摘要
为提高钻进效率,合理利用钻进过程中产生的热量,本文采用摩擦热能辅助机械能碎岩(简称:热‑机碎岩)的方法,将氮化硅作为摩擦元件引入孕镶金刚石钻头中,以提高钻头工作层的钻进性能。本文通过对钻头水口、摩擦元件的尺寸计算,钻头胎体、结构的设计,制造了一种新型热-机碎岩孕镶金刚石钻头(简称:热-机碎岩钻头),并与常规六水口钻头和三水口钻头开展了室内钻进试验对比。结果表明,与六水口钻头和三水口钻头相比,热-机碎岩钻头加入摩擦元件后能够因摩擦生热而使岩石产生弱化作用,钻头钻速提高,在相同钻井液流量下最高可比六水口钻头的机械钻速高33.3%。热-机碎岩钻头胎体的磨损程度比三水口钻头小,热‑机碎岩钻头可用于强研磨性地层的钻进。
近年来,随着钻探深度的增加,钻进条件越来越复杂,采用传统的机械碎岩方法已经很难满足深部硬岩钻进的要
摩擦热-机械碎岩技术是借助钻头钻进岩石过程中产生的摩擦热来辅助机械碎岩的一种方法。钻头与岩石产生摩擦导致温度升高,使得大多数岩石的强度明显降低,经过钻井液与岩石表面的热交换作用后,岩石表面会迅速冷却,内部产生极大的热冲击应力,使与钻头接触的岩石强度削弱,钻进速度大幅度提
上述研究的利用摩擦热碎岩的钻头主要是以切削软-中硬地层为主的硬质合金钻头。随着硬质合金钻头在地质钻探中的应用逐渐减少,对热-机碎岩钻头的研究也相应减少。孕镶金刚石钻头是硬岩钻进中最常用的钻
热-机碎岩金刚石钻头在钻进过程中,摩擦元件周期性地对孔底岩石进行摩擦加热,同时钻井液对岩石又有冷却作用。摩擦元件的尺寸、钻井液流经钻头的水口尺寸和数量是决定孔底接触温度的重要参数。为保证摩擦热和冷热交替作用更为显著,有必要对钻头水口和摩擦元件的结构参数进行设计计算。
热-机碎岩钻头钻进孔底岩石过程中会出现周期性的胎体摩擦加热(加热的最高温度为Thot)和钻井液冷却(冷却的最低温度为Tcool),使得岩石表层在热冲击作用下产生裂

图1 岩石裂纹受到热冲击产生向外扩展的拉应力
Fig.1 Rock cracks produce outward expanding tensile stress caused by thermal shock
裂纹的最大拉应力可由
(1) |
式中:β——岩石热膨胀系数,1
拉应力σ的大小取决于岩石本身的热物理参数及受到的加热冷却温度梯度(Thot-Tcool),因此裂纹并不会在钻井液冷却瞬间立刻扩展,力的作用存在一个最小延迟时间。当钻井液作用时间时,岩石仅在拉应力的作用下被拉伸,裂纹未发生扩展;当钻井液作用时间时,裂纹扩展,岩石表层出现弱化现象。取临界值作为钻井液作用时间,其与钻头水口的最小宽度l0有关,可通过计算确定。
若已知钻头直径、钻井液作用时间和钻头转速,可得钻头线速度u:
(2) |
即:
(3) |
式中:D——钻头外径,mm;n——钻头转速,r/min。
已有研究得
由
由
将常规六水口钻头胎体块的其中3块作为摩擦元件胎块,其余3块与它们之间的一个水口形成新的金刚石胎块,与摩擦元件胎块相连,形成三水口钻头(参见

图2 热-机碎岩钻头胎体结构
Fig.2 Matrix structure of the thermo‑mechanical impregnated diamond bit
钻头胎体面积可由
(4) |
式中:m——水口数;b——水口宽度,mm;a——胎体厚度,mm。
钻头胎体中金刚石的浓度为80%(400%浓度制),金刚石的粒径为35/40目。为保证加入摩擦元件前后金刚石受到的压力一致,加入的摩擦元件的面积需要等效于原钻头失去的金刚石的有效面积。80%浓度金刚石占金刚石底唇面面积的20%,则每个胎块上摩擦元件所占面积可由
(5) |
计算可得每个摩擦元件胎块中摩擦元件材料所占面积至少为42.7 m
热‑机碎岩钻头胎体的设计主要包括胎体材料耐磨性、包镶能力,金刚石粒径、浓度,以及摩擦元件材料、尺寸、排布方式的选
通常情况下胎体的硬度越小,胎体与岩石的接触面积越大,摩擦所获得的热量也就越高,并且软胎体也有利于摩擦元件的有效露出。因此,综合考虑坚硬岩石的可钻性和研磨性,同时兼顾胎体与热‑机碎岩相适应的性质,选用的胎体材料为吉林省勘探技术研究所提供的软胎体64号配方,胎体配方成分如
热-机碎岩钻头主要通过摩擦元件与岩石的摩擦生热弱化岩石,因此摩擦元件应耐高温、耐摩擦,并具有较高的抗压强度,以保证孔底所必需的温度。本研究选择氮化硅(Si3N4)作为摩擦元件材
本文设计的热‑机碎岩孕镶金刚石钻头胎体为摩擦元件胎块-水口-金刚石胎块交替的结构。摩擦元件与岩石相互摩擦使岩石表层温度升高,随后钻井液从钻头水口流出,冲刷岩石使之迅速冷却,使岩石内部出现内应力导致裂纹产生,最后由金刚石对经过热冲击弱化的岩石进行破碎。热-机碎岩钻头胎体结构如
本文设计的热-机碎岩钻头的外径为59.5 mm、内径为41.5 mm。胎体工作层高度5 mm。钻头有3个矩形水口,水口宽度5.5 mm、高度8 mm。钻头结构如

图3 钻头结构示意
Fig.3 Structure of the drill bit
