Critical Investigation of Wear Behaviour of WC Drill Bit Buttons

Mining and petroleum drill bits are subjected to highly abrasive rock and high-velocity fluids that cause severe wear and erosion in service. To augment the rate of penetration and minimize the cost per foot, such drill bits are subjected to increasing rotary speeds and weight. A rotary/percussive drill typically hits the rock 50 times per second with hydraulic impact pressure of about 170–200 bar and feed pressure of about 90–100 bar, while rotating at 75–200 rpm. The drill rig delivers a high-velocity flow of drilling fluid onto the rock surface to dislodge cuttings and cool the bit. The impingement of high-velocity drilling fluid with entrained cuttings accelerates the erosion rate of the bit. Also, high service temperature contributes to softening of the rock for increased penetration. Hence, there is a need to optimize the drilling process and balance the wear rate and penetration rate simultaneously. This paper presents an experimental scanning electron microscopy (SEM) study of electroplated (nickel-bonded) diamond drills for different wear modes.     

基于单柱齿破岩过程的高压液动冲击回转钻进试验研究

针对煤矿井下穿层钻孔硬岩钻进效率低的难题,基于冲击回转钻进机理和Wassara高压液动冲击器主要特点,分析柱齿在冲击荷载下形成的破碎坑形态,并将其划分为崩解区、密实区、开裂区和弹性区。在此基础之上,对柱齿连续破岩的大间隔冲击和小间隔冲击2种情况进行过程分析,结合淮南潘三矿现场试验条件讨论高压液动冲击回转钻进工艺参数,优选高压液动冲击回转钻进配套钻机、冲击器、钻杆、钻头和清水泵,及主要技术参数。试验结果表明：当清水压力在15 MPa以上时,高压液动冲击回转钻进的平均机械钻速为24.67 m/h,与采用该技术之前的8.48 m/h机械钻速相比提高了约1.9倍;并采用回归分析拟合得到机械钻速与水压之间的线性关系,经过数理统计的F检验,F=8.82大于F_0.05(1,7),验证了回归结果是显著的,机械钻速随水压的增大而线性增大。高压液动冲击回转钻进技术可有效提高煤矿井下硬岩层钻进效率,保障煤矿安全高效生产。     

岩层联络孔冲剪复合碎岩原理可行性研究

“以孔代巷”是煤矿井下钻探技术研究的重要方向,具有效率高、成本低等优点,但在岩层中施工大直径联络孔时,采用多级扩孔方式,存在提下钻等辅助时间长,成孔效率低的问题。在不改变钻探装备配置基础上,通过结构和工艺创新,提出冲击和剪切复合碎岩原理,即将高压水-冲击器-内钎头冲击碎岩和钻机-钻杆柱-外切PDC钻头剪切碎岩创造性地结合在一起,以冲击功预裂地层,破坏岩层的整体构造应力,同时钻机驱动外切PDC钻头对预裂后的外侧岩石进行剪切破碎,由此实现“小马拉大车”的应用效果。研制了?153 mm冲剪复合钻头,采用ZDY3200S分体式小型钻机在硬质砂岩地层中进行试验,平均机械钻速8.3 m/h,最大机械钻速可达10 m/h,且转速和钻压对机械钻速影响较小,结果证明冲剪复合碎岩原理具有可行性,为煤矿井下岩层联络孔优快成孔提供了新的研究思路。      

Comparison of Drilling Performance of Chisel and Button Bits on the Electro Hydraulic Driller

Electro hydraulic drillers have been widely used in mining for drilling and roof-bolting. In the drilling process, the performance of the machine is predicted by selecting an appropriate bit type prior to drilling operations. In this paper, a series of field drilling studies were conducted in order to examine and compare the performance of chisel and button bits including wear on the bits. The effects of taper angle on chisel bits, which are at angles of 105°, 110° and 120°, were investigated in terms of rate of penetration, instantaneous drilling rate and specific energy. The results of drilling and abrasivity tests performed in the laboratory supported the outcome of the field studies. Based on laboratory studies and field observations, it was proven that the conglomerate encountered, though it is very abrasive, is easy to drill. The cutter life in the encountered series is also longer in sandstone formation compared to the conglomerate. Additionally, button bits resulted in lower specific energy and higher penetration rates relative to chisel bits, regardless of their taper angles. The results were also supported with statistical analyses.     

