U.S. patent application number 14/375081 was filed with the patent office on 2014-12-04 for core barrel valve assembly.
This patent application is currently assigned to ATLAS COPCO CANADA INC.. The applicant listed for this patent is ATLAS COPCO CANADA INC.. Invention is credited to Paul Lambert, Patrick Lu, Patrick Salvador.
Application Number | 20140353039 14/375081 |
Document ID | / |
Family ID | 48872849 |
Filed Date | 2014-12-04 |
United States Patent
Application |
20140353039 |
Kind Code |
A1 |
Lambert; Paul ; et
al. |
December 4, 2014 |
CORE BARREL VALVE ASSEMBLY
Abstract
A valve assembly for use in an inner tube member of a core
barrel head assembly positionable within a drill string of a
drilling apparatus. The valve assembly works using two separate
surfaces A and B and a biasing element with a force F.sub.S. When
hydrostatic pressure is present forces are created on these
surfaces: F.sub.A and F.sub.B. These forces have a direct
relationship with pressure, as an increase in pressure will
increase the force and vice versa. The surface areas are designed
such that: F.sub.A>F.sub.B+F.sub.S, which will maintain the
valve closed while under a predetermined fluid pressure, indicating
to the driller that the inner tube has landed. When the driller
relieves the fluid pressure and the pressure decreases, the force
difference between F.sub.A, F.sub.B and F.sub.S decreases until
F.sub.A<F.sub.B+F.sub.S, thus opening the valve for
drilling.
Inventors: |
Lambert; Paul; (Chambly,
CA) ; Salvador; Patrick; (North Bay, CA) ; Lu;
Patrick; (North Bay, CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ATLAS COPCO CANADA INC. |
Canada |
|
CA |
|
|
Assignee: |
ATLAS COPCO CANADA INC.
Dollard-des-Ormeaux,
QC
|
Family ID: |
48872849 |
Appl. No.: |
14/375081 |
Filed: |
January 27, 2012 |
PCT Filed: |
January 27, 2012 |
PCT NO: |
PCT/CA2012/050046 |
371 Date: |
July 28, 2014 |
Current U.S.
Class: |
175/57 ;
175/317 |
Current CPC
Class: |
E21B 25/02 20130101;
Y10T 137/7854 20150401; E21B 34/06 20130101; Y10T 137/0396
20150401; Y10T 137/7069 20150401; F16K 35/06 20130101; E21B 34/08
20130101 |
Class at
Publication: |
175/57 ;
175/317 |
International
Class: |
E21B 34/06 20060101
E21B034/06 |
Claims
1. A valve assembly for use in a core barrel head assembly
positionable within a drill string of a drilling apparatus, the
valve assembly comprising: a landing shoulder; at least one
upstream fluid flow port positionable within a fluid line of the
drilling apparatus upstream of the landing shoulder; at least one
downstream fluid flow port positionable within the fluid line of
the drilling apparatus downstream of the landing shoulder; at least
one fluid pressure communication port positionable within the fluid
line of the drilling apparatus; a movable valve element having a
first side in fluid communication with pressurized fluid through
the at least one pressure communication port and having a first
surface that is influenced in the supply direction by a force
F.sub.A from said fluid, and a second side facing in the opposite
direction, in fluid communication with pressurized fluid through
the at least one upstream fluid flow port and having a second
surface that is influenced in the opposite direction by a force
F.sub.B from said fluid; at least one biasing element for opening
the valve assembly by displacing the valve element from a closed
position to an open position, wherein the area of said second
surface is greater than that of said first surface so that the
force influencing the valve element in a closing direction, in the
form of the force F.sub.B from the pressurized fluid acting on said
second surface exceeds the force influencing the valve element in
an opening direction, in a form of combining a force Fs from the
biasing element and the force F.sub.A from the pressurized fluid
acting on said first surface, whereby the valve element is retained
in the closed position of the valve when pressurized fluid is
supplied and wherein the at least one fluid pressure communication
port and the at least one upstream fluid flow port form two sets of
ports, the first set for fluid pressure communication with the
movable valve element, and the second set for fluid flow required
for drilling in which the fluid flow is blocked or opened by the
movable valve element.
2. The valve assembly according to claim 1, wherein, upon a
reduction in the supply of pressurized fluid to the closed valve, a
pressure force differential decreases between said first and second
sides, and the biasing element then urges the valve element to be
displaced from said closed position to said open position.
3. The valve assembly according to claim 1, further comprising: a
locking device for mechanically locking the valve element in its
closed position.
4. The valve assembly according to claim 3, wherein the locking
device comprises a pressure sleeve mechanically connected to a
latch locking mechanism of the inner tube member.
