U.S. patent application number 14/451630 was filed with the patent office on 2016-02-11 for system and method for communicating complex downhole information.
This patent application is currently assigned to National Oilwell Varco, L.P.. The applicant listed for this patent is National Oilwell Varco, L.P.. Invention is credited to Michael GAINES, Robert Eugene MEBANE, III.
Application Number | 20160040526 14/451630 |
Document ID | / |
Family ID | 55267056 |
Filed Date | 2016-02-11 |
United States Patent
Application |
20160040526 |
Kind Code |
A1 |
MEBANE, III; Robert Eugene ;
et al. |
February 11, 2016 |
SYSTEM AND METHOD FOR COMMUNICATING COMPLEX DOWNHOLE
INFORMATION
Abstract
A system and method for communicating downhole information
through a wellbore to a surface location includes a drill string
with a downhole tool, a pump for flowing drilling mud through the
drill string and wellbore, a valve for flow restriction of the
drilling mud, a sensing module for measuring downhole conditions in
first and second orientations of the downhole tool, an actuator
between two static positions, and a detector for measurement values
at the surface location correlative to time between changes of
pressure of the drilling mud. The time between pressure changes, as
the actuator moves between static positions, conveys encoded data
to the detector. The encoded data is compiled from downhole
conditions measured by the sensing module, in addition to
orientation of the downhole tool. Complex downhole conditions
dependent on knowing the multiple orientations of the sensing
module can now be communicated by a pressure releasing encoding
system.
Inventors: |
MEBANE, III; Robert Eugene;
(Austin, TX) ; GAINES; Michael; (Houston,
TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
National Oilwell Varco, L.P. |
Houston |
TX |
US |
|
|
Assignee: |
National Oilwell Varco,
L.P.
|
Family ID: |
55267056 |
Appl. No.: |
14/451630 |
Filed: |
August 5, 2014 |
Current U.S.
Class: |
175/45 |
Current CPC
Class: |
E21B 7/04 20130101; E21B
34/06 20130101; E21B 47/24 20200501; E21B 47/024 20130101 |
International
Class: |
E21B 47/12 20060101
E21B047/12; E21B 34/06 20060101 E21B034/06; E21B 7/04 20060101
E21B007/04; E21B 47/024 20060101 E21B047/024 |
Claims
1. A system for communicating downhole information through a
wellbore to a surface location comprising: a drill string with a
downhole tool at an end thereof, said downhole tool having a first
orientation and a second orientation; a pumping means for pumping
drilling mud into the wellbore, said pumping means being positioned
at the surface location and being in fluid connection with said
drill string; and a valve means for providing a flow restriction to
said drilling mud passing through said downhole tool, said valve
means being suitable for controlling a flow of said drilling mud in
said downhole tool; a sensing module being positioned in said
downhole tool and being comprised of a first sensor means for
measuring a first downhole condition in said first orientation, and
a second sensor means for measuring a second downhole condition in
said second orientation, said first orientation being different
from said second orientation; an actuator means cooperative with
the valve means for fixing said valve means in at least two static
positions in timed relation to any downhole information from said
sensing module; and a detector means positioned at the surface
location and cooperative with said drilling mud passing through
said downhole tool for providing a measurement value at the surface
location correlative to time between changes of pressure of said
drilling mud.
2. The system for communicating downhole information, according to
claim 1, wherein said first orientation is generally vertical,
wherein said second orientation is generally lateral, wherein said
first sensor means is comprised of an inclination sensor, said
first downhole condition being angle of inclination, and wherein
said second sensor means is comprised of an inclination sensor,
said second downhole condition being toolface inclination.
3. The system for communicating downhole information, according to
claim 1, wherein said first orientation is generally vertical,
wherein said second orientation is more than 20 degrees from
vertical, wherein said first sensor means is comprised of an
inclination sensor calibrated for a vertical direction, said first
downhole condition being angle of inclination, and wherein said
second sensor means is comprised of an inclination sensor
calibrated for a toolface direction, said second downhole condition
being toolface inclination.
4. The system for communicating downhole information, according to
claim 1, wherein said sensing module further comprises: a third
sensor means for measuring a third downhole condition in said first
orientation and in said second orientation.
5. The system for communicating downhole information, according to
claim 4, wherein said third sensor means is comprised of an azimuth
sensor, said third downhole condition being direction of slant in
said first orientation, said third downhole condition being
direction of toolface inclination in said second orientation.
6. The system for communicating downhole information, according to
claim 1, further comprising: a means for switching between
measuring said first downhole condition by said first sensor means
and measuring said second downhole condition by said second sensor
means, in coordination with said downhole tool switching between
said first orientation and said second orientation
respectively.
7. The system for communicating downhole information, according to
claim 1, said detector means comprising: means for detecting
orientation of said downhole tool; a logic means for correlating a
sensed time between controlled static pressure drops across the
valve means to the first downhole condition, the second downhole
condition, and orientation of said downhole tool; and a display
means for providing a generally real-time humanly perceivable
indication of downhole conditions, according to said orientation of
said downhole tool.
