HORIZONTAL DIRECTIONAL DRILLING: NEW ERA FOR UNDERGROUND UTILITIES

Transcription

1 HORIZONTAL DIRECTIONAL DRILLING: NEW ERA FOR UNDERGROUND UTILITIES Siddharth J. Jariwala 1, Prof. Jayeshkumar Pitroda 2, Prof. J. J. Bhavsar 3 1 P. G. Student (C.E & M), B.V.M Engineering College, Vallabh Vidhyanagar, siddharthjariwala510@gmail.com 2 Assistant Professor and Research Scholar, Civil Engineering Department, B.V.M. Engineering College, Vallabh Vidyanagar-Gujarat-India, jayesh.pitroda@bvmengineering.ac.in 3 Associate Professor, P.G. Cordinator of Construction Engineering & Management, B.V.M Engineering College, Vallabh Vidyanagar-Gujarat-India, jaydev_2004@yahoo.co.in ABSTRACT: Horizontal directional drilling (HDD) was pioneered in the United States for an innovative road boring contractor who successfully completed a 183 m river crossing using a modified rod pushing a tool with no steering capability. Horizontal Directional Drilling (HDD) is defined as A steerable system for the installation of pipes, conduits, and cables in a shallow arc using a surfaced launched drilling rig. Traditionally HDD is applied to large scale crossings such as rivers in which a fluid filled pilot hole is drilled without rotating the drill string, and this is then enlarged by a wash over the pipe and back reamer to the size required by the product. It is currently an efficient, safe, cost effective method for highway bores and is the current industry standard for Trenchless technology for bores between 2 and 48-inch diameters. The main objective is to install such services without using traditional trenching methods, helping to avoid any unnecessary environmental impact and provide added security. This paper focus on new era for construction sector of underground utilities in India. Keywords: Horizontal Directional Drilling, Environmental, Underground, Utilities INTRODUCTION Horizontal Directional Drilling (HDD) is defined as A steerable system for the installation of pipes, conduits, and cables in a shallow arc using a surfaced launched drilling rig. Traditionally HDD is applied to large scale crossings such as rivers in which a fluid filled pilot hole is drilled without rotating the drill string, and this is then enlarged by a wash over the pipe and back reamer to the size required by the product. This technology has been in existence since the 1970 s. It is currently an efficient, safe, cost effective method for highway bores and is the current industry standard for Trenchless technology for bores between 2 to 48-inch in diameters. Horizontal directional drilling(hdd) is also known as Directional Boring. HDD is used when trenching or excavating is not practical. HDD is used for installing infrastructure such as telecommunications and power cable conduits, water lines, sewer lines, gas lines, oil lines, product pipelines, and environmental remediation casings. The main objective is to install such services without using traditional trenching methods, helping to avoid any unnecessary environmental impact and provide added security. 1

2 Figure 1: Entry Pit Figure 2: Exit Pit COMPONENTS A directional drill rig sized for the job at hand. Drill rods linked together to form a drill string for advancing the drill bit and for pulling back reamers and products. A transmitter/receiver for tracking and recording the location of the drill and product. A tank for mixing and holding drilling fluid. A pump for circulating the drilling fluid. PROCESS OF HDD Figure 3: Components of Horizontal Directional Drilling (HDD) Stage 1 :- Site Investigation and Design Stage 2:-Pilot Hole Drilling Stage 3:-Hole Enlargement Stage 4:- Pullback 2

3 Stage 1:- Site Investigation and Design Project designs start with the gathering of necessary information. This information includes the, site survey including locations of existing pipelines and services, and a Geotechnical site investigation. This will determine the tools necessary to successfully drill the crossing and determine the design. Stage 2:- Pilot Hole Drilling Figure 4: Site Investigation and Design The pilot hole is drilled from the entry point to the exit point following a previously designed profile and alignment. The drilling tools and rig equipment selected for each job is largely determined based on the results of the Geotechnical investigation and the size of the crossing (length and diameter). During the pilot hole drilling, a directional guidance system is used to navigate the pilot hole along its pre-designed profile. The entry angle of the drill string is typically 8 to 16 degrees. The drill string, is advanced by a combination of rotation torque and thrust supplied by the rig. So that it allows the operator to change the direction to navigate the pilot hole along its pre-designed profile. There are many types of bits designed to navigate through different types of soil, from clays and sands to rock. Most drill bits have a slant-face. 3

4 To move in a straight line, the rig operator both rotates and pushes the drill string. To change direction, the operator, stops rotating the drill string and pushes the string. The path will change in the direction that the bit s slant-face is pointing. On-board controls allow the operator to monitor the orientation of the bit and the change in the general direction of the bore. A walkover tracking system is used to help guide and monitor the location of the bore. The system is comprised of a transmitter and receiver. The transmitter emits a continuous magnetic signal, which is picked up by a portable handheld receiver. Stage 3:- Hole Enlargement Figure 5: Pilot Hole Drilling In small diameter crossings the pipeline may be directly installed in the pilot hole. However in most cases pilot hole enlarging, known as prereaming, will be necessary. Pre-reaming is required to provide a bore diameter large enough so that the pipeline can be installed in the drilled crossing. Based on the final desired diameter and soil conditions this process may include one or more stages. Figure 6: Hole Enlargement 4

