Note: Descriptions are shown in the official language in which they were submitted.
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PCT/AU2011/000954
CORE SAMPLE ORIENTATION SYSTEM, DEVICE AND METHOD
TECHNICAL FIELD
The present invention relates to a system, device and method for use in
determining the orientation of a core sample relative to a body of material
from
which the core sample has been obtained.
BACKGROUND
Core orientation is the process of obtaining and marking the orientation of
a core sample from a drilling operation. The orientation of the sample is
determined with regard to its original position in a body of material, such as
rock
or ore deposits underground.
Core orientation is recorded during drilling, and analysis is undertaken
during core logging. The core logging process requires the use of systems to
measure the angles of the geological features, such as an integrated core
logging
system.
Whilst depth and azimuth are used as important indicators of core position,
they are generally inadequate on their own to determine the original position
and
attitude of subsurface geological features. Core orientation i.e. which side
of the
core was facing the bottom (or top) of a borehole and rotational orientation
compared to surrounding material, enables such details to be determined.
Through core orientation, it is possible to understand the geology of a
subsurface region and from that make strategic decisions on future mining or
drilling operations, such as economic feasibility, predicted ore body volume,
and
layout planning. In the construction industry, core
orientation can reveal
geological features that may affect siting or structural foundations for
buildings
Core samples are cylindrical in shape, typically around 3 metres long, and
are obtained by drilling with an annular hollow core drill into subsurface
material,
such as sediment and rock, and recoverying the core sample. A diamond tipped
dril bit is used at the end of the hollow drill string. As the drill
progresses deeper,
more sections of hollow steel drill tube are added to extend the drill string.
An
inner tube assembly captures the core sample. This inner tube assembly
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remains stationary while the outer tubes rotate with the drill bit. Thus, the
core
sample is pushed into the inner tube.
A 'back end' assembly connects to a greaser. This greaser lubricates the
back end assembly which rotates with the outer casing while the greaser
remains
stationary with the inner tubing.
Once a core sample is cut, the inner tube assembly is recovered by
winching to the surface. After removal of the back end assembly from the inner
tube assembly, the core sample is recovered and catalogued for analysis.
Various core orientation systems have previously been used or proposed.
Traditional systems use a spear and clay impression arrangement where a spear
is thrown down the drill string and makes an impression in clay material at an
upper end of the core sample. This impression can be used to vindicate the
orientation of the core at the time and position the spear impacted the clay.
A more recent system of determining core oprientation is proposed in
Australian patent number 2006100113 (also as US patent number 7,584,055).
This patent document describes a core orientation device for a core drill. The
device provides signals associated with a physical orientation of a core
orientation device for a particular moment in time. The device includes a
memory
for storing and providing the orientation data when required. The system
described in AU 2006100113 provides a two unit replacement for the greaser
described above. A first orientation system unit houses electronics and a
battery
used to record orientation data, and the second greaser unit is an extended
greaser accommodating a physical screw on connector for the first unit as well
as
serving as the greaser. This combination forms part of the inner tube assembly
with the core tube, orientation system 'first' unit and the connector/greaser
'second' unit. However, as a result of the now extended length of the combined
orientation system and greaser units compared with a standard greaser only
unit,
the outer drill string casing now requires a matching extension piece to
extend the
outer casing an equal amount. The core orientation system has a display on one
face which is used when setting up the unit prior to deployment, and to
indicate
core sample alignment when the core sample is recovered. At the surface before
removing the core sample from the inner tube assembly, the operator views the
display fitted on the system. The display indicates for the operator to rotate
the
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unit and the sample within the tube until the whole core tube and sample is
oriented with the lower section of the core sample at the lower end of the
tube.
The core sample is marked (usually by pencil) before being removed from the
core for future analysis.
However, the device described in AU 2006100113 has been found to have
certain limitations. The orientation unit is connected to the greaser by a
screw
thread and o-ring seal arrangement. In the harsh down hole environment within
the drill string, it has been realised that the o-ring seals are not always
effective
and can let fluid into the space between the orientation unit and the greaser.