Blast Design Using Measurement While Drilling Parameters

Measurement while drilling (MWD) techniques can provide a useful tool to aid drill and blast engineers in open cut mining. By avoiding time consuming tasks such as scan-lines and rock sample collection for laboratory tests, MWD techniques can not only save time but also improve the reliability of the blast design by providing the drill and blast engineer with the information specially tailored for use. While most mines use a standard blast pattern and charge per blasthole, based on a single rock factor for the entire bench or blast region, information derived from the MWD parameters can improve the blast design by providing more accurate rock properties for each individual blasthole. From this, decisions can be made on the most appropriate type and amount of explosive charge to place in a per blasthole or to optimise the inter-hole timing detonation time of different decks and blastholes. Where real-time calculations are feasible, the system could extend the present blast design even be used to determine the placement of subsequent holes towards a more appropriate blasthole pattern design like asymmetrical blasting.     

煤矿井下可退式卡瓦打捞筒的研制及应用

煤矿井下卡钻、埋钻导致的孔内断钻杆事故时常发生,目前常用的公母丝锥造扣的打捞方法成功率较低,不仅耗费大量的人力物力,还会影响煤矿开采生产进度。基于此,设计了井下可退式卡瓦打捞筒,通过外筒的螺旋锥面驱动卡瓦径向卡紧断裂的钻杆,实现起拔打捞井内钻杆。卡瓦抱紧钻杆的结构设计,提高了打捞筒对断裂钻具的把持力。控制环的键槽结构设计,实现了复杂工况下可退式操作。分析了打捞作业时钻机回转扭矩产生的切应力与打捞筒强度的关系、钻机起拔力产生的正应力与打捞筒强度的关系,为打捞筒壁厚参数设计提供理论支持;分析了钻机起拔力转换为卡瓦对钻杆抱紧力的公式,验证了卡瓦打捞筒打捞孔内钻具的可行性;试制的打捞筒在山西新源煤矿井下现场进行了打捞试验,试验表明其结构设计合理,打捞性能可靠。本研究为煤矿井下处理复杂钻孔断钻事故提供新型工具,为打捞工具结构设计提供了理论依据。      

大切削具钻头回转钻进的分析

根据刃具斜切入破岩的一些试验研究成果，分析了大切削量钻头的钻进过程，推导出了大切削量钻头进行回转钻进的机械钻速公式。     

ZYXC-244机械式旋冲螺杆钻具的研制与应用

针对现有常规螺杆钻具在研磨性强、可钻性差的难钻地层中存在破岩能量不足、机械钻速低、钻头消耗量大的问题,引入旋冲钻井破岩理念及轴向机械冲击破岩功能,研制了集合旁通阀总成、动力总成、传动总成和冲击总成于一体的ZYXC-244机械式旋冲螺杆（新型螺杆）,并创新设计了防掉功能。通过对新型螺杆主要性能参数计算模型的分析,获取了其主要性能参数的特征变化曲线。新型螺杆先后在足203H1-3井和大湾4011-2井的须家河组等地层进行了现场应用,应用效果表明,新型螺杆进尺分别为685.00 m和72.53 m时与常规螺杆相比,机械钻速分别提高了38.2%和31.5%,节省了起下钻2次和2只钻头消耗,为难钻地层的提速提效提供了有效的技术手段。     