8. A system for communicating downhole information through a
wellbore to a surface location comprising: a drill string with a
downhole tool at an end thereof, said downhole tool having a first
orientation and a second orientation; a pumping means for pumping
drilling mud into the wellbore, said pumping means being positioned
at the surface location and being in fluid connection with said
drill string; and a valve means for providing a flow restriction to
said drilling mud passing through said downhole tool, said valve
means being suitable for controlling a flow of said drilling mud in
said downhole tool; a sensing module being positioned in said
downhole tool and being comprised of a sensor means for measuring a
first downhole condition in said first orientation and measuring a
second downhole condition in said second orientation, said first
orientation being different from said second orientation; an
actuator means cooperative with the valve means for fixing said
valve means in at least two static positions in timed relation to
any downhole information from said sensing module; and a detector
means positioned at the surface location and cooperative with said
drilling mud passing through said downhole tool for providing a
measurement value at the surface location correlative to time
between changes of pressure of said drilling mud.
9. The system for communicating downhole information, according to
claim 8, wherein said sensor means is comprised of an azimuth
sensor, said first downhole condition being direction of slant in
said first orientation, said second downhole condition being
direction of toolface in said second orientation.
10. The system for communicating downhole information, according to
claim 8, further comprising: means for detecting orientation of
said downhole tool; and a logic means for correlating a sensed time
between controlled static pressure drops across the valve means to
downhole conditions, according to orientation of said downhole
tool.
11. The system for communicating downhole information, according to
claim 8, wherein said sensor means is selected from a group
consisting of an azimuth sensor, a magnetometer, a transducer, a
gamma scintillator, nuclear detectors, an accelerometer, and a
magnetic resonance imaging device.
12. The system for communicating downhole information, according to
claim 11, further comprising: means for detecting orientation of
said downhole tool; and a logic means for correlating a sensed time
between controlled static pressure drops across the valve means to
downhole conditions, according to orientation of said downhole
tool.
13. A method for communicating downhole information through a
wellbore to a surface location, said wellbore having a drilling mud
circulation system therein, the circulation system being through a
drill string, a downhole tool, and an interior of said wellbore,
the method comprising the steps of: positioning a valve means in a
fluid passageway of said downhole tool; positioning an actuator
means cooperative with said valve means for fixing said valve means
in at least two static positions; forming a flow restriction within
the circulation system at said downhole tool, said flow restriction
being comprised of said valve means and said actuator means;
sensing said first downhole condition in said first orientation;
applying a quantified pressure of drilling mud in the circulation
system against said flow restriction; releasing a first percentage
of pressure within said flow restriction at a first time; releasing
a second percentage of pressure within said flow restriction at a
second time, a time between said first time and said second time
being correlative to said first downhole condition; determining
said first downhole condition at a surface location by sensing the
time between said first time and said second time and according to
orientation of said downhole tool; sensing said second downhole
condition in said second orientation, said first orientation being
different from said second orientation; repeating releases of
percentages of pressure within said flow restriction at additional
times, at least one of said additional times being correlative to
said second downhole condition; and determining said second
downhole condition at a surface location by sensing the time
between said additional times and according to orientation of said
downhole tool.
14. The method for communicating downhole information, according to
claim 13, further comprising the steps of: switching between
determining said first downhole condition by said first sensor
means and determining said second downhole condition by said second
sensor means, in coordination with said downhole tool switching
between said first orientation and said second orientation
respectively.
15. The method for communicating downhole information, according to
claim 13, wherein the step of sensing said first downhole condition
in said first orientation comprises taking a measurement with a
first sensor, and wherein the step of sensing said second downhole
condition in said second orientation comprises taking a measurement
with a second sensor.
16. The method for communicating downhole information, according to
claim 15, wherein said first sensor is comprised of an inclination
sensor, said first downhole condition being angle of inclination,
and wherein said second sensor is comprised of an inclination
sensor, said second downhole condition being toolface
inclination.
17. The method for communicating downhole information, according to
claim 13, further comprising the steps of: sensing a third downhole
condition in said first orientation and in said second orientation;
repeating releases of percentages of pressure within said flow
restriction at additional times, said additional times being
correlative to said third downhole condition; and determining said
third downhole condition at a surface location by sensing the time
between said additional times and according to orientation of said
downhole tool.
18. The method for communicating downhole information, according to
claim 13, wherein the step of sensing said first downhole condition
in said first orientation comprises taking a measurement with a
sensor, wherein the step of sensing said second downhole condition
in said second orientation comprised taking a measurement with said
sensor.
19. The method for communicating downhole information, according to
claim 18, wherein said sensor means is comprised of an azimuth
sensor, said first downhole condition being direction of slant in
said first orientation, said second downhole condition being
direction of toolface in said second orientation.
20. The system for communicating downhole information, according to
claim 18, further comprising the steps of: detecting orientation of
said downhole tool; and correlating a sensed time between
controlled static pressure drops across the valve means to first
and second downhole conditions, according to orientation of said
downhole tool.
Description
RELATED U.S. APPLICATIONS
[0001] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
REFERENCE TO MICROFICHE APPENDIX
[0003] Not applicable.