The
display unit allows fluid into the electronics of the orientation, resulting
in a risk of
fault or failure of the device. Furthermore, the orientation unit must be
disassembled from the greaser unit before the display and orientation unit can
be
viewed, rotated and the required core orientation displayed. Thus, the device
of
AU 2006100113 requires manual manipulation before any reading can be viewed
on the display, if the display and the electronics have survived any ingress
of fluid
past the o-ring seal.
It has therefore been found desirable to provide an improved core
orientation system, device and method that alleviates these problems whilst
facilitating more reliable data recovery.
SUMMARY OF THE INVENTION
With the aforementioned in view, in one aspect the present invention
provides a core sample orientation system configured to provide an indication
of
the orientation of a core sample relative to a body of material from which the
core
has been recovered, the system including a hermetically sealed core sample
orientation data gathering device deployable as part of a downhole core sample
assembly, the device including communication means arranged to communicate
obtained core sample orientation data to a remote orientation data indication
display device having an orientation data display.
A further aspect of the present invention provides a hermetically sealed
core sample orientation data gathering device when deployed as part of a core
sample orientation system for providing an indication of the orientation of a
core
sample relative to a body of material from which the core has been extracted,
the
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orientation data gathering device including communication means for providing
core sample orientation data to a remote orientation data electronic device
having
an orientation data display.
Thus, the orientation data gathering device of the present system being
hermetically sealed avoids risk of ingress of liquid when the downhole,
thereby
leading to more reliable data gathering operations without the need to recover
the
device prematurely in order to repair or replace a faulty device, or risk
completing
a core sampling operation but find at the surface that no data can be
recovered
and the core orientation cannot be accurately determined.
The orientation data gathering device may be connected to a standard
greaser unit, thereby allowing known equipment to be used and avoiding the
need for specialised greaser to be adopted. Because the orientation data
gathering device is hermetically sealed to ensure no liquid gets in to the
device
when deployed downhole, and the device has communication means to send
data signals to a remote display, no o-ring seal to the greaser is required.
This
saves on unreliable o-ring seals, reduces risk of damage through water ingress
and loss of data, as well as the time saved in not having to recover the
damaged
device and redeploy a replacement.
The system may further include timer means to commence multiple time
intervals for the device to obtain orientation data. A time interval may be
synchronised at an orientation reading time and the time interval related to a
predetermined time interval. This may be achieved by use of the remote
orientation data electronic communication device.
System start up, setup, stop and data recovery functions may be carried
out using the remote orientation data electronic communication device to
operate
the orientation data gathering device.
The orientation data gathering device may have one or more visual
indicators to show an operator one or more required directions of rotation of
a
recovered core sample assembly for determining orientation of the core sample,
and once a required core sample orientation has been established, the remote
orientation data electronic communication device may interrogate the
orientation
data gathering device to obtain orientation data.
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Communication between the orientation data gathering device and the
remote orientation data electronic communication device is by wireless
communication, such as infra red communication.
The remote orientation data electronic communication device may include
a display to show visual information relating to the obtained orientation
data, such
as an indication that sufficient data has been obtained, that the data is
correctly
and safely stored and/or that data has been transferred from the orientation
data
gathering device to the remote orientation data electronic communication
device.
The orientation data gathering device may include one or more visual
and/or audible indicators relating to a direction of rotation of the device
when
determining core sample orientation and/or when a required core sample
orientation has been determined. For example, illuminated indicators may be
provided on the device, such as on an end of the exposed when the greaser is
removed. A particular colour, number of lights or direction indication may
illuminate to indicate that the device and the core sample need rotating in
one
direction, and a different colour, number of lights or direction indication
may
illuminate to show an opposite rotation direction is needed. These may be
augmented by or replaced by audible indications, such as respective numbers of
'bleeps'. An illuminated and/or audible indication may be given when a
required
core sample orientation is achieved. For example, both direction lights or
audible
signals may be given at the same time.
The remote orientation data communication device may also give an
indication of the required direction of rotation and/or required core sample
orientation.
The remote orientation data communication device may include or be a
handheld unit. This unit may include a battery for power, which may be a
rechargeable battery.