5. The valve assembly according to claim 3, wherein the valve
element comprises: a valve body comprising the second surface; and
a valve piston comprising: a piston element comprising the first
surface; a slotted stem linking the piston element to the valve
body; and a pin attached to piston element and projecting radially
away from the piston element, and wherein the locking device
comprises: an upper latch body having a first profiled slot
cooperating with the pin, said first slot comprising a main portion
extending along an axial direction and a secondary portion
extending in a direction transverse and radial to said axial
direction; and a latch retracting case coaxially displaceable with
respect to the upper latch body and overlapping over the upper
latch body, the latch retracting case having a second profiled slot
cooperating with the pin, said second slot comprising a main
portion extending along the axial direction and a secondary portion
extending in a direction transverse to said axial direction,
parallel to the transverse direction in which the secondary portion
of the first slot extends, said latch retracting case cooperating
with a latch locking mechanism of the inner tube member, such that
the valve element is locked and the latch retracting case prevents
the latch locking mechanism from engaging with latches of the core
barrel head assembly upon displacement of the pin in the secondary
portions of the first and second profiled slots.
6. A method for operating a valve assembly for use in a core barrel
head assembly positionable within a drill string of a drilling
apparatus driven by pressurized fluid, the valve assembly
comprising: a landing shoulder; at least one upstream fluid flow
port positionable within a fluid line of the drilling apparatus
upstream of the landing shoulder; at least one downstream fluid
flow port positionable within the fluid line of the drilling
apparatus downstream of the landing shoulder; at least one fluid
pressure communication port positionable within the fluid line of
the drilling apparatus; a movable valve element having a first side
in fluid communication with pressurized fluid through the at least
one pressure port and having a first surface that is influenced in
the supply direction by a force F.sub.A from said fluid, and a
second side facing in the opposite direction, in fluid
communication with pressurized fluid through the at least one
upstream fluid flow port and having a second surface that is
influenced in the opposite direction by a force F.sub.B from said
fluid; at least one biasing element for opening the valve assembly
by displacing the valve element from a closed position to an open
position, wherein the area of said second surface is greater than
that of said first surface so that the force influencing the valve
element in a closing direction, in the form of the force F.sub.B
from the pressurized fluid acting on said second surface exceeds
the force influencing the valve element in an opening direction, in
a form of combining a force Fs from the biasing element and the
force F.sub.A from the pressurized fluid acting on said first
surface and wherein the at least one fluid pressure communication
port and the at least one upstream fluid flow port form two sets of
ports, the first set for fluid pressure communication with the
movable valve element, and the second set for fluid flow required
for drilling in which the fluid flow is blocked or opened by the
movable valve element, the method comprising: supplying the
pressurized fluid to the valve element in said closed position
whereupon the valve assembly remains closed; reducing the supply of
pressurized fluid to the closed valve assembly; and allowing a
pressure force differential to decrease between said first and
second sides, thereby enabling the biasing element to urge the
valve element towards the open position, and thereby allowing fluid
flow through the at least one upstream fluid flow port.
7. The method according to claim 6, wherein the valve assembly
further comprises a locking device for mechanically locking the
valve element in said closed position, wherein during supplying the
pressurized fluid the valve element is in a mechanically locked
closed position, the method further comprising: causing the locking
device to cease locking the valve element in the closed position
after supplying the pressurized fluid and before reducing the
supply of pressurized fluid.
8. The method according to claim 7, wherein the locking device
comprises a pressure sleeve mechanically connected to a latch
locking mechanism of the inner tube member and supplying
pressurized fluid further comprises allowing fluid pressure to
displace the pressure sleeve and engage a latch lock of the latch
locking mechanism.
9. The method according to claim 7, wherein the valve element
comprises: a valve body comprising the second surface; and a valve
piston comprising: a piston element comprising the first surface; a
slotted stem linking the piston element to the valve body; and a
pin attached to piston element and projecting radially away from
the piston element, wherein the locking device comprises: an upper
latch body having a first profiled slot cooperating with the pin,
said first slot comprising a main portion extending along an axial
direction and a secondary portion extending in a direction
transverse and radial to said axial direction; and a latch
retracting case coaxially displaceable with respect to the upper
latch body and overlapping over the upper latch body, the latch
retracting case having a second profiled slot cooperating with the
pin, said second slot comprising a main portion extending along the
axial direction and a secondary portion extending in a direction
transverse to said axial direction, parallel to the transverse
direction in which the secondary portion of the first slot extends,
said latch retracting case cooperating with a latch locking
mechanism of the inner tube member, such that the valve element is
locked and the latch retracting case prevents the latch locking
mechanism from engaging with latches of the core barrel head
assembly upon displacement of the pin in the secondary portions of
the first and second profiled slots, and wherein supplying
pressurized fluid further comprises displacing the pin from the
secondary portions to the main portions of the first and second
profiled slots, upon proper deployment of the latch locking
mechanism, thereby allowing axial movement of the pin and valve
piston.