煤矿井下碎软煤层泡沫钻进技术及应用

针对煤矿井下碎软煤层瓦斯抽采中风压空气钻进施工中排粉能力有限，易造成粉尘污染问题，提出采用煤矿井下泡沫灌注系统及宽翼螺旋钻杆进行高效泡沫钻进的技术方案。通过对钻孔环空间隙流场的数值模拟，研究宽翼螺旋钻杆结构对泡沫钻进高效排粉的影响，确定头数3、槽宽26 mm、螺距110 mm为宽翼螺旋钻杆的优化结构参数。在淮北某矿3204工作面碎软煤层中进行了深度达195 m的本煤层钻孔试验，结果表明，相对于中风压空气钻进工艺，钻进回转阻力降低了42%~48%，表现出高效的排粉效果，可提高煤矿井下碎软煤层钻孔深度和成孔率。该工艺可为类似煤矿井下深钻孔施工提供借鉴。      

煤层顶板大直径定向钻孔用双级双速PDC钻头设计及应用

大直径定向钻进成孔技术的发展, 为“以孔代巷”技术抽采采空区上隅角瓦斯提供了技术支持。受限于井下设备条件, 常规大直径钻孔主要采用逐级扩孔工艺。然而, 逐级扩孔钻进需要多次提钻、下钻, 辅助时间长、工人劳动强度大。为提高煤层顶板大直径钻孔成孔效率, 开发了双级双速钻进工艺, 该工艺采用螺杆马达与钻机分别驱动一级、二级钻头进行单次双级扩孔钻进, 可大大提高成孔效率。通过分析双级双速钻进工艺特点、拟钻地层岩性等, 从剖面形状、切削齿排布、水路设计以及导向器设计等方面设计了双级双速钻头, 该钻头采用球头螺旋形导向器, 更容易沿既有钻孔轨迹钻进; 采用等切削布齿, 提高破岩效率、降低切削齿不均匀磨损, 进而提高钻头寿命与钻进效率。设计的双级双速钻头进行了现场试验, 试验表明双级双速钻头能够沿先导孔钻进, 较常规逐级扩孔钻头综合效率提高25%以上, 使用后钻头磨损均匀, 满足了双级双速工艺要求, 大大提高了煤层顶板大直径钻孔施工效率。      

硬岩PDC定向钻头优化设计及其表面增材技术研究

定向长钻孔是煤矿瓦斯、水害治理的主要技术手段,PDC定向钻头性能是影响坚硬地层钻进效率的重要因素。针对煤层顶底板岩层定向长钻孔施工中出现因PDC钻头体断翼、PDC崩齿等问题导致的频繁起下钻、施工效率低等现象,采用等切削布齿原则对刀翼布齿进行优化,有效降低切削齿冲击破坏;通过流体力学仿真分析,优化钻头水力参数,保证岩屑及时排出孔底,防止切削齿因重复破碎岩石导致过早损坏;通过仿真分析,优选大直径PDC异型齿,提高切削齿耐磨和抗冲击性能;引入表面增材制造技术,通过优化等离子(PTA)增材制造工艺参数,实现了兼具胎体耐磨耐冲蚀和钢体强韧性的WC基复合钻头体加工工艺。新研制的PDC定向钻头,在淮南顾桥煤矿北区底板探放水钻孔中进行了现场试验。结果表明：钻进致密、坚硬灰岩地层时,2只钻头寿命分别达到827、810 m,相对于以前的?120 mm胎体式定向钻头平均寿命300 m有较大幅度的提高,并降低了上下钻等辅助作业时间,提高了施工效率,达到了硬岩定向长钻孔提速增效的目标,为硬岩定向长钻孔用PDC钻头设计和制造工艺开发提供了新的解决方案。     

