Fangchao Zhou , Guoying Wang , Housheng Jia , Gan Feng , Lei Wang , Norbert Klitzsch , Chuanliang Yan , Shaowei Liu , Zhazha Hu , Shuai Heng , Yihe Yu , Wen Wang
{"title":"研究了实时高温和循环液氮冷却对花岗岩巴西劈裂试件的影响","authors":"Fangchao Zhou , Guoying Wang , Housheng Jia , Gan Feng , Lei Wang , Norbert Klitzsch , Chuanliang Yan , Shaowei Liu , Zhazha Hu , Shuai Heng , Yihe Yu , Wen Wang","doi":"10.1016/j.engfracmech.2025.111574","DOIUrl":null,"url":null,"abstract":"<div><div>After liquid nitrogen (LN<sub>2</sub>) fracturing stimulates the hot dry rock reservoir, thermal conduction from the surrounding rock gradually restores the fractured reservoir to high temperatures. The mechanical behavior of the reservoir under real-time high temperature conditions following LN<sub>2</sub> cooling cycles significantly influences the development of fracture networks and wellbore stability. Therefore, in this paper, investigating the effects of real-time high temperature and circulating LN<sub>2</sub> cooling on the granite Brazilian splitting test specimens. Results indicate that the real-time high temperature conditions further reduce the bond stress between the minerals, reduces the brittle-ductile transition threshold to 500℃ (600℃ at room temperature). Under the same LN<sub>2</sub> cooling cycles, tensile strength at real-time high temperature was lower than that at room temperature (except at 100℃). Compared with room temperature conditions, the tensile strength at 100℃ increased by 6.91%, while the tensile strength at 200℃, 300℃, 400℃, 500℃ and 600℃ decreased by 7.83%, 10.67%, 29.93%, 25.91% and 4.84%, respectively. In addition, compared with room temperature, the cross-section roughness at 500℃ and 600℃ increased by 7.29% and 14.66%, respectively, and Z<sub>2</sub> increased by 8.87% and 18.79%, respectively, under real-time high temperature conditions, and the acoustic emission signal was more active during the loading process, which indicated that real-time high temperature conditions promoted the initiation and propagation of microcracks. Microstructural analysis suggests that quartz α-β phase transition (573℃) and thermal expansion mismatches are key factors in thermal damage. These findings provide insights into the stability assessment of Enhanced Geothermal System reservoirs.</div></div>","PeriodicalId":11576,"journal":{"name":"Engineering Fracture Mechanics","volume":"328 ","pages":"Article 111574"},"PeriodicalIF":5.3000,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Investigating the effects of real-time high temperature and circulating liquid nitrogen cooling on the granite Brazilian splitting test specimens\",\"authors\":\"Fangchao Zhou , Guoying Wang , Housheng Jia , Gan Feng , Lei Wang , Norbert Klitzsch , Chuanliang Yan , Shaowei Liu , Zhazha Hu , Shuai Heng , Yihe Yu , Wen Wang\",\"doi\":\"10.1016/j.engfracmech.2025.111574\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>After liquid nitrogen (LN<sub>2</sub>) fracturing stimulates the hot dry rock reservoir, thermal conduction from the surrounding rock gradually restores the fractured reservoir to high temperatures. The mechanical behavior of the reservoir under real-time high temperature conditions following LN<sub>2</sub> cooling cycles significantly influences the development of fracture networks and wellbore stability. Therefore, in this paper, investigating the effects of real-time high temperature and circulating LN<sub>2</sub> cooling on the granite Brazilian splitting test specimens. Results indicate that the real-time high temperature conditions further reduce the bond stress between the minerals, reduces the brittle-ductile transition threshold to 500℃ (600℃ at room temperature). Under the same LN<sub>2</sub> cooling cycles, tensile strength at real-time high temperature was lower than that at room temperature (except at 100℃). Compared with room temperature conditions, the tensile strength at 100℃ increased by 6.91%, while the tensile strength at 200℃, 300℃, 400℃, 500℃ and 600℃ decreased by 7.83%, 10.67%, 29.93%, 25.91% and 4.84%, respectively. In addition, compared with room temperature, the cross-section roughness at 500℃ and 600℃ increased by 7.29% and 14.66%, respectively, and Z<sub>2</sub> increased by 8.87% and 18.79%, respectively, under real-time high temperature conditions, and the acoustic emission signal was more active during the loading process, which indicated that real-time high temperature conditions promoted the initiation and propagation of microcracks. Microstructural analysis suggests that quartz α-β phase transition (573℃) and thermal expansion mismatches are key factors in thermal damage. These findings provide insights into the stability assessment of Enhanced Geothermal System reservoirs.</div></div>\",\"PeriodicalId\":11576,\"journal\":{\"name\":\"Engineering Fracture Mechanics\",\"volume\":\"328 \",\"pages\":\"Article 111574\"},\"PeriodicalIF\":5.3000,\"publicationDate\":\"2025-09-24\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Engineering Fracture Mechanics\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0013794425007751\",\"RegionNum\":2,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MECHANICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Engineering Fracture Mechanics","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0013794425007751","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MECHANICS","Score":null,"Total":0}
Investigating the effects of real-time high temperature and circulating liquid nitrogen cooling on the granite Brazilian splitting test specimens
After liquid nitrogen (LN2) fracturing stimulates the hot dry rock reservoir, thermal conduction from the surrounding rock gradually restores the fractured reservoir to high temperatures. The mechanical behavior of the reservoir under real-time high temperature conditions following LN2 cooling cycles significantly influences the development of fracture networks and wellbore stability. Therefore, in this paper, investigating the effects of real-time high temperature and circulating LN2 cooling on the granite Brazilian splitting test specimens. Results indicate that the real-time high temperature conditions further reduce the bond stress between the minerals, reduces the brittle-ductile transition threshold to 500℃ (600℃ at room temperature). Under the same LN2 cooling cycles, tensile strength at real-time high temperature was lower than that at room temperature (except at 100℃). Compared with room temperature conditions, the tensile strength at 100℃ increased by 6.91%, while the tensile strength at 200℃, 300℃, 400℃, 500℃ and 600℃ decreased by 7.83%, 10.67%, 29.93%, 25.91% and 4.84%, respectively. In addition, compared with room temperature, the cross-section roughness at 500℃ and 600℃ increased by 7.29% and 14.66%, respectively, and Z2 increased by 8.87% and 18.79%, respectively, under real-time high temperature conditions, and the acoustic emission signal was more active during the loading process, which indicated that real-time high temperature conditions promoted the initiation and propagation of microcracks. Microstructural analysis suggests that quartz α-β phase transition (573℃) and thermal expansion mismatches are key factors in thermal damage. These findings provide insights into the stability assessment of Enhanced Geothermal System reservoirs.
期刊介绍:
EFM covers a broad range of topics in fracture mechanics to be of interest and use to both researchers and practitioners. Contributions are welcome which address the fracture behavior of conventional engineering material systems as well as newly emerging material systems. Contributions on developments in the areas of mechanics and materials science strongly related to fracture mechanics are also welcome. Papers on fatigue are welcome if they treat the fatigue process using the methods of fracture mechanics.