A further aspect of the present invention provides a method of obtaining
core sample orientation data, the method including:
a) deploying a core sample orientation data gathering device as part of
a core sample gathering system;
b) obtaining a core sample from a subsurface body of material using
the apparatus;
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C) using the orientation data gathering device to determine the
orientation of the core sample relative to the subsurface body of material;
and
d) using a remote communication device to obtain from said
orientation data gathering device data relating to the orientation of the core
sample.
The method may further include hermetically sealing the core sample
orientation data gathering device prior to deployment.
Following recovery of the device, core orientation indications may be given
by one or more illuminated and/or audible indications. Coloured indications
may
be used to determine a required orientation of the core sample. For example,
the
orientation data gathering device may include lights, such as LEDs, whereby an
indication is given to rotate the core sample in a first direction or in a
second
opposite direction to obtain a required core sample orientation position, or
lights
may be used to indicate when a required orientation position has been
obtained.
The method may include deploying the orientation data gathering device
leading a greaser. The greaser device may preferably be a standard greaser.
Multiple time intervals may be measured by the device. These time
intervals can be used to determine data gathering events, such as position,
magnetic flux, gravity, velocity etc. A time interval can be synchronised to a
specific down hole data gathering event.
Data may be obtained from the orientation data gathering device by
communication with a remote device, such as by an infra red link or other
wireless communication, such as radio link, between the orientation data
gathering device and an orientation data communication device.
A data gathering device according to one or more forms of the present
invention does not continuously take 'core orientation' readings while in use.
Instead, such a device determines when the device is 'motionless' (through its
in-
built firmware algorithms and sensors) before taking orientation readings.
This
arrangement of orientation recording confirms that the device only records
valid
data, i.e. while motionless, as the in-built sensors would otherwise present
faulty
or indeterminate readings.
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If an operator erroneously selects a time interval for 'core orientation' (via
the handheld unit while the data gathering device is still in motion), after
retrieving
the core sample, algorithms programmed into the device will determine the
'best-
approximate' time interval relative to the device being 'steady' or
'motionless' at a
time before or after a time selection by the operator using a hand held unit
to
communicate with the device as part of an embodiment of the system. The event
and time difference will also be reported to the operator to confirm
acceptance of
that recorded data.
After core retrieval, the data gathering device provides an indication, using
one or more light emitting diodes (LEDs), used to determine correct
orientation of
the core sample after rotating the device and core tube assembly in either
direction (no indication of left or right direction is required). The LEDs do
not
necessarily indicate direction, but provides 'multi-level-speed' LED flashing
rates,
followed by a steady ON state LED illumination to determine correct core
orientation.
According to one or more embodiments of the present invention, before
inserting the down-hole data gathering device into a drill hole, and after
retrieving
the same unit with the obtained core sample, the wireless handheld unit can
start/stop or interrogate the down-hole device without having to remove or
unscrew the unit from the drill-string or core tube sections. The handheld
unit
does not need to be attached, screwed in, mounted to or wedged to any part of
the tubing or GCOU assembly during any operation).
Start/stop operations, setting the exact time for orientation, interrogating
and
recording 'confirmed-accurate' operator orientation procedure, may all be
performed using a remote wireless hand-held unit communicating with the data
gathering device unit that was down the drill hole.
Visual indication of core sample orientation may be provided through at least
one aperture in a sidewall of a section of a downhole assembly. Core sample
orientation indications may be as light through at least one aperture in the
sidewall of a section of the downhole assembly, such as a greaser unit. Core
sample orientation visual indications may be provided from one or more light
emitters via at least one light reflector, and preferably reflecting that
emitted light
out through the at least one aperture.
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BRIEF DESCRIPTION OF THE DRAWINGS
Figures 1 and 2 show features of a known core sample orientation system.
Figures 3 and 4 show features of an arrangement of a core sample
orientation system according to an embodiment of the present invention.
Figure 5 shows a core sample orientation data gathering device according
to an embodiment of the present invention.
Figure 6 shows a hand held device for interrogating the core sample
orientation data gathering device according to an embodiment of the present
invention.
