Downhole Turbine Communication
In one aspect of the present invention a downhole drill string assembly includes a bore there through to receive a flow of drilling fluid, a signal generator that produces a signal in the drilling fluid by rotating within the flow, a processing unit disposed within the assembly, and a flow guide that directs drilling fluid to the signal generator. The flow guide is in communication with the processing unit so that in response to commands received from the processing unit, the signal generator produces a signal in the drilling fluid by the flow guide changing its position.
Measurement while drilling is a system that can be used to communicate between a downhole tool and surface equipment in a downhole drill string. Such system may include mud pulse telemetry, which sends signals through the fluid in the drill string's bore. The prior art discloses mud pulse telemetry systems.
One such mud pulse telemetry system is disclosed in U.S. Pat. No. 5,215,152 to Duckworth, which is herein incorporated by reference for all that it contains. Duckworth discloses a rotating pulse valve for use in a mud pulse telemetry system is presented. In accordance with the invention, a valve is diametrically mounted in a channel of a segment of a drill string wherein drilling fluids flows. The valve comprises blades which are configured so as to be impelled (i.e., rotated) by the flow of the drilling fluid. An escapement mechanism is employed to restrain the valve in selected positions thereby at least partially obstructing the flow of the drilling fluid which results in generating positive pressure pulses or waves in the drilling fluid in response to downhole conditions.
Another such mud pulse telemetry system is disclosed in U.S. Pat. No. 6,097,310 to Harrell, which is herein incorporated by reference for all that it contains. Harrell discloses a mud pulse telemetry system uses a downhole pulser to produce sequences of positing and/or negative pulses according to a selected pattern. Positive pulses, a negative pulses, and combinations thereof may be produced. A flow rate sensor at the surface measures changes in the flow rate at the top of the wellbore instead of or in addition to changed in the pressure. The flow rate changes are detectable even though the pressure pulses themselves may have a poor signal to noise ratio. This enables the invention to function effectively in underbalanced drilling wherein the use of light muds with a high gas content is required. One embodiment of the invention uses a conventional downhole pulser with the main valve closed and the pilot valve operating in a direct pulse mode.
BRIEF SUMMARY OF THE INVENTIONIn one aspect of the present invention a downhole drill string assembly includes a bore there through to receive a flow of drilling fluid, a signal generator that produces a signal in the drilling fluid by rotating within the flow, a processing unit disposed within the assembly, and a flow guide that directs drilling fluid to the signal generator. The flow guide is in communication with the processing unit so that in response to commands received from the processing unit, the signal generator produces a signal in the drilling fluid by the flow guide changing its position.
The flow guide may be located up stream and proximal to the signal generator. It may be comprised of a plurality of flow blades wherein the plurality of flow blades is mechanically connected to a rotatable plate. The flow guide may alter the flow of the drilling fluid such that the flow guide itself produces a signal. If the signal is generated from the flow guide itself or from the signal generator, the flow guide determines the frequency and the bandwidth of the signal. The signal produced may be a sound wave or a pressure wave.
The signal generator may include a turbine which would be exposed to the drilling fluid. A fluid guide, in communication with the processing unit, may alter the angle of attack of the drilling fluid across the turbine or the fluid may be altered by the flow guide so that the turbine produces a signal.
In the presence of a turbine, the signal generator may include a rotary valve. The rotary valve is located down stream and in mechanical communication with the turbine, and exposed to the drilling fluid. The rotary valve may comprise a stator plate and a rotor plate. Both the stator plate and the rotor may comprise a plurality of ports. The rotor plate may rotate around a center axis according to the rotation of the turbine. As the rotor plate rotates, the port on the rotor plate and the ports on the stator plate align or misalign, thus, altering the flow of the drilling fluid producing a signal.
The downhole drill string assembly may also include a signal sensor. The signal sensor would be exposed to the drilling fluid and in communication with the processing unit. In response to a signal received by the signal sensor, the signal generator may repeat the signal.
