AIR HAMMER OPTIMIZATION USING ACOUSTIC TELEMETRY

OPTIMISATION D'UN MARTEAU PNEUMATIQUE A L'AIDE DE TELEMESURE ACOUSTIQUE

English Abstract

A system and method of optimizing air hammer performance in a well drilling rig whereby an electronic acoustic receiver (EAR) is used to monitor the effects of changing any of the operating parameters under his or her control. The signals are visually presented to the drill operator based on an EAR's output, along with current settings, allowing the drill operator to dial in the parameters of his or her choice until the optimal frequency of the air hammer is regained. The visual output displays the amplitude response of acoustic waves being detected and decoded at the surface by the EAR. The drill operator can observe and use this information to determine the changes necessary in the operating parameters to return the hammer to optimal frequency, and thus optimal performance.

French Abstract

L'invention concerne un système et un procédé permettant d'optimiser les performances d'un marteau pneumatique dans un appareil de forage de puits, de sorte qu'un récepteur acoustique électronique (EAR) soit utilisé pour surveiller les effets de la modification de l'un quelconque des paramètres fonctionnels sous son contrôle. Les signaux sont présentés visuellement au foreur sur la base d'une sortie d'EAR, en même temps que les paramètres actuels, ce qui permet au foreur de composer les paramètres de son choix jusqu'à retrouver la fréquence optimale du marteau pneumatique. La sortie visuelle affiche la réponse en amplitude des ondes acoustiques qui sont détectées et décodées sur la surface par l'EAR. Le foreur peut observer et utiliser ces informations pour déterminer les modifications qu'il faut apporter aux paramètres fonctionnels afin que le marteau revienne à une fréquence optimale, et ainsi à des performances optimales.

Claims

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CLAIMS

Having thus described the invention, what is claimed as new and desired to be
secured by
Letters Patent is:

1. A system for optimizing air hammer performance in a well drilling rig
including a drillstring, which comprises:
an air compressor connected to the drillstring;
a bit connected to the drillstring;
a controller connected to the compressor and the drillstring;
an air hammer attached to a downhole end of the drillstring, said air hammer
having
performance parameters including a percussive rate corresponding to an air
flow
from said compressor and bit weight, a penetration rate, and a frequency
response;
an acoustic telemetry subsystem associated with the air hammer and adapted for
transmitting said frequency response via acoustic waves along the drillstring;
and
said controller programmed to adjust an operating parameter of said air hammer
in
response to said frequency response, said operating parameters including air
flow
from said compressor and said bit weight.

2. The according to claim 1, further comprising:
an electronic acoustic receiver (EAR) connected to the drillstring and the
controller, said
EAR being adapted for receiving acoustic waves therefrom and detecting the air

hammer frequency response.

3. The system according to claim 1, further comprising:
a display device connected to said controller and adapted for displaying a
real-time graphic
display of the frequency response of said air hammer.

4. The system according to claim 1, further comprising:
said controller being adapted to adjust said air flow to said air hammer, said
air- flow
comprising an operating parameter of said air hammer.


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5. The system according to claim 1, further comprising:
said controller being adapted to adjust said bit weight on said air hammer,
said bit weight
comprising an operating parameter of said air hammer.

6. The system according to claim 1, further comprising:
an actuator, connected to said compressor;
said controller adapted for operating said actuator; and
said controller including a manually selectable input for selecting parameters
such as bit
weight, air flow, and hammer rate, and a feedback input, the feedback input
being
responsive to said frequency response.

7. A system for optimizing air hammer performance in a well drilling rig
including a drillstring, which comprises:
an air compressor connected to the drillstring;
a bit connected to the drillstring;
a controller connected to the compressor and the drillstring;
an air hammer attached to a downhole end of the drillstring, said air hammer
having
performance parameters including a percussive rate corresponding to an air
flow
from said compressor and bit weight, a penetration rate, and a frequency
response;
an acoustic telemetry subsystem associated with the air hammer and adapted for
transmitting said frequency response via acoustic waves along the drillstring;
and
said controller programmed to adjust an operating parameter of said air hammer
in
response to said frequency response, said operating parameters including air
flow
from said compressor and said bit weight.
an electronic acoustic receiver (EAR) connected to the drillstring and the
controller, said
EAR being adapted for receiving acoustic waves therefrom and detecting the air

hammer frequency response.
a display device connected to said controller and adapted for displaying a
real-time graphic
display of the frequency response of said air hammer.
said controller adapted to adjust said air flow to said air hammer, said air
flow comprising
an operating parameter of said air hammer.


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said controller adapted to adjust said bit weight on said air hammer, said bit
weight
comprising an operating parameter of said air hammer.
an actuator, connected to said compressor;
said controller adapted for operating said actuator; and
said controller including a manually selectable input for selecting parameters
such as bit
weight, air flow, and hammer rate,, and a feedback input, the feedback input
being
responsive to said frequency response.