Figure 7 shows an indicator window end of a core sample orientation
device according to an embodiment of the present invention wherethrough
indicator lights can show when illuminated.
Figures 8a and 8b show an alternative embodiment of a data gathering
device of the present invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
In figures 1 and 2, a known prior art inner tube assembly 10 replaces a
standard greaser with a two unit system 14,16 utilising a specialised greaser
unit
14 and electronics unit 16 particular to the two unit system. The electronics
unit
is sealed to the greaser unit by o-rings, which have a tendency to fail in use
and
allow liquid into the electronics unit, risking loss of data and/or display
failure.
The electronics unit has an LCD display 18 at one end. This allows for setting
up
of the system prior to deployment and to indicate visually alignment of the
core
sample when retrieved to the surface. The greaser unit is connected to a
backend assembly 20 and the electronics unit 16 is connected to a sample tube
22 for receiving a core sample 24. The electronics unit is arranged to record
orientation data every few seconds during core sampling. The start time is
synchronised with actual time using a common stop watch. The units are then
lowered into the drill string outer casing to commence core sampling. After
drilling and capturing a core sample in the inner core sample tube, the
operator
stops the stop watch and retrieves the core sample tube back to the surface.
At
the surface, before removing the core sample from the inner tube, the operator
views the LCD display 18, if it is still working, which steps the operator
through
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instructions to rotate the core tube 22 until the core sample 24 lower section
is at
the core tube lower end 26 . The core sample is then marked and stored for
future analysis.
Referring to figure 2, the known electronics unit 16 of figure 1 includes
accelerometers 28, a memory 30, a timer 32 and the aforementioned display 18.
The system 40 according to an embodiment of the present invention will
hereinafter be described with reference to figures 3 to 6.
An outer drilling tube 34 consisting of connectable hollow steel tubes 34a-n
has an extension piece 36 connected inline between two adjacent tubes in order
to compensate the length of the outer drilling tube in relation to the
additional
length gained by the inner tube assembly 40 due to the core sample orientation
data gathering device 42.
The core sample orientation data gathering device 42 is a fully sealed
cylindrical unit with screw threads at either end. A first end 44 connects to
a
standard length and size greaser unit 46 and a second end 48 connects to a
core
sample tube 50. The greaser unit connects to a standard backend assembly 20.
There are no LCD display panels, indicators or switches mounted on the
device. LED indicators are provided at one end 44, the greaser end, that are
used in determining correct orientation of the core sample once the core and
the
device are recovered back a the surface. Figure 7 shows an example of the
indicator end 44 of the core sample orientation data gathering device 42.
In figure 5, the core sample orientation data gathering device 42 is shown
in close up. The end 44 for connecting to the greaser unit 46 includes a
window
(not shown in figure 5 - see figure 7). One or more LED lights are provided
sealed within the device 42 behind the window. A coloured light indication is
given to indicate which way (clockwise or anti-clockwise) the device 42 must
be
rotated to obtain a desired orientation of the core sample still within the
inner tube
assembly that is connected to the core sample orientation data gathering
device
42. For example, a red light may be given to indicate to rotate the device
(and
thus the core sample) anticlockwise or to the left, and a green light may be
given
to indicate to rotate the device clockwise or to the right. A combined red and
green indication, or a white light indication, or other indication can be
given, such
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as flashing lights, to indicate that the core sample is correctly orientated
and
ready for marking.
Figure 6 shows an embodiment of the hand held device 60 which receives
wirelessly receives data or signals from the core sample orientation data
gathering device 42. The core sample orientation data gathering device 42
includes a transmitter which can use line of sight data transfer through the
window, such as by infra red data transfer, or a wireless radio transmission.
The
communication device 60 can store the signals or data received from the core
sample orientation data gathering device 42. The communication device 60
includes a display 62 and navigation buttons 64,66, and a data
accept/confirmation button 68. Also, the hand held device is protected from
impact or heavy use by a shock and water resistant coating or casing 70
incorporating protective corners of a rubberised material.
Setting up of the device is carried out before insertion into the drill hole.