设计的热-机碎岩钻头由中频感应热压法制备,其制备工艺流程与常规孕镶金刚石钻头类

图4 烧结制备的钻头
Fig.4 Sintered drill bit
利用常规六水口钻头、热-机碎岩钻头和三水口钻头(与热‑机碎岩钻头结构相同,摩擦元件胎块中不含摩擦元件)对可钻性9级、强研磨性的中粒黑云二长花岗岩进行室内钻进试验,研究不同钻进参数组合下的钻头的钻进效率和磨损情况。岩体体积尺寸为24.5 cm×24.5 cm×48 cm,试验时环境温度为18 ℃。主要试验设备有XY-4型立轴式钻机,PMB-50型泥浆泵。钻进参数
采用KZR90-08V0型无纸记录仪,配套Pt100型防水热电偶,测量并记录钻头与孔底岩石的接触温度。热电偶安装与测试见

图5 热电偶安装与测试
Fig.5 Thermo‑couple installation and testing
孔底接触温度、机械钻速等钻进试验测试结果如

图6 钻进试验测试结果
Fig.6 Drilling test results
从
三水口钻头在10 L/min时钻速较低,其原因是三水口钻头在钻进过程中大部分都是胎体磨损,没有摩擦元件支撑,而且泵量低,导致排粉效果不好,岩屑分布在金刚石区域(从后面图片也可以看出来),影响钻头钻进效率,在泵量达到20 L/min时,达到了钻压、转速、泵量、岩石温度的较好匹配,摩擦热发挥作用,也有足够的钻井液冷却和排粉,因此机械钻速有所上升。

图7 热-机碎岩钻头钻进试验后摩擦元件高度位置
Fig.7 Height position of the friction element of the thermo‑mechanical diamond bit after drilling experiment
六水口钻头、三水口钻头和热-机碎岩钻头胎体唇面磨损和侧面氧化痕迹情况如

图8 钻头胎体唇面磨损和侧面氧化痕迹
Fig.8 Lip surface wear and side oxidation traces
of the drill body
通过对比
向孕镶金刚石钻头中加入摩擦元件,设计制备了一种热-机碎岩钻头,并进行了钻进试验。与常规六水口钻头和三水口钻头相比,得到了以下结论:
(1)与常规六水口钻头和三水口钻头相比,热-机碎岩钻头加入摩擦元件后能够因摩擦生热而弱化岩石,使得钻头钻速提高,在相同钻井液流量下最高可比六水口钻头的机械钻速提高33.3%。
(2)热-机碎岩钻头在钻进试验后胎体磨损程度比三水口钻头小,因此,热-机碎岩钻头可用于强研磨性地层的钻进。
(3)虽然本研究设计的热-机碎岩钻头有了初步的研究成果,但尚未完全解决高温对金刚石、胎体热损伤的影响,因此碎岩效率的提升效果可能受金刚石石墨化、胎体软化等影响有所降低。在未来的研究中,可能会采用高温合金、立方氮化硼等作为热碎岩专用基体和磨料代替传统64号配方与金刚石颗粒,提高热辅助碎岩的钻速提升效果。
参考文献(References)
沈立娜,阮海龙,李春,等.坚硬致密“打滑”地层新型自锐金刚石钻头的研究[J].探矿工程(岩土钻掘工程),2014,41(11):57-59. [百度学术]
SHEN Lina, RUAN Hailong, LI Chun, et al. Study on a new type self‑sharpening diamond bit for drilling in hard‑compact‑slipping formation[J]. Exploration Engineering (Rock & Soil Drilling and Tunneling), 2014,41(11):57-59. [百度学术]
Edoardo Rossi, Shahin Jamali, Volker Wittig, et al. A combined thermo‑mechanical drilling technology for deep geothermal and hard rock reservoirs[J]. Geothermics, 2020,85:101771. [百度学术]
赵秉成,陈晨,房治强,等.非常规碎岩技术的研究进展[J].中国矿业,2010,19(4):87-88,112. [百度学术]
ZHAO Bingcheng, CHEN Chen, FANG Zhiqiang, et al. Research and development of unconventional rock fragmentation[J]. China Mining Magazine, 2010,19(4):87-88,112. [百度学术]
闫铁,杜婕妤,李玮,等.高效破岩前沿钻井技术综述[J].石油矿场机械,2012,41(1):50-55. [百度学术]
