Digital monitoring of rotary-percussive drilling with down-the-hole hammer for profiling weathered granitic ground

Rock and geotechnical engineering investigations involve drilling holes in ground with or without retrieving soil and rock samples to construct the subsurface ground profile.On the basis of an actual soil nailing drilling for a slope stability project in Hong Kong,this paper further develops the drilling process monitoring(DPM)method for digitally profiling the subsurface geomaterials of weathered granitic rocks using a compressed airflow driven percussive-rotary drilling machine with down-the-hole(DTH)hammer.Seven transducers are installed on the drilling machine and record the chuck displacement,DTH rotational speed,and five pressures from five compressed airflows in real-time series.The mechanism and operations of the drilling machine are elaborated in detail,which is essential for understanding and evaluating the drilling data.A MATLAB program is developed to automatically filter the recorded drilling data in time series and classify them into different drilling processes in sub-time series.These processes include penetration,push-in with or without rod,pull-back with or without rod,rod-tightening and rod-untightening.The drilling data are further reconstructed to plot the curve of drill-bit depth versus the net drilling time along each of the six drillholes.Each curve is found to contain multiple linear segments with a constant penetration rate,which implies a zone of homogenous geomaterial with different weathering grades.The effect from fluctuation of the applied pressures is evaluated quantitatively.Detailed analyses are presented for accurately assess and verify the underground profiling and strength in weathered granitic rock,which provided the basis of using DPM method to confidently assess drilling measurements to interpret the subsurface profile in real time.

Study on the general layout of semi-submersible offshore drilling platforms based on process flow

The general layout of 6th generation semi-submersible drilling platforms is the main factor impacting the efficiency of their drilling operations. This paper provides a compound/integrated algorithm based on process flow that is aimed at improving efficiency, while giving attention to stability and safety at the same time. The paper describes the process flow of dual drilling centers and a hierarchical division of rigs based on the different modes of transportation of various drilling support systems. The general layout-centripetal overall arrangement spatially was determined based on drilling efficiency. We derived our modules according to drilling functionality; the modules became our basic layout units. We applied different layout algorithm to mark out the upper and lower decks. That is, the upper deck was designed based on the lowest transportation cost while the lower deck＇s calculations were based on the best-fit scope. Storage configurations in columns and pontoons were also considered for the layout design. Finally the center of gravity was taken into consideration and the general layout was adjusted accordingly, to result in an optimal center of gravity. The methodology of the general layout can provide a reference for implementation of domestic designs of semi-submersible rigs.

In situ strength profiles along two adjacent vertical drillholes from digitalization of hydraulic rotary drilling

Drilling speed and associated analyses from factual field data of hydraulic rotary drilling have not been fully utilized.The paper provides the reference and comparison for the utilization of drilling information from two adjacent vertical drillholes that were formed with the same hydraulic rotary drilling machine and bit.The analysis of original factual data is presented to obtain the constant drilling speed during net drilling process.According to the factual data along two adjacent drillholes,the digitalization results respectively include 461 linear zones and 210 linear zones with their constant drilling speeds and associated drilling parameters.The digitalization results can accurately present the spatial distributions and interface boundaries of drilled geomaterials and the results are consistent with the paralleled site loggings.The weighted average drilling speeds from 2.335 m/min to 0.044 m/min represent 13 types of drilled geomaterials from soils to hard rocks.The quantitative relation between drilling speed and strength property is provided.The digitalization results can statistically profile the basic strength quality grades of III to VI from soils to hard rocks.The thickness distributions of four strength quality grades are presented for each individual type of geomaterials along two drillholes.In total,50.2%of geomaterials from drillhole A are grade IV and 57.4%of geomaterials from drillhole B are grade III.The digitalization results can offer an accurate and cost-effective tool to quantitatively describe the spatial distribution and in situ strength profile of drilled geomaterials in the current drilling projects.

