摘要
目前浅部易开采煤炭资源逐渐枯竭,传统钻进技术在深层煤炭资源勘探开发时往往面临破岩效率低、钻进成本高和环境污染等问题。因此,亟需引入新型辅助钻井破岩技术破解此类难题。聚焦于新型激光辅助破岩技术,以坚硬砂岩为研究对象,系统开展了不同时长激光作用后砂岩的力学、可钻性试验,旨在探究激光作用下坚硬砂岩温度场时空演变特性、砂岩表面裂纹的扩展特征及力学参数和钻进效率。结果表明,随着激光作用时间的增加,砂岩表面裂纹由2条逐渐扩展为5条,裂纹面积由6.78 mm^(2)增加到36.85 mm^(2);温度场的演化特征符合高斯分布规律,由热熔融区向低热区呈环状递减,激光照射15 s后达到热平衡,温度场演化趋于稳定;激光照射50 s后砂岩抗压强度、弹性模量降幅最高分别可达74.6%、92.7%,轴向峰值应变从0.52%不断增加到1.65%,表明岩石经激光作用后呈现由弹性状态向半塑性/塑性状态转变的趋势;激光作用50 s后砂岩进尺速率由0.09 mm/s增加到4.30 mm/s,失重比由2.73%增加到27.36%;合理设置激光参数有助于提高破岩效率与降低钻进成本,在照射20 s时砂岩进尺速率和失重比增幅最大,此时可达到更快更经济的破岩目的;研究初步论证了激光辅助破岩技术的高效性与可行性,为深部高效破岩钻进技术提供理论基础。
Over recent years,shallow coal resources that can be easily mined have been gradually exhausted.As a result,conventional drilling techniques tend to face challenges such as low rock-breaking efficiency,high drilling costs,and environmental pollution in the exploration and exploitation of deep coal resources.Therefore,there is an urgent need to introduce a new auxiliary rock-breaking technique for drilling.Focusing on the new laser-assisted rock-breaking technology,this study systematically conducted mechanical and drillability tests on sandstones after laser irradiation for different durations,aiming to explore the temporal and spatial evolution of the temperature field of hard sandstones,the propagation of cracks on the sandstone surfaces,and the mechanical parameters and drilling efficiency of sandstones under laser irradiation.The results are as follows.(1)With an increase in laser irradiation time,the number of cracks on the sandstone surface gradually increased from two to five,with the cracking area increasing from 6.78 mm^(2) to 36.85 mm^(2).(2)The evolution of the temperature field exhibited the Gaussian distribution,presenting a circular decrement from the hot-melt zone to the low-heat zone.After 15 s of laser irradiation,the thermal equilibrium was reached,with the evolution of the temperature field tending to be stabilized.(3)After 50 s of laser irradiation,the compressive strength and elastic modulus of sandstones decreased by up to 74.6%and 92.7%,respectively,and the axial peak strain increased from 0.52%to 1.65%.These results indicate that sandstones shifted from an elastic state to a semiplastic/plastic state after laser irradiation.(4)After 50 s of laser irradiation,the penetration rate of sandstones increased from 0.09 mm/s to 4.30 mm/s,and the weight loss ratio increased from 2.73%to 27.36%.(5)Appropriately setting laser parameters could improve rock-breaking efficiency and reduce drilling costs.The penetration rate and weight loss ratio of sandstones increased the most after 20 s of laser irrad
作者
杨磊
杨本高
刘军军
周雪敏
谢晶
王晨
郭辰辰
高明忠
YANG Lei;YANG Bengao;LIU Junjun;ZHOU Xuemin;XIE Jing;WANG Chen;GUO Chenchen;GAO Mingzhong(State Key Laboratory of Intelligent Construction and Healthy Operation and Maintenance of Deep Underground Engineering,Sichuan University,Chengdu 610065,China;College of Water Resource&Hydropower,Sichuan University,Chengdu 610065,China;Guangdong Provincial Key Laboratory of Deep Earth Sciences and Geothermal Energy Exploitation and Utilization,Shenzhen University,Shenzhen 518060,China;State Key Laboratory of Coal Mining and Clean Utilization,Beijing 100013,China)
出处
《煤田地质与勘探》
EI
CAS
CSCD
北大核心
2023年第8期171-180,共10页
Coal Geology & Exploration
基金
煤炭资源高效开采与洁净利用国家重点实验室开放基金项目(2021-CMCU-KFZD001)
四川省自然科学基金重大项目(2023NSFSC0004)。
关键词
钻探破岩
砂岩
激光辅助破岩
破岩效率
drilling rock-breaking
sandstone
laser-assisted rock breaking
rock-breaking efficiency