YAN Tie, DU Jieyu, LI Wei, et al. Synthesizing comment on efficient rock fragmentation method in frontier drilling technology[J]. Oil Field Equipment, 2012,41(1):50-55. [百度学术]
刘柏禄,潘建忠,谢世勇.岩石破碎方法的研究现状及展望[J].中国钨业,2011,26(1):15-19. [百度学术]
LIU Bailu, PAN Jianzhong, XIE Shiyong. On the research development of rock fragmentation and its prospect[J]. China Tungsten Industry, 2011,26(1):15-19. [百度学术]
金雪萌,黄宇渊,袁钟涛,等.高效破岩新方法研究进展及其应用前景分析[J].石油化工应用,2019,38(5):1-6. [百度学术]
JIN Xuemeng, HUANG Yuyuan, YUAN Zhongtao, et al. Research progress and application prospects of new methods for efficient rock breaking[J]. Petrochemical Industry Application, 2019,38(5):1-6. [百度学术]
Edoardo Rossi, Michael A. Kant, Claudio Madonna, et al. The effects of high heating rate and high temperature on the rock strength: feasibility study of a thermally assisted drilling method[J]. Rock Mechanics and Rock Engineering, 2018,51(9):2957-2964. [百度学术]
张辉,蔡志翔,姜敞,等.深部岩石高效破碎方法研究[J].西部探矿工程,2018,30(9):75-79. [百度学术]
ZHANG Hui, CAI Zhixiang, JIANG Chang, et al. Research on high efficient fragmentation method of deep rock[J]. West‑China Exploration Engineering, 2018,30(9):75-79. [百度学术]
Edoardo Rossi, Shahin Jamali, Dennis Schwarz, et al. Field test of a combined thermo‑mechanical drilling technology. mode Ⅱ: flame‑assisted rotary drilling[J]. Journal of Petroleum Science and Engineering,2020,190:106880. [百度学术]
张祖培,张书刚.热能-机械碎岩机理及其应用[J].探矿工程,1997(3):22-24. [百度学术]
ZHANG Zupei, ZHANG Shugang. Thermo‑mechanical rock fragmentation mechanism and its applications[J]. Exploration Engineering, 1997(3):22-24. [百度学术]
徐金鉴,姚天骄,王子祥,等.热机碎岩技术研究[J].资源信息与工程,2017,32(5):108-110. [百度学术]
XU Jinjian, YAO Tianjiao, WANG Zixiang, et al. Research on thermo‑mechanical drilling technology[J]. Resource Information and Engineering, 2017,32(5):108-110. [百度学术]
赵建康,孙友宏,张祖培.摩擦热‑机械碎岩钻进技术试验研究[J].探矿工程(岩土钻掘工程),2004,31(12):36-39. [百度学术]
ZHAO Jiankang, SUN Youhong, ZHANG Zupei. Study on drilling technology of thermo‑mechanical rock fragmentation[J]. Exploration Engineering (Rock & Soil Drilling and Tunneling), 2004,31(12):36-39. [百度学术]
高科,张祖培,孙友宏,等.热机碎岩钻头摩擦元件材料研究[J].矿冶工程,2005(2):85-87. [百度学术]