8. A method of optimizing air hammer performance in a drilling rig including
a wellhead and a drillstring, which method includes the steps of:
providing a compressor at the wellhead;
providing an air hammer;
providing a bit connected to said drillstring;
mounting said air hammer on a downhole end of said drillstring;
pumping compressed air from said compressor to said air hammer via said
drillstring;
producing a frequency response with said air hammer in operation;
transmitting said frequency response with acoustic telemetry to the wellhead
via said
drillstring;
providing a controller at said wellhead;
connecting the controller to the compressor;
providing a feedback signal from said air hammer via said drillstring to said
controller; and
adjusting an operating parameter with said controller for optimizing
performance of said
air hammer, said operating parameters including air flow from said compressor
and
said bit weight.

9. The method of claim 8, including the additional steps of:
providing an electronic acoustic receiver (EAR) at the wellhead;
connecting the EAR to the drillstring and the controller; and
detecting with the EAR an air hammer frequency response in the form of
acoustic waves.
10. The method of claim 8, including the additional steps of:


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displaying as visual output on said display device an amplitude response of
said acoustic
waves being detected and decoded;
processing said amplitude to show a Fourier transform of said amplitude
response; and
selecting other information relevant to the operation of the air hammer drill
system on said
display device.

11. A method of optimizing air hammer performance in a drilling rig
including a wellhead and a drillstring, which method includes the steps of
providing a compressor at the wellhead;
providing an air hammer;
providing a bit connected to said drillstring;
mounting said air hammer on a downhole end of said drillstring;
pumping compressed air from said compressor to said air hammer via said
drillstring;
producing a frequency response with said air hammer in operation;
transmitting said frequency response with acoustic telemetry to the wellhead
via said
drillstring;
providing a controller at said wellhead;
connecting the controller to the compressor;
providing a feedback signal from said air hammer via said drillstring to said
controller; and
providing an electronic acoustic receiver (EAR) at the wellhead;
connecting the EAR to the drillstring and the controller;
detecting with the EAR an air hammer frequency response in the form of
acoustic waves.
displaying as visual output on said display device an amplitude response of
said acoustic
waves being detected and decoded;
processing said amplitude to show a Fourier transform of said amplitude
response; and
selecting other information relevant to the operation of the air hammer drill
system on said
display device; and
adjusting the operating parameters with said controller for optimizing
performance of said
air hammer, said operating parameters including air flow from said compressor
and
said bit weight.

Description

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AIR HAMMER OPTIMIZATION USING ACOUSTIC TELEMETRY
CROSS REFERENCE TO RELATED APPLICATION

[00011 This application claims priority in U.S. Provisional Patent
ApplicationNo.
61/187,200, filed June 15, 2009, which is incorporated herein by reference.
This application relates to U.S. Patent Application No. 12/697,93'8, filed
February 1, 2010, which is-incorporated herein by reference.

BACKGROUND OF THE INVENTION
1. Field of the invention

[00021 The present invention relates generally to telemetry apparatus and
methods, and more particularly to a method utilizing telemetry data for the
optimization of the performance of air hammer type drilling systems for the
well drilling and production (e.g., oil and gas) industry.

2. Description of the Related Art

[00031 Acoustic telemetry is a method of communication used, far example, in
the well drilling and production industry. In a typical drilling environment,
acoustic extensional carrier waves from an acoustic telemetry device are
modulated in order to carry information via the drillpipe as the transmission
medium to the surface. Upon arrival at the surface, the waves are detected,
decoded and displayed in order that drillers, geologists and others helping
steer
or control the well are provided with drilling and formation data.

[00041 It is well known that acoustic extensional waves can propagate through
drill pipe if they contain frequencies that correspond with the passbands
formed
by the regular mechanical dimensions of drill pipe. Use of this communications
channel enables real-time drilling telemetry to be the means by which drilling
parameters (such as directional and formation) measured relatively close to
the


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drill bit are sent to the surface. At the surface, the signals can be detected
by a
sensitive accelerometer whereby, after filtering and amplifying the signal,
well
information may be made available to the driller. An example of such a system
is an Electronic Acoustic Receiver (EAR), which is detection and amplifying
means to connect to a processor module and an RF system, thereby enabling
two-way communication between the driller and the EAR.

[00051 Many practical mechanical means are utilized when drilling for oil and
gas. A modem and popular approach is to `hammer' at rock formations rather
than using traditional rotary drills, which are limited to moving forward.
Hammer drilling requires that the drilling fluid be a gas.rather than a
liquid,
whereas rotary drilling requires the drilling fluid to be a liquid.
Traditional
rotary drill liquid motors used to rotate the drill bit are replaced by an air
hammer in modem hammer drilling machines. This air hammer pounds the rock
into small pieces by a rapid axial reciprocating motion.

