Challenges and Prospects of the Use of Horizontal Directional Drilling Techniques for Laying Oil and Gas Pipelines in Nigeria

Abstract

Nigeria pipelines especially the petroleum and petroleum product pipelines are always vandalized by the sabotage. Huge amount of money is expended to put the damaged pipeline in good shape, and petroleum and petroleum product transfer is sometimes hampered due to leakages and damages caused by the oil thieves. Also huge money is being budgeted yearly to secure the pipelines. To combat this problem, Horizontal Directional Drilling (HDD) is being proposed. HDD is a method of installing underground pipes and conduits along a prescribed bore path from the surface, with minimal impact to the surrounding area. Installation lengths up to 6500ft and depth of 200ft have been completed and diameters up to 48 in. have been installed in shorter runs. The process begins when a directional bore machine pushes a bore head connected to hollow pipe into the ground at an angle. As each joint of drill pipe is pushed into the ground a new one is added behind. In rock, a mud motor, which converts the hydraulic pressure of the drilling fluid into mechanical rotation, is used to rotate the bit and the drill pipe is not continuously rotated. Steerage is accomplished by aligning the angle of the mud motor to the desired direction. This paper investigates the challenges and prospects of using the HDD technique to lay pipeline to a greater depth/distance that will be inaccessible by the oil thieves. The construction process (pilot hole, reaming and pullback) along with the major components (drill rig, drill pipe, slurry, slurry recycling, survey equipment, drill bits, and reamers) is discussed. The advantages of cost reduction, and environmental, social and time benefits were examined in this study. The challenges of proper soils information, subsurface conditions, training and knowledge, drilling fluids and binding of the drill pipe and reamer/bit are highlighted.