BACKGROUND OF THE INVENTION
[0004] 1. Field of the Invention
[0005] The present invention relates to a system and method for
transmitting downhole information to a surface location. More
particularly, the present invention relates to a system and method
for communicating downhole information from multiple orientations
of a downhole tool through pressure release encoding. The present
invention also relates to a system and method with a means to
detect vertical and lateral orientation of a downhole tool. More
particularly, the present invention relates to adjusting
interpretation of data from the sensors measuring downhole
conditions, according to the detected orientation of the downhole
tool.
[0006] 2. Description of Related Art Including Information
Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
[0007] Natural resources, such as ground water, natural gas, and
petroleum, are deposited underground. Drilling is part of a process
for extracting those resources from their remote location. A well
or borehole can be created by use of a drilling rig to rotate a
drill string, which has a drill bit attached at its end in order to
bore into the ground to a desired depth. Drill collars and drill
pipe sections add length, weight and support along the drill string
as the borehole deepens, and different types of drill bits cut into
all types of rock formations and soil combinations. In rotary
drilling, the drill bit is rotated by rotating the drill string at
the surface. Rotary drilling can be efficient for boring vertically
into the ground, because there is only one direction of the drill
bit. In directional drilling, the drill bit can be rotated by a
downhole mud motor or other device, including types of rotary
assemblies, coupled to the drill bit. The drill bit can deviate
from vertical, so as to slant the borehole or even angle the
borehole towards horizontal. In a steerable drill string, the mud
motor is bent at a slight angle to the centerline of the drill bit
so as to create a side force that directs the path of the drill bit
away from a straight line.
[0008] Drilling fluid or drilling mud pumps through the inside of
the drill string, out of the drill bit by nozzles or jets, and up
the annulus to the surface, in order to create the proper physical
and hydrostatic conditions to safely drill the well. Additionally,
the rock cuttings are removed from the borehole in the drilling mud
circulation flowing to the surface.
[0009] The distal end of a drill string is the bottom hole assembly
(BHA), which includes the drill bit, the drilling sub and drill
collars. In "measurement while drilling" (MWD) or "logging while
drilling" (LWD) applications, sensing modules in the BHA, or other
downhole tools, provide information concerning the downhole
conditions, such as direction of the drilling. The actual sensors
may include devices to measure angle of inclination, azimuth and
toolface direction, including magnetometers and accelerometers.
This information can be used, for example, to control the direction
in which the drill bit should adjust, during directional drilling
or as steerable drilling.
[0010] Sensing modules can also provide useful downhole information
in real-time with regard to other aspects of the drilling
operation. For example, ultrasonic transducers monitor resistivity
of high frequency wavelength signals bounced back from the rock
formation downhole so that characteristics of the formation can be
determined. Water or hydrocarbons or rock at the downhole depth can
be mapped in real time. Other sensing modules can include magnetic
resonance imaging (MRI), gamma scintillators, and nuclear
detectors. Radioactivity, porosity, and density can be other
downhole conditions detected by some of these other sensing
modules.
[0011] The downhole information collected by the sensing modules is
transmitted to the surface for analysis. Mud pulse telemetry
receives data from the sensing modules, digitally encodes the data,
and actuates a pulser to send pressure pulses within the flow of
drilling mud. A receiver at the surface interprets the pressure
pulses to collect the encoded data. Conventional mud pulsers
require a large amount of power to actuate the valve and modulate
the drilling mud sufficient for detection at the surface.
Oscillating drilling mud for a pressure transducer to detect at the
surface is difficult to power and control. More recent developments
in mud pulse telemetry include a pressure release encoding system
to reduce the power requirements and to increase efficiency for
generating pulses through the drilling mud. In particular, only a
small amount of power is needed because the mud pump becomes the
primary energy source of the pressure release encoding system. A
valve means restricts mud flow, and a brake means progressively
releases the valve means to create the pressure drop. The pressure
drop is generated by setting an equilibrium pressure gradient
across the valve means based on the mud pump energy, releasing the
brake means to a second position, and resetting the equilibrium
pressure gradient across the valve means based on the mud pump
energy again. No additional modulation or actuation of the drilling
mud is required by this pressure release encoding system. There is
no additional manipulation of the originating mud pump delivering
the drilling mud to the borehole at a set rate and pressure.
[0012] For pressure release encoding systems, additional
information must be encoded when the downhole tool, such as a BHA,
changes orientation. The actual sensors of a sensing module measure
the same properties in any orientation. However, a change in
orientation of the downhole tool affects how these measured
properties relate to downhole conditions. For example, an
accelerometer measures inclination angle. The deviation from
vertical is detected so that the slant of the borehole can be
monitored for directional drilling. If the orientation changes
toward lateral or horizontal, then the accelerometer can no longer
measure deviation from vertical. Some inclination sensors have a
range of 0 to 20 degrees, such that more than 20 degrees of slant
exceeds the range of the inclinations sensor. There is no more
useful information from the inclinations sensor past 20 degrees
from vertical. Measurements past 20 degrees of slant would show no
changes, but that lack of change does not mean that the downhole
condition is vertical anymore.
