locations. The computational framework to calculate the breakdown pressure envelope and optimal perforation directions is applicable to arbitrary well trajectory. The fracturing system has been used to provide pre-fracturing suggestions for wells landed in deep and tight sandstone reservoirs, which is very efficient for identifying locations with good rock typing and relatively low breakdown pressure. Also, it can indicate whether oriented perforation should be used further for alleviating breakdown issue. By taking these efforts and procedures, the fracturing success rate for deep and tight sandstone gas reservoirs can be improved, which has been verified in practice. Example studies from the field will be provided to demonstrate the fracturing system's performance and applicability.</p></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"3 3","pages":"Article 100131"},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773230424000301/pdfft?md5=af614c51c2461bb548190b223ef967a2&pid=1-s2.0-S2773230424000301-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141054854","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Introducing a new rock abrasivity index using a scaled down disc cutter","authors":"Maziar Moradi ,&nbsp;Mohammad Hossein Khosravi ,&nbsp;Jafar Khademi Hamidi","doi":"10.1016/j.rockmb.2024.100130","DOIUrl":"10.1016/j.rockmb.2024.100130","url":null,"abstract":"<div><p>Rock abrasivity influences wear of cutting tools and consequently, performance of mechanized tunneling machines. Several methods have been proposed to evaluate rock abrasivity in recent decades, each one has its own advantages. In this paper, a new method is introduced to estimate wear of disc cutters based on rock cutting tests using scaled down discs (i.e. 54 and 72 ​mm diameter). The discs are made of H13 steel, which is a common steel type in producing real-scale discs, with hardness of 32 and 54 HRC. The small-scale linear rock cutting machine and a new abrasion test apparatus, namely University of Tehran abrasivity test machine, are utilized to perform the tests. Tip width of the worn discs is monitored and presented as the function of the accumulated test run to classify the rock abrasion. Abrasivity tests show that by increasing the UCS of the rock samples, wear rate is doubled gradually that reveals the sensitivity of the test procedure to the main parameters affecting the abrasivity of hard rocks. For the rocks with the highest UCS, the normal wear stops after performing 5 to 10 rounds of the tests, and then, deformation of the disc tip is detectable. Two abrasivity indices are defined based on the abrasivity tests results and their correlations with CAI and UCS are established. Comparison of the established correlations in this study with previous investigations demonstrates the sensitivity of the indices to the parameters affecting wear of the disc cutters and repeatability of the outputs obtained from abrasivity tests using scaled down discs. Findings of this study can be used to enhance the accuracy of rock abrasivity classifications.</p></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"3 3","pages":"Article 100130"},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773230424000295/pdfft?md5=54e93e2d82a4896e23e7a480829ef2d9&pid=1-s2.0-S2773230424000295-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141023358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two-phase flow thermo-hydro-mechanical modeling for a water flooding field case","authors":"Yuhao Liu ,&nbsp;Fengshou Zhang ,&nbsp;Dingwei Weng ,&nbsp;Hongbo Liang ,&nbsp;Chunming He ,&nbsp;Keita Yoshioka","doi":"10.1016/j.rockmb.2024.100125","DOIUrl":"10.1016/j.rockmb.2024.100125","url":null,"abstract":"<div><p>Simulation of subsurface energy system involves multi-physical processes such as thermal, hydraulical, and mechanical (THM) processes, and requires a so-called THM coupled modeling approach. THM coupled modeling is commonly performed in geothermal energy production. However, for hydrocarbon extraction, we need to consider multiphase flow additionally. In this paper, we describe a three-dimensional numerical model of non-isothermal two-phase flow in the deformable porous medium by integrating governing equations of two-phase mixture in the porous media flow in the reservoir. To account for inter-woven impacts in subsurface conditions, we introduced a temperature-dependent fluid viscosity and a fluid density along with a strain-dependent reservoir permeability. Subsequently, we performed numerical experiments of a ten-year water flooding process employing the open-source parallelized code, OpenGeoSys. We considered different well patterns with colder water injection in realistic scenarios. Our results demonstrate that our model can simulate complex interactions of temperature, pore pressure, subsurface stress and water saturation simultaneously to evaluate the recovery performance. High temperature can promote fluid flow while cold water injection under non-isothermal conditions causes the normal stress reduction by significant thermal stress. Under different well patterns the displacement efficiency will be changed by the relative location between injection and production wells. This finding has provided the important reference for fluid flow and induced stress evolution during hydrocarbon exploitation under the environment of large reservoir depth and high temperature.