[00061 Air hammers require a number of parameters to be in balance in order to
achieve efficient forward progress. The main issues are to balance the air
flow
to the hammer with an appropriate weight of the hammer bit. If there is too
much weight on the bit the hammer stroke. is reduced, resulting, in reduced
penetration of the rock. Similarly, if there is too little weight on the bit
then the
work done by the hammer is reduced, again resulting; in reduced rock
penetration. If the air flow powering the hammer is too.-small, rock fragments
may not clear the device and may jam the mechanism, whereas too, much
airflow can result in hammer bit damage. A balance of these parameters results
in an ideal frequency and optimized rate of rock penetration.


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BRIEF SUMMARY OF THE INVENTION

[00071 It is an object of the present invention to immediately provide
feedback to
drill operators utilizing-air hammer drill systems. This invention provides
the
driller a direct visual indication of this event, and immediately shows
effects
due to changing any ofthe parameters under his or her control (e.g. air flow
and
hammer weight).

[00081 The signals are provided to the driller by the EAR's output being
visually
presented to the driller, along with current settings. This allows the driller
to dial
in the parameters of his or her choice until the optimal frequency is
regained.

[00091 The visual output on screen displays the amplitude response of acoustic
waves being detected and decoded at the surface by the EAR. It is then
possible to
process these amplitudes so that they show the Fourier transform of the
amplitude
response.

[00101 The advantage to such a system is that the transform shows the
frequency
response in real time of the air hammer working. As the hammer changes the
rate
at which it strikes the rock, the frequency display will faithfully follow by
means
of the acoustic channel from the hammer to the EAR at the surface.

[00111 It is this information that the drill operator can observe and use to
determine the changes necessary in the system parameters to return the hammer
to
optimal frequency, and thus optimal performance. Any deviations from this
necessitated by changing rock conditions can be accommodated by surface
control, and the effect of these changes become immediately apparent, thereby
enabling to just timely feedback to the driller but also the means to automate
the
changes necessary for optimal performance.


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BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In the accompanying drawings, which illustrate the principles of the
present invention and an exemplary embodiment thereof:

[00131 FIG. I is a diagram of the normal passbands of Range 2 drilling pipe;
and
[0014] FIG. 2 is an example of an EAR's output being visually presented on a
computer screen.

[001] FIG. 3 is a diagram of a typical drilling rig, including an air hammer
optimization system embodying an aspect of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] In the following description, reference is made to "up" and
".down"waves,
but this is merely for convenience and clarity. It is to be understood that
the
present invention is not to be limited in this manner to conceptually simple
applications in acoustic communication from the downhole end of the drill-
string
to the surface. It will be readily apparent to one skilled in the art that the
present
invention applies equally, for example, of subsurface stations, such as would
be
found in telemetry repeaters.

[0017] Referring. to the drawings in more detail, FIG. 1 displays the normal
passbands of Range 2 pipe. This is one example of what information may be
provided during drilling operations, and the present invention is in no way
limited
to only Range 2 pipe.


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[00181 FIG. 2 shows an example of a visual display a drill operator may see
while
operating the air hammer drill with the present invention. The display would.
appear on a computer screen, accessible by the driller, and directly connected
to
the air hammer drill system as well as the EAR. Results displayed on the
screen
are to be in real time, with the amplitude response of acoustic waves being
detected and decoded at the surface displayed on the screen. Other information
relevant to the operation of the air hammer drill system is individually
selectable
and viewable on screen.

[0019] The reference numeral 2 generally designates an air hammer optimization
system. Without limitation on the generality of useful applications of the
system
2, an exemplary application is in a drilling rig 4 as shown in a very
simplified
form in FIG. 3. For example, the rig 4 can include a derrick 6 suspending an
air
hammer actuator 8, which receives gas via a compressor hose 20 for pumping
downhole into a drillstring 22. The drillstring 22 and the air hammer actuator
8
are connected to the system 2 which includes an EAR/detector 16, an amplifier
14, a filter 12, and a controller 10. The drillstring 22 connects to multiple
drill
pipe sections 24, which are interconnected by tool joints 18, thus forming a
drillstring of considerable length, e.g. several kilometers, which can be
guided
downwardly and/or- laterally-sin l-known to niigues- The dri-listring-22-
terminates at an air hammer apparatus 32. In FIG. 3 we have shown acoustic
modules (isolator 30 and transmitter 28) as separate from the conventional air
hammer simply for clarity. Other rig configurations can likewise employ the
air
hammer optimization system of the present invention, including top-drive,
coiled
tubing, etc.

[00201 Information such as that contained in FIG. I will pass up a
drrillstring or up
the drill pipe and be read by an EAR. This information will then be decoded,
and
relevant information will be displayed on screen. Relevant information
includes,
but is not limited to, bit weight, air flow, hammer rate, and relevant;
frequencies.
This information can be used by the drill operator or by a system designed to


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automatically return the drill operation to optimal rock penetration by
recalibrating bit weight, air flow, and other parameters.

Representative Drawing