[0013] In another example, a magnetometer measures azimuth. The
direction of slant from vertical is detected, not just the slant
itself, can be monitored for directional drilling. When the
orientation changes toward lateral or horizontal, then the
magnetometer measures direction from horizontal, not vertical. The
directional data is no longer direction of slant, but rather
direction of the toolface. The tool face can be moving up, down or
side to side through the formation, not just deviating from
vertical. The same measurements and readings are being produced
from the magnetometer, but the downhole condition has changed from
direction of slant from vertical to direction of the toolface.
[0014] It is an object of the present invention to provide an
embodiment of a system and method for communicating downhole
information through pressure release encoding to the surface.
[0015] It is an object of the present invention to provide an
embodiment of a system and method for communicating downhole
information collected from a sensing module on a downhole tool,
such as a BHA, in different orientations.
[0016] It is another object of the present invention to provide an
embodiment of a system and method for communicating downhole
information collected from a sensing module in vertical and lateral
orientations.
[0017] It is still another object of the present invention to
provide an embodiment of a system and method for communicating
downhole information collected from a sensing module measuring
properties in vertical and lateral orientations.
[0018] It is an object of the present invention to provide an
embodiment of a system and method for communicating downhole
information with a means to detect vertical and lateral orientation
of a downhole tool.
[0019] It is another object of the present invention to provide an
embodiment of a system and method for communicating downhole
information, according to detected orientation of the downhole
tool.
[0020] It is still another object of the present invention to
provide an embodiment of a system and method for communicating
downhole information according to detected orientation of the
downhole tool through pressure release encoding.
[0021] It is an object of the present invention to provide an
embodiment of a system and method for communicating downhole
information from a complex sensing module through pressure release
encoding to the surface.
[0022] These and other objectives and advantages of the present
invention will become apparent from a reading of the attached
specifications and appended claims.
SUMMARY OF THE INVENTION
[0023] Embodiments of the system for communicating downhole
information through a wellbore to a surface location include
communicating complex downhole information dependent upon
orientation. Prior art systems convey simple downhole information
easily, such as the angle of inclination of the drilling sub in a
wellbore. However, the same sensors for angle of inclination no
longer measure that same downhole information, when the orientation
of the downhole tool changes too much. The direction can be
changed, such that the sensor no longer functions or the
calibration no longer corresponds to the new orientation. For
directional drilling beyond straight vertical drilling, the
orientation of the downhole changes frequently. Embodiments of the
system and method of the present invention accommodate the changes
in orientation and communication of this more complex downhole
information through a pressure releasing encoding system.
[0024] The system of the present invention includes a drill string
with a downhole tool at an end thereof, a pumping means for pumping
drilling mud through the wellbore, the drill string, and the
downhole tool, a valve means for providing a flow restriction to
the drilling mud passing through the downhole tool, a sensing
module positioned in the downhole tool, an actuator means
cooperative with the valve means, and a detector means at the
surface location. The drilling mud is fluid and circulates through
the wellbore, drill string, and downhole tool to the surface
location. The wellbore, drill string, and downhole tool are in
fluid connection. The pump means can be located at the surface
location. The valve means controls flow of the drilling mud through
the downhole tool. The actuator means fixes the valve means in at
least two static positions. The actuator means can be a hydraulic
brake that releases the valve to move between the static positions.
The time between pressure changes at the static positions relate to
downhole information from the sensing module. The detector means is
cooperative with the drilling mud passing through the downhole
tool, such that the time between pressure changes at the downhole
tool can be measured at the surface location. The measurement value
of the detector means at the surface location is the communication
of downhole information to the surface location. The changes of
pressure of the drilling mud convey the downhole conditions
measured by the sensing module.
[0025] The downhole tool has a first orientation and a second
orientation. The downhole tool can be a drilling sub, drilling
collar, stabilizer or other attachment to the drill string. The
first orientation is different from the second orientation. The
first orientation can be vertical, while the second orientation is
lateral. Alternatively, the first orientation can be vertical,
while the second orientation is more than twenty degrees from
vertical. As long as the first and second orientations are
different, the sensing module on the downhole tool measures
different downhole conditions with the same sensors. The more
complex downhole conditions can be encoded for communication to the
surface location, instead of the only simple downhole
conditions.
[0026] Embodiments of the sensing module include a first sensor
means for measuring a first downhole condition in the first
orientation, and a second sensor means for measuring a second
downhole condition in the second orientation. The sensor means and
the orientation determines the downhole condition, such that the
downhole condition is now more complex. When the first orientation
is generally vertical and the second orientation is generally
lateral, the first sensor means can be an inclination sensor and
the second sensor means can be an inclination sensor. Thus, the
first downhole condition is angle of inclination, while the sensing
module and downhole tool are in the vertical orientation. The
second downhole condition is toolface inclination, while the
sensing module and downhole tool are in the lateral
orientation.
