U.S. patent application number 13/136169 was filed with the patent office on 2012-02-02 for hydraulic lubricator for use at a wellhead.
This patent application is currently assigned to High Tech Tools, LLC. Invention is credited to Jose Villa.
Application Number | 20120024521 13/136169 |
Document ID | / |
Family ID | 45525526 |
Filed Date | 2012-02-02 |
United States Patent
Application |
20120024521 |
Kind Code |
A1 |
Villa; Jose |
February 2, 2012 |
Hydraulic lubricator for use at a wellhead
Abstract
A lubricator for use at a wellhead such as an oil or natural gas
well. The lubricator has a polished rod on which an item, such as a
back pressure valve, may be disposed for placement, for example to
isolate the wellhead from the well pressure to permit wellhead
servicing. The rod is moved by hydraulic power, rather than
manually. A piston is connected to the polished rod within the
lubricator barrel. Hydraulic pressure within the barrel, above or
below the piston, is controlled to cause the rod to move up and
down, under power, to permit the rod and items thereon to be
lowered and retrieved.
Inventors: |
Villa; Jose; (Aztec,
NM) |
Assignee: |
High Tech Tools, LLC
Aztec
NM
|
Family ID: |
45525526 |
Appl. No.: |
13/136169 |
Filed: |
July 26, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61400385 |
Jul 27, 2010 |
|
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Current U.S.
Class: |
166/75.11 |
Current CPC
Class: |
E21B 23/08 20130101;
E21B 33/068 20130101 |
Class at
Publication: |
166/75.11 |
International
Class: |
E21B 33/068 20060101
E21B033/068; E21B 23/08 20060101 E21B023/08 |
Claims
1. A wellhead lubricator apparatus comprising: a barrel portion
detachably engageable with a yoke assembly mountable upon a
wellhead, the barrel portion comprising: a barrel housing; a rod
movable coaxially within the barrel housing and having a segment of
the rod variably extendable from an end of the barrel housing and
into the yoke assembly; a piston secured to the rod and movable
within the barrel housing; and hydraulic means for controllably
driving the piston to-and-fro within the barrel housing, thereby
moving the rod axially in relation to the barrel housing and yoke
assembly.
2. A lubricator apparatus for use at an oil or gas wellhead,
comprising: a yoke assembly removably mountable to a wellhead, and
a barrel portion, detachably engageable with the yoke assembly,
comprising: a barrel housing having a first end and a second end; a
rod movable coaxially within the barrel housing and having a
segment of the rod variably extendable from the barrel housing
second end; a piston secured to the rod and movable within the
barrel housing, there being defined in the barrel housing a head
space between the piston and the barrel housing first end and a
barrel space between the piston and the barrel housing second end;
an upper port defined in the barrel housing for permitting a
hydraulic fluid to enter or exit the head space; a lower port
defined in the barrel housing for permitting hydraulic fluid to
enter or exit the barrel space; and a valve for regulating
hydraulic pressure in the head space or the barrel space, thereby
controllably driving the piston to-and-fro within the barrel
housing and moving the rod axially in the barrel housing.
3. An apparatus according to claim 2 wherein the barrel portion has
a screwed engagement with the yoke portion by means of a steel
swage.
4. An apparatus according to claim 3, wherein the second end of the
barrel housing is secured within a female side of the swage by a
pressure gland for containing hydraulic pressure within an interior
of the barrel housing.
5. An apparatus according to claim 4 wherein the swage has a
screwed engagement with a union atop the yoke assembly, and the
tool rod movably extends axially through the gland and the swage,
and into the yoke assembly.
6. An apparatus according to claim 2 wherein the valve comprises a
valve in fluid communication with the upper port and with the fluid
port, and further wherein the lower port and the upper port are in
fluid communication with hoses for delivering hydraulic pressure
separately to each of the ports.
7. An apparatus according to claim 6 wherein the valve comprises a
needle valve for controlling hydraulic fluid flow between the upper
fluid port and the lower fluid port, whereby the needle valve
closed prevents hydraulic fluid from moving directly between the
ports while the needle valve open allows hydraulic pressure
equalization to occur between the ports.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of the filing of U.S.
Provisional Application Ser. No. 61/400,385, entitled "Hydraulic
Lubricator," filed 27 Jul. 2010, the entire disclosure of which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] This invention relates to a lubricator for use at oil and
gas wells, and in particular to a hydraulic lubricator apparatus
and system that minimizes manual manipulation of the lubricator
rod.
BACKGROUND OF THE INVENTION
[0003] In many down-hole operations conducted in the oil and gas
exploration and extraction industry, "lubricators" are used to
manage well pressure when it becomes necessary to access the
pressurized well. A lubricator may be supported in a derrick or
from a crane jib.