Cooling and Crack Suppression of Bone Material Drilling Based on Microtextured Bit Modeled on Dung Beetle

In recent years,the number of patients with orthopedic diseases such as cervical spondylosis has increased,resulting in an increase in the demand for orthopedic surgery.However,thermal necrosis and bone cracks caused by surgery severely restrict the development and progression of orthopedic surgery.For the material of cutting tool processing bone in bone surgery of drilling high temperature lead to cell death,easy to produce the problem such as crack cause secondary damage effects to restore,in this paper,a bionic drill was designed based on the micro-structure of the dung beetle's head and back.The microstructure configuration parameters were optimized by numerical analysis,and making use of the optical fiber laser marking machine preparation of bionic bit;through drilling test,the mathematical model of drilling temperature and crack generation based on micro-structure characteristic parameters was established by infrared thermal imaging technology and acoustic emission signal technology,and the cooling mechanism and crack suppression strategy were studied.The experimental results show that when the speed is 60 m/min,the cooling effects of the bionic bit T1 and T2 are 15.31%and 19.78%,respectively,and both kinds of bits show obvious crack suppression effect.The research in this paper provides a new idea for precision and efficient machining of bone materials,and the research results will help to improve the design and manufacturing technology and theoretical research level in the field of bone drilling tools.

Simulation of Shallow Gas Invasion Process During Deepwater Drilling and Its Control Measures

Shallow gas is considered one of the most serious geological hazards in deepwater drilling because it has the characteristics of suddenness and is difficult to deal with.To perform a quantitative evaluation of shallow gas risk during deepwater drilling,a numerical model for calculating gas invasion volume is established based on gas-water two-phase flow theory.The model considers the effect of the dynamic drilling process,and the influencing factors which affect the gas invasion volume are analyzed.Results indicate that the gas invasion rate and accumulated gas invasion volume increase with increasing bottom-hole pressure difference.A linear relationship exists between gas invasion volume and bottom-hole pressure difference.The duration of gas invasion increases as the shallow gas zone thickness increases,and the accumulated gas invasion volume grows as shallow gas zone thickness increases.The increase in formation permeability,water depth,and rate of penetration will enhance the gas invasion rate.However,these three factors can hardly affect the accumulated gas invasion volume.The gas flow rate increases significantly with increasing burial depth of shallow gas.On the basis of influencing factor analysis,a series of methods that consider different risk levels is proposed to control shallow gas,which can provide a reference for the prevention of shallow gas disasters during deepwater drilling.

Influence of process parameters on drilling characteristics of Al 1050 sheet with thickness of 0.2 mm using pulsed Nd:YAG laser

The object of this work is to investigate the influence of process parameters on drilling characteristics of an Al 1050 sheet with a thickness of 0.2 mm using a pulsed Nd:YAG laser through numerical analyses and experiments. By comparing the numerical analyses with the experiments, a proper numerical model was obtained. From the results of the numerical analyses and the experiments, the effects of process parameters on entrance diameters of drilled holes, shapes of the holes, taper angles of the holes and temperature distributions in the vicinity of the holes were examined quantitatively. In addition, the optimal drilling condition was estimated to improve the quality of the drilled holes.

CAx Process Chain for Automated Laser Drilling of Tool Molds

Rotation sintering, also known as slush molding, is used to manufacture molded skins, such as dashboards or door interior panels for cars. At present, approximately 80% of such molded skins are manufactured using electroforms to achieve the complex free-form surfaces, and surface structures, such as leather graining that the industry demands. The manufacture of these electroforms is, however, time-consuming and expensive. This project aims to replace conventional electroforms with laser-drilled molds. Holes in tool molds should be drilled by using laser radiation as part of an automated process. The system consists of a robot with a fiber-laser beam source. A CAx （computer-aided x） process chain has been developed for this purpose in which the CAD （computer-aided design） data of the tool molds are processed, drill hole fields generated, and a machine-specific RC （robot control） program created. Process-specific fundamentals, such as suitable process windows and process control, have been devised to manufacture holes using fiber laser radiation The advantages of the new laser-drilled tool molds may result in substituting them for conventional electroforms, allowing old markets to be re-entered or additional markets to be created and targeted through new molds or lower costs.