[0027] Embodiments of the sensing module also include a sensor
means for measuring a first downhole condition in the first
orientation and for measuring a second downhole condition in the
second orientation. The same sensor measures the same property in
different orientations, such that the data relates to different
downhole conditions. Measurements in one orientation relate to a
different downhole condition in another orientation. The sensor
means and the orientation determines the downhole condition, such
that the downhole condition remains complex. When the sensor means
is comprised of an azimuth sensor, such as a magnetometer, the
first downhole condition is the direction of slant from vertical,
and the second downhole condition is direction of toolface. The
directional measurement of the azimuth is the same, but the added
information of orientation makes the downhole condition information
more complex. This additional information can also be communicated
to the surface location with the changes in pressure according to
the actuator means. Other sensors, including an azimuth sensor, a
magnetometer, a transducer, a gamma scintillator, nuclear
detectors, an accelerometer, and a magnetic resonance imaging
device can incorporate the orientation information for more complex
downhole conditions too.
[0028] A switch and logic means can be incorporated in some
embodiments to encode the downhole condition with the complexity of
orientation data. The switch can activate either the first sensor
means or second sensor means, according to position of the downhole
tool. For example, if both the first sensor means and the second
sensor means are inclination sensors, the system can alternate
between sensing the slant of vertical drilling and the direction of
the toolface for lateral drilling. Alternatively, if the
inclination sensor is an accelerometer with a range of twenty
degrees from vertical in the first orientation, the switch
deactivates the inclination sensor above twenty degrees from
vertical, while activating another inclination sensor to cover the
range remaining above twenty degrees from vertical.
[0029] There is a drilling mud circulation system, defined by the
drilling mud flowing through the drill string, the downhole tool,
and the wellbore. Embodiments of the method for communicating the
complex downhole information through the wellbore to the surface
location include positioning the valve means in a fluid passageway
of the downhole tool, positioning the actuator means cooperative
with the valve means for fixing the valve means in at least two
static positions, and forming a flow restriction within the
circulation system at the downhole tool, the flow restriction being
comprised of the valve means and the actuator means. A quantified
pressure of drilling mud in the circulation system is applied
against the flow restriction for a stable pressure powered by the
originating mud pump.
[0030] Next, the first downhole condition in the first orientation
is measured. A first percentage of pressure within the flow
restriction is released at a first time, and the valve means moves
to another static position. A pressure drop in the drilling mud is
created. A second percentage of pressure within the flow
restriction is released at a second time, and the valve means moves
to another status position. Another pressure drop in the drilling
mud is created. The time between the first pressure drop at the
first time and the second pressure drop at the second time is
correlative to the first downhole condition in the first
orientation. The method further includes determining the first
downhole condition at a surface location by sensing the time
between the first pressure drop at the first time and the second
pressure drop at the second time, according to orientation of the
downhole tool. Repeating releases of percentages of pressure,
within the flow restriction at additional times, communicates
additional downhole conditions, such as the second downhole
condition in the second orientation.
[0031] In other embodiments of the method, a single sensor can
measure the first downhole condition in the first orientation and
the second downhole condition in the second orientation. These
sensors do not deactivate or require re-calibration to take
measurements again, such as inclination sensors. These sensors can
be an azimuth sensor, a magnetometer, a transducer, a gamma
scintillator, nuclear detectors, or a magnetic resonance imaging
device. The method of the present invention detects orientation of
the downhole tool, and correlating a sensed time between controlled
static pressure drops across the valve means to first and second
downhole conditions, according to orientation of the downhole tool.
Complex downhole conditions, including orientation data, are
conveyed to the surface location by a pressure release encoding
system.
BRIEF DESCRIPTION OF THE DRAWINGS
[0032] FIG. 1 is a schematic view illustrating the system of the
present invention in association with components of a conventional
drilling rig, showing vertical orientation of the downhole
tool.
[0033] FIG. 2 is a partial exploded sectional view, showing a
downhole tool of the present invention as a drilling sub attached
to the drill string.
[0034] FIG. 3 is a schematic view illustrating the system of the
present invention in association with components of a conventional
drilling rig, showing another orientation of the downhole tool,
deviating from vertical.
[0035] FIG. 4 is a schematic view illustrating the system of the
present invention in association with components of a conventional
drilling rig, showing still another orientation of the downhole
tool, being generally lateral.
[0036] FIG. 5 is a cross-sectional view of a downhole tool with a
sensing module, according to the system of the present
invention.
[0037] FIG. 6 is a block diagram of a microprocessor-based
electronics section of the downhole tool of the present
invention.
DETAILED DESCRIPTION OF THE DRAWINGS
[0038] Referring to FIGS. 1-6, there are embodiments of the system
10 for communicating downhole information through a wellbore 12 to
a surface location 14. FIGS. 1, 3 and 4 show a drilling rig 30
located at a site above the wellbore 12. The drill string 16 is
supported by the derrick 18 and has drill collars 20 and a drill
bit 22. A drill sub 24 is also shown. The drill collars 20, drill
bit 22, and drill sub 24 may be considered downhole tools 28 for
purposes of the present application. Other downhole tools 28, such
as stabilizers on the drill string 16, can also have sensors.
Embodiments of the present invention include any downhole tool 28
with a sensing module 32, valve means 34 and actuator means 36.