[0004] Accordingly a lubricator, in this field of endeavor,
essentially is a high-pressure pipe fitted to the top of a wellhead
(e.g. a "Christmas tree" in the art) so that various items and
down-hole tools can be inserted into a high-pressure oil or gas (or
other) well. U.S. Pat. No. 7,699,099 to Bolding et al., and my
co-pending U.S. patent application Ser. No. 12/930,188 filed 30
Dec. 2010, which are here incorporated by reference, offer recent
disclosures regarding well head "Christmas tree" components and
configurations.
[0005] The top of the lubricator assembly features a high-pressure
section and sealing components. The tool(s) to be placed into the
well are placed in the lubricator. The lubricator is temporarily
installed upon the "tree" and tested. After testing, lubricator
valve(s) are opened to equalize to wellbore pressure. The top
valves of the "tree" are then opened to allow the tools to drop (or
be pumped by hydraulic pressure) down the bore. Removal of the
down-hole tool(s) is accomplished by the reverse process; the tool
is pulled up the bore and into the lubricator under wellbore
pressure, the tree valves are closed, and the wellbore pressure
within the lubricator is bled off. After the high pressure in the
lubricator is safely released, the lubricator can be opened. In
short, a lubricator provides a sort of "pressure lock" via which
tools may be inserted into and retrieved from a well which is under
pressure.
[0006] A broad survey of background art for lubricators generally
is provided by U.S. Pat. Nos. 6,827,147 to Dallas, 5,893,417 to
Pizzolato, 4,062,406 to Akkerman et al., and 3,924,686 to Arnold,
the entire disclosures of which are incorporated herein by
reference.
SUMMARY OF THE INVENTION
Disclosure of the Invention
[0007] There is disclosed lubricator apparatus and method for use
at a wellhead such as an oil or natural gas well. The lubricator
has a polished rod on which an item, such as a back pressure valve,
may be disposed for placement, for example to isolate the wellhead
from the well pressure to permit wellhead servicing. The rod is
moved by hydraulic power, rather than manually. A piston is
connected to the polished rod within the lubricator barrel.
Hydraulic pressure within the barrel, above or below the piston, is
controlled to cause the rod to move up and down, under power, to
permit the rod and items thereon to be lowered and retrieved.
[0008] In a preferred embodiment, the lubricator has a yoke
assembly removably mountable to a wellhead, and a barrel portion,
detachably engageable with the yoke assembly. The barrel portion
has a barrel housing having a first end and a second end, a rod
movable coaxially within the barrel housing and having a segment of
the rod variably extendable from the barrel housing second end, and
a piston secured to the rod and movable within the barrel housing,
there being defined in the barrel housing a head space between the
piston and the barrel housing first end and a barrel space between
the piston and the barrel housing second end. An upper port is
defined in the barrel housing for permitting a hydraulic fluid to
enter or exit the head space, and a lower port is defined in the
barrel housing for permitting hydraulic fluid to enter or exit the
barrel space. At least one valve is provided for regulating
hydraulic pressure in the head space or the barrel space, thereby
controllably driving the piston to-and-fro within the barrel
housing and moving the rod axially in the barrel housing.
[0009] This disclosure provides a means of safely and hydraulically
actuating the main rod or tube of a lubricator.
[0010] There is provided lubricator apparatus which replaces known
manually-operated lubricator rods.
[0011] Accordingly, there also is provided a method for rapid and
safe change-out of devices used in well head equipment.
[0012] A primary object of the present invention is to provide a
method and apparatus for hydraulically moving the polished tool rod
of an oilfield lubricator.
[0013] A primary advantage of the present invention is that it
replaces manual actuation of a lubricator rod with hydraulic
actuation of the rod to provide a more secure and safe
operation.
[0014] Other objects, advantages and novel features, and further
scope of applicability of the present invention will be set forth
in part in the detailed description to follow, taken in conjunction
with the accompanying drawings, and in part will become apparent to
those skilled in the art upon examination of the following, or may
be learned by practice of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The accompanying drawings, which are incorporated into and
form a part of the specification, illustrate several embodiments of
the present invention and, together with the description, serve to
explain the principles of the invention. The drawings are only for
the purpose of illustrating a preferred embodiment of the invention
and are not to be construed as limiting the invention. In the
drawings:
[0016] FIG. 1 is a diagrammatic side view of a type of lubricator
generally in accordance with the prior art;
[0017] FIG. 2 is an enlarged view of a portion of the lubricator
seen in FIG. 1, diagramming some of the components used to control
pressures in the lubricator;
[0018] FIG. 3 is a partially exploded, partial sectional side view
of a lubricator apparatus, showing the barrel portion and certain
components attachable to the distal end of the polished tool
rod;
[0019] FIG. 4 is a side view of the barrel portion of the
lubricator apparatus according to the present disclosure;
[0020] FIG. 4A is an enlarged view of a portion of the barrel
portion of the lubricator depicted in
[0021] FIG. 4;
[0022] FIG. 5 is a side sectional and schematic view of the barrel
portion of the lubricator apparatus according to the present
disclosure;
[0023] FIG. 6 is a perspective illustration of the complete
lubricator apparatus according to the present disclosure, suspended
by a crane on a service vehicle, and showing the hydraulic cables
running from the hydraulic power take-off on the vehicle to the
body of the lubricator;
[0024] FIG. 7 is an enlarged side view of the lubricator apparatus
seen in FIG. 6; and
[0025] FIG. 8 illustrates a suitable control panel on the vehicle
seen in FIG. 6, usable to remotely control the actuation of the
polished tool rod in the lubricator.