An Application of a Multi-Tier Data Warehouse in Oil and Gas Drilling Information Management

Expenditure on wells constitute a significant part of the operational costs for a petroleum enterprise, where most of the cost results from drilling. This has prompted drilling departments to continuously look for ways to reduce their drilling costs and be as efficient as possible. A system called the Drilling Comprehensive Information Management and Application System (DCIMAS) is developed and presented here, with an aim at collecting, storing and making full use of the valuable well data and information relating to all drilling activities and operations. The DCIMAS comprises three main parts, including a data collection and transmission system, a data warehouse (DW) management system, and an integrated platform of core applications. With the support of the application platform, the DW management system is introduced, whereby the operation data are captured at well sites and transmitted electronically to a data warehouse via transmission equipment and ETL (extract, transformation and load) tools. With the high quality of the data guaranteed, our central task is to make the best use of the operation data and information for drilling analysis and to provide further information to guide later production stages. Applications have been developed and integrated on a uniform platform to interface directly with different layers of the multi-tier DW. Now, engineers in every department spend less time on data handling and more time on applying technology in their real work with the system.

Study on the evaluation index system and evaluation method for self-elevating drilling unit design

In the process of designing self-elevating drilling unit, it is important, yet complicated, to use comparison and filtering to select the optimum scheme from the feasible ones. In this research, an index system and methodology for the evaluation of self-elevating drilling unit was proposed. Based on this, a multi-objective combinatorial optimization model was developed, using the improved grey relation Analysis （GRA）, in which the analytic hierarchy process （AHP） was used to determine the weights of the evaluating indices. It considered the connections within the indices, reflecting the objective nature of things, and also considered the subjective interests of ship owners and the needs of designers. The evaluation index system and evaluation method can be used in the selection of an optimal scheme and advanced assessment. A case study shows the index system and evaluation method are scientific, reasonable, and easy to put into practice. At the same time, such an evaluation index system and evaluation method will be helpful for making decisions for other mobile platforms.

Main technical innovations of Songke Well No.2 Drilling Project

Songke Well No.2,one of the main part of the scientific drilling project in Songliao Basin,which was drilled 7018 m and acquired the part of cores continuously from the Low Cretaceous to the Carboniferous and the Permian from the 2843 m deep,can be considered as the deepest continental drilling project in Asia.Aiming at the features of longer well sections,larger diameters and multiple spud-ins for coring of Songke Well No.2,this project broke through the "coring in small diameter and reaming in large diameter"spud-in drilling-completion procedures which are always used in large-diameter-well coring for continental scientific drilling projects in domestic and overseas and the drilling method of short-singlecylinder roundtrip footage.At the same time,"coring in the same diameter and completing drilling at one single diameter"was achieved at all φ311 mm and φ216 mm coring sections of more than one thousand meters long,high-efficient operation with "drilling long footage with drill tools combined in multicylinders"was achieved at deep coring section.Four world drilling records were created which include more than a thousand meters continuous coring at φ311 mm,and the footage per roundtrip footage at φ311 mm,φ216 mm and φ152 mm is all more than 30 m,all of these breakthroughs reduced at least 300 days for this project;moreover,considering the characteristics of formations that the geothermal gradient is high in the drilled sections and the inside-well temperature is over 240℃ after drilling completion,a formate-polymer water-based mud system was developed by compounding attapulgite and sodium bentonite and by adding independently developed high-temperature stabilizer,which can provide critical technical support for successful well completion at 7018 m in the super-high-temperature environment It is the first time that the water-based mud is operated at the working temperature higher than 240℃ in China;Besides,considering the high-quality requirement on cores imposed by the project,the method "mechanical cored is charge"to discharge core nondestructively on the ground was worked out,and more than 4000 m scatheless cores were discharged out of the drill pipes while maintaining original stratum structures.

A Predictive Model of Enhanced Oil Recovery by Infill Drilling and Its Application

Infill drilling is now recognized as a viable improved recovery process. However, the reliable prediction of incremental recovery by infill drilling cannot be readily and accurately determined by present techniques. This paper proposes a hybrid predictive model of stream tube simulation and numerical simulation by using the contemporary theory of fluid flow in porous media. The model calculates the geometries of stream tubes, remaining oil distribution and water cut at different development stages in the near future, and uses a three-dimensional simulation to track fluid movement in each stream tube slice. This will help reservoir engineers to determine the feasibility of infill drilling. This predictive model is used to forecast the degree of control of well pattern, the ultimate incremental recovery of infill wells within an inverted 5-spot case in an oilfield and the economic benefit is also analyzed.