10. A wire line core drill system, comprising: a wire line core
drill having an inner tube configured to collect core samples, an
outer tube connected to a drill bit, and a valve assembly situated
at the rear end of the inner tube, said valve assembly controlling
the supply of a flushing medium in the form of a pressurized fluid,
wherein the valve assembly comprises a landing shoulder, at least
one upstream fluid flow port positionable within a fluid line of
the drilling apparatus upstream of the landing shoulder, at least
one downstream fluid flow port positionable within the fluid line
of the drilling apparatus downstream of the landing shoulder, at
least one fluid pressure communication port positionable within the
fluid line of the drilling apparatus, a movable valve element
having a first side in fluid communication with pressurized fluid
through the at least one pressure communication port and having a
first surface that is influenced in the supply direction by a force
F.sub.A from said fluid, and a second side facing in the opposite
direction, in fluid communication with pressurized fluid through
the at least one upstream fluid flow port and having a second
surface that is influenced in the opposite direction by a force
F.sub.B from said fluid, and at least one biasing element for
opening the valve assembly by displacing the valve element from a
closed position to an open position, wherein the area of said
second surface is greater than that of said first surface so that
the force influencing the valve element in a closing direction, in
the form of the force F.sub.B from the pressurized fluid acting on
said second surface exceeds the force influencing the valve element
in an opening direction, in a form of combining a force Fs from the
biasing element and the force F.sub.A from the pressurized fluid
actin on said first surface, whereby the valve element is retained
in the closed position of the valve when pressurized fluid is
supplied and wherein the at least one fluid pressure communication
port and the at least one upstream fluid flow port form two sets of
ports, the first set for fluid pressure communication with the
movable valve element, and the second set for fluid flow required
for drilling in which the fluid flow is blocked or opened by the
movable valve element.
Description
FIELD OF THE INVENTION
[0001] The present invention generally relates to core barrels.
More specifically, it relates to a core barrel head assembly.
BACKGROUND OF THE INVENTION
[0002] It is known in various connections to use valves that
control the supply of a fluid by being opened when they are
subjected to a certain pressure from the fluid. One such
application is in wire line core drilling, as will be described
below.
[0003] When performing exploratory drilling to collect rock samples
from depths of from several hundred to a couple of thousand meters,
double core tubes are used having an inner and an outer tube. The
sample is collected in the inner tube, which usually has a length
of a few meters. When the inner tube is full this is usually
detected by means of a manometer or the like that measures the
flushing water pressure in the core tube. A retriever device
suspended on a wire is lowered into the tube for retracting the
inner tube with the sample, said retriever device comprising a
gripping means in the form of a claw or "spearhead" arranged to
engage with a gripping means arranged on/in the upper end of the
inner tube. When the wire is then tautened the inner tube is
disengaged from the outer tube, and the inner tube with the sample
can be hoisted up. Conversely, the claw and the gripping means on
the inner tube can be used to lower a new inner tube. Equipment of
this type is generally known as a wire line system.
[0004] When a new inner tube is inserted it is important to be able
to ascertain that the inner tube really has reached right down to
the bottom of the outer tube and has assumed its correct position
for drilling, before drilling is commenced. Ascertainment that the
tube can no longer move, but is firmly held is generally taken as
an indication that the inner tube has reached its correct position.
According to known technology, therefore, the gripping means is
often designed to be combined with some type of locking member that
firmly locks the inner tube in relation to the outer tube when the
inner tube has reached the correct position. This locking member
usually consists of a hook-like device, preferably spring-loaded, a
locking claw or latch that engages with recesses or shoulders
arranged in the inside of the outer tube. Actual insertion of the
inner tube is usually performed by the inner tube being "pumped"
along inside the drill string with the aid of water. When the inner
tube is firmly in place the water pressure will increase to such an
extent that a valve arranged for flushing medium in the inner tube
is released.
[0005] One problem with such known arrangements is that when the
inner tube is inserted into the drill string it sometimes catches
before it has reached the correct position for drilling. With
designs currently in use, the increase in water pressure then
occurring will release the flushing valve before the inner tube has
reached its correct position and, in the worst case, drilling will
be commenced. This primarily entails a disadvantage from the
financial point of view since the drilling will be into thin air.
There is also a risk of the core at the bottom being destroyed.
Hence it is useful to provide a landing indicator system in order
to ensure that the inner tube has reached its correct position.
[0006] The current industry standard to provide a landing indicator
system uses a ball and bushing or plunger (ball attached to
retracting case) and bushing as a valve assembly with short signal
duration.
[0007] The current standard for a core barrel valves has a pressure
signal that is very short in duration and can be easily missed by
the driller and is not reliable on deeper holes and requires
frequent replacement. Previously known valves with sustained
pressure signals were not reliable due to mud and debris jamming
the moving parts of the valve. Previous valves also were limited in
hole conditions with a very low water table and very deep holes, as
they could not cope with the large differences in hydrostatic
pressure.
[0008] The system described in U.S. Pat. No. 6,708,784 attempted to
remedy some of the above-described problems. U.S. Pat. No.