GAO Ke, ZHANG Zupei, SUN Youhong, et al. Researches on friction element of thermal‑mechanical bit[J]. Mining and Metallurgical Engineering, 2005(2):85-87. [百度学术]
吴金刚,谭忠盛,吴景华.规划求解法研究热机碎岩胎体配方[J].北京交通大学学报,2006(1):63-65,70. [百度学术]
WU Jingang, TAN Zhongsheng, WU Jinghua. Research on aspect of matrix in the thermo‑mechanical drilling by programming design[J]. Journal of Beijing Jiaotong University, 2006(1):63-65,70. [百度学术]
赵建康,孙友宏,张祖培.热机碎岩钻进工艺中钻进规程参数的理论分析[J].地质与勘探,2001(2):94-96. [百度学术]
ZHAO Jiankang, SUN Youhong, ZHANG Zupei. Studying on thermo‑mechanical drilling regime parameters[J]. Geology and Prospecting, 2001(2):94-96. [百度学术]
吴景华,孙友宏,李军.热机碎岩钻进工艺的试验研究[J].探矿工程(岩土钻掘工程),2008,35(1):9-11. [百度学术]
WU Jinghua, SUN Youhong, LI Jun. Testing study of thermo‑chemical drilling technology[J]. Exploration Engineering (Rock & Soil Drilling and Tunneling), 2008,35(1):9-11. [百度学术]
吴景华,孙友宏.热机碎岩钻具设计与工程试验研究[J].长春工程学院学报(自然科学版),2011,12(4):32-34. [百度学术]
WU Jinghua, SUN Youhong. Drill string design and engineering test research of thermo‑mechanical rock fragmentation[J]. Journal of Changchun Institute of Technology (Natural Sciences Edition), 2011,12(4):32-34. [百度学术]
汤凤林,沈中华,段隆臣,等.关于金刚石钻头底出刃锐化处理的试验研究[J].探矿工程(岩土钻掘工程),2017,44(9):58-64. [百度学术]
TANG Fenglin, SHEN Zhonghua, DUAN Longchen, et al. Experimental research on sharpening face exposure of diamond drill bit[J]. Exploration Engineering (Rock & Soil Drilling and Tunneling), 2017,44(9):58-64. [百度学术]
刘晓阳.孕镶金刚石-针状合金复合式取心钻头的应用研究[J].探矿工程(岩土钻掘工程),2009,36(S1):377-381. [百度学术]
LIU Xiaoyang. Research on the application of impregnated diamond‑needle alloy composite core bit[J]. Exploration Engineering (Rock & Soil Drilling and Tunneling), 2009,36(S1):377-381. [百度学术]
李成龙,赵江,段隆臣.CaF2/hBN自润滑Fe基孕镶金刚石钻头性能研究[J].探矿工程(岩土钻掘工程),2018,45(11):78-82. [百度学术]
LI Chenglong, ZHAO Jiang, DUAN Longchen. Study on the properties of Fe‑based impregnated diamond bits with CaF2/hBN self‑lubricating additives[J]. Exploration Engineering (Rock & Soil Drilling and Tunneling), 2018,45(11):78-82. [百度学术]
刘宝昌,曹鑫,计胜利,等.孔底流场和温度场数值模拟与试验研究——以取心孕镶金刚石钻头为例[J].金刚石与磨料磨具工程,2018,38(5):33-38. [百度学术]
