Horizontal directional drilling system and method
An adapter assembly for connection between a drill head of a horizontal directional drilling system and a utility line. A central housing body defines an interior space. A first end cap is secured to a first end of the central housing body. A second end cap is secured to a second end of the central housing body and configured to attach to the utility line. An electromagnetic (EM) sensor, including an antenna arrangement is configured to emit and receive EM signals, provided within the interior space of the central housing body. A connection structure at the first end cap is configured to attach to the drill head for pullback. The central housing body is at least partially transmissive to the EM signals, and the EM sensor is configured to receive electrical power and transmit data via wiring connected through at least one of the first and second end caps.
1. An adapter assembly for connection between a drill head of a horizontal directional drilling system and a utility line, the adapter assembly comprising:
a central housing body defining an interior space;
a first end cap secured to a first end of the central housing body;
a second end cap secured to a second end of the central housing body and configured to attach to the utility line;
an electromagnetic (EM) sensor, including an antenna arrangement configured to emit and receive EM signals, provided within the interior space of the central housing body; and
a connection structure at the first end cap configured to attach to the drill head for pullback,
wherein the central housing body is at least partially transmissive to the EM signals emitted and received by the EM sensor,
wherein the EM sensor is configured to receive electrical power and transmit data via wiring connected through at least one of the first and second end caps.
2. The adapter assembly of claim 1 , further comprising a camera facing outward from the second end cap.
3. The adapter assembly of claim 1 , wherein the central housing body is cylindrical-shaped.
4. The adapter assembly of claim 1 , wherein the first and second end caps have threaded portions and are secured to the central housing body, respectively, via first and second threaded adapters.
5. The adapter assembly of claim 1 , wherein the first and second end caps are anodized aluminum.
6. The adapter assembly of claim 1 , wherein the second end cap is configured to attach to the utility line directly.
7. The adapter assembly of claim 1 , wherein the second end cap is configured to attach to the utility line indirectly through a product attachment housing of the adapter assembly, wherein the second end cap and the product attachment housing are connected through a pair of wire ropes.
8. The adapter assembly of claim 1 , further comprising an electrical control subassembly provided within the central housing body, the electrical control subassembly including a downhole power line communication (PLC) encoder and a signal processor circuit connected to the antenna arrangement.
9. The adapter assembly of claim 8 , wherein the antenna arrangement includes a first antenna portion and a second antenna portion, and the first antenna portion is provided between the electrical control subassembly and the second antenna portion, wherein the wiring connects the second antenna portion to the electrical control subassembly, and the wiring extends through the first antenna portion.
10. The adapter assembly of claim 1 , wherein the central housing body is entirely transmissive to the EM signals emitted and received by the EM sensor.
11. The adapter assembly of claim 1 , wherein the central housing body includes antenna windows transmissive to the EM signals emitted and received by the EM sensor.
12. The adapter assembly of claim 1 , wherein the wiring includes internal conductors within the central housing body, external conductors outside the central housing body, and a connector establishing electrical contact between the internal and external conductors, wherein the connector is received in a corresponding cavity formed in the second end cap.
13. The adapter assembly of claim 12 , wherein the internal conductors are bonded to the connector to form a sealed connection.
14. A horizontal directional drilling system comprising:
a horizontal directional drilling machine;
a drill string terminating at a drill head and configured to be driven by the horizontal directional drilling machine to create an underground borehole extending at least partially horizontally between an entry point and an exit point;
an electromagnetic (EM) sensor, including an antenna arrangement, provided within a sensor housing coupled to the drill string; and
a product connection housing having a portion configured to secure a utility line for installation into the borehole during pullback of the drill string toward the entry point,
wherein the product connection housing is coupled to the sensor housing through a pair of flexible high-strength conductors, and
wherein the pair of flexible high-strength conductors are configured as load-bearing members to carry pullback loads between the sensor housing and the product connection housing.
15. The horizontal directional drilling system of claim 14 , wherein the product connection housing includes a body and two end caps secured at opposite ends thereof, wherein a first one of the two end caps establishes mechanical connections with the pair of flexible high-strength conductors and a second one of the two end caps provides the portion configured to secure the utility line.
16. The horizontal directional drilling system of claim 14 , wherein the sensor housing includes a cylindrical central housing body, a first end cap, and a second end cap, and wherein the central housing body is at least partially transmissive to EM signals emitted and received by the EM sensor.
17. The horizontal directional drilling system of claim 14 , wherein the pair of flexible high-strength conductors are stainless steel aircraft cable.
18. The horizontal directional drilling system of claim 14 , wherein the pair of flexible high-strength conductors are connected to an uphole power line communication (PLC) module for simultaneous half-duplex transmission of data from the electromagnetic sensor and power delivery from a power supply to the electromagnetic sensor.
19. The horizontal directional drilling system of claim 14 , further comprising an uphole module configured to receive data from the EM sensor, wherein the uphole module is connected to the EM sensor for transmission of the data through the pair of flexible high-strength conductors, through internal non-load-bearing conductors within the product connection housing, and through additional conductors extending along the utility line.
20. The horizontal directional drilling system of claim 14 , wherein the antenna arrangement of the EM sensor includes an electrical control subassembly, a first antenna portion, and a second antenna portion, and wherein wiring that connects the second antenna portion to the electrical control subassembly extends through the first antenna portion.