5 Stage 4:- Pullback Once the drilled hole has been enlarged to the required diameter and cleaned adequately, the pipeline is installed. When applicable, the pipeline is preassembled in a single string and placed on rollers prior to pullback. For pullback, a reamer is connected to the drill pipe. Behind the reamer a swivel is connected allowing the drill pipe to rotate the reamer without allowing the transfer of torque to the product pipe. The drill pipe is then pulled back towards the entry point until the pipeline is fully installed. WHY CHOOSE HDD? Figure 7: Pullback 5

6 Trenchless Method For Establishing New Lines : In the past, the only way to establish a new line was through expensive and damaging trench work. With directional boring you can get the advantages of Trenchless methods where a preexisting line is either unavailable or needs to be relocated. Saves Money : A significant portion of the cost of a new line goes into digging for a new line and putting back excavated material. Tap into significant cost savings and skip the damage that comes with traditional methods used to establish new lines. Saves Time : Drilling not only saves money, but it also creates a significant time savings. Without trenches to dig or material to put back, the completion time on projects using drilling is significantly less than with conventional methods. MAJOR SECTORS OF HDD The HDD industry is divided into three major sectors according to their typical application areas. Large-diameter HDD (maxi-hdd) Medium-diameter HDD (midi-hdd) Small-diameter HDD (mini-hdd, also called guided boring) System Description Product Pipe Diameter Maxi-HDD 600-1,200 mm (24-48 in) Midi-HDD mm (12-24 in) Depth Range 61 m (200 ft) 23 m (75 ft) Table 1 Typical Application Areas Drive Length 1,818 m (6,000 ft) 274 m (900 ft) Torque kn-m kn-m Thrust/ Pullback Machine Weight (Including truck) Typical Application 445 kn 267 kn River, Highway crossings kn 160 kn Under rivers and roadways Mini-HDD mm (2-12 in) ADVANTAGES OF HDD 4.5 m (15 ft) 182 m (600 ft) 1.3 kn-m Source: (Iseley and Gokhale, NCHRP Synthesis 1997) 89 kn 80 kn Telecom and Power cables, Gas lines Avoid damage to your building, landscaping and Hardscaping. Trenchless option for establishing a new line. Significant cost savings compared to conventional line installation methods. Shorter completion times & safer for the environment. Less invasive than the traditional open cut. Surface disturbance is minimized. More secure than above ground or trenched installations. Can make deep installations and avoid surface obstacles such as rivers, railways, or highways. 6

7 DISADVANTAGES OF HDD Special equipment and very high degrees of operation skill is required. As the cost of the equipment and the operation are high, bore length should be sufficient in order for it to be economical. Mainly steel pipe is being installed by the method. CONCLUSIONS In the present era of new developments, Trenchless technology is quite useful. The HDD is such a type of Trenchless technology which has the benefit of significant cost saving compared to the conventional line installation methods. Though the greater initial cost of special equipment and greater degree of operational skill requirement, this method is faster and avoids damage to an existing structure and operation time is very less, so very good alternative to many conventional time consuming methods. ACKNOWLEDGEMENT The Authors thankfully acknowledge to Dr. C. L. Patel, Chairman, Charutar Vidya Mandal, Er.V.M.Patel, Hon.Jt. Secretary, Charutar Vidya Mandal, Mr. Yatinbhai Desai, Jay Maharaj construction, Dr. F.S.Umrigar, Principal, B.V.M. Engineering College, Dr. L.B.Zala, Head and Professor, Civil Engineering Department, Dr. A. K. Verma, Head and Professor, Structural Engineering Department, B.V.M. Engineering College, Vallabh Vidyanagar, Gujarat, India for their motivations and infrastructural support to carry out this research. REFERENCES Diamond, W. P. and Oyler, D. C., 1986, "Direction Drilling for Degasfication of Coalbeds in Advance of Mining", in Methane Control Research: Summary of Results, , U.S. Bureau of Mines Bulletin 687, pp Guidelines,planning horizontal directional drilling for pipeline construction,,canadian association of petroleum producers(capp), CAPP publication Diamond, W. P., Bodden, W. R., Zuber, M. D., and Schraufnagel, R. A., 1989, "Measuring the Extent of Coalbed Gas Drainage after 10 Years of Production at the Oak Grove Pattern, Alabama", in Proceedings of the 1989 Coalbed Methane Symposium, April 17-20, 1989, Tuscaloosa, Alabama, pp Directional Crossing Contractors Association (DCCA). (1994). Guidelines for a Successful Directional Crossing Bid. Dr. Neeraja Lugani Sethi, Pre- Requisites for Trenchless Technology. Civil Engineering and Construction Review October Iseley, T. and Gokhale, S. (1997). Trenchless installation of conduits beneath roadways. NCHRP Synthesis 242. Jagadish Chandra, Trenchless Technology in India: Need of the New Millennium. Civil Engineering and Construction Review October Maninder Singh, Techniques of Trenchless Technology In Use In India. Civil Engineering and Construction Review October

8 Youssef Hashash & Jamie Javier University of Illinois at Urbana-Champaign, Evaluation of Horizontal Directional Drilling, November wtd/construction/seattle/smagnolia CSOStorage 8