Drilling-based measuring method for the c-φ parameter of rock and its field application

The technology of drilling tests makes it possible to obtain the strength parameter of rock accurately in situ. In this paper, a new rock cutting analysis model that considers the influence of the rock crushing zone(RCZ) is built. The formula for an ultimate cutting force is established based on the limit equilibrium principle. The relationship between digital drilling parameters(DDP) and the c-φ parameter(DDP-cφ formula, where c refers to the cohesion and φ refers to the internal friction angle) is derived, and the response of drilling parameters and cutting ratio to the strength parameters is analyzed. The drillingbased measuring method for the c-φ parameter of rock is constructed. The laboratory verification test is then completed, and the difference in results between the drilling test and the compression test is less than 6%. On this basis, in-situ rock drilling tests in a traffic tunnel and a coal mine roadway are carried out, and the strength parameters of the surrounding rock are effectively tested. The average difference ratio of the results is less than 11%, which verifies the effectiveness of the proposed method for obtaining the strength parameters based on digital drilling. This study provides methodological support for field testing of rock strength parameters.

Rock fracture density characterization using measurement while drilling(MWD) techniques

Accurate determination of rock mass properties is a critical part of open-pit mine planning activities to enable more prescriptive blast designs to achieve improved loading and hauling and downstream process efficiency. Better and more accurate blast practice that delivers enhanced outcomes(better fragmentation, improved diggability, less dilution, etc.) is a critical and fundamental element of being able to achieve an effective Mine-Mill approach at a mining operation. Based on previous work, it has been demonstrated that an accurate representation of the rock mass properties can be obtained from the analysis of variations in blasthole drill performance as derived from measurement while drilling(MWD) systems when using tricone bits. This paper further investigates how monitored rate of penetration,pulldown force, rotary torque, rotary speed and bailing air pressure responses can be used to determine the presence of open and partially open fractures having varying dip angles. Based on a correlation of geophysically measured fracture logs and monitored drill performance variables in the same blastholes, the results show that the latter responses can accurately determine open versus closed fractures. The results also identified that variations in rate of penetration and rotary torque show the most sensitivity in the presence of open fractures that intersect a vertical blasthole at near orthogonal angles.

ELF-EM Signal Processing While Drilling Based on Human-Computer Interaction Combined Algorithm

In the electromagnetic wave measurement while drilling(EM MWD), the extra low frequency electromagnetic wave(ELF-EM) below 20Hz was usually chosen as the carrier because of its transmission characteristics in the formation. However, as the drilling depth increases, the electromagnetic wave signals received on the ground gradually weaken, becoming lower than a certain signal-to-noise ratio(SNR)and making it impossible to be decoded or transmitted.The attenuation of electromagnetic wave in the formation is definitely one of the causes, but what matters more is the influence of environment noise at the well site, especially the in-band interference noise and random noise. Targeting at the out-of-band noise, the bandpass filter, which is invalid to the in-band noise,can be used to eliminate the noise out of the carrier’s main band. To cope with the question, an algorithm based on the human-computer interaction detection(HCID) was proposed in this paper that improves the SNR of ELF-EM signals, with the effective transmission distance of EM MWD increased. In this paper,the validity of the proposed HCID algorithm was verified through communication processing performance simulation and field data comparison, thus providing a reference for engineers and technicians in this field.Theoretical analysis and experimental data verification show that the combined algorithm decodes effectively under the in-band interference noise of-80d B SNR and in-band random noise of-17d B SNR.

Processing of measurement while drilling data for rock mass characterization

The information extracted from monitoring of rotary blasthole drills helps to optimize the overall mining operation. Rock hardness, drillability, blastability and specific energy of drilling are examples of parameters that have been estimated in the past using measurement while drilling techniques. In order to be able to properly utilize measurement while drilling techniques, it is important to properly collect, analyze and interpret extracted data. This paper deals with processing of measurement while drilling data such as rate of penetration, rotary speed, rotary torque and pulldown force collected from rotary blasthole drills.Different methods are discussed to calculate a true rate of penetration which is the most important monitored drill variable for use in rock mass characterization. Then specific energy of drilling is defined and calculated based on electrical and mechanical inputs and the results are compared. The results show that specific energy of drilling can be estimated using the drill's primary drive systems' electrical responses with good accuracy when compared to values based on mechanical inputs.