6,708,784 discloses method for a valve, the valve comprising a
movable valve element having a first side facing a means for
supplying pressurized fluid and influenced in the supply direction
by a force from said fluid, and a second side influenced in
opposite direction by a force from said fluid. The valve is
provided with at least one connection connecting the first side of
the valve element with the second side of the valve element, and
also comprises a spring for opening the valve by displacing the
valve element from a closed position to an open position. The
method comprises the following steps: a pressurized fluid is
supplied to the valve in the closed position so that the valve
remains closed; the supply of pressurised fluid to the closed valve
ceases, a pressure force differential then decreases between the
first and second sides thereby enabling the spring to open the
valve, and a pressurized fluid is supplied to the valve in the open
position and the valve remains open.
[0009] However, the valve assembly described in U.S. Pat. No.
6,708,784 is not self-resetting and does not function properly when
debris and/or additives are present in the flushing medium.
[0010] Consequently, there is still presently a need for a valve
assembly for a landing indicator system that is self-resetting and
that will work with debris and/or additives in the flushing medium,
while functioning properly in low water level conditions and in
shallow holes.
SUMMARY OF THE INVENTION
[0011] It is an object of the present invention to provide a valve
assembly that addresses at least one of the above-mentioned
needs.
[0012] Accordingly, the present invention provides a valve assembly
for use in a core barrel head assembly positionable within a drill
string of a drilling apparatus, the valve assembly comprising:
[0013] a landing shoulder; [0014] at least one upstream fluid flow
port positionable within a fluid line of the drilling apparatus
upstream of the landing shoulder; [0015] at least one downstream
fluid flow port positionable within the fluid line of the drilling
apparatus downstream of the landing shoulder; [0016] at least one
fluid pressure communication port positionable within the fluid
line of the drilling apparatus; [0017] a movable valve element
having a first side in fluid communication with pressurized fluid
through the at least one pressure port and having a first surface
that is influenced in the supply direction by a force F.sub.A from
said fluid, and a second side facing in the opposite direction, in
fluid communication with pressurized fluid through the at least one
upstream fluid flow port and having a second surface that is
influenced in the opposite direction by a force F.sub.B from said
fluid; [0018] at least one biasing element for opening the valve
assembly by displacing the valve element from a closed position to
an open position, wherein the area of said second surface is
greater than that of said first surface so that the force
influencing the valve element in a closing direction, in the form
of the force F.sub.B from the pressurized fluid acting on said
second surface exceeds the force influencing the valve element in
an opening direction, in the form of the combined force Fs from the
biasing element and the force F.sub.A from the pressurized fluid
acting on said first surface, whereby the valve element is retained
in the closed position of the valve when pressurized fluid is
supplied.
[0019] According to the present invention, there is also provided a
method for operating a valve assembly for use in a core barrel head
assembly positionable within a drill string of a drilling apparatus
driven by pressurized fluid, the valve assembly comprising: [0020]
a landing shoulder; [0021] at least one upstream fluid flow port
positionable within a fluid line of the drilling apparatus upstream
of the landing shoulder; [0022] at least one downstream fluid flow
port positionable within the fluid line of the drilling apparatus
downstream of the landing shoulder; [0023] at least one fluid
pressure communication port positionable within the fluid line of
the drilling apparatus; [0024] a movable valve element having a
first side in fluid communication with pressurized fluid through
the at least one pressure port and having a first surface that is
influenced in the supply direction by a force F.sub.A from said
fluid, and a second side facing in the opposite direction, in fluid
communication with pressurized fluid through the at least one
upstream fluid flow port and having a second surface that is
influenced in the opposite direction by a force F.sub.B from said
fluid; [0025] at least one biasing element for opening the valve
assembly by displacing the valve element from a closed position to
an open position, [0026] wherein the area of said second surface is
greater than that of said first surface so that the force
influencing the valve element in a closing direction, in the form
of the force F.sub.B from the pressurized fluid acting on said
second surface exceeds the force influencing the valve element in
an opening direction, in the form of the combined force Fs from the
biasing element and the force F.sub.A from the pressurized fluid
acting on said first surface, the method comprising the steps of:
[0027] a) supplying the pressurized fluid to the valve element in
its closed position whereupon the valve assembly remains closed;
[0028] b) reducing the supply of pressurized fluid to the closed
valve assembly; and [0029] c) allowing a pressure force
differential to decrease between said first and second sides,
thereby enabling the biasing element to urge the valve element
towards the open position, and thereby allowing fluid flow through
the at least one upstream fluid flow port.
[0030] In accordance with the present invention, there is also
provided wire line core drill system comprising a wire line core
drill having an inner tube by means of which core samples are
collected, an outer tube connected to a drill bit, and a valve
assembly situated at the rear end of the inner tube, the valve
assembly controlling the supply of a flushing medium in the form of
a pressurized fluid, wherein the valve assembly is constructed as
described above.
[0031] The valve assembly according to the present invention
provides two separate ports upstream of the landing shoulder and
allowing fluid pressure to apply a force on two different surfaces
eliminating small fluid passages that are prone to blockage from
debris and allowing for significantly less restricted flow for
drilling when the valve is open. Fluid pressure can be required to
lock the latches engaged in the drill string. This ensures that the
valve assembly will remain closed when the head has landed but
fluid pressure has not yet built up. This feature also greatly
decreases the pressure applied by the latches to the inside wall of
the drill string while it is travelling down the drill string,
greatly reducing the friction, decreasing wear on the latches and
decreasing the time to travel to the bottom of the hole. The valve
assembly can thus function in low water level conditions and in
shallow holes.
