Maximum drilling length of HDD method
The horizontal drilling technology has long ceased to be exotic. A lot of companies offer various drilling services. When standard methods of trench laying do not work, horizontal directional drilling become a unique opportunity. This idea was published in 1960s in the US by Martin Cherrington, who founded the first company specializing in trenchless technology.
The possibilities of trenchless pipelaying depend on maximum drilling length. It is possible to lay a gas or pipeline under the standing buildings, objects with high cultural value, highways by the HDD method. In some cases, horizontal directional drilling provides significant advantages. For example, the use of HDD allows to save money in comparison with trench methods, while deep trenching (from 1.5 m). In order to choose an appropriate contractor, it’s necessary to define possibilities of trench boring.
Nowadays trenchless technologies are developing rapidly. Due to economic efficiency and broad options, engineers offer a wide variety of equipment for trenchless pipeline construction in different price ranges.
HDD methods vary in the presence of casing pipes, possibility of wash drilling, controllability.
The essential difference of horizontal directional drilling technology is the absence of trenches between starting and finishing drilling points.
In general, the HDD technology consists of several stages:
- Pilot bore drilling. At this stage, the primary routing for communications is carried out by use of a drill head. In modern mid-range drilling rigs this process is under the direct control of the operator, who can receive the signals about position of the drilling head by using a locator. The operator can correct the direction of movement of the drill head, which makes it possible to create a finishing point at the project site.
- The reamer is connected to the drilling rig instead of the drill head for the well reaming. With its help the well increases in diameter to required dimensions. For laying utility lines by the HDD method, the optimal well diameter is bigger than the pipe diameter by 30%.
- Laying pipelines.
Diameter of laying pipes
In order to lay the pipeline without obstructions, the pipe diameter must be somewhat smaller than the well size. The diameters of the produced wells depend heavily on the type of drilling rig. Enlargement of the well diameter leads to shortening of the pipeline.
What is the minimum and maximum length of the transition?
The possibilities of horizontal directional drilling are large enough. Drill length can range from hundred meters to several kilometers, depending on the technical characteristics of the drilling rig. The greatest distance is defined by total length of the drill rods, which used in the drilling facilities.