![]() ![]() Artificial filter-packing technology is not yet perfected for HDD wells. The well intake structure typically consists of either standalone screen or prepacked screen. Once the borehole has been reamed to the required diameter, well completion materials are pushed into place in the open borehole. In most cases with blind wells, the borehole is stabilized by casing and cementing through the curvature prior to drilling the horizontal portion of the borehole. Reaming is accomplished by pushing and rotating the drill bit as it follows the pilot bore to its completion depth. Once the targeted depth is reached, the drill string is rotated to horizontal for the required distance before being terminated in the subsurface at the targeted point ( Fig. Blind wells drilled for oilfield applications may start either vertically or on an incline, while those drilled for environmental applications, due to their shallow true vertical depth (TVD), generally start only on an incline. ![]() Blind wells are generally used in deep subsurface oilfield applications to increase recovery of oil and gas, or in relatively shallow environmental remediation applications where the target formation is located under a building or some other obstacle. HDD wells are classified as being either blind or continuous. The recent introduction of fusible PVC piping has allowed PVC piping to be more widely used in HDD installations of water pipe, telecommunications, and electrical conduit that were previously dominated by PE pipes. Most pipelines installed by this process are fusion-welded continuous HDPE pipes, although steel, ductile iron, and PVC pipes are also installed by this process. HDD is often employed when an open-cut excavation is unsuitable, such as at a railway crossing or river crossing. During the last stage of reaming, the service pipe is pulled back into the bore. Successive reamers are then pulled back to enlarge the bore diameter to the desired size. The bore is steered to create an initial hole at the required line and grade. First, a pilot bore is made with a suitably sized drilling rig. Horizontal directional drilling (HDD) consists of several installation steps. Thomas Walsh, in Applied Plastics Engineering Handbook (Second Edition), 2017 32.25.2 Horizontal Directional Drilling Most pipelines installed by this process are fusion welded continuous HDPE pipes, although steel, ductile iron, and PVC pipes are also installed by this process. HDD is often employed when an open cut excavation is unsuitable such as at a railway crossing or river crossing. ![]() First, a pilot bore is made with a suitable-sized drilling rig. Horizontal directional drilling consists of several installation steps. Thomas Walsh, in Applied Plastics Engineering Handbook, 2011 34.29.2 Horizontal Directional Drilling (HDD) The Plastic Piping Industry in North America ![]()
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