[0026] The drawings are intended to be diagrammatic only, and are
not necessarily to scale either within a particular figure or
between figures. Like numerals are used to denote the same or
similar components throughout the several figures.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Best Modes for Carrying Out the Invention
[0027] The present invention relates to an apparatus and method for
the hydraulic operation of a lubricator. To insert down-hole tools
into an oil or gas wellbore, or to perform maintenance or repair to
the blowout preventer stack (BOP), it frequently is required to
isolate the well's blowout BOP or "Christmas tree" from the
pressure within the well. For example, it may be desired to install
in the well tubing, below the tree, a back pressure valve (BPV). A
properly selected and installed BPV blocks the well pressure coming
up from the well during the removal of the BOP and during
installation of, or repairs to, the Christmas tree.
[0028] Use of the hydraulic lubricator disclosed herein in a
correct and controlled environment allows a trained service
technician to complete safely the foregoing tasks with no strain.
The hydraulic lubricator can be actuated by hydraulic pressure to
allow the polished rod inside the described barrel to scope in and
out, which allows assorted plugs to be set below the BOP or
Christmas tree under wellbore pressure (or without pressure).
[0029] The normal purposes and procedural steps known in the art
for installing and operating a well head lubricator tool are
generally followed per known conventions, except as described in
detail below. Rather, the presently disclosed apparatus offers an
advantageous improvement, useable in cooperation with known
lubricator devices (for example the 10,000 PSI WP Lubricator, Stock
Number A1800-4V, available from G. B. International, Ltd., of
Friendswood, Tex.). Among the improvements described herein, the
present apparatus and system permits the polished tool rod in the
lubricator to be manipulated hydraulically rather than manually.
Nevertheless, standard safety precautions, and operating protocols,
should otherwise be observed and followed.
[0030] The lubricator, with a back pressure valve (BPV) attached,
is mounted on the top of the Christmas tree. In most operations, a
one-way "H" Back Pressure Valve is used. However, if the BOP stack
itself is being tested a two-way BPV is indicated.
[0031] In the present disclosure, the polished tool rod is extended
down through the tree by regulated hydraulic force, allowing the
threaded BPV to be screwed into the threaded top of the well's
tubing hanger. The rod is then retrieved under the controlled
hydraulic power. The lubricator may then be removed from the tree.
After maintenance or repair has been completed, or the down-hole
tool placed, the BPV must be retrieved to resume productive
operation of the well. The lubricator is again connected to the
tree cap, and the tool rod again hydraulically inserted down into
the tree. Pressure in the tree can then again be equalized, and the
BPV engaged and removed using the lubricator.
[0032] Combined reference is invited to FIGS. 1 and 2, diagramming
generally a typical lubricator device. In this disclosure, "up" and
"down," and "upper" or lower," shall have conventional meanings in
the frame of reference provided by FIGS. 1 and 2, as well as by
FIGS. 3, 6 and 7 in the drawings, in which the apparatus is seen
positioned vertically, which is the use position. The lubricator 10
has a yoke portion 20 and a barrel portion 30. The bottom of the
barrel portion 30 is securely yet detachably connectable to the top
of the yoke portion 20. A tool rod 34 (which preferably is
polished) is within the barrel's interior bore or hollow, and is
movable coaxially relative to the barrel housing 32; a distal or
lower segment of the rod extends from the barrel such that a
portion of the rod 34 is accessible through the access window 45 of
the yoke portion 20.
[0033] An eye or hook 35 ordinarily is provided upon the proximate
or upper first end 63 of the barrel housing 32 to assist in lifting
and manipulating the lubricator 10 into position atop a wellhead 49
for use. In a known lubricator device 10, the tool rod 34 is moved
manually by field workers relative to the barrel 30 and yoke
assembly 20 to place or retrieve a BPV removably attached to the
distal or lower end of the rod 34. Such movement is accomplished
manually, in which one or more operators grip the polished tool rod
34, typically with a Parmelee wrench, where the rod 34 is
accessible in the open window 45 of the yoke assembly 20. Using the
Parmelee wrench(es), the operators(s) with considerable effort
manually move the rod 34 up and down within the lubricator 10--a
tiring, inefficient, and potentially dangerous activity that is
obviated by the present invention. The manual gripping and up or
down forced movement is manually applied to the rod 34 only where
it is accessible in the yoke window 45.
