Data Transfer In A Two-Pipe Directional Drilling System
A downhole tool for a dual member drill string for detecting information and sending a signal containing that information up a wireline. The tool comprises a beacon supported on a housing for collection of orientation information. The wireline is located within a drill stem in the housing. The beacon communicates a signal to the wireline using a slip ring or a receiver for receiving a wireless signal from the beacon. The downhole tool may have a steering feature such as a deflection shoe for changing the path of the downhole tool.
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This application claims the benefit of provisional patent application Ser. No. 61/447,762, filed on Mar. 1, 2011, the entire contents of which are incorporated herein by reference.
FIELD OF THE INVENTIONThe present invention relates to a data transfer method and apparatus for a two-pipe horizontal directional drilling (HDD) system.
SUMMARY OF THE INVENTIONThe present invention is directed to a downhole tool for a dual member drill string. The drill string comprises an inner member and an outer member. The downhole tool comprises a housing coupled to the outer member, an inner drive shaft coupled to the inner member, a beacon supported by the housing, a wireline disposed within the inner member, and a data relay connection. The beacon detects orientation information and transfers a signal. The wireline carries the signal. A data relay connection receives the signal from the beacon and transmits it to the wireline.
In another embodiment, the present invention is directed to a method for communication of data along a drill string. The drill string comprises an inner member and an outer member. The method comprises detecting information at a beacon wherein the beacon is rotationally coupled to the outer member, transmitting a signal containing the information from the beacon to a receiver supported on a downhole tool, wherein the receiver is rotationally coupled to the inner member, and transmitting the information from the receiver to a wireline for transmission of information along a drill string to an operator.
Directional drilling systems which utilize a dual member drill string for transferring thrust and rotation from the drilling unit to the bit and drilling head for creating underground bores are disclosed in U.S. Pat. No. 5,490,569 issued to Brotherton et al., the contents of which are incorporated by reference. Most commonly with these systems, the housing of the dual member drill string connects to a downhole tool having a bend, or other feature, for biasing the drilling bit to one side of the bore hole to create a curved bore path when the housing is advanced forward without rotation of the housing such as the system disclosed in the Brotherton patent. The inner member of the dual member drill string is generally connected to a drill bit which cuts the soil or rock at the end of the bore hole when rotated. Such systems have proven effective in drilling a variety of ground conditions ranging from homogeneous soil, to cobbles, to solid competent rock.
With reference now to
Usually, it is advantageous to include orientation sensors and transmitters on the outer member of a drill string 12 or at an exterior of a downhole tool 10 housing. However, in order to facilitate the integrity and stability of a wireline through the drill string 12, it is advantageous to include the wireline within the inner member of a drill string 12. As the inner member and outer members are independently rotatable, it is not feasible to simply place a wireline inside the outer member, or to run a wireline from the outer member to the inner member as rotation may cause the wire to wrap around inner elements of the downhole tool 10 and drill string 12. Therefore, this invention provides a downhole tool 10 for transferring a signal sent by a beacon or transmitter on an outside of a downhole tool to a wireline on an inside of a drill string.
With reference to
The steering feature 28 of the downhole tool 10 biases the bit 30 to one side of a bore path. As shown, the steering feature 28, or deflection shoe, comprises an integrally formed bent sub, but also may comprise an externally attached structure or a portion of the beacon cover 27. Alternatively, a housing 20 where the longitudinal axis of the inner drive shaft 18 is offset from the longitudinal axis of the housing could serve as the biasing mechanism. Steering feature 28 may be located either in front of beacon 26 as shown in
The wireline 22 is disposed within the inner drive shaft 18 and connected to the data relay receiver 24 and is adapted to transfer information through the inner drive shaft 18 and inner member 14 to a drilling machine comprising an above ground receiver (not shown). In addition the wireline 22 may be adapted to carry electrical power from the uphole for the electronic components in data relay receiver 24, and in beacon 26 in those embodiments where an electrical connection exists between the wireline and the beacon. Alternatively, the inner drive shaft 18 and inner member 14 may themselves transfer information through the conduction of electric signals to and from the data relay receiver 24 as discussed in the text related to
The beacon 26 provides information about the downhole tool 10 orientation, position, and other operational parameters of the beacon and conditions proximate the downhole tool 10. The beacon 26 is located in a side of the housing 20 of the downhole tool 10 as shown. The beacon 26 may be end-loaded or side-loaded in the housing 20. Information is sent via a data signal to a receiver, such as the data relay receiver 24 or an above ground receiver 13. In a preferred embodiment, the information is encoded on a modulated dipole magnetic field produced by the beacon 26. In each of the embodiments of the current invention, the beacon 26 may be adapted such that beacon information may be transmitted to the walkover tracking system 13 and along wireline 22 substantially simultaneously.