ZDY25000LDK智能化定向钻进装备关键技术研究

利用顺煤层、顶板高位钻孔抽采煤层气是当前煤矿井下煤层气综合治理最直接、有效的方法。提高定向钻孔钻进速度和起伏变化大、薄厚不均煤层中的钻遇率,降低施工人员劳动强度,提高钻孔事故预防能力,适应煤矿智能化发展需求,满足煤矿井下长距离定向钻孔施工的智能化钻进装备是当前煤矿井下钻探领域亟待解决的重要问题。基于地质导向和旋转导向钻进施工对钻机精确控制的实际需求,以及煤矿智能化发展的迫切需要,提出了基于防爆电液控制技术的煤矿井下长距离定向钻进装备自动化控制和分体紧凑布局设计的集成化解决方案。重点解决总体紧凑布局设计、关键执行部件设计、自动装卸钻杆技术、防爆电液控制技术、大流量泥浆泵单元设计等设计和技术。研制的ZDY25000LDK智能化定向钻进装备,实现了长距离定向钻进施工过程中自动化装卸钻杆控制、智能化定向钻进施工、参数实时监测以及典型故障智能诊断与预警等功能,使定向钻进装备的智能化水平得到全面提升,为旋转导向和地质导向施工,以及“以孔代巷”大直径定向钻孔高效施工提供了可靠装备保障。      

煤矿井下钻探装备技术现状及展望

煤矿井下钻探装备对保障矿井安全高效生产起着至关重要的作用,经过四十多年的发展,其技术水平得到很大的提高。结合产品特点、技术类型和应用领域,总体介绍了国内外煤矿井下钻探装备的技术现状,分析了国外钻机的应用效果和存在问题,重点对国内钻机开发的历程和现状进行概述,详细论述了分体钻机、履带式钻机、电液控制钻机、胶轮自行式钻机和定向钻机5个具有代表性机型的技术现状,对产品开发思路和相关应用情况也做了必要阐述,最后分析了煤矿井下钻探装备的信息化、自动化和智能化的发展趋势。      

煤矿用自动化钻机远程监测系统研制

根据国家能源装备制造、煤矿机器人和煤矿智能化发展等政策要求,结合煤炭设备少人化、智能化发展趋势,针对现有煤矿井下钻机参数显示不全、缺乏有效监测、维修不便等问题,为实现自动化钻机地面远程监测,利用传感测量、软件开发、虚拟现实、网络通信、视频监测等技术研制了一种煤矿用自动化钻机远程监测系统。该远程监测系统包括了钻机主体、机载设备、网络通信部分和远程监测服务器。钻机主体为ZDY4500LFK型煤矿用钻机;机载设备包括了控制器和传感器组,用于实现钻机参数采集;网络通信部分包括了交换机、网关等,实现井下和地面的通信;远程监测服务器实现钻机参数和工况的监测。该系统研制后在鄂尔多斯华兴能源有限责任公司唐家会煤矿进行了现场试验,结果显示,该系统数据传输准确,可实现自动化钻机的地面监测功能,为煤矿钻机的少人化、智能化提供了保障。      

煤矿井下定向钻进配套钻头的选型与使用

合理选配和使用钻头是提高钻进效率和节省钻进成本的关键。结合煤矿井下定向钻孔施工的特点,提出了配套钻头的一般要求。介绍了目前常用钻头的类型和特点,重点介绍了3种不同冠部形状的导向钻头的适用性及选型依据。总结了钻头合理使用的注意事项,为煤矿井下定向钻孔施工合理选择和使用钻头提供了参考依据。      

基于钻进能量理论的隧道凝灰岩地层界面识别及围岩分级方法

钻机钻进过程中钻头旋转产生的扭矩以及作用于钻头的轴推进力是破碎岩石的能量来源,当钻进条件确定时,可用破碎单位体积岩石的实际能耗来反映岩石的物理力学性质。基于此原理在青岛胶州湾海底隧道FK4+375.5的上断面进行了超前地质探孔作业,得到凝灰岩地层中的钻进参数及钻进能量随钻头位移的变化曲线,并利用能量理论对钻进过程中监测的钻机参数进行分析,研究发现：在凝灰岩中,数字钻机参数与围岩岩性响应程度较高,围岩完整、坚硬、无裂隙水时,整体钻进参数值较高;围岩裂隙发育、含水或有断层、夹泥层时,钻进速度、推进力、转速、扭矩、打击能等数据会突变,其值变小。分析所得结果与钻孔取芯、TSP超前预报等物探手段得到的结果基本一致。并采用能量法对围岩进行分析,利用钻进比能划分相应的岩体区段,判断出围岩等级。通过对能量曲线的分析发现,在凝灰岩地层中,当钻进能量小于0.95 kJ时会出现断层或较大的节理裂隙区。     