[0034] FIG. 3 shows that that the yoke assembly 20 according to the
present disclosure has, for example, a 2-inch 1502 Union male 41,
with nut, on the adapter end, for securely yet removably connecting
the yoke assembly 20 (and thus the lubricator 10) to the wellhead
according generally to convention. Similarly, for example, a 2-inch
1502 female union 42 on the extension end of the lubricator yoke
assembly 20 provides for the screwed connection of any of a variety
of sizes/lengths of barrels 36. Switching of barrel sizes permits
the use of tool rods 34 of different lengths, to customize the
lubricator 10 to the particular application or the heights of
different BOPs or Christmas trees. Again, seen in FIG. 3 running
through the yoke assembly 20, is the tool rod 34, which is movable
up and down. The rod 34 is used ultimately to manipulate a
removably attached item, for common example a BVP 37. In the yoke
assembly 20 are two packing glands 22, 22' (ordinarily with Chevron
style packing) to retain fluid pressures within the lubricator
during use. Central to the functioning of the lubricator 10 are
four needle valves 24, 25, 26, and 27, used to equalize and bleed
off pressure in the lubricator, according to known conventions. A
pressure gauge 18 normally is installed in the cross portion on the
lubricator manifold 33 of the yoke assembly 20.
[0035] Referring to FIG. 3, it is seen that a polished rod adapter
38 is removably but reliably attached to the distal end of the tool
rod 34, as by means of a pin-and-channel connection. The polished
rod adapter 38 permits a running and retrieving tool 39 (any of a
number of running tools known in the art) to be securely but
releasably connected to the distal end of the tool rod 34. Such
connections often are by means of special set screw type junctions.
Running and retrieving tools include, for example, solid stringer
type running tools, or sliding thread type running and retrieving
tools for larger BVPs 37. The running tool 39 in turn can have a
threaded engagement with any of a number of tools, particularly for
instance, a BVP 37 of selected and suitable type and
specification.
[0036] The advantageous elements of the presently disclosed
apparatus are best depicted in FIGS. 4 and 5. According to the
invention, a specialized barrel portion 36 is provided for
attachment to the female union 42 (FIG. 3) of the usual yoke
assembly 20. Thus, to practice the present invention, a
conventional barrel portion 30 (FIGS. 1 and 2) is removed from the
yoke assembly 20 and replaced by the improved barrel portion 36
(FIGS. 4 and 5) of the present disclosure. It is noted that the
yoke assembly 20 and its components are assembled and function
generally in accordance with a known lubricator device, except
especially that the rod 34 in the presently disclosed apparatus
need not be forced up and down manually via the access of the yoke
window 45. Rather, the presently disclosed innovation occurs
primarily in the specialized barrel portion 36 which is suited for
screwed engagement with a yoke portion 20 by means of a suitable
steel swage 43.
[0037] Continued reference is made to FIGS. 4 and 5. In the present
apparatus and method, the lower or distal second end 48 of the
barrel housing 32 is secured within the female side of the swage 43
by means of a pressure gland 46 having suitable packing to contain
fluid pressure within the interior of barrel housing 32. The tool
rod 34 movably extends through the gland 46 and axially through the
swage 43 and on into the yoke assembly 20. The swage 43 has a
secure screwed engagement with the female union 42 (FIG. 3) atop
the proximate end of the yoke assembly 20. Thus, the specialized
barrel portion 36 of the present apparatus may be interchanged with
conventional barrel portions 30 known in the art. (Again, the
barrel portion 36 of the present disclosure is substituted for a
conventional barrel portion 30 (FIGS. 1 and 2) on the yoke assembly
20.)
[0038] A piston 50 is secured at or near the upper or proximate end
of the tool rod 34. The outside diameter of the piston 50
approximates the inside diameter of the barrel housing 32, such
that the moveable piston has a snug sliding contact with the inside
of the barrel housing. Suitable glands or O-ring packing 51 provide
a pressure seal between the piston 50 and the inside wall of the
barrel housing 32, yet permit the piston to undergo reciprocal
movement within the barrel housing.
[0039] Reciprocal movement of the tool rod 34 is provided by
hydraulic pressure acting on the faces of the piston 50. To provide
for such regulated pressure changes, a proximate or upper fluid
port 52 is defined through the wall of the barrel housing 32 very
near its (proximate or upper) first end 63. Upper fluid port 52
permits the flow of hydraulic fluid into or out of the head space
53 between the piston 50 and the closed, upper, first end 63 of the
barrel housing 32. Further, a lower fluid port 56 penetrates the
wall of the barrel housing 32 near its distal or lower second end
48, near the gland 46. Lower fluid port 56 permits the flow of
hydraulic fluid into or out of the barrel space 57 within the
barrel housing between the piston 50 and the gland 46.