Measurement of Forces and Torques during Non-Homogeneous Material Drilling Operation

The purpose of this study is to measure the forces and torques produced in the drilling process of a non-homogenous material （bone）. An automated 5 DoF CataLyst-5 robot is used during the drilling process and it is integrated to a 6 DoF force-torque sensor. A force-torque controller which is built in the Matlab Simulink environment is employed to control the drilling process of the bone. Different feed rate is used during the experimental process of the bone drilling operation. The sensor is calibrated to measure the tri-axial direction of the resultant forces and torques. The profiles of the forces and torques obtained are non-linear due to the diversity of the bone density. The profiles generated also indicated fluctuation in the interface layers of the bone.

Non-contact measurement and multi-objective analysis of drilling temperature when drilling B_4C reinforced aluminum composites

Non-contact measurements of machining temperatures were performed with optical pyrometer when drilling particle（B4C） reinforced metal matrix composites（MMCs） with different drills. The effect of particle content, cutting speed, feed rate and tool material on the maximum drilling temperature was investigated. The drilling parameters were optimized based on multiple performance characteristics in terms of the maximum cutting temperature and tool wear. According to the results, the most influential control factors on the cutting temperatures are found to be particle fraction, feed rate and interaction between the cutting speed and particle content, respectively. The influences of the cutting speed and drill material on the drilling temperature are found to be relatively lower for the used range of parameters. Minimum cutting temperatures are obtained with lower particle fraction and cutting speed, with relatively higher feed rates and carbide tools. The results reveal that optimal combination of the drilling parameters can be used to obtain both minimum cutting temperature and tool wear.

Formation permeability evaluation and productivity prediction based on mobility from pressure measurement while drilling

Based on the measurement mechanism of mobility in pressure measurement while drilling, through analyzing a large number of mobility data, it is found that under the condition of water-based mud drilling, the product of mobility from pressure measurement while drilling and the viscosity of mud filtrate is infinitely close to the water phase permeability under the residual oil in relative permeability experiment. Based on this, a method converting the mobility from pressure measurement while drilling to core permeability is proposed, and the permeability based on Timur formula has been established. Application of this method in Penglai 19-9 oilfield of Bohai Sea shows:(1) Compared with the permeability calculated by the model of adjacent oilfields, the permeability calculated by this model is more consistent with the permeability calculated by core analysis.(2) Based on the new model, the correlation between the calculated mobility of well logging and the actual drilling specific productivity index bas been established. Compared with the relationship established by using the permeability model of an adjacent oilfield, the correlation of the new model is better.(3) Productivity of four directional wells was predicted, and the prediction results are in good agreement with the actual production after drilling.

A Petrophysical Approach to Evaluation from Measured While Drilling Gamma Ray, Case Study in the Powder River and Delaware Basins

One of the most common subsurface data sets that is easily accessible and often underutilized is the acquired measuring while drilling (MWD) gamma ray (GR-GAPI) log. Data is acquired from a given gamma ray tool positioned within the drill string and pulsed up to the surface through the mud column in the wellbore. Typical use of the data is for subsurface geologists, drillers and others to correlate the data to known stratigraphic signatures and steer wells through horizontal target zones. Through that correlation, an association to the geologic stratigraphic column can be made and the team of subsurface scientists adjusts where, how fast, and why they choose to continue drilling. The technique of correlation applies to both the conventional and unconventional application. In the unconventional application, the data is also typically acquired along the length of the horizontal wellbore. From a petrophysical standpoint, just acquiring a gamma ray can limit the amount of information and ability to fully evaluate the properties along the length of the well. In this study, we share and demonstrate how to utilize the MWD GR for petrophysical evaluation beyond just a volume of shale or volume of clay interpretation. The workflow will allow full integration of a comprehensive petrophysical evaluation that can then be utilized to support all subsurface understandings and modelling efforts.