[0032] The valve assembly according to certain embodiments of the
present invention can also be self-resetting, a feature not present
in the system described in U.S. Pat. No. 6,708,784. The system
described in U.S. Pat. No. 6,705,784 would also not function
properly when debris was present between sliding surfaces of the
valves. However, the valve assembly according to the present also
provides a reduced sliding surface area with seals added to block
debris from entering these areas.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The foregoing summary, as well as the detailed description
of the preferred embodiments of the present invention, will be
better understood when read in conjunction with the appended
drawings. For the purpose of illustrating the invention, there is
shown in the drawings, which are diagrammatic, embodiments that are
presently preferred. It should be understood, however, that the
present invention is not limited to the precise arrangements and
instrumentalities shown. In the drawings:
[0034] FIG. 1 is an exploded view of a head assembly according to a
preferred embodiment of the present invention, with interchangeable
mid latch bodies.
[0035] FIGS. 2A to 2C are cross-sectional side views of a head
assembly according to another preferred embodiment of the present
invention.
[0036] FIGS. 3A to 3C are detailed cross-sectional side views of
the head assembly corresponding to the views shown in FIGS. 6A to
6C, illustrating flow streamlines through the valve assembly.
[0037] FIGS. 4A to 4D are partial detailed cross-sectional side
views of the head assembly with a valve assembly according to
another preferred embodiment of the present invention, illustrating
a preferred sequential use of the valve assembly.
[0038] FIGS. 5A and 5B are partial side views of an upper latch
body and latch retracting case of the head assembly shown in FIGS.
6A to 6C.
[0039] FIGS. 6A and 6B are a partial cross-sectional view of a
valve assembly and partial side view of a joined upper latch body
and latch retracting case, respectively, of the head assembly shown
in FIGS. 6A to 6C, during a descent phase of a preferred sequential
use of the valve assembly.
[0040] FIGS. 7A and 7B are a partial cross-sectional view of a
valve assembly and partial side view of a joined upper latch body
and latch retracting case, respectively, of the head assembly shown
in FIGS. 6A to 6C, during a signal phase of a preferred sequential
use of the valve assembly.
[0041] FIGS. 8A and 8B are a partial cross-sectional view of a
valve assembly and partial side view of a joined upper latch body
and latch retracting case, respectively, of the head assembly shown
in FIGS. 6A to 6C, during a working phase of a preferred sequential
use of the valve assembly.
[0042] FIGS. 9A and 9B are a partial cross-sectional view of a
valve assembly and partial side view of a joined upper latch body
and latch retracting case, respectively, of the head assembly shown
in FIGS. 6A to 6C, during a transition to the retracting/retrieval
phase of a preferred sequential use of the valve assembly.
[0043] FIGS. 10A and 10B are a partial cross-sectional view of a
valve assembly and partial side view of a joined upper latch body
and latch retracting case, respectively, of the head assembly shown
in FIGS. 6A to 6C, during a retracting/retrieval phase of a
preferred sequential use of the valve assembly.
PREFERRED EMBODIMENTS OF THE PRESENT INVENTION
[0044] Before any embodiments of the invention are explained in
detail, it is to be understood that the invention is not limited in
its application to the details of construction and the arrangement
of components set forth in the following description or illustrated
in the following drawings. The invention is capable of other
embodiments and of being practiced or of being carried out in
various ways. Also, it is to be understood that the phraseology and
terminology used herein is for the purpose of description and
should not be regarded as limiting. The use of "including,"
"comprising," or "having" and variations thereof herein is meant to
encompass the items listed thereafter and equivalents thereof as
well as additional items. Unless specified or limited otherwise,
the terms "mounted," "connected," "supported," and "coupled" and
variations thereof are used broadly and encompass both direct and
indirect mountings, connections, supports, and couplings and are
thus intended to include direct connections between two members
without any other members interposed therebetween and indirect
connections between members in which one or more other members are
interposed therebetween. Further, "connected" and "coupled" are not
restricted to physical or mechanical connections or couplings.
Additionally, the words "lower", "upper", "upward", "down" and
"downward" designate directions in the drawings to which reference
is made. The terminology includes the words specifically mentioned
above, derivatives thereof, and words or similar import.
[0045] Referring now to the drawings in detail, wherein like
numbers are used to indicate like elements throughout, there is
shown in FIG. 1 an exploded view of a presently preferred
embodiment of an core barrel head assembly 10 for a drilling
apparatus.