[0040] Accordingly, axial to-and-fro movement of the piston 50, and
thus the tool rod 34, can be controllably accomplished by regulated
changes in relative fluid pressure between the head space 53 (FIG.
5) and the barrel space 57. Referring to FIG. 5 and especially FIG.
4A, a first pressure tee 59 is provided in the lower fluid port 56
for providing sealed fluid communication to both a quick-coupling
connector 60 and a first aperture of a needle valve 61, which are
connected to the tee fixture 59. The first quick-coupling connector
60 is of any suitable connector type known in the art of hydraulic
systems for providing a reliable, but readily releasable, sealed
fluid connection between the one leg of the tee fixture 59 and a
first lower hydraulic pressure hose 65. The first or lower hose 65
is in fluid communication with a source of regulated hydraulic
pressure, preferably a conventional power-take-off of an internal
combustion engine or other motor, mounted on a service truck 100
(FIG. 6), by which hydraulic fluid can be driven under pressure
through the lower hose 65, through the lower fluid port 56 via the
lower tee 59, and into the barrel space 57.
[0041] Referring still to FIGS. 4A and 5 particularly, the other,
second, aperture of the needle valve 61 is in fluid communication
with a second, upper, pressure tee fixture 66, which may be mounted
by a bracket 71 on the exterior of the barrel housing 32. A first
leg of the upper tee fixture 66 is connected to a second or upper
quick-coupling connector 68, also a connector known in the art for
providing a reliable and releasable fluid connection between the
one leg of the upper tee fixture 66 and a second driving hydraulic
pressure hose 70. The upper or second driving hose 70 also is in
communication with a source of regulated hydraulic pressure, so
that an operator of the present apparatus can controllably direct
pressurized hydraulic fluid toward the upper tee 66 via the
coupling connector 68. The second leg of the upper tee 66 is in
fluid communication with a hydraulic transmission hose 72. The
upper end (remote from upper tee 66) of the transmission hose 72
has a sealed fluid connection to the upper fluid port 52, so that
hydraulic fluid can be conveyed from the upper tee fixture 66 into
the piston head space 53.
[0042] The needle valve 61 thus provides a fluid connection between
the two tee fixtures 59, 66, and thus a means for controlling
hydraulic fluid flow between the upper fluid port 52 and the lower
fluid port 56. Closing the needle valve 61 prevents any fluid from
moving directly between the ports 52, 56, while an open needle
valve 61 allows fluid flow, and thus pressure equalization, to
occur between the barrel fluid ports 52, 56. The pressure hoses 65,
70 deliver hydraulic fluid and pressure separately and (when the
valve 61 is closed) independently to the respective tees 59, 66,
and thus separately to the ports 52, 56. The condition or degree of
separate delivery is controlled by the discretionary actuation of
the valve 61.
[0043] Thus the valve 61 is in fluid communication with the upper
port 52 and with the lower port 56, but also so that the lower port
and the upper port are in fluid communication with the hoses 65, 60
which can deliver hydraulic pressure separately to each of the
ports (via the respective tees) as indicated in FIG. 5. The valve
61 (preferably but not necessarily a needle valve) may be
manipulated to control hydraulic fluid flow between the upper fluid
port 52 and the lower fluid port 56; the valve in a closed
condition prevents hydraulic fluid from moving directly between the
ports, while when valve is open it allows hydraulic pressure
equalization to occur between the ports.
[0044] From the foregoing, and with reference to FIGS. 4, 4A, and
5, it is evident that the power provided by a source of hydraulic
pressure, such a hydraulic power take-off of a truck-mounted
internal combustion engine (FIG. 6), can be harnessed to drive a
controlled reciprocal movement of the piston 50. With the needle
valve 61 closed, hydraulic pressure can be delivered via the upper
driving hose 70, through the upper tee fixture 66, and to the upper
fluid port 52. Fluid passing through the upper fluid port 52 and
into the head space 53, increasing the hydraulic pressure in the
head space, moves the piston 50 axially downward (i.e., to the
right in FIGS. 4 and 5), away from the closed upper end 63 of the
barrel housing 32. Because the piston 50 is fixed to the tool rod
34, movement of the piston induces corresponding movement of the
tool rod. Likewise, hydraulic fluid can be controllably pumped
through the first driving hose 65, through the lower tee fixture 59
and into the barrel space 57 via the lower fluid port 56.
Increasing fluid pressure via the lower port 56 will increase fluid
volume within the barrel space 57, and the increased pressure
within the barrel space will drive the piston 50 axially upward
(i.e., to the left in FIGS. 4 and 5), toward the upper first end 63
of the barrel housing 32. The tool rod 34 moves accordingly.