In addition, the beacon 26 may be configured to provide a reading of azimuth, or longitudinal heading of the downhole tool 10. To do this the beacon 26 may comprise magnetic field sensors to determine the heading of the downhole tool 10 relative to the earth's magnetic field, or to an artificially induced magnetic field created by passing a current through a loop on the surface of the ground as is known in the art of directional drilling. To provide an azimuth reading based on a magnetic field reading, the housing 20 and other components of the downhole tool 10 are preferably composed of a durable non-magnetic material such as high strength austenitic stainless steel, or a nickel-based metallic alloy.
In the embodiment shown in
Referring now to
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When utilizing the gyroscope 64 located within the rotating inner drive member, a special technique may be used for mapping the bore. Gyroscopic sensors are generally limited in the rate of rotation of the instrument can undergo and still provide an accurate measurement of angle or rate of angular movement, depending on the type of gyroscope. In addition, rotation of the drill stem while mapping may provide a completely erroneous reading of position, since the axis of the bore hole is generally a linear feature with only slight curvature. One preferred technique for utilizing the gyroscope 64 with the sensor package 62 to map the bore hole is given below.
When performing rotary drilling operations in rock formations, it is common for a driller once they have completed advancing a drill string 12 to its full extent, to retract the drilling tool 10 one full joint of pipe such that it is at the same position as at the end of the forewardmost advance of the previous pipe and then thrust the bit back down to the bottom of the hole while pumping drilling fluid. A result of this action is a large surge of drilling fluid flowing back from the face of the hole. This helps to clear any cuttings which may have settled around the drilling tool 10 during the drilling operation. For mapping the bore, the driller will advance the drilling tool 10 to the extent allowed by the drill string 12. He or she will then retract the drilling tool as if performing a standard swab of the hole. Once the drilling tool 10 is retracted the full length of the drill string 12, the rotation of the inner member 14 and inner drive shaft 18 will be stopped. At this time the gyroscope 64 will be powered up and allowed to settle. The drilling tool 10 is then advanced to the bottom of the bore hole without rotation of the inner drive shaft 18. As the drilling tool 10 is advanced, angular changes, or rate changes transmitted by the gyroscope 64 are recorded. A carriage position transducer (not shown) located on boring unit 11 will simultaneously measure the distance of advance of the pipe going into the hole. The angular data, or angular rate data, from the gyroscope 64 will then be integrated with the carriage advance distance serving as the incremental value, dx, for the integration and the new position of the drilling tool at the end of the borehole can then be calculated in a stepwise fashion as the bore proceeds.
To facilitate steering of the drilling tool 10, the sensor package 62 may also provide an indication of a roll position and, thus, the orientation of the steering feature 28 of the drilling tool. One method for accomplishing this task is to have the gyroscopic sensor housed in a non-magnetic material as disclosed earlier in this text. A protrusion 67, or roll timing pin, composed of a ferrous, magnetic material may extend from the interior of the data transmission sub to a position near the outer surface of the compartment where the gyroscopic sensor is housed as shown in
Alternatively, if the entire drill string 12 included outer member 16 with single-orientation castellations 54 (
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Various modifications can be made in the design and operation of the present invention without departing from the spirit thereof. Thus, while the principal preferred construction and modes of operation of the invention have been explained in what is now considered to represent its best embodiments, as herein illustrated and described, it should be understood that the invention may be practiced otherwise than as specifically illustrated and described.