[0046] The core barrel head assembly 10 is positionable within a
drill string of a drilling apparatus. The core barrel head assembly
10 comprises an upper latch body 12 and a lower latch body 14. The
head assembly 10 further comprises a mid latch body 16 separating
the upper latch body 12 from the lower latch body 14 and removably
coupling the upper latch body 12 to the lower latch body 14. FIG. 1
shows three different sample embodiments of the mid latch body 16A,
16B, 16C to illustrate the interchangeability of the mid latch body
16. In all cases, the mid latch body 16 is removably coupled to the
upper latch body 12 and the lower latch body 14. The mid latch body
16 houses a landing indicator device 18. A common central bore 20
is formed by the upper latch body 12, the lower latch body 14 and
the mid latch body 16.
[0047] Preferably, as illustrated in FIG. 1, the head assembly
includes an upper latch body 12 with a latching assembly 30 and
fluid pressure communication ports 32. The lower latch body 14
holds a landing shoulder 34 by a removable sleeve 36 and includes
fluid flow ports 38 downstream of the landing shoulder. The mid
latch body component 16 also has fluid flow ports 40 upstream of
the landing shoulder, and connects the upper and lower latch
bodies, 12,14, with a central bore 20 connecting the fluid flow
ports 38,40. The mid latch body 16 contains a valving mechanism 42
which can provide a landing indication signal. The common central
bore 20 is present through all body components. The head assembly
preferably includes of two sets of ports: the first set for fluid
pressure communication with the internal valving mechanism 42, the
second set for fluid flow required for drilling in which the fluid
flow is blocked or opened by the internal valving mechanism 42.
This fluid port design offers the advantages of increased fluid
flow during drilling which means it is less likely to collect
debris and pack with mud and thus results also in a more efficient
pumping system, compared to a head assembly where all the fluid
circulates through a single port system upstream of the landing
shoulder (thus more subject to blockage) from the upper latch body
to the lower latch body, with no bypass port. Given the
reconfigurable nature of the head assembly, different valving
systems can be used depending on drilling conditions and also can
be easily upgraded when a newer type of valve is developed. FIG. 1
illustrates an example of three different head assemblies in which
the upper 12 and lower 14 latch bodies are similar and could be
shared, but where a changeout of the mid latch body 16 allows the
use of different valving mechanism designs that can be tailored to
a specific drilling condition.
[0048] The following sections will illustrate different valving
mechanisms that can be changed out through different mid latch
bodies 16 while also benefiting from the advantages of having the
distinct fluid pressure communication ports 32 and fluid flow ports
40 upstream of the landing shoulder.
Fluid Controlled Valves
[0049] FIG. 2A-10B show different embodiments of a head assembly in
accordance with another preferred embodiment of the present
invention. Once again, the head assembly allows for an
interchangeable mid latch body 16 between an upper latch body 12
and a lower latch body 14. Also, the valving assembly in the mid
latch body benefits from the use of separate pressure communication
ports 32 and fluid flow ports 40. The head assembly includes a
valve assembly 100 for use in a core barrel head assembly 10
positionable within a drill string of a drilling apparatus. The
valve assembly 100 comprises at least one pressure port 32 formed
in a sidewall of the core barrel head assembly 100 upstream of the
landing shoulder. There is also at least one fluid flow port 40
formed in the sidewall of the core barrel head assembly 100
upstream of the landing shoulder. The valve assembly 100 also
includes a movable valve element 218 having a first side 220 in
fluid communication with pressurized fluid through the head
assembly and having a first surface that is influenced in the
supply direction by a force F.sub.A from said fluid. A second side
222 faces in the opposite direction, in fluid communication with
the pressurized fluid through the head assembly and having a second
surface that is influenced in the opposite direction by a force
F.sub.B from the fluid. A biasing element, such as a spring 224 or
any equivalent resilient element is provided for urging the valve
assembly towards an opened configuration by displacing the valve
element 218 from a closed position, blocking the at least one fluid
flow port 40, to an open position. The biasing element or spring
may be designed to be adjustable
[0050] The area of the second surface is greater than that of the
first surface so that the force influencing the valve element 218
in a closing direction, in the form of the force F.sub.B from the
pressurized fluid acting on the second surface exceeds the force
influencing the valve element in an opening direction, in the form
of the combined force Fs from the spring and the force F.sub.A from
the pressurized fluid acting on the first surface, whereby the
valve element is retained in the closed position of the valve when
pressurized fluid is supplied, as illustrated in FIGS. 2A and
3A
[0051] Preferably, upon a reduction in the supply of pressurized
fluid to the closed valve, the pressure force differential
decreases between said first and second sides 220,222, and the
spring 224 then urges the valve element 218 to be displaced from
its closed position to its open position unblocking the at least
one fluid flow port 40 as shown in FIGS. 2B and 3B.
[0052] Preferably, the valve assembly further comprises a locking
device for mechanically locking the valve element in its closed
position. In one possible embodiment illustrated in FIG. 4A to 4D,
the locking device comprises a pressure sleeve 226 mechanically
connected through the retracting case 28 to a latch locking
mechanism 232 of the inner tube member. Another possible embodiment
of the locking device is illustrated in FIG. 2A to 3C and FIG.
5A-10B and will be described in further detail below.