[0039] The present invention is a system 10 for communicating
complex downhole information dependent upon orientation of the
downhole tool 28. FIG. 1 shows one orientation of at least one
downhole tool 28 as vertical; the drill sub 24, in particular, can
be considered the downhole tool 28 for an embodiment of the present
invention. FIG. 3 shows another orientation of the downhole tool 28
deviated from vertical; and FIG. 4 shows still another orientation
of the downhole tool 28 as generally lateral. Simple downhole
information can be conveyed to the surface location 14 easily, such
as the angle of inclination of the drilling sub 24 in a wellbore
12. However, the same sensing module 32 for angle of inclination no
longer measure angle of inclination, when the orientation of the
downhole tool 28 changes too much. FIGS. 1 and 3 show the drill sub
24 measuring angle of inclination so that the deviation from
vertical can be measured. FIG. 4 shows a different orientation so
that the sensing module 32 in the drill sub 24 is no longer aligned
to measure angle of inclination for deviation from vertical. The
calibration of the sensing module 32 also may no longer correspond
to the new orientation. For directional drilling beyond straight
vertical drilling, the orientation of the downhole tool 28 changes
frequently. Embodiments of the system 10 and method of the present
invention accommodate the changes in orientation and communication
of this more complex downhole information through a pressure
releasing encoding system.
[0040] FIGS. 1, 3 and 4 also show the circulation system for
drilling mud through the system 10. There is a pumping means 40
connected through stand pipes and mud hoses to the drill string 16.
Drilling mud flows from the pumping means 40, down through the
drill string 16, passing through the downhole tools 28, exiting
from the drill bit 22, up the wellbore 12, and back to the surface
location 14. FIGS. 1, 3 and 4 show the drilling mud in a mud pit 38
at the surface location 14.
[0041] Embodiments of the system 10 of the present invention
include a drill string 16 with a downhole tool 28 at an end
thereof, a pumping means 40 for pumping drilling mud through the
wellbore 12, the drill string 16, and the downhole tool 28, a valve
means 34 for providing a flow restriction to the drilling mud
passing through the downhole tool 28, a sensing module 32
positioned in the downhole tool 28, an actuator means 36
cooperative with the valve means 34, and a detector means 42 at the
surface location 14. FIGS. 1, 3 and 4 show the wellbore 12, drill
string 16, and downhole tool 28 in fluid connection.
[0042] FIGS. 2 and 5 show embodiments of the downhole tool 28 of
the present invention. FIG. 2 shows a partial cut-away view with
the downhole tool 28 having an interior passageway 44 extending
axially longitudinally therethrough. The drilling mud flows through
this passageway 44. A valve means 34, such as any float valve, is
positioned to one end of the downhole tool 28 within passageway 44.
The valve means 34 controls flow of the drilling mud through the
downhole tool 28. FIG. 5 shows a valve means 34 as a float valve
with a housing, shaft and float. FIG. 2 also shows the actuator
means 36 placed in the passageway 44 to engage the valve means 34
in at least two static positions. The actuator means 36 can be a
hydraulic brake that releases the valve means 34 to move between
the static positions. The time between pressure changes at the
static positions relate to downhole information from the sensing
module 32. FIG. 5 shows the actuator means 36 as a hydraulic brake.
The hydraulic brake section includes the hydraulic actuator piston
fixed to a piston rod extended outwardly of a brake housing. The
piston rod has end suitable for abutting the piston stem of the
float valve of the valve means 34. FIG. 5 also shows the sensing
module 32 in the downhole tool 28. The placement is fixed in the
downhole tool 28, such that changing orientation of the downhole
tool 28 changes orientation of the sensing module 32.
[0043] At the surface location 14, embodiments of the present
invention have the detector means 42 cooperative with the drilling
mud passing through the downhole tool 28, such that the time
between pressure changes at the downhole tool 28 can be measured at
the surface location 14.
[0044] FIGS. 1, 3 and 4 shows the detector means 42 comprised of a
computer 46 with a processor and logic means 48 to interpret
encoded data from the drilling mud.
[0045] The measurement value of the detector means 42 at the
surface location is the communication of downhole information to
the surface location 14. The changes of pressure of the drilling
mud convey the downhole conditions measured by the sensing module
32.
[0046] Embodiments of the system 10 of the present invention show
the downhole tool 28 having a first orientation and a second
orientation. The first orientation is different from the second
orientation. The first orientation can be vertical as shown in
FIGS. 1 and 3, while the second orientation is lateral as shown in
FIG. 4. Alternatively, the first orientation can be vertical as in
FIGS. 1 and 3, while the second orientation is defined as more than
twenty degrees from vertical as in FIG. 4. The "more than twenty
degrees from vertical" embodiment is relevant to current
inclination sensors, which are calibrated to measure deviations
from vertical from zero to twenty degrees. Once past twenty
degrees, these inclination sensors no longer function as
calibrated. The information gathered from these inclination sensors
no longer provides useful data. A second sensor must be calibrated
to measure beyond twenty degrees from vertical, and the system must
recognize that data from that inclination sensor is no longer
relevant. As long as the first and second orientations are
different, the sensing module 32 on the downhole tool 28 may be
measuring different downhole conditions with the same sensors. The
data collected must be interpreted and coded differently than a
system with just one orientation. With the present invention, the
more complex downhole conditions can be encoded for communication
to the surface location 14, instead of the only simple downhole
conditions.