MWD技术在隧道爆破中的研究与应用

钻爆法是隧道工程中最常见的岩石破碎方法,其作业效率很大程度上取决于岩体的强度特性和结构特性。对比常规钻探取心和地球物理探测技术的基础上,叙述了一种更快速、更廉价地获取地质信息的勘探技术——随钻测量技术(MWD)。综述了2种利用随钻测量技术评估钻爆作业炸药单耗的方法:一是首先利用随钻参数判别岩体质量,进而判断岩体可爆性、估算炸药单耗;二是直接利用随钻参数,建立随钻参数与炸药单耗之间的相互关系。之后介绍了随钻测量技术在隧道工程领域的应用以及取得的成效,总结了随钻测量研究与应用过程中所面临的困难与挑战,并给出了结论与建议。

Use of drilling performance to improve rock-breakage efficiencies:A part of mine-to-mill optimization studies in a hard-rock mine

In a hard-rock mine,blasting is an important rock-breakage process that impacts energy consumption both in downstream comminution processes and mine productivity.Optimizing the blast fragmentation to improve rock-breakage efficiencies during crushing and grinding is key to mine-to-mill(MTM)optimization.This study explores the use of monitoring while drilling(MWD)data to achieve this goal.Representative penetration rates(PRs)were extracted from blastholes to estimate intact rock properties and predict the breakage efficiencies that directly affect comminution energy consumption.Two intact rock properties,tensile strength(TS)and Bond work index(BWI),were correlated with the PR data to predict these efficiencies in crushing and grinding,respectively.Because of the complexity of the raw MWD data and effects of various disturbances,the MWD data was preprocessed and normalized to achieve a representative PR value at each blasthole.This preprocessing entailed defining valid PR ranges from the MWD data that could eliminate the noise related to discontinuity features in the rock mass structure as well as errors in operator behaviors.The PR data was also normalized using the adjusted penetration rate(APR)to minimize the effects of mechanical factors such as drill feed force,torque,and rotational speed.To correlate the representative APR value with intact rock properties,TS and BWI,various laboratory experiments were conducted:drilling tests using a high-precision coring machine,Brazilian disc tests,and Bond grindability tests.Based on the results of these experiments,models were developed to predict rock-breakage efficiencies during crushing and grinding based on APR.The result of this study can be used to obtain blast energy designs that consider comminution energy consumption and efficiency in the downstream rock-breakage processes.

An intelligent identification method of safety risk while drilling in gas drilling

In view of the shortcomings of current intelligent drilling technology in drilling condition representation, sample collection, data processing and feature extraction, an intelligent identification method of safety risk while drilling was established. The correlation analysis method was used to determine correlation parameters indicating gas drilling safety risk. By collecting monitoring data in the safety risk period of more than 20 wells, a sample database of a variety of safety risks in gas drilling was established, and the number of samples was expanded by using the method of few-shot learning. According to the forms of gas drilling monitoring data samples, a two-layer convolution neural network architecture was designed, and multiple convolution cores of different sizes and weights were set to realize the vertical and horizontal convolution computations of samples to extract and learn the variation law and correlation characteristics of multiple monitoring parameters. Finally, based on the training results of neural network, samples of different kinds of safety risks were selected to enhance the recognition accuracy. Compared with the traditional BP(error back propagation) full-connected neural network architecture, this method can more deeply and effectively identify safety risk characteristics in gas drilling, and thus identify and predict risks in advance, which is conducive to avoid and quickly solve safety risks while drilling. Field application has proved that this method has an identification accuracy of various safety risks while drilling in the process of gas drilling of about 90% and is practical.

Similarity evaluation of stratum anti-drilling ability and a new method of drill bit selection

Considering the stratum anti-drilling ability,drill bit working conditions,drill bit application effect and drill bit economic benefits,the similarity of stratum anti-drilling ability was evaluated by grey relational analysis theory to screen out candidate drill bits with reference values.A new comprehensive performance evaluation model of drill bit was established by constructing the absolute ideal solution,changing the relative distance measurement method,and introducing entropy weight to work out the closeness between the candidate drill bits and ideal drill bits and select the reasonable drill bit.Through the construction of absolute ideal solution,improvement of relative distance measurement method and introduction of entropy weight,the inherent defects of TOPSIS decision analysis method,such as non-absolute order,reverse order and unreasonable weight setting,can be overcome.Simple in calculation and easy to understand,the new bit selection method has good adaptability to drill bit selection using dynamic change drill bit database.Field application has proved that the drill bits selected by the new drill bit selection method had significant increase in average rate of penetration,low wear rate,and good compatibility with the drilled formations in actual drilling.This new method of drill bit selection can be used as a technical means to select drill bits with high efficiency,long life and good economics in oilfields.