[0053] According to the present invention, there is also provided a
method for operating the valve assembly for use in a core barrel
head assembly positionable within a drill string of a drilling
apparatus driven by pressurized fluid, the method comprising the
steps of: [0054] a) supplying the pressurized fluid to the valve
element 218 in its closed position whereupon the valve assembly
remains closed; [0055] b) reducing the supply of pressurized fluid
to the closed valve assembly; and [0056] c) allowing a pressure
force differential to decrease between the first and second sides
220,222, thereby enabling the biasing means 224 to urge the valve
element 18 towards the open position, and thereby allowing fluid
flow through the at least one fluid flow port and remain open.
[0057] Preferably, when the valve assembly 100 further comprises a
locking device for mechanically locking the valve element in its
closed position, in step a), the valve element is in a mechanically
locked closed position, and the method further comprises the step,
between steps a) and b) of: [0058] i) causing the locking device to
cease locking the valve element 218 in the closed position.
[0059] Preferably, the locking device comprises a pressure sleeve
226 mechanically connected to a latch locking mechanism 232 of the
head assembly and step i) further comprises the step of allowing
fluid pressure to displace the pressure sleeve 226 and engage a
latch lock 228 of the latch locking mechanism 232.
[0060] As mentioned above, another embodiment of the fluid
controlled valve assembly, and in particular the locking device,
illustrated in FIG. 2A-3C and 5A-10B, will now be presented.
Preferably, the valve element is a two-piece valve comprising a
valve body 250 and a valve piston 252. The valve body 250 is used
to selectively block the fluid flow port 40 and includes a side 222
which applies a force to urge the valve assembly towards a closed
configuration. The valve piston 252 includes a side 220 which
applies a force to urge the valve assembly towards an open
configuration, The valve piston 252 further comprises a slotted
stem 254 to allow fluid flow to flush debris and a pin 256 to
co-operate with the profiled slots in the upper latch body 12 and
latch retracting case 28 to be able to selectively lock the valve
assembly in a closed configuration.
[0061] Preferably, as better shown in FIG. 5A the upper latch body
12 comprises a profiled slot 258 to co-operate with the pin 256 of
the valve piston 252 to lock the valve-in the closed position and
allow the valve to move to the open position after a predetermined
rise in fluid pressure. More specifically, the profiled slot 258
allows axial movement of the pin within the main slot portion 260.
A top end 262 of the slot 258 extends at an angle transversely with
respect to the main slot portion, at least partially radially and
towards the opposite bottom end to prevent the pin 256 from moving
downward. The pin 256 is held in the radially extended slot
position by the spring 224 that biases the valve assembly towards
the open position.
[0062] Preferably, as the fluid pressure rises and the force on the
surface of side 220 overcomes the spring force, both valve body 250
and piston 252 will move up and the pin 256 on the valve piston 252
will be directed by the angled slot extension 262 to move the pin
256 radially (or rotate it) towards the main slot portion 260 to
allow for axial movement of the pin and hence the valve member when
the pressure is released.
[0063] Preferably, as shown in FIG. 5B, the latch retracting case
28 also has a profiled slot 270 to cooperate with the pin 256 on
the valve piston 252. The latch retracting case 28 automatically
moves the pin 256 to the locked position on the profiled slot 258
of the upper latch body 12 when the latches 142 are retracted. The
profiled slot thus helps to hold the latch retracting case 28 and
latch lock in an intermediate up position such that the latch lock
is not engaged to the latches 142, greatly reducing the latch drag
on the drill rod during descent.
[0064] The profiled slot 270 allows for axial movement of the pin
256 within a main slot portion 272. A bottom end 274 of the slot
extends at an angle with respect to the main slot portion 272, at
least partially radially and axially lower than the main slot
portion 272, thus rotating the pin 256 towards the locked position
in the upper latch body 12 when the latch retracting case 28 is
moved up to retract the latches 142. The pin 256 during the latch
retraction can then extend back towards the bottom end 274 in a
direction parallel to the main slot.
[0065] Preferably, when released from the overshot and during
descent, the biasing means 280, such as a spring or other
equivalent resilient element, in the retracting case 28 will bias
the retracting case 28 towards the down position. The bottom end
portion 274 of the profiled slot 270 will prevent the retracting
case 28 from moving to the fully down position as it is being held
in an intermediate up position, preventing the latch lock from
engaging with the latches 142, once again greatly reducing the
latch drag on the drill rod during descent.
[0066] An operational sequence of the valve assembly will now be
described. Reference will be made to components illustrated in the
two different groups of embodiments illustrated respectively in
FIG. 2A to 3C/5A to 10B and FIG. 4A to 4D.
