Analysis of steering in horizontal directional drilling installations using down-hole motors

Horizontal directional drilling is becoming an increasingly popular technique for the installation of pipes in urbanised environments or in locations where trenching is difficult, such as under rivers or railways. This technique utilises down-hole bits to create the bore before it is expanded with back-reamers to allow installation of the product pipe. Controlling the path of the bore is critical to the success of many horizontal directional drilling installations and the potential inability to maintain such positional control is a factor that prevents the widespread adoption of this technique in place of traditional open cut methods.Two types of drill bit are commonly used in horizontal directional drilling; shaped jet-cutting bits and bits mounted on bent-subs and driven by mud-motors, the former being utilised in weak ground conditions and the latter in stronger formations. This paper analyses a dataset of survey data from pilot bores for fifty-four HDD installations that used mud-motors to investigate the parameters that impact upon the control of the position of the drilling bit. The drives are broken down into sections of rotary and slide drilled borepath and these are investigated separately. Drilling practice, drilling equipment, length of drive and the geology in which the bore is being established will have an effect upon the ability to control the position of the drilling bit.     

Theoretical model for calculating pulling loads for pipes in horizontal directional drilling

The paper presents a model for calculating installation loads imposed on pipes during the pulling operation in horizontal directional drilling. The model is implemented into a numerical program PipeForce 2005. The analysis includes pulling load contributions from directional changes, fluidic drag, solid friction and pipe’s weight. The emphasis in this paper is on details related to directional changes during the HDD installation. The formulation approximates the borepath as series of linear segments between the measured points (field-measured locations of the drilling head) and predicts the shape of the pipe in the borepath. Based on this shape, the layout of the borepath and the pipe stiffness, the contact forces between the pipe and the borepath are evaluated using the theory of deflections of flexible bars. The pulling force for the pipe is calculated to equilibrate the weight of the pipe and friction between the pipe and the soil and between the pipe and the drilling fluid. A comparison of theoretical predictions and field data is presented.     

A decision support system for horizontal directional drilling

Horizontal directional drilling (HDD) was pioneered in the US in the early 1970s. Through the integration of vertical oil well drilling technology with modern survey and steering techniques, horizontal directional drilling methods have the capability of undertaking a wide range of pipe installations, from large-diameter river crossings to small-diameter cable pipes. HDD has gained in popularity, as it is able to install underground pipes with minimum impact on society and the environment. Although HDD has been used for over three decades, it is necessary to evaluate the suitability and appropriateness of HDD methods on a project-to-project basis by considering a large number of factors that influence this decision-making. The lack of a systematic tool contributes to the difficulty of making effective decisions. This paper discusses the development of the framework for a decision support system (DSS) to assist in the selection of appropriate equipment/technique for HDD projects. Decision making criteria and rules are developed through literature review, analysis of field data compiled from the completed HDD projects, and investigations of ongoing projects. This DSS is most appropriate for use by contractors and asset managers at project planning stages.     

Modeling of annular fluid pressures in horizontal boring

Horizontal directional drilling (HDD) is minimally-intrusive construction method for installing underground utilities and pipelines. Today, HDD is becoming widely accepted as a cost-effective alternative to traditional open-cut construction. The occurrence of hydraulic fracturing, resulting in the migration of drilling fluid to the surface, has placed the HDD process under scrutiny, especially when considered for projects in environmentally sensitive areas. Hydraulic fracturing results when fluidic pressure within the borehole exceeds the shear strength or undrained cohesion of the strata. Models have been developed to predict borehole pressures; however, there is only limited information available on the properties of drilling returns obtained during HDD installations. A research program was undertaken to determine flow characteristics for drilling returns under a variety of soil conditions and bore penetration rates. Soil samples were gathered based on the Unified Soil Classification System (USCS) and their rheological properties were obtained for different drilling fluids and slurry densities. Presented in this paper is a methodology for predicting borehole fluid pressures over a wide range of project parameters that can be used as a guide to minimize the occurrence of hydraulic fracturing.     