Claims
1. A downhole tool for a dual member drill string comprising an inner member and an outer member, the downhole tool comprising:
- a housing coupled to the outer member;
- an inner drive shaft coupled to the inner member;
- a beacon supported by the housing to detect orientation information and transfer a signal;
- a wireline disposed within the inner member to carry the signal; and
- a data relay connection to receive the signal from the beacon and transmit it to the wireline.
2. The downhole tool of claim 1 wherein the data relay connection comprises a receiver coupled to the inner member.
3. The downhole tool of claim 1 wherein the data relay connection comprises a slip ring, the slip ring comprising:
- a first portion coupled to the drill stem in electrical communication with the wireline; and
- a second portion coupled to the housing and in electrical communication with the beacon;
- wherein the first portion is in electrical communication with the second portion.
4. The downhole tool of claim 1 wherein the data relay connection comprises an inductive data connection between the inner and outer members.
5. The downhole tool of claim 1 wherein the downhole tool comprises a steering feature.
6. The downhole tool of claim 5 wherein the steering feature is located between the data relay connection and the beacon.
7. The downhole tool of claim 5 wherein the steering feature consists of a bend in the downhole tool.
8. The downhole tool of claim 5 wherein the steering feature is located at an opposite side of the outer member from the beacon.
9. The downhole tool of claim 1 wherein the data relay connection is located between the beacon and the drill string.
10. The downhole tool of claim 1 wherein the housing comprises a castellation for transmission of torque from the outer member.
11. The downhole tool of claim 1 wherein the beacon is located on the housing.
12. The downhole tool of claim 11 wherein the data relay connection comprises a receiver coupled to the inner member.
13. The downhole tool of claim 11 wherein the data relay connection comprises a slip ring, the slip ring comprising:
- a first portion coupled to the drill stem in electrical communication with the wireline; and
- a second portion coupled to the housing and in electrical communication with the beacon;
- wherein the first portion is in electrical communication with the second portion.
14. The downhole tool of claim 1 further comprising a gyroscope sensor.
15. The downhole tool of claim 1 further comprising a receiver housing coupled to the drill stem and extending beyond the housing, wherein the data relay connection is secured to the receiver housing.
16. The downhole tool of claim 16 wherein the beacon is secured to the receiver housing.
17. The downhole tool of claim 16 wherein the data relay connection comprises:
- a coil adapted to receive the signal from the beacon; and
- an electronics board adapted to configure the signal for transmission through the wireline.
18. A method for communication of data along a drill string, the drill string comprising an inner member and an outer member, the method comprising:
- detecting information at a beacon wherein the beacon is rotationally coupled to the outer member;
- transmitting a signal containing the information from the beacon to a receiver supported on a downhole tool, wherein the receiver is rotationally coupled to the inner member; and
- transmitting the information from the receiver to a wireline for transmission of information along a drill string to an operator.
19. The method of claim 18 wherein the signal is transmitted from the beacon to the receiver wirelessly.
20. The method of claim 18 wherein the signal is transmitted from the beacon to the receiver through a slip ring, wherein the slip ring comprises a first portion rotationally coupled to the inner member and a second portion rotationally coupled to the outer member.
21. The method of claim 18 wherein the signal is transmitted from the beacon to the receiver through an inductive coupling, wherein the inductive coupling comprises a first portion rotationally coupled to the inner member and a second portion rotationally coupled to the outer member.
22. The method of claim 18 wherein the information from the beacon may be read either through an above ground receiving unit, or through a wireline within the drill string.
Type: Application
Filed: Mar 1, 2012
Publication Date: Jan 17, 2013
Applicant: The Charles Machine Works, Inc. (Perry, OK)
Inventors: Richard F. Sharp (Perry, OK), Travis W. Woodson (Orlando, OK), Floyd R. Gunsaulis (Perry, OK)
Application Number: 13/410,075
International Classification: E21B 47/02 (20060101);