A plurality of signal generators may be disposed within the drill string.
Changing the rotational speed of the turbine will change the frequency that the ports align and misalign, thereby, changing the signal's frequency. In some embodiments, the signal generated by the signal generator may be a sound wave, a pressure wave or combinations thereof.
Thus, the signal's frequency is dependent on the flow guide's position. The position of the flow blade may cause a more or less aggressive attack angle. In some embodiments, the flow blades 401 may even rotate such that the fluid flow is blocked off. By changing the generated signal's frequency, encoded signals may be transmitted through the fluid in the drill string's bore. One advantage of the present invention, the is quick response time to change the turbine's rotation, and thereby, change the signal generators frequency change.
Communicating quickly in a well bore is essential, especially in emergency situations. Further, when multiple sensors and downhole instrumentation are trying to send signals to the surface through the signal generator, quick signals are desirable. The prevent invention's response time to changing the signal generator's frequency enables more encode messages to be sent to the surface in a shorter amount of time.
Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention.
Claims
1. A downhole drill string assembly, comprising:
- a bore there through to receive a flow of drilling fluid;
- a signal generator that produces a signal in the drilling fluid when rotating within the flow;
- a processing unit disposed within the assembly; and
- a flow guide that directs drilling fluid to the signal generator;
- wherein the flow guide is in communication with the processing unit so that in response to commands received from the processing unit, the signal generator produces a signal in the drilling fluid by the flow guide changing its position.
2. The assembly of claim 1, wherein flow guide is in communication with the processing unit so that in response to commands received from the processing unit the flow guide alters the flow of the drilling fluid such that a signal is produced.
3. The assembly of claim 1, wherein the signal generator comprises a turbine disposed within the bore and exposed to the drilling fluid.
4. The assembly of claim 3, wherein the flow guide is in communication with the processing unit so that in response to commands received from the processing unit, the flow guide alters an angle of attack of the drilling fluid across the turbine.
5. The assembly of claim 3, wherein the flow guide is in communication with the processing unit so that in response to commands received from the processing unit, the flow guide alters the flow of the drilling fluid across the turbine such that the turbine produces a signal.
6. The assembly of claim 3, wherein the signal generator comprises a rotary valve disposed within the bore, is located down stream from and in mechanical communication with the turbine, and exposed to the drilling fluid.
7. The assembly of claim 5, wherein the rotary valve comprises a stator plate and a rotor plate with each comprising a plurality of ports.
8. The assembly of claim 7, wherein as the rotor plate rotates around a center axis, the ports on the rotor plate and the ports on the stator plate align or misalign thus altering the flow of the drilling fluid such that a signal is produced.
9. The assembly of claim 1, further comprising a signal sensor disposed within the bore and exposed to the drilling fluid and in communication with the processing unit.
10. The assembly of claim 9, wherein in response to a signal received by the signal sensor, the signal generator repeats the signal.
11. The assembly of claim 1, further comprising a plurality of signal generators located within the drill string.
12. The assembly of claim 1, wherein the flow guide is up stream and proximal to the signal generator.
13. The assembly of claim 1, wherein the flow guide determines the frequency of the signal.
14. The assembly of claim 1, wherein the flow guide determines the bandwidth of the signal.
15. The assembly of claim 1, wherein the signal is a sound wave.
16. The assembly of claim 1, wherein the signal is a pressure wave.
17. The assembly of claim 1, wherein the flow guide comprises a plurality of flow blades.
18. The assembly of claim 17, wherein the plurality of flow blades is mechanically connected to a rotatable plate that moves the blades.
Type: Application
Filed: May 12, 2010
Publication Date: Nov 17, 2011
Inventors: David R. Hall (Provo, UT), Scott Dahlgren (Alpine, UT)
Application Number: 12/778,623
International Classification: E21B 47/18 (20060101);