Descent
[0067] Before inserting the inner tube head assembly in the drill
string, the latch retracting case 28 is pulled up (right side in
FIG. 2A, 4A or 6A) to its first position. This will disengage the
latch lock 228 and allow the latches 142 to move freely from the
engaged position to the retracted position and vice versa. The
valve biasing means 224 and retracting case biasing means 236 are
compressed. In the embodiment shown in FIG. 4A, the latch retracing
case 28 is directly connected to the pressure sleeve 226. The
pressure sleeve 226 and/or the latch retracting case 28 are held in
this first position (with a mechanical lock) as it is travelling
through the drill string, to reduce the latch drag on the drill rod
during descent. In the embodiment shown in FIG. 2A or 6A-6B, the
pin 256 attached to the valve piston 252 is constrained through
interaction with profiled slots 258, 270 and thus prevented from
moving down to lock the latches 142, thereby reducing latch drag on
the drill rod. The valve body 250 blocks fluid flow through the
fluid flow port 40.
Signal
[0068] When the head assembly 10 has landed in the correct
position, for the embodiment shown in FIG. 4B, fluid pressure will
increase and act on the surface 220 and push with a force at a
first predetermined value less than a second predetermined value,
such as for example, maximum pump pressure, to move the pressure
sleeve 226 down and engage the latch lock 228 with which it is
directly connected through the latch retracting case 28. In this
configuration, the latches 142 are engaged and locked into the
outer tube and the valve element 218, which is connected to the
retracting case 28 by slot 242 is allowed to operate normally. If
the latches 142 are not in the correct position, the latch lock 228
and its directly connected components will not be able to move down
to the second position and allow the valve to operate normally.
Fluid pressure will remain high even after it has been released to
the atmosphere, indicating to the driller that the latches are not
properly engaged and corrective action must be taken. In the second
position, the fluid pressure continues to rise and acts on first
surface 220 through pressure communication port 32 and second
surface 222 through fluid flow port 38. The first surface area is
smaller than the second surface area such that when fluid pressure
is present, the force generated by the second surface area is
greater than the combined force generated by the first surface area
and the force of the spring 224. This will maintain the valve in
the closed position while fluid pressure is acting on the
valve.
[0069] For the embodiment shown in FIG. 7A-7B, under similar fluid
pressure conditions, the increased pressure will displace the valve
body 250 and valve piston 252 up, which through interaction with
the profiled slots 258,260, induces rotation of the pin 256 out of
its locked configuration. This permits the valve piston 252 to move
and allows the retracting case 28 to descend while the latches 142
become engaged. However, if the latches 142 are jammed, the
retracting case 28 will not move down, thus blocking movement of
the valve 252 piston and valve assembly and preventing opening of
the fluid flow port 40.
Working
[0070] For the embodiment shown in FIG. 4C, when the fluid pump is
stopped and the pressure is relieved, a pressure force differential
decreases between the first and second surfaces 220,222 so that the
biasing means 224 or spring force will move the valve element 218
down to an open, third position. The pump will then be turned back
on and drilling fluid will flow freely through fluid flow port 40
to the drill bit for drilling.
[0071] For the embodiment shown in FIGS. 2B and 8A, 8B, once fluid
pressure is relieved, the biasing means 224 or spring force also
overcomes the pressure force differential between the first and
second surfaces 220,222 to urge the valve element 218 towards an
open position. In this configuration, fluid flows through the slots
in the valve piston 254 and through the valve body 250 into the
central bore 20.
Retracting/Retrieval
[0072] When the inner tube is full of core, the retrieval device or
overshot is sent down the drill string and connects to the
spearhead 50. For the embodiment shown in FIG. 4D, the spearhead
50, which is connected to the retracting case 28 is pulled up for
retrieval and moves the retracting case 28 up past the first
position it had during descent to its fourth position. The valve
element 218 and valve body 250, being slideably connected to the
retracting case 28, is moved up past the first position as well to
allow fluid to flow through the apertures 260. When the overshot is
disconnected from the spearhead 50, the spring 236 will return the
valve assembly to the first descent position and it will be ready
for the next trip down the hole.
[0073] For the embodiment shown in FIGS. 2C and 9A-9B, under
similar conditions, retraction of the retracting case 28, induces
rotation of the pin 256 towards a locked configuration thus keeping
the latches 142 in an unlatched configuration and minimize drag of
the latches on the drill rod during retrieval of the spearhead 50.
This configuration also positions the valve body 250 in a
configuration which keeps the fluid flow port 40 open during the
retrieval operation.
Reset
[0074] For the embodiment shown in FIG. 10A-10B, once the valve
assembly is returned to the surface, the valve body 150 must be
displaced manually at the surface location in order to position the
valve body 150 in a closed configuration that will be ready once
again for the next descent down the hole. For the embodiment shown
in FIGS. 4A-4D, the reset can be done automatically.
[0075] The present invention also provides a wire line core drill
system comprising a wire line core drill having an inner tube by
means of which core samples are collected, an outer tube connected
to a drill bit, and a valve assembly situated at the rear end of
the inner tube, said valve assembly controlling the supply of a
flushing medium in the form of a pressurized fluid, wherein the
valve assembly is constructed as described in one of the
embodiments provided above.
[0076] Although preferred embodiments of the present invention have
been described in detail herein and illustrated in the accompanying
drawing, it is to be understood that the invention is not limited
to these precise embodiments and that various changes and
modifications may be effected therein without departing from the
scope of the present invention.
* * * * *