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.

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.

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.

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.

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.

Fhe application of electromagnetic-induction on the measurement of sea ice thickness in the Antarctic

海冰作为冰雪圈中的重要组成部分,对气候变化十分敏感,海冰物理过程研究需要得到精确的海冰厚度。本文介绍一种能够高效探测海冰厚度的电磁感应方法及其在南极考察中的成功应用。该方法针对海冰和海水的电特性,利用电磁场原理精确探测仪器至冰水交界面的距离,以实现海冰厚度的测定。通过电磁感应(EM)仪观测的视电导率与同点位钻孔测量数据对比分析,获得视电导率与海冰厚度的转换关系式,通过对该关系式计算出的海冰厚度进行验证,表明电磁感应技术能够获得可靠的海冰厚度数据,相对平均误差仅为 5.5%。对探测剖面的海冰厚度统计表明,2005-2006年夏季南极内拉峡湾内海冰以平整冰为主,其厚度范围在0.8m到1.4m之间。

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。

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。

基于惯性测量单元的旋挖钻机钻具姿态测量方法

为实时获取钻孔过程中钻具的姿态信息,提高机手掌握成孔垂直度,设计了一种基于惯性测量单元的钻具姿态测量方法。该方法采用三轴加速度计、磁力计和陀螺仪构成惯性测量单元,建立基于四元数的姿态测量非线性模型,并采用基于四元数的扩展卡尔曼滤波算法,有效降低振动等干扰信号的影响,提高钻具姿态解算的准确性。实验结果表明,该方法能够有效避免振动对动态测量的干扰,实现旋挖钻机姿态的准确测量,为旋挖钻机施工提供实时、准确的姿态监测手段,为桩基施工质量提供重要保障。

基于BPSK解调算法的随钻测量无线通信系统的搭建

地质勘测中,确保勘测数据的精准并能够随时根据钻井情况调整姿势是钻井工程的技术关键。当前国内外随钻测量系统通信技术主要是基于脉冲数据传输方案,这种技术传输性能弱、局限性大。引入随钻测量无线电磁传输技术解决钻井通信问题,基于BPSK(Binary Phase Shift Keying)调制方案,对通信传输系统进行优化,并做通信实验测试。结果表明BPSK方案能很好提升信号宽带能力,传输速率达到100 bit/s,误码率<0.1%,有效解决载波问题,同时工频信号与噪声信号抗干扰能力进一步提升。研究内容对地质钻井平台精准控制具有较大意义。