摘要
地热井井筒围岩裂纹类型对地热钻井及地热开采至关重要,冲击钻进时会在井筒周围产生大量的冲击裂纹,不仅减少了地热钻井过程中划眼时间、还增加了射孔深度、又促进了干热岩储层的水力增产。文章通过对冲击钻进后的花岗岩进行染色剂染色实验,来探究井筒周围裂纹的分布情况。实验结果表明,冲击钻进后花岗岩井筒周围存在着大量区域化分布的冲击裂纹,相比于常规回转钻进,冲击钻进对井筒周围岩体的破坏距离约为金刚石回转钻进的5~7倍。通过数值模拟对井筒周围的冲击应力、应变分布进行了研究,数值模拟结果表明,冲击应力、应变分布与实验中裂纹分布基本一致,为地热开发中划眼、射孔、水力压裂等钻井的后续工作提供了重要的参考。
Distribution of cracks around geothermal wellbore is extremely important to geothermal drilling and production,because percussive drilling makes a large amount of cracks around the wall of a wellbore,and this helps to save reaming time,extend perforation range and increase hydraulic-fracturing-sustained productivity of Enhanced Geothermal Systems(EGS)during geothermal well drilling.Cracks distributing disciplinarian of granite drilled by percussion method was studied and discussed by means of dyeing experiment.According to the results,it was showed that,a large number of cracks will be produced regionally around the wall of granite wellbore after percussive drilling.Compared with conventional rotary drilling,the length of cracks created by percussive drilling was 5~7 times as by diamond rotary drilling.As well,the impact stress and strain were studied by the way of numerical simulation.It showed a satisfying consistence between dyeing experiment and numerical simulation.And these consistent results can provide theoretical support for reaming,perforating,hydraulic fracturing and other drilling subsequent works of geothermal resource exploration and development.
作者
孙永兴
范黎明
SUN Yongxing;FAN Liming(College of Tourism and Geographical Science,Leshan Normal University,Leshan Sichuan 614000,China)
出处
《乐山师范学院学报》
2022年第8期59-63,共5页
Journal of Leshan Normal University
基金
四川省科技创新人才项目“环保智能钻井实时优化导航系统研究”(2020JDRC0063)
四川省社会科学研究“十三五”规划2020年度课题“四川红层丹霞地貌形成机理及其旅游资源HSE管理研究”(SC20EZD015)
乐山师范学院科研项目“环保智能化钻井提速系统研究”(XJR19007)。
关键词
花岗岩裂纹
冲击钻进
地热能
干热岩
染色试验
Granite Cracks
Percussive Drilling
Geothermal
EGS
Dyeing Experiment
