Pipe connection through a pulling head and a swivel Pertinent hydraulic and caliber tests are carried out before the pullback. It has welded joints covered with shrink sleeves ready for pullback. The pipeline should be constructed behind the insertion pit on a path aligned with the axis of the borehole. The installation of the pipeline inside the borehole is the most critical stage, as the borehole is gradually occupied by an element alien to the drilling process and precautions should be increased so as to facilitate its smooth insertion. This is the final stage and the one which we have been working for. it allows precise tracking below large water surfaces.it is not affected by ferromagnetic materials, such as rocks of volcanic origin or neighboring metallic elements or pipelines, which change the magnetic field,.it finds the true north in accordance with the Earth’s rotation, which is different and more useful than the magnetic north,.Even though less frequently used because of its greater operational complexity, in combination with accelerometers, it provides an extremely accurate tracking tool, possessing three significant advantages over the magnetometers: It travels in the probe inside the nonmagnetic housing, and, as do the electromagnetic systems, feeds and connects with computers in the control cabin through cables threaded through the drill pipe string. Solenoid Tracking system with GyrocompassĪ gyrocompass is a nonmagnetic compass constructed so as to be able to use the precision of its effect in the guidance of more complex directional drilling. This coil creates an independent magnetic field which allows for a better control of the drill path depth and advance by means of triangulation. So as to achieve greater control of the drill path, electromagnetic guidance systems are linked with the layout of an electrified coil on ground surface. Machine Screens Controller Magnetic grid or solenoid verification system Here they are decoded within an interface which feeds the computer and by means of a program then shows the location of the probe. These signals are transmitted by means of electronic impulses which travel through a cable threaded through the drill string to the drillers’ cabin. In this system the probe emits signals corresponding to its inclination, dial position and magnetic azimuth. Probe emitting radio frequency signals 2.- Electromagnetic wire line tracking The drilling tool must be guided along its underground path and to that end three different tracking methods are used: 1.- Tracking with walkover system Installs underground urban networks without the need of open cut trenches.Guarantees long term integrity of installed network.Minimizes slope and coastline disturbance. Attenuates adverse effects of construction process.Ensures continuity of land and river traffic.Bypasses underground networks and obstacles.Assists passage of fish and protects aquatic plants.Reduces execution time by increasing productivity and efficiency.It is fundamentally used for the installation of general product, oil and gas pipelines, multi duct casings and electrical and fiber optic communication lines. Horizontal Directional Drilling (HDD) is an environmentally friendly technology used for the underground installation of pipeline networks by non-destructive means below interferences such as watercourses, river valleys, swamps, erosive furrows, paved roads or highways, rail tracks, hills and buildings.
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