</p></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"3 3","pages":"Article 100125"},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773230424000246/pdfft?md5=25609c61705c5a0dac2d977b949fefb3&pid=1-s2.0-S2773230424000246-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140761318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation on acoustic emission precursor of rockburst based on unsupervised machine learning method","authors":"Jie Sun ,&nbsp;Dongqiao Liu ,&nbsp;Pengfei He ,&nbsp;Longji Guo ,&nbsp;Binghao Cao ,&nbsp;Lei Zhang ,&nbsp;Zhe Li","doi":"10.1016/j.rockmb.2023.100099","DOIUrl":"10.1016/j.rockmb.2023.100099","url":null,"abstract":"<div><p>The key to achieving rockburst warning lies in the understanding of rockburst precursors. Considering the correlation characteristics of rockburst acoustic emission (AE) parameters, a self-organizing map neural network (SOMNN) based method for rockburst precursor inversion was proposed. The feature of this method lies in a cyclic data segmentation iteration process based on the thinking of “interference signal screening”, “key signal extraction”, and “precursor signal inversion”. The rationality of this method has been verified in three groups of rockburst experiments. The results revealed that rockburst AE precursor signals consist of a series of signals characterized by long duration, high energy, low average frequency, high energy amplitude, and low peak frequency. Subsequently, potential value in long term rockburst warning of the precursor obtained in this study was shown via the comparison of conventional precursors. Finally, a preliminary interpretation for rockburst precursor was proposed under the framework of AE parameters physical significance, and it is revealed that AE precursor signals are likely linked to the creation of large-scale tensile cracks before rockburst.</p></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"3 2","pages":"Article 100099"},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773230423000720/pdfft?md5=5e69e0b7cccc66235baf286ec3566a76&pid=1-s2.0-S2773230423000720-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139638955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compaction and seepage characteristics of broken coal and rock masses in coal mining: A review in laboratory tests","authors":"Cun Zhang ,&nbsp;Yanhong Chen ,&nbsp;Zhaopeng Ren ,&nbsp;Fangtian Wang","doi":"10.1016/j.rockmb.2024.100102","DOIUrl":"10.1016/j.rockmb.2024.100102","url":null,"abstract":"<div><p>Broken coal and rock (BCR) are an important component medium of the caving zone in the goaf (or gob), as well as the main filling material of fault fracture zone and collapse column. The compaction seepage characteristics of BCR directly affect the safe and efficient mining of coal mines. Thus, numerous laboratory studies have focused on the compaction seepage characteristics of BCR. This paper first outlines the engineering problems involved in the BCR during coal mining including the air leakage, the spontaneous combustion, the gas drainage, and the underground reservoirs in the goaf. Water inrush related to tectonics such as faults and collapse columns and surface subsidence related to coal gangue filling and mining also involve the compaction seepage characteristics of BCR. Based on the field problems of BCR, many attempts have been made to mimic field environments in laboratory tests. The experimental equipment (cavity size and shape, acoustic emission, CT, etc.) and experimental design for the BCR were firstly reviewed. The main objects of laboratory analysis can be divided into compression tests and seepage test. During the compaction test, the main research focuses on the bearing deformation characteristics (stress-strain curve), pore evolution characteristics, and re-crushing characteristics of BCR. The seepage test mainly uses gas or water as the main medium to study the evolution characteristics of permeability under different compaction stress conditions. In the laboratory tests, factors such as the type of coal and rock mass, particle size, particle shape, water pressure, temperature, and stress path are usually considered. The lateral compression test of BCR can be divided into three stages, including the self-adjustment stage, the broken stage, and the elastic stage or stable stage. At each stage, stress, deformation, porosity, energy, particle size and breakage rate all have their own characteristics. Seepage test regarding the water permeability experiment of BCR is actually belong to variable mass seepage. While the experimental test still focuses on the influence of stress on the pore structure of BCR in terms of gas permeability. Finally, future laboratory tests focus on the BCR related coal mining including scaling up, long term loading and water immersion, mining stress path matching were discussed.