[0045] A person skilled in the art recognizes that when the piston
50 is moving, a vent or "bleed" is required to relieve hydraulic
pressure in the confined interior space (either the head space 53
or the barrel space 57) toward which the piston 50 moves. Such
pressure relief can be and preferably is provided by employing an
essentially closed hydraulic circuit. Thus, for example, when fluid
is positively pumped into the head space 53 via the upper fluid
port 52, it simultaneously can be permitted to exit the barrel
space 57 via the lower fluid port 56 (by active pumping action by
the external source of hydraulic power via the hose 65, or merely
by the action of the moving piston 50), and vice-versa.
[0046] By regulated operation of the foregoing described hydraulic
means, the axial up-and-down movement of the tool rod 34 is
accomplished under regulated hydraulic driving power, rather than
manually. The need for field technicians to manhandle the rod into
and out of place, by gripping the rod 34 with a Parmelee wrench or
other tool, is reduced or eliminated.
[0047] The practice of the invention can be further characterized
as follows.
[0048] Before using the hydraulic lubricator apparatus 10, it is
recommended that a job hazard assessment be prepared and discussed
with all well site personnel. The responsible operators should
pre-check all equipment, including well equipment, to assure safe
operation. The tools and hydraulic lubricator are inspected that
everything is in good working condition. Before beginning lifting
or working with any equipment, operators should assure that all
lifting equipment and tools are the right lift rating and are free
from damage.
[0049] The height of the Christmas tree must be determined, since
the overall stroke distance of the hydraulic lubricator 10 must
exceed the height of the tree. The appropriate size and type of the
BPV is determined, and the BPV selected, based on the wellhead
equipment type and conditions. The appropriate running and
retrieval tool 39 is obtained to install the BPV 37 on the well
tubing hanger. The yoke portion 20 of the lubricator itself
preferably is pressure-tested (and repaired, if needed) according
to known procedures.
[0050] A service truck 100 equipped with a small crane lift (FIG.
6) and a power take-off (PTO) for driving an auxiliary hydraulic
system is brought to the well head. A spotter assists the person
that is operating the truck 100, to assure safe backing and proper
placement of the truck. The parking brake and wheel chocks are
applied to secure the vehicle from movement.
[0051] With the installation of a PTO on the transmission on the
truck 100, a control valve can actuate up-and-down the tool rod 34
of the lubricator 10. Two-fifty-foot hydraulic hoses 65, 70 run
from the lubricator to the control valve. In front of the truck's
work bed is a tank (not shown) holding 140 gallons of water, and in
the center of the bed is a tank containing for example about 40
gallons of hydraulic oil. The hoist 102 which is mounted at the bed
of the truck 100 preferably can extend out up to approximately 15.5
feet and be capable of lifting about 3,200 pounds at 75
degrees--more than capable of rigging up the hydraulic lubricator
on any wellhead equipment up to about nine feet tall.
[0052] The running and retrieval tool 39 is attached to the tool
rod 34 as indicated in FIG. 3. The BPV 37 is screwed or otherwise
appropriately attached onto the running and retrieval tool 39, also
as suggested in FIG. 3.
[0053] The Christmas tree itself (not shown, but according to
ordinary norms and configurations) is managed according to known
protocols for use of conventional lubricators. Succinctly, the wing
valve (or valves) must be closed to stop the flow from the well in
the tree. Any equipment above the swab valve that will not be
needed to complete the task is removed. The master valve(s) and
swab valve are opened to essentially open the "run" of the tree,
after which the pressure at the top of the tree is checked and
double-checked. The swab valve is closed, pressure bled off, and
the tree cap connector disconnected.
[0054] Reference is made to FIGS. 6 and 7. The hoist or crane 102
is attached to the top end (e.g. by eye bolt 35) of the lubricator
10, and the crane actuated to bring the lubricator 10 to an upward
position, as seen in FIGS. 6 and 7. Taglines may be attached to the
eye bolt 35 on the top of, and also near the bottom (bottom tagline
105 in FIG. 7) of the lubricator 10, to facilitate safely guiding
the lubricator to the top of the Christmas tree. Preferably, a work
spool and B2P adapter, using a flow tee with a 2-inch ball valve
connected on the side, are fastened atop of the Christmas tree.
[0055] The main lubricator hydraulic hoses, i.e., driving hoses 65
and 70 are run to the lubricator 10 from the hydraulic pressure
sources at the truck 100. The first driving hose 65 is connected to
the lower fluid port 56 of the lubricator barrel 32 by means of the
first quick-coupling connector 60, and the second driving hose 70
is connected to the second, upper fluid port 52 by means of the
upper quick-coupling connector 68. The power take-off (from truck
100) that actuates the hydraulic pump may then be actuated. The
hydraulic lubricator 10 is raised with the hoist 102 to a height
sufficient to permit the distal end of the tool rod 34 to be
extended from below, out the bottom flange of the yoke assembly 20,
permitting attachment of the running and retrieval tool 39 to the
rod adapter 38 on the distal end of the rod 34. The lubricator 10
is raised above the wellhead, and its distal end is placed in
registration with the top of the Christmas tree (not shown, but
according to convention), using taglines to guide the lubricator
into position. The operators then tighten the connector bolts to
secure the bottom of the lubricator onto the B2P adapter flange (on
the tree).