Experimental strain analysis for polyethylene pipes installed by horizontal directional drilling

The results of five field tests on instrumented polyethylene (PE) pipes installed using horizontal directional drilling (HDD) are presented in the paper. The focus is on mechanical behavior of pipes, their stiffness, strength and deformations. The testing methodology is presented and correlation between different readings is discussed. The test results are presented in a form of pipe strains along the borepaths and vs. time of installation. The test program involved 200 mm (8 inch) diameter, standard dimension ratio (SDR) 17 and 150 mm (6 inch) diameter, SDR 11, high density and medium density polyethylene pipes pulled along 90 and 177 m borepaths. The parameters were the quality of the drilling fluids, the ratio of borehole to pipe diameters, pipe material, and construction sequence. The presented results show the variation of pipe strains with time and along the borepath. Strain gauge readings indicate both flexural and axial deformations. Included in the paper are also readings from a load cell indicating the value of the pulling force. The experimental results are analyzed in terms of different mechanisms that contribute to the increase of the pulling forces and straining of the pipe. Influence of the field test parameters is presented. Conclusions are drawn on the effects of the mechanisms and test parameters on the pipe mechanical behavior.     

Mechanical modelling for pipes in horizontal directional drilling

This paper presents a new technique to predict forces and deformations of pipes installed underground by horizontal directional drilling (HDD). The proposed technique consists of several models each describing different aspects of mechanics of HDD. It allows prediction of the shape of the pipe in the borepath. Based on the pipe shape, shape of the borepath and pipe stiffness, the contact forces between the pipe and the borepath are calculated. The contact forces cause friction and thus axial pulling force is induced to equilibrate the frictional forces and the weight of the pipe. The analytical model is used to study the stresses and strains on two pipes that were tested in the field. The theoretical results are compared with the strains measured in the field.     

Data acquisition and factors impacting productivity of Horizontal Directional Drilling (HDD)

Contractors, consultants, and decision makers are challenged to estimate time and cost of new pipe installations using Horizontal Directional Drilling (HDD). This is because productivity prediction and cost estimation of HDD involves a large number of objective and subjective factors that need to be considered. Therefore, the main objective of the present research is to identify and study the factors that affect productivity of HDD operations. To achieve this objective a thorough literature review is carried out and data on potential factors impacting productivity are collected from HDD experts across North America and abroad. The presented research identifies 13 factors classified under four main categories: managerial, mechanical, environmental and pipe physical conditions. The impact of these factors on HDD productivity is assessed within three types of soils: clay, rock, and sand. Analytical hierarchy process (AHP) technique is used to quantify this impact and rank these factors according to their relative importance. Results show that pipe diameter, operator and crew skills, soil type, and steering problems have the highest impact on HDD productivity as evaluated by many experts in the field. However, pipe type, length and depth are the least impacting factors. This analysis is proved to be helpful for contractors, consultants and HDD professionals in predicting execution time and estimating cost of HDD projects during the pre-construction phase.     

特深地下管线探测的理论研究与应用实践

在最近几年间,由于非开挖管线施工工艺技术的先进性、优越性所带来的经济效益和社会效益,非开挖技术特别是水平定向钻（HDD）技术越来越多地应用于穿越江河、建筑等各种地下管线施工,这就意味着长距离和深的管线,常有大于300n1长和5m深的管线。它向我们提出了探测地下管线技术的挑战。本文研究了探测这类特深管线在不同深度、不同电流情况的H,H2磁场分量剖面曲线,列举了在广州市2个埋深〉5ITI的管线探测的实例。     

广州番禺某段定向钻LNG管线探测的验证

广东液化天燃气(LNG)输气干线项目一期工程的广州段中,水平定向钻技术在铺设穿越江河、铁路、公路及建筑物等的地下管线施工方面得到大量的应用。水平定向施工的管线往往埋深大于5m,因此,有必要对埋深大于5m的管线探测方法及结果进行验证。本文详细介绍了番禺海傍的LNG定向钻管线的探测方法,也提出了深度模拟计算公式,水冲法钻探验证的方法。本次钻探结果表明:探测埋深小于7m时可以满足精度要求,探测埋深大于7m时,要进行必要的深度修正。     