</p></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"3 2","pages":"Article 100102"},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773230424000015/pdfft?md5=e5eefe4269414403091b6837a973079f&pid=1-s2.0-S2773230424000015-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139537027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geothermal extraction performance in fractured granite from Gonghe Basin, Qinghai province, China: Long-term injection and production experiment","authors":"Haiyan Zhu ,&nbsp;Shijie Chen ,&nbsp;Qiang Fu ,&nbsp;Peng Zhao ,&nbsp;John D. McLennan","doi":"10.1016/j.rockmb.2024.100113","DOIUrl":"https://doi.org/10.1016/j.rockmb.2024.100113","url":null,"abstract":"<div><p>The efficient exploitation of geothermal energy through enhanced geothermal systems (EGS) has been a relevant topic for hot dry rock (HDR) geothermal resources. When cryogenic fluid is injected into a thermal reservoir, improving heat exchange efficiency is key to achieving the optimal exploitation of HDR. In this paper, granite outcrops from Gonghe Basin were used as the testing sample. The natural fractures in the granite samples were relatively well developed. To simulate long-term injection and production from multi-wells in situ, physical experiments were performed in a newly-developed, in-house large-scale true triaxial experimental system. Geothermal extraction performance of an HDR was simulated for long-term injection and production operations. Simultaneously, the mode of one-injection and multiple-production wells was represented. In the paper, the effects of the production-injection well spacing, the number of production wells and the injection rate on the production temperature and flow rate are discussed. The results show that, during long-term injection and production, there are two stages of production temperature variation, namely stabilization and attenuation. When the number of the production wells is increased, the heat extraction efficiency is accelerated. Moreover, competitive diversion of fluid among fractures occurred due to different conductivities. Furthermore, under different production modes, the production flow rate contributed differently to the heat extraction. Finally, the effect of the production-injection wells spacing on the heat exchange performance was analyzed; this is mainly reflected in the change of the effective heat exchange area between the rock and the injected fluid. The results emphasize the importance of designing an appropriate production mode and optimizing the injection-production parameters to ensure efficient HDR exploitation.</p></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"3 2","pages":"Article 100113"},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S277323042400012X/pdfft?md5=56093ca29e92b22dc88e7ac131be559a&pid=1-s2.0-S277323042400012X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140138168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment and optimization of fracture-karst cave connectivity in horizontal well hydraulic fracturing of carbonate reservoirs","authors":"Tiankui Guo ,&nbsp;Mingkun Lv ,&nbsp;Pandeng Luo ,&nbsp;Xin Yang ,&nbsp;Ming Chen ,&nbsp;Dingwei Weng ,&nbsp;Zhanqing Qu ,&nbsp;Yiwen Liu","doi":"10.1016/j.rockmb.2024.100112","DOIUrl":"https://doi.org/10.1016/j.rockmb.2024.100112","url":null,"abstract":"<div><p>The karst cave serves as the primary storage space in carbonate reservoirs. Simultaneously connecting multiple karst caves through hydraulic fracturing is key to the efficient development of carbonate reservoirs. However, there is lack of systematic research on the mechanisms and influencing factors of fracture propagation in carbonate rocks. This paper established models including karst cave models, single natural fracture-cave models, and multiple natural fracture-cave models based on the discrete lattice method. It thoroughly studied how geological and operational factors affect the fracture propagation and the connectivity of karst caves. The final step involved establishing a prototype well model and optimizing operation parameters. The research indicates that an increase in the Young's modulus and pore pressure of karst cave could facilitate hydraulic fracture connecting with caves. When the pore pressure is lower than that in the matrix, it will generate a repulsive effect on hydraulic fractures. The natural fracture along the hydraulic fracture path significantly facilitates the connection with caves. When the wellbore azimuth is less than 60°, the fracture's diversion radius is small, and hydraulic fractures primarily connect with karst cave through natural fractures. When the wellbore azimuth exceeds 60°, the fracture's diversion radius increases. Under the combined action of hydraulic fractures and natural fractures, the stimulated volume of the karst cave noticeably increases. Under the same liquid volume, increasing the injection rate could enhance the cave stimulated volume. Combining the findings from numerical simulation studies resulted in the development of a diagram that depicts the connectivity of karst caves, providing valuable insight for hydraulic fracturing operations in carbonate reservoirs.</p></div>","PeriodicalId":101137,"journal":{"name":"Rock Mechanics Bulletin","volume":"3 2","pages":"Article 100112"},"PeriodicalIF":0.0,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2773230424000118/pdfft?md5=74ceb5cea1d1ab2a89dbd88ecefa7a18&pid=1-s2.0-S2773230424000118-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140122998","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}