[0056] Once the lubricator 10 is secured to the top of the tree,
the operator opens needle valve 26 and needle valve 27 on the
lubricator yoke assembly 20; the operators listen for pressure from
below the Christmas tree master valve when the opening of the
master valve is begun. (If there is no sign of pressure on yoke
valve 27, but there is on yoke valve 26, the lubricator's
equalizing tube might be shut or have an obstruction.) The operator
then begins opening slowly the master valve on the Christmas
tree.
[0057] It is necessary to calculate the number of incremental
strokes of the tool rod 34 needed to move the BPV 37 (attached to
the distal end of the rod) the proper distance through the tree for
seating into the threads at the top of the tubing hanger. To do so,
the depth to the tree's master valve and tubing plug is measured.
(The measurement is taken from the bottom of the wing of lubricator
to the middle of the lockdown pin gland nut.) Referring for example
to FIG. 3, the length of the segment of the tool rod 34 that is
exposed in the window of the yoke assembly 20 (between the gland
nuts 44 of the packing glands 22, 22') is measured. The distance
between the gland nuts 44 is then divided by the length of the
depth distance to the plug. The rod 34 is marked at the top gland
nut 44, and the rod 34 is then stroked slowly down (manually if
necessary) until the mark is immediately adjacent the bottom gland
nut 44'. This process is repeated to calculate the number of
incremental strokes needed to move the tool rod through the
accurate full rod stroke distance, to seat the BPV 37 at the plug
(i.e., the distance the tool rod will need to be moved to reach the
tubing hanger).
[0058] The lubricator 10, installed atop the wellhead's tree, is
then operated. First, needle valve 26 and needle valve 27 on the
yoke assembly 20 are closed, and needle valve 24 and needle valve
25 are opened, which equalizes pressure within the lubricator 10
(that is, throughout the yoke assembly 20, according to known
lubricator functions). The resulting equalization of pressure
allows the tool rod 34 to shift relatively freely up and down.
[0059] The swab valve on the Christmas tree is then slowly opened,
the operators taking care to observe whether the lubricator 10 is
holding the well pressure. The swab valve is shut immediately if it
is evident that the lubricator will not contain the pressure; in
the event leaks are discovered, the swab valve is closed again, the
lubricator repaired, and swab valve reopened.
[0060] With the lubricator 10 under equalized pressure (the well
working pressure), the operators use a control panel 110 (FIG. 8)
on the field vehicle 100 to regulate hydraulic pressure in the
drive hoses 65, 70 leading from the hydraulic power take-off to the
lubricator 10. The control panel 110 seen in FIG. 8 is exemplary
only, and is configured according to principles known in the art of
vehicle-mounted hydraulic equipment systems. The control panel 110
may have a prime hydraulic pump on-off switch 112, as well as a
valving switch 114 used to regulate both the speed and direction of
the movement of the piston 50 within the barrel housing 32.
[0061] The tool rod 34 is lowered from the lubricator 10 and
through the Christmas tree toward the tubing hanger by hydraulics.
Having reference to FIGS. 4-7, the needle valve 61 is closed. The
operator, using the control panel 110, controllably pumps fluid
through the upper driving hose 70 to the upper fluid port 52 in the
barrel housing 32. The resulting fluid movement is through the
upper tee 66 and transmission tube 72 to the upper port 52. Fluid
enters the head space 53 between the piston 50 and the closed upper
or first end 63 of the barrel housing 32, thus pressurizing the
head space and driving the piston, and thus the tool rod 34,
downward. Valved regulation (via regulator 114) of the hydraulic
system (according to known conventions) permits the operator to
control the rate of descent of the tool rod 34. Fluid concurrently
exits the lower fluid port 56, so that hydraulic pressure is not
increased unduly in the barrel space 57 due to movement of the
piston 50.
[0062] The tool rod 34 is pushed down hydraulically until it stops
when the BPV 37 contacts the tubing hanger. The operators
preferably monitor the distance the rod 34 has travelled, to see
that it travels approximately the complete stroke distance
(calculated as described above) before stopping, to prevent under-
or over-extension of the rod. For example, if movement of the tool
rod 34 stops before it has moved the calculated approximate
distance, the operators check to assure that all the valves in the
well head tree are completely open to permit passage there-through
of the rod and BPV 37. In any event, care is taken to assure that
the BPV 37 or other tool at the distal end of the rod 34 is not
forcibly jammed into the tubing hanger by excessive hydraulic
force. Attentive regulation of the hydraulic driving action on the
piston 50 prevents over-extension of the rod 34.