Data retrieval is carried out by infra red communication between the core
sample
orientation data gathering device 42 and a core orientation data receiver (see
figure 6) or communication device 60. After recovering the core sample inner
tube back at the surface, and before removing the core sample from the tube,
the
operator removes the 'back end assembly, and the attached greaser unit. The
operator then uses the remote communication device to obtain orientation data
from the core sample orientation data gathering device using an line of sight
wireless infra red communication between the remote device and the core sample
orientation data gathering device. However, it will be appreciated that
communication of data between the core sample orientation data gathering
device 42 and the communication device 60 may be by other wireless means,
such as by radio transmission.
The whole inner tube 50, core sample 52 and core sample orientation data
gathering device 42 are rotated as necessary to determine a required
orientation
of the core sample. The indicators on the greaser end of the core sample
orientation data gathering device 42 indicate to the operator which direction,
clockwise or anti-clockwise, to rotate the core sample. One colour of
indicator is
used to indicate clockwise rotation and another colour to indicate anti-
clockwise
rotation is required. This is carried out until the core sample is orientated
with its
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lower section at the lower end of the tube. The core sample is then marked for
correct orientation and then used for analysis.
As shown in figure 7, the indicator window end 44 of the core sample
orientation data gathering device 42 includes a window 72. The indicator
lights
can be seen through this window at least when illuminated. In this embodiment,
two lights, red and green LEDs are shown. The left hand 74 (red) LED
illuminates to indicate to a user to rotate the device 42 anti-clockwise. The
right
hand 76 (green) LED illuminates to indicate to a user to rotate the device 42
anti-
clockwise. When correct core sample orientation is achieved, both LEDs might
illuminate, such as steady or flashing red and green, or another illuminated
indication might be given, such as a white light (steady or flashing).
The visual and/or audible indicators, under certain site and/or
environmental conditions, may not be sufficiently visible or audible. They may
be
hard to see in bright light conditions or hard to hear in loud working
environments.
Thus, an additional or alternative means and/or method may be utilised to
ensure
that the core sample has been correctly orientated. The outer casing or body
or
an end of the core sample data gathering device 42 may have angular degree
marks. These may be scribed, etched, machined, moulded or otherwise
provided, such as by printing or painting, on the device 42. For example, as
shown in figure 7 dashes equally spaced around the outside parameter (each
representing one or more angular degrees of the full circle or perimeter).
Further
scribing of a number every five dashes starting with the number "0" then 5,
10, 15
etc. until 355. When the core is retrieved and the orientation device
communicates with the hand held communicator 60, additional information is
transmitted from the orientation device to the communicator 60, such as a
number between Zero and 359 (inclusive) denoting an angular degree of rotation
of the core sample orientation data gathering device and the core sample. When
the core is oriented during one or more embodiments of the method of the
present invention, scribing on the core sample orientation data gathering
device
42 number on the top side should be the same as the number transmitted to the
communicator 60, which re-confirms correct orientation. Thus, if the visual or
audible means for indicating core orientation are not useful or available,
then the
core is oriented using the angular degree arrangement (top side) to match the
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number transmitted, and then this would be audited using the communicator 60
as is the case now.
The core sample orientation data gathering device of the present invention
is hermetically sealed against ingress of water or other liquids, even at
operative
borehole depths and conditions. No additional or alternative sealing, such as
separate o-ring seals between the greaser and core sample orientation data
gathering device or between the inner core tube and the core sample
orientation
data gathering device are required. Thus, maintenance or risk of ingress of
liquid
are not of concern.
Additionally, only the greaser needs to be separated from the core sample
orientation data gathering device in order to obtain access and communicate
with
the device to obtain core orientation data. Likewise, setup prior to
deployment is
improved in terms of time and ease of use by not requiring a specialised back
end
assembly, rather, a standard greaser and back end assembly is used. This also
improves compatibility with standard systems.
Obtaining core orientation is made easier by only requiring two colours
lights to indicate one or other direction of rotation to establish correct
core
orientation prior to marking. The indicators form part of the sealed device
and
can be low power consumption LED lights. Alternatively, flashing lights may be
used. For example, a certain frequency or number of flashes for one direction
and another frequency or number of flashes for the other direction of
rotation. A
steady light could be given when correct orientation is achieved.