定向钻井MWD工具面角数据分析

定向钻井过程中,正确地判断滑动钻进和复合钻进井段分析钻井过程是非常必要的。通过对大量实际MWD工具面角数据的观察和归纳总结,发现了滑动钻进和复合钻进的工具面角数据特征:当滑动钻进时,工具面角是围绕均值小幅波动的平稳序列;当复合钻进时,工具面角无规则地剧烈震荡。对于给定的一个数据窗口,使用频数分析方法求出了井段工具面角均值的近似值;通过定义最小波动值,求出了偏离均值的例外点集合。根据最小井段长度限制、最多例外点个数、最小波动值等参数,提出了滑动井段的判别算法。对于MWD工具面角的历史数据或者实时数据,使用数据窗口扫描方法,能从MWD工具面角数据中正确地划分出滑动钻进井段和复合钻进井段。实际钻进数据算例表明,该算法是快速、有效的。该算法既能对MWD工具面角数据做事后分析,也能用于实时在线分析。

MWD磁干扰的判断和矫正

在定向井和水平井施工过程中,用于轨迹控制的随钻测量(MWD)无线随钻测斜仪器是不可缺少的。该仪器通过探管内的磁通门传感器和重力加速的传感器测量井眼状态(井斜、方位、工具面等)。在介绍MWD仪器测量原理的基础上,分析了磁干扰的原因,并进一步的分析了施工过程中遇到磁干扰时的判断方法,以及径向轴向矫正磁干扰的简单方法,可为现场工程师提供一定的指导建议。

干热岩定向钻井关键技术研究与应用

为推动干热岩产业化步伐,中国地质调查局在青海共和盆地部署了我国首例干热岩试验性开发工程,采用一口直井注入和两口定向井采出的开发模式,文章就定向井钻井关键技术进行研究与应用。青海共和盆地干热岩主要为花岗岩,地层硬度大、研磨性强、温度高,加上大规模储存改造的影响,定向井钻井作业存在机械钻速低、碎岩工具寿命短、测量仪器耐温差、信号不稳定、井眼轨迹控制难度大等技术难题。为保证钻井作业顺利推进,从井眼轨迹控制、提高井下工具耐温耐磨能力、提高钻井液高温流变性能、钻井液主动降温等技术手段入手,创新研发了耐高温MWD、抗高温聚合物钻井液体系、螺旋板式钻井液冷却装置等关键技术与装备,优选了“牙轮钻头+单弯螺杆+MWD”钻具组合,安全高效地完成了双靶点定向井施工,AB靶心的中靶精度分别为4.85 m和8.97 m,钻井周期缩短20%以上,并取得了最高进尺175.00 m、最快机械钻速3.74 m/h的提速增效成果。

基于无线电磁传输的防冲钻孔机器人钻进轨迹随钻测量方法

防冲钻孔机器人是高地应力矿井实现无人化卸压的必要装备,研发可靠的钻进轨迹随钻测量系统是保障钻孔卸压效果的重要措施。为此,在分析钻进轨迹算随钻测量基本原理的基础上,研制了基于无线电磁传输技术的钻进轨迹随钻测量钻杆;分析了不同电磁信号调制方式的频谱效益和抗噪声性能,设计了钻杆姿态信号的频移键控(FSK)调制和解调流程,进而开发了先放大后滤波的微弱信号调理系统,设计了相应的功能电路,并基于Multisim软件对其进行了测试,各电路模块满足设计要求。对比分析了5种轨迹解算算法的精度和执行效率,选择了均角全距法进行钻进轨迹解算,研究了基于小波滤波的惯性测量单元测量数据振动误差处理方法,验证了小波滤波算法对于提高姿态角解算精度的有效性。提出了基于拉线位移传感器与机器人动作标志位的钻进深度测量方法,并开展了地面试验与井下试验。试验结果表明:所设计的微弱信号调理系统可以实现煤矿井下微弱信号的接收与处理,基于拉线位移传感器与机器人动作标志位的钻进深度测量方法可以提高钻进轨迹的拟合精度。