[0063] Once the BPV 37 has contacted the threaded top of the tubing
hanger, the tool rod 34 is rotated (i.e., counterclockwise)
according to convention to threadably engage the BPV into the
tubing hanger plug. (This rotation conventionally is done manually
with a Parmelee wrench gripped about the portion of the rod 34
exposed in the yoke portion 20.) The needle valve 61 remains open
during this process, so that the effort to screw the BPV 37 is not
impeded by the pressure in the barrel space 57. The pressure
increase in the barrel space 57 otherwise resulting in the further
downward movement of the tool rod 34 is relieved through the needle
valve 61, which (when open) permits ready pressure equalization
between the barrel space 57 and the head space 53. The number of
rod rotations is counted to assure that the BPV 37 is properly and
fully screwed into place. After the tool rod 34 is rotated two or
three times, the operators preferably attempt manually to lift the
tool rod to test whether the BPV 37 is secured to the tubing
hanger. If the rod 34 is easily pulled up, the need is indicated to
move it lower and re-align the BPV 37 with the tubing hanger
orifice. Depending on the type of running and retrieval tool 39
being used, there are known modes for determining whether and when
the BPV 37 is fully engaged into the tubing hanger.
[0064] Methods known in the art are then employed to disengage the
running and retrieval tool 39 from the BPV 37, leaving the latter
engaged into the tubing hanger. The proper mode of disengagement
depends upon the type of running and retrieval tool 39 being
utilized, but is known to those skilled in the art. Whether
disengagement has occurred may be tested, checking whether the rod
34 can be manually lifted slightly.
[0065] The tool rod 34 also may be raised hydraulically. First, the
needle valve 24 and the needle valve 25 on the yoke 20 are closed.
The operators then carefully open the needle valve 26 a small
amount to slowly bleed off lubricator pressure.
[0066] The tool rod 34 is raised from within the wellhead equipment
or tree by reversing the previously described hydraulic operations.
The needle valve 61 is closed. The operator re-engages the
hydraulic system to pressurize the barrel space 57 via fluid
movement into the barrel space. Fluid transmission occurs through
the first driving hose 65 to the first quick-coupling connector 60,
the lower pressure tee 59, and on through the lower fluid port 56.
The increasing pressure in the barrel space 57 pushes against the
piston 50 driving it axially upward within the barrel housing 32,
pulling the tool rod 34 upward with it. Pressure in the head space
53 is correspondingly reduced, and pressure relieved by fluid
exiting outward through the upper fluid port 52 and into the
transmission tube 72. The tool rod 34 is hydraulically raised the
distance required to extract the running and retrieval tool 39 an
adequately from the wellhead tree.
[0067] After the tool rod 34 is completely raised, it may be
removed. The swab valve on the tree is closed securely, and valves
26 and 27 on the lubricator manifold are carefully opened to bleed
off all the pressure in the lubricator 10. Once all the pressure is
safely bled off from the lubricator 10 according to known
protocols, the operators may begin to remove the bolts from the
work spool on top of the tree's master valve. Using the
vehicle-mounted hoist or crane 102, the lubricator 10 and work
spool are raised, and the lubricator moved carefully away from
wellhead and lowered to ground level. The lubricator may then be
dissembled as appropriate and stowed on the vehicle 100 for
transport. The necessary equipment is installed or re-installed on
the wellhead, and tested as needed.
[0068] The system allows a service person to set a tubing hanger
with a back pressure valve under pressure, and to retrieve that
same tubing hanger in a controlled environment. The system may
include a service truck to be able to perform a hydro test and
operate the hydraulic lubricator. A hydraulic lubricator according
to this disclosure can pull up to about 7,830 pounds of upward
force and push up to about 9,800 pounds of downward force.
[0069] It is seen, therefore, that a hydraulic lubricator is
provided which eliminates the need to move the tool rod 34 up and
down manually during well maintenance. While the proper seating and
screwing of a BPV 37 may require manual rotation of the rod
according to known procedures, the technician no longer must lift
and lower the rod 34 through its full stroke by gripping the rod
with a wrench, and forcing it up or down incrementally--often while
in an awkward bodily position or at a potentially hazardous
location many feet above the ground. Rather, the tool rod 34 is
lifted and lowered within the lubricator 10 by means of hydraulic
power, controlled at a control panel 110 safely and conveniently
located upon the service vehicle 100, such as a diesel engine
truck.
[0070] Although the invention has been described in detail with
particular reference to these preferred embodiments, other
embodiments can achieve the same results. Variations and
modifications of the present invention will be obvious to those
skilled in the art and it is intended to cover all such
modifications and equivalents. The entire disclosures of all
applications and patents cited above are hereby incorporated by
reference.
* * * * *