Parametric study examining the short and long term response of HDPE pipes when installed by horizontal directional drilling

Estimation of the pulling forces is an important step in the successful design of a horizontal directional drilling installation. Estimation of axial stress distribution along the pipe is also important for the prediction of its long term performance. This paper presents the results of a parametric investigation of the effect of different installation parameters on the short and long term response of the new pipe. The investigation was carried out using procedure HDDPIPE developed by the authors for the analysis of polymer and steel pipes installed by horizontal directional drilling. The results show that stresses and strains continue to change along the pipe throughout its service life. Some installation parameters have significant effects on the short term installation loads, as well as the long term axial stresses and, potentially influence expected service life. The study demonstrates that half of the maximum short term axial stress during installation can be used as a conservative measure of long term axial stress. Less conservative estimates can be obtained using the authors’ new calculation procedure.     

GPS-RTK在水平定向钻管线铺设工程中的应用

介绍了GPS-RTK技术在水平定向钻管线铺设工程中轴线的放样方法与精度要求，将孔内随钻测量仪的控向数据与RTK放样数据进行比较，分析了GPS—RTK放样精度，实现了管道轴线放样，确保了定向钻地下沿轴线穿越的精确性。     

Implementing quality control in HDD projects—a North American prospective

The Horizontal Directional Drilling (HDD) industry in North America has experienced a tremendous rate of growth within the last decade. However, the development of acceptable operating standards and quality control (QC) and quality assurance (QA) procedures significantly lags behind the current utilization level of HDD. This gap is now considered to be one of the main obstacles for wider acceptance of HDD by the engineering community in North America. This paper describes various risks and quality-related problems in HDD practice. Recent efforts to promote and regulate quality project delivery in HDD projects are outlined. Thereafter, quality control and quality assurance are defined in the context of HDD. It is recommended that a universally recognized standard such as ISO 9000 be adopted as the basis for an industry-wide quality management system. Examples of how to customize selected ISO 9000 clauses to meet the directional drilling industry's QC/QA needs are given. Additionally, a new approach for QC during HDD installation is described and its merits discussed.     

燃气用PE管水平定向钻进若干问题探讨

对水平定向钻进工程中PE管材受力公式的各变量进行分析,提出减小管材拉伸应力的措施,分析了燃气用PE管水平定向钻进技术存在的问题。     

Stress–strain measurements for HDPE pipe during and after simulated installation by horizontal directional drilling

Results from physical experiments conducted on high-density polyethylene pipe samples are reported to quantify the axial stress–strain–time behaviour during simulated installation, strain recovery, and axial restraint stages of installation using horizontal directional drilling. During the simulated installation stage, axial strains progressively accumulated as the pipes were subjected to a cyclic stress history simulating the force required to actively pull the pipe through the ground. Once installed, the pipe samples were unloaded and a portion of the axial strain accumulated was recovered. From this point, the pipe length was fixed simulating the pipe response as it is attached to a rigid structure. The resistance imposed to prevent any additional strain recovery produced tensile axial stress in the pipe. A parametric study showed that the maximum strain accumulated during installation depends mainly on the magnitude of the pulling force. The tensile axial stress redeveloped after being restrained was found to depend on the pulling force, length of pipe installed, and recovery time. Tensile axial stress levels redeveloped in the pipes did not exceed possible long-term performance limits for the particular high-density polyethylene tested even when the short-term performance limits were exceeded by a factor of 1.5.     