孕镶金刚石钻头磨损机理研究

孕镶金刚石钻头通过钻头胎体的持续磨损实现金刚石的自锐和高效破岩。因此,研究金刚石钻头磨损的影响因素及其影响程度和影响机理,对孕镶金刚石钻头的设计和使用非常重要。本次研究探讨了岩石物理力学性质、钻头胎体性能和钻进工艺参数等因素对孕镶金刚石钻头磨损过程和磨损机理的影响。分析表明,对钻头磨损最为显著的影响因素是岩石中的硬质颗粒导致的磨粒磨损,其次是钻头胎体与岩粉之间的粘着磨损,以及冲洗液中岩粉颗粒导致的冲蚀磨损。在此基础上,以不同硬度的钻头胎体摩擦磨损试验结果为例,探讨了钻头胎体性能及其内部硬质点对钻头磨损的影响机理。该研究成果可为科学设计与合理使用孕镶金刚石钻头提供依据。     

Laboratory investigations on rotary diamond drilling

Extensive laboratory drilling investigations were conducted on a wide variety of rocks to study the inter-dependence of machine as well as rock parameters on the performance of the drilling operation. Detailed physical and mechanical properties of all the rock types were determined to study the influence of the rock properties on the drilling performance. The effect of PEO (poly-ethylene-oxide) added to the drilling water was also studied. Slake durability tests were conducted in plain water as well as a PEO mixed water medium to observe the effects of PEO on the surface properties of the rock. An attempt is also made to understand the different modes of wear of impregnated diamond bits in the rotary drilling operation.     

井下定向钻进用小直径通缆水力振荡器的研制

针对煤矿井下定向钻进过程中由于托压效应引起的钻进摩阻大、钻进效率低、钻孔深度受限等问题，提出通过钻柱振动减阻的技术思路。采用理论分析和数值模拟进行激振力、激振频率等关键技术参数的设计，研制ø89 mm小直径通缆水力振荡器。在室内测试碟簧和圆柱弹簧两种辅助复位原件结构的振荡器性能，并在淮南张集煤矿井下进行实钻试验。结果表明:碟簧式水力振荡器在300 L/min流量时，最大压降1.9 MPa、激振力8.11 kN、频率13 Hz，适合安装在近钻头位置辅助减阻；圆柱弹簧式水力振荡器频率在300 L/min流量时，模拟测试150 m通缆定向管柱最大变形量2.86 mm，最大复位力7.98 kN，频率11 Hz，适合安装在钻柱中间主要减阻；在张集矿井下-600 m疏水巷10号孔定向钻进产生明显托压时使用圆柱弹簧式水力振荡器，使平均钻压降低33%，钻效提高126%，显著降低钻进摩阻，提高定向钻进效率。研制的ø89 mm小直径通缆水力振荡器为煤矿水平定向钻进中托压问题提供一种新的解决方法。      

Sound level produced during rock drilling vis-à-vis rock properties

The process of drilling, in general, always produces sound. Though sound is used as a diagnostic tool in mechanical industry, its application in predicting rock property is not much explored. In this study, an attempt has been made to estimate rock properties such as uniaxial compressive strength, Schmidt rebound number and Young's modulus using sound level produced during rotary drilling. For this purpose, a computer numerical controlled vertical milling centre was used for drilling holes with drill bit diameters ranging from 6 to 20 mm with a shank length of 40 mm. Fourteen different rock types were tested. The study was carried out to develop the empirical relations using multiple regression analysis between sound level produced during drilling and rock properties considering the effects of drill bit diameter, drill bit speed and drill bit penetration rate. The F-test was used to check the validity of the developed models. The measured rock property values and the values calculated from the developed regression model are fairly close, indicating that the developed models could be efficiently used with acceptable accuracy in prediction of rock properties.