[0047] FIG. 6 shows a block diagram of embodiments of the sensing
module 32 in the downhole tool 28 of FIG. 5. The sensing module 32
can include a first sensor means 50 for measuring a first downhole
condition in the first orientation, and a second sensor means 52
for measuring a second downhole condition in the second
orientation. The sensor means 50, 52 and the orientation determines
the downhole condition, such that the data collected for the
downhole condition is now more complex. When the first orientation
is generally vertical and the second orientation is generally
lateral, as in FIGS. 1 and 3 to FIG. 4, the first sensor means 50
can be an inclination sensor and the second sensor means 52 can be
an inclination sensor. In that embodiment, the first downhole
condition is angle of inclination. The deviation from vertical can
be determined for guiding a slanted wellbore 12. Certain formations
underground can be avoided. FIGS. 1 and 3 show this first
orientation with the sensing module 32 and downhole tool 28 being
in a generally vertical orientation. In the same embodiment, the
second downhole condition is toolface inclination because the
sensing module 32 and downhole tool 28 are now in the lateral
orientation, as in FIG. 4. In the second sensor means 52 is an
inclination sensor calibrated for the lateral orientation. The
measurements no longer detect deviation from vertical, but rather
toolface inclination, that is, whether the toolface is moving up,
down or side-to-side. The sensing module 32 recognizes that the
orientation changed so that the first sensor means 50 is no longer
providing useful data for deviation from vertical. The sensing
module 32 also recognizes that the second sensor means 52 is now
active and providing useful information for the inclination of the
toolface. The present invention can now communicate this complex
downhole condition to the surface location 14.
[0048] The embodiments of FIG. 6 show the system 10 with the
microprocessor 100 to coordinate all data to be communicated to the
surface. There is a clock 102, a serial port 104 for connecting to
other downhole tools on the drill string 16, and inputs from the
pressure sensor 106 and valve control 108 of the actuator means 36.
The sensing module 32 data can be compiled for the complex downhole
information conveyed through the drilling mud.
[0049] FIG. 6 also shows a third sensor means 54. This third sensor
means 54 can be an azimuth sensor, a magnetometer, a transducer, a
gamma scintillator, nuclear detectors, an accelerometer, a magnetic
resonance imaging device or other measurement device. The third
sensor means 54 measures a third downhole condition to contribute
further to the encoded data communicated through the drilling mud
to the surface location 14. For example, a third sensor means 54 as
an azimuth sensor gives directional information. When combined with
the first sensor means 50 in the first orientation, the complex
downhole condition is the deviation from vertical and the direction
of the deviation. The encoded data reveals that the wellbore is
slanted and the direction of the slant. This encoded data is more
useful for guiding directional drilling. When combined in the
system 10 with the second sensor means 52 in the second
orientation, the complex downhole condition is the toolface
inclination and direction of the deviation. The encoded data
reveals that the toolface of the downhole tool 28 is moving at an
angle and the direction of that angle, such as moving to the left
or right and how much to the left or right. This encoded data is
more useful for steering around formations and deposits in
directional drilling also.
[0050] The system 10 further includes a switch means to deactivate
the first sensor means 50, when the orientation changes. For
example, when the orientation passes twenty degrees from vertical,
the inclination sensor of the first sensor means 50 can be
deactivated because no more useful information is being measured.
The system 10 will now active the second sensor means 52 to begin
collecting data, since the orientation is now in the second
orientation of the downhole tool 28. The switch means moves back
and forth, as the downhole tool 28 can move in all directions. The
downhole tool 28 may return to a generally vertical orientation,
returning to the first orientation, so that the first sensor means
50 can collect relevant deviation from vertical data again.
[0051] Embodiments of the system 10 include the computer 46 with
the logic means and display means for the encoded data from the
drilling mud. The complex downhole conditions are interpreted from
the encoded data, including the detected orientation of the
downhole tool. Any means to detect the orientation of the downhole
tool contributes to the encoded data from the sensing module 32.
The means for detecting may be compass or bubble devices on
inclination sensors as either the first or second sensor means 50,
52 or a device separate from the first and second sensor means 50,
52.
[0052] An alternate embodiment of the sensing module 32' is shown
in FIG. 6. This embodiment of the sensing module 32' has a single
sensor means 56 for measuring a first downhole condition in the
first orientation and for measuring a second downhole condition in
the second orientation. The same sensor means 56 measures the same
property in different orientations, such that the data relates to
different downhole conditions. For example, the single sensor means
56 can be a magnetometer, which is an azimuth sensor for direction.
In the first orientation, the azimuth sensor measures the direction
of the slant of the downhole tool 28 (but not the amount of slant,
which would come from a different sensor). The direction of the
slant is the first downhole condition. In the second orientation,
the azimuth sensor measures the direction of the toolface
inclination, which is still directional information. The amount of
inclination of the toolface may be provided by another sensor. In
this alternative embodiment, there is no need for a second sensor
means in the second orientation. The same sensor can be used in the
second orientation, but the significance of the data collected is
now different. The system 10 of the present invention still
accounts for this increased complexity of the data. It is not
enough to collect the directional data because the orientation
information must also be considered for the directional data to be
properly interpreted. The present invention communicates this level
of complex downhole information. Measurements in one orientation
relate to a different downhole condition in another orientation.