非开挖定向钻技术在城市燃气建设中的应用

结合燃气管道非开挖定向钻穿越快速公路的工程实例,分析了定向钻技术决定工程成败的技术关键点,总结了穿越工程中轨迹设计、泥浆配置、管线探测、管材连接、导向钻进、扩孔护壁、回拖等方面的实践经验。     

Development and applications of trenchless technology in China

Trenchless technology has developed for almost 10 years in China since the first symposium on trenchless technology was held in Beijing (Peking) in 1996 and the China Society for Trenchless Technology-CSTT was established in 1998. Driven by the dramatically increased demand for underground pipeline installation throughout the nation, China has made significant progress in research and development in trenchless technology in the past 10 years. For example, there are more than 200 contractors engaged in trenchless construction, using more than 2000 horizontal directional drilling machines, among which approximately 700 have been introduced in the last year, and the biggest HDD rig in the world is now in China. In addition, China has made many achievements in education, research, and new products development and has accomplished many challenging projects in terms of complexity, diameter and distance in this field. There is a huge market potential for trenchless technology in mainland China.This paper presents the latest research, education, training, marketing and technical status of trenchless technology in China, and discusses the potential market, trends and factors that will influence trenchless technology in the next decade in China.     

Querung des Elbe‐Seitenkanals und des Mittellandkanals mittels Horizontal‐Directional‐Drilling für eine 380‐km‐Pipeline

Crossing of the Elbe‐Seitenkanal and the Mittellandkanal using HDD‐Technology for a 380 km long pipeline. The federal network of waterways and canals today comprises approximately 7500 km of inland waterways. Not restricted to economic use in transportation, the waterways also have a function in the water supply and distribution (water for industry and agriculture, flood protection etc.). As owner of federal waterways, the Federal Republic of Germany, according to the Basic law, section 87 and 89, manages these by an independent administrative authority, the Wasser‐ und Schifffahrtsverwaltung des Bundes (WSV), localy represented by the appropriate office, the Wasser‐ und Schifffahrtsamt (WSA). The WSA acts according to § 31 WaStrG as authorizing agency for river‐ and navigation‐specific police approval of third‐party installations intended for crossing or culverting the Federal Waterway route, as in this case. In the course of constructing a 380 km long pipeline from Stade to Teutschenthal (PST) a total of 203 horizontal directional drillings (HDD) were carried out. 24 of them concerned the crossing of big rivers and channels. Two technically extremely demanding projects proved to be the crossing of the Elbe‐Seitenkanal (ESK) and the crossing of the Mittellandkanal (MLK).     

水平定向钻技术在排水管道中的应用

随着城市化的发展,市政基础设施建设日益完善,水平定向钻逐渐被广泛应用于市政排水管道中。以江门市荷塘镇生活污水处理厂二期截污管网工程为例,由于本工程不具被明开挖施工条件,敷设的污水管道全部采用水平定向钻牵引施工,针对本工程的特点,对牵引管和沉井施工技术进行了详细介绍。     

水平定向钻技术在排水管道中的应用

随着城市化的发展,市政基础设施建设日益完善,水平定向钻逐渐被广泛应用于市政排水管道中。以江门市荷塘镇生活污水处理厂二期截污管网工程为例,由于本工程不具被明开挖施工条件,敷设的污水管道全部采用水平定向钻牵引施工,针对本工程的特点,对牵引管和沉井施工技术进行了详细介绍。     

非开挖水平定向钻钻杆全尺寸疲劳试验研究

水平定向钻进是一种不开挖地表面铺设管道或电缆的一种非开挖工法。水平定向钻施工过程中扭矩、推力和拉力都通过钻杆进行传递,钻杆失效或断裂将导致整个工程的失败。钻杆失效的原因包括粘扣、胀扣和疲劳破坏,目前通过小尺寸试样的S-N曲线对于水平定向钻钻杆在弯扭阻力状态下的疲劳破坏进行研究,全尺寸的疲劳破坏实验研究非常有限。本论文根据水平定向钻施工特点,选择常用水平定向钻杆作为研究对象,进行了全尺寸水平定向钻钻杆疲劳破坏试验。本论文首先介绍了基于裂纹扩展预测方法推导的钻杆疲劳寿命计算公式,然后设计研发了水平定向钻钻杆疲劳测试系统,并对64 mm×3000 mm水平定向钻杆在弯扭复合应力作用下的疲劳破坏过程进行了实验研究。研究结果表明,提出的基于裂纹扩展预测方法的计算结果与试验结果基本一致,该疲劳破坏计算方法具有一定的准确性与安全性。