Horizontal Directional Drilling-Length Detection Technology While Drilling Based on Bi-Electro-Magnetic Sensing

Abstract

The drilling length is an important parameter in the process of horizontal directional drilling (HDD) exploration and recovery, but there has been a lack of accurate, automatically obtained statistics regarding this parameter. Herein, a technique for real-time HDD length detection and a management system based on the electromagnetic detection method with a microprocessor and two magnetoresistive sensors employing the software LabVIEW are proposed. The basic principle is to detect the change in the magnetic-field strength near a current coil while the drill stem and drill-stem joint successively pass through the current coil forward or backward. The detection system consists of a hardware subsystem and a software subsystem. The hardware subsystem employs a single-chip microprocessor as the main controller. A current coil is installed in front of the clamping unit, and two magneto resistive sensors are installed on the sides of the coil symmetrically and perpendicular to the direction of movement of the drill pipe. Their responses are used to judge whether the drill-stem joint is passing through the clamping unit; then, the order of their responses is used to judge the movement direction. The software subsystem is composed of a visual software running on the host computer and a software running in the slave microprocessor. The host-computer software processes, displays, and saves the drilling-length data, whereas the slave microprocessor software operates the hardware system. A combined test demonstrated the feasibility of the entire drilling-length detection system.

Downhole Applications of Magnetic Sensors

“…MR sensors have been used in commercial applications operating at temperatures up to 225 °C, pressures up to 20,000 psi and mechanical shocks up to 1500 g [ 132 ]. Recent research has also shown that MR sensors can be used to calculate the length of directional wells, where the length can be used in fitting the drilling profile, computing the deviation, designing the drilling profile, and developing an algorithm for automated directional drilling [ 133 ], to measure NMR signals at room temperature [ 134 ] and operate at temperatures up to 175 °C for 5000 h with low energy consumption [ 128 ]. Apart from meeting the criteria for use in harsh environments low power consumption is a key advantage in these sensors since power is at a premium in downhole environments.…”

Electro-Mechanical Design and Creep Analysis of Proposed Enclosure for Flexible Gas Insulated Line Regarding Subsurface Metropolitan Applications of High-Voltage Transmission Lines

“…Moreover, FGIL provides following advantages in contrast to the conventional rigid GIL: Acceleration dampers are not required; there is no need for corrosion protection; the incorporation of structural flexibility; a substantially reduced bending radius and lay length, as well as lesser required land area at bends. Moreover, studies [38][39][40] mentioned that flexible enclosures and cables, like FGIL, are feasible for horizontal directional drilling (HDD) based subsurface laying technique which eliminates the trench requirement and is advantageous regarding cable and pipe laying in urban localities. FGIL is basically comprised of a flexible-stranded-conductor, flexible-thermoplasticenclosure, open cell foam of significant structural strength for concentric conductor alignment and a compressed mixture of dielectric gases as the primary insulation medium.…”