Confirmed correct core alignment is registered in the remote
communication device 60. This provides for an audit trail, and the data can be
readily transferred to computer for analysis and manipulation. This also
provides
reassurance of accuracy of sampling and orientation to operators, geologists
and
exploration/mining/construction companies.
In use, the core inner tube 50, data gathering device 42 and greaser 46
are connected together in that order and lowered into a core sampling outer
tube
having an annular diamond drill bit at the furthest end. Once a core sample is
obtained, the inner tube assembly with the data gathering device and greaser
are
recovered back to the surface, the back end assembly 20 and greaser are
removed. Using an infra red link or other wireless link, the data gathering
device
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is put into orientation indicating mode by the remote communication device 60.
The core sample and data gathering device are then rotated either clockwise or
anti clockwise to establish a required orientation position. The remote
communication device is then used to communicate with the data gathering
device to obtain core sample orientation data from the data gathering device.
No
LCD or other display is needed on the data gathering device that might
otherwise
risk leakage in use and ingress of liquid or failure of the display due to
display
power demands on the limited battery life or display failure due to the harsh
environment downhole. The required orientation of the core sample is then
marked and the core sample can be stored and used for future analysis. The
received data can be transferred to a computer for analysis.
According to an alternative embodiment of the present invention shown in
figures 8a and 8b, a data gathering device 80 houses the light emitters 74,76.
Light from these emitters (e.g. LEDs) passes through the window 72 (shown in
figure 7). Reference arrow A refers to the drill bit end direction, and
reference
arrow B refers to the backend assembly direction. An optical adapter 82 is
provided at the end 42 of the device and which adapter extends into the
greaser
unit 46 when connected thereto. The optical adapter has a reflective material.
The greaser unit 46 has apertures 84 that allow light therethrough. Light from
the
emitters is directed onto at least one reflector 86 of the adapter. The
emitted and
reflected light can be observed through the apertures 84 in the greaser. It
will be
appreciated that the adapter need not extend into a greaser. A tube section or
other component having at least one aperture to observe the light through is
sufficient. The red-green indications (or whatever selected colour combination
of
light is used) can be observed through the aperture(s) when rotating the
device to
obtain core sample orientation. Thus, advantageously, when the data gathering
device and core sample are recovered from down the hole, the data gathering
device need not be separated from the greaser in order to determine a required
orientation of the core sample. Wireless communication to a remote device,
such
as a hand held device, to transfer data between the data gathering device and
the
remote device, can also be effected by transmitting through the at least one
aperture.
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Embodiments of the present invention provide the advantage of a fully
operating downhole tool/device without having to disconnect or disassemble any
part of the tool/device from the inner tube and/or from the backend assembly
or
any other part of the drilling assembly that the tool/device would need to be
assembled within for its normal operation. Disconnecting or disassembling the
tool/device from the backend and/or inner tube risks failure of seals at those
connections and/or risks cross threading of the joining thread. Also, because
those sections are threaded together with high force, it takes substantial
manual
force and large equipment to separate the sections. High surrounding pressure
in
the drill hole means that the connecting seals between sections must function
perfectly otherwise water and dirt may ingress into and damage the device.
Having a tool/device that does not need to be separated from the inner tube
and/or backend sections in order to determine core sample orientation and/or
to
gather data recorded by the device/tool means that there is less risk of
equipment
failure and drilling downtime, as well as reduced equipment handling time
through
not having to separate the sections in order to otherwise obtain core sample
orientation. Known systems require end on interrogation of the device/tool. By
providing a sealed device/tool and the facility to determine orientation of
the core
sample, by observing the orientation indications through one or more apertures
in
the side of the greaser or other section, reliability and efficiency of core
sample
collection and orientating is improved. Consequently operational personnel
risk
injury, as well as additional downtime of the drilling operation. Without
having to
separate the tool/device from the inner tube and/or backend, the orientation
of the
core sample can be determined and the gathered information retrieved with less
drilling delay and risk of equipment damage/failure.