LIU Baochang, CAO Xin, JI Shengli, et al. Simulation and experimental research on flow field and temperature field of diamond impregnated drill bit[J]. Diamond & Abrasives Engineering, 2018,38(5):33-38. [百度学术]
钱磊,王晓川,康勇,等.岩石取芯切削钻进过程温度分析与试验研究[J].中南大学学报(自然科学版),2020,51(5):1402-1409. [百度学术]
QIAN Lei, WANG Xiaochuan, KANG Yong, et al. Temperature analysis and experimental study of core drill cutting and drilling process[J]. Journal of Central South University (Science and Technology), 2020,51(5):1402-1409. [百度学术]
王殿江,袁公昱.孕镶金刚石钻头工作温升的实验研究[J].探矿工程,1991(6):1-3. [百度学术]
WANG Dianjiang, YUAN Gongyu. An experimental research on the working temperature rising for impregnated diamond bit[J]. Exploration Engineering, 1991(6):1-3. [百度学术]
罗江.温度应力诱发的岩石裂纹扩展研究[D].大连:大连理工大学,2018. [百度学术]
LUO Jiang. Study on rock crack propagation induced by temperature stress[D]. Dalian: Dalian University of Technology, 2018. [百度学术]
熊继有,钱声华,孙文涛,等.石油工程中岩石裂纹扩展与破坏机理研究[J].地下空间,2002(2):157-160,189. [百度学术]
XIONG Jiyou, QIAN Shenghua, SUN Wentao, et al. Research on the mechanism of rock crack propagation and failure in petroleum engineering[J]. Underground Space, 2002(2):157-160,189. [百度学术]
蔡双有.大体积混凝土裂缝控制技术在工程中的应用研究[J].科技经济导刊,2021,29(23):76-77. [百度学术]
CAI Shuangyou. Research on application of crack control technology for mass concrete in engineering[J]. Technology and Economic Guide, 2021,29(23):76-77. [百度学术]
韩哲.摩擦热能辅助碎岩孕镶金刚石钻头研究[D].长春:吉林大学,2020. [百度学术]
HAN Zhe. Research on impregnated diamond drill bit with friction thermal energy generating elements[D]. Changchun: Jilin University, 2020. [百度学术]
寇绍全,O.Alm.微裂隙和花岗岩的抗拉强度[J].力学学报,1987(4):366-373. [百度学术]
KOU Shaoquan, O. Alm. Microcracks and the tensile strength of granite[J]. Chinese Journal of Theoretical and Applied Mechanics, 1987(4):366-373. [百度学术]
朱振南,田红,董楠楠,等.高温花岗岩遇水冷却后物理力学特性试验研究[J].岩土力学,2018,39(S2):169-176. [百度学术]
ZHU Zhennan, TIAN Hong, DONG Nannan, et al. Experimental study of physico‑mechanical properties of heat‑treated granite by water cooling[J]. Rock and Soil Mechanics, 2018,39(S2):169-176. [百度学术]
蒋青光,张绍和.深部岩芯钻探孕镶金刚石钻头参数设计机理探讨[J].西部探矿工程,2012,24(12):58-62. [百度学术]