Instrumented borehole drilling for interface identification in intricate weathered granite ground engineering

The successful application in drilling for HK simple weathered granite foundation has revealed its further use in instru- mented drilling system as a ground investigation tool in the detection of other lithology formations, geohazards, underground water, and boundary of orebody. To expand the further use and test the accuracy in identification of formation, an R-20 rotary-hydraulic drill rig was instrumented with a digital drilling process monitoring system （DPM） for drilling in an intricate decomposed granite site. In this test ground, the boreholes revealed that the weathered granite alternately changes between moderate and strong. The qualitative and quantitative analysis of the penetrating parameters, indicates the effective thrust force, rotary speed, flushing pressure, penetrating rate, and displacement of the bit fluctuate at ground interfaces. It shows that the parameters get a good response with the change of rock strength at the interfaces, which can reveal the change of the intricate granite formation. Besides, a variable-slope method has been established, for identification of dominative and subsidiary interfaces in the granite site. The result from a t-test shows that the confi- dence of the instrumented drilling system in identification of the geotechnical interfaces is up to 99%.

Automatic de-noising and recognition algorithm for drilling fluid pulse signal

Wavelet forced de-noising algorithm is suitable for denoising of unsteady drilling fluid pulse signal, including baseline drift rectification and two-stage de-noising processing of frame synchronization signal and instruction signal. Two-stage de-noising processing can reduce the impact of baseline drift and determine automatic peak detection threshold range for signal recognition by distinguishing different features of frame synchronization pulse and instruction pulse. Rising and falling edge relative protruding threshold is defined for peak detection in signal recognition, which can make full use of the degree of the signal peak change and detect peaks flexibly with rising and falling edge relative protruding threshold combination. A synchronous decoding method was designed to reduce position uncertainty of the frame synchronization pulse and eliminate the accumulative error of time base drift, which determines the first instruction pulse position according to position of the frame synchronization pulse and decodes subsequent instruction pulse by taking current instruction pulse as new bit synchronization pulse. Special tool software was developed to tune algorithm parameters, which has a decoding success rate of about 95% for the universal coded signals. For the special coded signals with check byte, decoding success rate using the automatic threshold adjustment algorithm is as high as 99%.

矿山救援钻孔中井涌井漏事故预警预测

为解决矿山应急救援钻孔作业过程中井涌井漏事故预警预测困难等问题,建立了基于机器学习的钻进过程井涌井漏事故预警预测模型。首先对井涌井漏事故发生初期时的钻进参数进行事故表征参数分析;其次对事故表征参数进行数据清洗处理,在此基础上,通过XGBoost事故诊断预警模型对井涌井漏事故进行早期诊断识别;随后建立PSO-LSTM事故发展预测模型,对事故发生后的孔底压力参数发展趋势进行预测,提前掌握钻进事故发展状态;最后通过实际钻进数据对预警预测模型的有效性进行验证。结果表明:XGBoost事故诊断预警模型能根据总池体积、立管压力、出入口流量差和动力头负荷这4种钻进参数的异常变化,快速准确诊断钻进过程中的井涌井漏事故;PSO-LSTM事故发展状态预测模型能充分学习孔底压力参数发展规律,综合EMAP、EMA、ERMS、R2这4项误差评价指标,PSO-LSTM模型相较于BP、RNN、SVM模型的预测性能最佳,能准确预测事故发生之后的孔底压力发展趋势,提前掌握井涌井漏事故的严重程度和发展态势。研究结果丰富了钻进过程井涌井漏事故预警预测方法,提高了矿山事故地面救援的可靠性,对矿山应急救援钻孔作业过程中事故控制有着借鉴与指导作用。