The sensor means and the orientation determines the downhole
condition, such that the downhole condition remains complex. Other
sensors, including a transducer, a gamma scintillator, nuclear
detectors, an accelerometer, and a magnetic resonance imaging
device can incorporate the first and second orientation information
for more complex downhole conditions too. The same detector means
42 with computer 46 and microprocessor 100 of FIG. 6 can be applied
to an embodiment with a single sensor in the sensing module 32'.
The orientation information can be applied to this alternative
embodiment.
[0053] The present invention also includes the method for
communicating the complex downhole information through a pressure
releasing encoding system. With the drilling mud circulation,
defined by the drilling mud flowing through the drill string 16,
the downhole tool 28, and the wellbore 12, embodiments of the
method for communicating the complex downhole information through
the wellbore 12 to the surface location 14 include positioning the
valve means 34 in a fluid passageway 44 of the downhole tool 28,
positioning the actuator means 36 cooperative with the valve means
34 for fixing the valve means 34 in at least two static positions,
and forming a flow restriction within the circulation system at the
downhole tool 28. The flow restriction is comprised of the valve
means 34 and the actuator means 36. A quantified pressure of
drilling mud in the circulation system is applied against the flow
restriction for a stable pressure powered by the originating mud
pump means 40. The energy from the originating pump 40 supplies the
energy for the pulse through the drilling mud, instead of requiring
power for modulating the drilling mud. The pressure release
encoding of the present invention is based on setting an
equilibrium pressure by the pump means 40 across the valve means 34
and then releasing the valve means 34 by the actuator means 36 to a
new position, where the equilibrium pressure re-establishes. The
change is pressure is the pulse receivable at the surface location
14.
[0054] In embodiments of the method, the time between the pressure
changes is encoded data related to the downhole information. In the
present invention, it is the complex downhole information that is
communicated to the surface location 14. In the method, the first
downhole condition in the first orientation is measured. For
example, the sensing module 32 measures the deviation from vertical
by an inclination sensor as the first sensor means 50. A first
percentage of pressure within the flow restriction is released at a
first time, and the valve means 34 moves to another static
position. A pressure drop in the drilling mud is created. A second
percentage of pressure within the flow restriction is released at a
second time, and the valve means 34 moves to another static
position. Another pressure drop in the drilling mud is created. The
time between the first pressure drop at the first time and the
second pressure drop at the second time is correlative to the first
downhole condition in the first orientation. The measurement is
communicated to the surface location along with the orientation
information, as complex downhole information.
[0055] The method further includes determining the second downhole
condition at a surface location by sensing the time between another
set of pressure drops, according to orientation of the downhole
tool. Repeating releases of percentages of pressure, within the
flow restriction at additional times, communicates additional
downhole conditions, such as the second downhole condition from a
second sensor means 52 in the second orientation. The complex
downhole information can now be communicated with the same pressure
releasing encoding.
[0056] Various embodiments of the method include gathering the
complex downhole information from other sensing modules 32 and 32'.
For one embodiment, a single sensor measures the first downhole
condition in the first orientation and the second downhole
condition in the second orientation. The azimuth sensor is one type
of sensor that provides both first and second downhole conditions.
Other sensors that do not deactivate nor require re-calibration to
take measurements again, may also be single sensors providing the
complex downhole information. Again, the method of the present
invention, detects orientation of the downhole tool and the
measurement from the sensor to correlate the sensed time between
controlled static pressure drops across the valve means to the
first and second downhole conditions, according to orientation of
the downhole tool. Complex downhole conditions, including
orientation data, are conveyed to the surface location by a
pressure release encoding system.
[0057] The present invention provides a system and method for
communicating downhole information through pressure release
encoding to the surface. The pressure release encoding based on the
originating mud pump powers the transmission through the drilling
mud. The changes in pressure communicate complex downhole
information gathered from a sensing module at the downhole
location. The sensing module can be placed in any downhole tool,
including a BHA or drill sub, specifically. Alternate drill collar
or stabilizers may also contain the valve, actuator, and sensing
module required. There is also a means for detecting orientation of
the downhole tool, so that the orientations of the sensors of the
sensing module are known. Known bubble or compass devices can
detect vertical and lateral orientations. Other sensors may,
themselves, be calibrated for certain orientations, such as an
inclination sensor with a range of zero to twenty degrees from
vertical or another range. The present invention address the
orientation as a complicating factor in the interpretation of the
plain measurement data previously conveyed. The sensing module in
vertical and lateral orientations is now applied to a pressure
releasing encoding so that pressure releasing encoding communicates
more useful information, especially for directional and steering
drilling operations. A drill bit can be more accurately steered
through a formation with the MWD or real time data supplied by the
complex downhole information of the present invention. Pressure
releasing encoding and advanced sensing modules of the present
invention allow for more relevant downhole data to be conveyed
through drilling mud to the surface.
[0058] The foregoing disclosure and description of the invention is
illustrative and explanatory thereof. Various changes in the
details of the illustrated structures, construction and method can
be made without departing from the true spirit of the
invention.
* * * * *