JIANG Qingguang, ZHANG Shaohe. Discussion on the parameter design mechanism of impregnated diamond bit for deep core drilling[J]. West‑China Exploration Engineering, 2012,24(12):58-62. [百度学术]
高玉彬,陈洋.钻进坚硬致密岩层的金刚石钻头试验研究[J].超硬材料工程,2021,33(3):1-6. [百度学术]
GAO Yubin, CHEN Yang. Experimental study of diamond bit for drilling hard and compact rock[J]. Superhard Material Engineering, 2021,33(3):1-6. [百度学术]
孙亚光,贺胜利,刘荣安,等.氮化硅陶瓷的制备与应用[J].中国陶瓷工业,2016,23(5):31-34. [百度学术]
SUN Yaguang, HE Shengli, LIU Rongan, et al. Preparation and application of silicon nitride ceramics[J]. China Ceramic Industry, 2016,23(5):31-34. [百度学术]
王磊,陈佰辉,汪洪民,等.青海野马泉矿区钻头水口改进的研究[J].探矿工程(岩土钻掘工程),2013,40(9):47-51. [百度学术]
WANG Lei, CHEN Baihui, WANG Hongmin, et al. Study on the improvement of bit water outlets in Yemaquan mine of Qinghai[J]. Exploration Engineering (Rock & Soil Drilling and Tunneling), 2013,40(9):47-51. [百度学术]
汤凤林,彭莉,Чихоткин В. Ф.,等.关于提高金刚石钻头胎体耐磨性的试验研究[J].探矿工程(岩土钻掘工程),2016,43(1):7-13. [百度学术]
TANG Fenglin, PENG Li, CHIKHOTKIN V. F., et al. Experimental research on matrix wear resistance (matrix hardness) of impregnated diamond bit[J]. Exploration Engineering (Rock & Soil Drilling and Tunneling), 2016,43(1):7-13. [百度学术]
汤凤林,Нескоромных В. В.,宁伏龙,等.金刚石钻进岩石破碎过程及其与规程参数关系的研究[J].钻探工程,2021,48(10):43-55. [百度学术]
TANG Fenglin, NESKOROMNYH V. V., NING Fulong, et al. Research on the rock fragmentation process and its relationship with drilling parameters in diamond drilling[J]. Drilling Engineering, 2021,48(10):43-55. [百度学术]
汤凤林,Чихоткин В. Ф.,段隆臣,等.机械钻速与金刚石底出刃、钻进规程参数关系的试验研究[J].探矿工程(岩土钻掘工程),2019,46(12):73-79. [百度学术]
TANG Fenglin, CHIKHOTKIN V. F., DUAN Longchen, et al. Experimental research on dependence of penetration rate on diamond exposure at bit face and drilling parameters[J]. Exploration Engineering (Rock & Soil Drilling and Tunneling), 2019,46(12):73-79. [百度学术]
汤凤林,Чихоткин В. Ф.,高申友,等.关于金刚石钻进规程参数合理配合的分析研究[J].探矿工程(岩土钻掘工程),2015,42 (10):76-80. [百度学术]
TANG Fenglin, CHIKHOTKIN V. F., GAO Shenyou, et al. Analytical research on rational combination of dilling parameters in diamond dilling engineering[J]. Exploration Engineering (Rock & Soil Drilling and Tunneling), 2015,42(10):76-80. [百度学术]