煤矿井下钻探数字化监测系统

针对煤矿井下钻探存在孔底工程参数测量困难、钻探数据准确性和完整性不足、钻探数据融合应用不够等问题,设计了一种煤矿井下钻探数字化监测系统。该系统由数据来源层、虚拟模型层、数据处理层和钻探服务层构成:数据来源层为虚拟模型层提供数据支撑,虚拟模型层通过仿真模拟分析生成新的数据并反馈至数据来源层;数据处理层接收到数据来源层和虚拟模型层提供的数据后,进行数据清洗、转换及合并等处理;钻探服务层通过后台数据管理端的权限设置,为不同层级用户提供数据显示、查询、分析、报警等服务。将钻探数据按时序特征分为事前数据(钻探施工之前根据钻孔设计资料和施工方案等获取的数据)、实时数据(包括钻探过程设备实时监测的参数和钻场视频等)和延时数据(孔底随钻测量装置采集的参数),针对这3类钻探数据设计了数据处理流程,并建立了由接入层、汇聚层和核心层组成的系统通信网络架构。工程实践结果表明:该系统实现了煤矿井下钻探施工数据的采集、传输、显示与动态管理,满足钻探施工过程监测和数据管理的需求,具有较好的实时性和准确性。该系统为煤矿井下钻探智能化施工和精细化管理提供了技术支撑。

GFRP/Al叠层材料钻削力与制孔质量的实验研究

复合材料与金属组成的叠层结构已在航空航天领域广泛使用,然而在复合材料/金属叠层结构上钻削高质量的孔仍是一个挑战。本文旨在研究钻削工艺参数对GFRP/Al叠层材料钻削轴向力和制孔表面质量的影响。使用普通硬质合金麻花钻对GFRP/Al叠层材料进行“一次性”钻孔,并通过Kistler测力仪测量钻削轴向力。结果表明,最大钻削轴向力随每转进给量增加几乎线性增加,随主轴转速增加小幅降低。钻削工艺参数影响铝合金和GFRP制孔表面质量,高每转进给量会降低铝合金制孔出口毛刺,但是会增加GFRP制孔出口损伤;高主轴转速会增加铝合金制孔出口毛刺和GFRP制孔出口损伤。与每转进给量相比,主轴转速对铝合金和GFRP制孔质量影响更大。

铀矿地质钻探移动式泥浆净化设备设计

环保要求和泥浆性能维护在地质勘探中的重要性日渐突显,使得铀矿钻探建设对泥浆清洁处理的标准变得更为严格。基于铀矿钻探工作单孔施工周期较短、机台搬家频次较高以及泥浆处理量较小的特点,研制了一种适用于砂岩型铀矿钻探的移动式泥浆净化设备。该设备采用模块化集成设计,主要由泥浆收集系统、除砂系统、自动化控制系统等组成,整合泥浆收集、净化、排放等多项传统泥浆处理设备设施及工艺,并可实现拖拽行走,在机台短途搬迁时能有效节约人力、物力。现场试验证明,该设备在砂岩型铀矿钻探过程中实现了优良的环保效果和经济效益,达成了一次配浆多孔使用和泥浆零排放的目标,并提高了钻孔质量。

车用CFRP材料超声振动钻孔工艺优化及质量分析

为了提高难加工增强体碳纤维复合材料(CFRP)的钻孔加工性能,在螺旋铣加基础上增加了超声振动辅助。设计了不同工艺条件对CFRP超声振动螺旋铣孔实施测试,对比了各条件下CFRP超声辅助螺旋铣孔的切削力差异,测试了孔加工质量状态。研究结果表明:采用超声振动螺旋铣方法处理可以避免引起分层现象,保证同一部位纤维与树脂基体相互形成更紧密结构。综合工艺参数对切削力和切削温度的影响,确定一下参数范围是比较优秀的:主轴转速4000r/min,螺距0.15mm,切向进给量0.04mm。CFRP分层状态受到切削刃锋利性以及材料去除率的综合影响,调整工艺参数能够有效的控制材料去除量,对切削力和切削温度起到很好的调节效果,进而减小分层损伤。

大型钻探设备支承底盘焊接工艺优化研究

大型支承底盘作为大型钻探设备的支承平台,通常由大量钢板通过焊接装配而成,焊接残余应力和残余变形会对底盘的强度和刚度产生一定的影响。本文运用有限元分析方法,选取高斯移动热源,针对大型支承底盘中具有代表性的T形焊接接头建立了有限元模型,分别采用4种不同的焊接顺序和焊接速度,分析了其对焊接应力和变形的影响,得到了优化的焊接顺序和焊接速度。在此基础上,对底盘的整体焊接方案做出优化,对比分析了优化前后的焊接应力和变形,结果表明:优化后残余应力减少了约7%,最大变形减少了约26%。研究成果可为焊接工艺的制定提供参考。