Power-V诱导的钻柱黏滑振动特征分析

黏滑是石油钻井过程中影响钻井效率和井下钻柱安全的一种振动形式.垂直钻井系统Power-V在提供有效控斜力的同时,还会诱导钻柱黏滑振动.通过研究垂直钻井系统Power-V与井壁的接触作用及钻头与地层的相互作用模型,基于钻柱动力学有限元方法,深入分析Power-V的作用机理,研究其对扭转振动的影响,指出Power-V和井壁间的相互作用会导致钻柱与井壁的摩阻显著增加,进而引起摩阻扭矩的增大,诱导井下黏滑振动.实测振动数据证实,Power-V与井壁间的相互作用是引起钻柱黏滑振动的关键因素.这对于揭示黏滑振动的成因和更好地发挥Power-V的作用具有重要意义.

井下工程参数随钻测量系统研制

钻探过程中,随钻实时测量近钻头工程参数是动态调控钻探工艺的重要依据。针对钻探过程中各项工程参数测量的需要,设计了一套井下工程参数随钻测量系统。通过室内模拟试验环境对随钻测量系统进行了试验测试,结果表明,该系统能够测量井下温度、压力、扭矩、轴压及振动等工程参数,且测量误差较小,满足实际钻探项目的需求。

基于MGMA的随钻陀螺仪误差在线补偿

针对随钻测量MEMS陀螺仪输出精度低的问题,提出一种基于磁-重力蜉蝣算法(MGMA)的陀螺误差在线补偿方法。首先,分析随钻陀螺误差来源并推导出误差补偿模型;其次,利用MEMS加速度计无累积误差的特点,根据重力向量叉乘得到向量夹角作为目标函数;此外,考虑到实际钻进时强振动和冲击对加速度计输出的不利影响,利用MEMS磁强计抗振的特点,设计磁模值相对误差约束条件。然后,在MA基础上,针对随钻恶劣环境影响下的陀螺误差参数不断变化问题,根据陀螺和磁强计输出之间的关系自适应确定搜索上下界;并利用重力模值相对误差设计惯性权重,平衡算法的全局探索和局部开发能力;最后,利用磁-重力模值相对误差在子代中引入变异扰动策略,减小陷入局部最优的可能。实验结果表明,经MGMA补偿后的陀螺输出误差明显减小,井斜角误差由9.75°降低至1.52°,且相比于PSO和MA算法具有速度快、精度高的优势。

钻柱振动的主被动控制研究进展与展望

在油气井钻进作业过程中,钻柱长期工作在充满钻井液的狭长井筒里,其受到井底压力、摩擦、岩石硬度变化的影响,受力情况非常复杂,会产生多种形式的振动,这些是影响钻具寿命和钻进效率的最主要因素。为系统分析工程界和学术界长期以来普遍关注的钻柱系统振动的有效控制问题,对近几十年来国内外在钻杆振动控制上使用的各种方法进行了分类和归纳,总结了各种方法的特点、应用场景以及不足之处,并对钻柱系统振动控制技术的发展趋势进行了展望。研究结果表明:(1)现有的钻柱振动主动控制主要集中于单一方向(扭转振动)和2个方向的耦联振动(纵扭耦联振动),且控制参数主要集中于钻压和扭矩,仅控制单方向的振动和单参数的调节,效果将很难保证;(2)被动控制是通过改变钻柱系统自身的结构或设计参数来抑制其振动,控制过程不受结构响应和外部干扰的影响,虽然效果有较大的局限性,但仍应在设计阶段给与足够的重视;(3)今后钻柱振动控制将朝着同时基于地面和井下测量数据,纵、横、扭3个方向联合控制的方向发展。结论认为,钻杆振动往往是几种基本振动形式的耦联,并具有明显的非线性特征,基于数据驱动的钻进系统动力学建模、考虑模型不确定性的现代鲁棒自适应控制技术以及新兴的人工智能技术将会成为未来钻柱振动研究和发展的主流趋势。