U.S. patent application number 14/556325 was filed with the patent office on 2015-06-18 for system and method for monitoring and controlling snubbing slips.
This patent application is currently assigned to SNUBCO MANUFACTURING INC.. The applicant listed for this patent is Troy LEBLANC, Shawn McKINNON, John TASKINEN, Lance THORNELL. Invention is credited to Troy LEBLANC, Shawn McKINNON, John TASKINEN, Lance THORNELL.
Application Number | 20150167446 14/556325 |
Document ID | / |
Family ID | 53367798 |
Filed Date | 2015-06-18 |
United States Patent
Application |
20150167446 |
Kind Code |
A1 |
TASKINEN; John ; et
al. |
June 18, 2015 |
SYSTEM AND METHOD FOR MONITORING AND CONTROLLING SNUBBING SLIPS
Abstract
A system and method for monitoring and controlling a snubbing
unit having traveling slips and stationary slips are provided.
Position sensors are associated with the slips for directly or
indirectly detecting opened and closed positions of the slips,
including detecting a rotational position of a crankshaft that
drives the slips into engagement with a pipe. Load sensors are
associated with the slips for detecting load status of the slips. A
control system receives input signals from the sensors, and
confirms that either the traveling slips or the stationary slips
are loaded before releasing or allowing the release the opposing
set of slips, when transferring the pipe string load from the one
set of slips to the other set of slips.
Inventors: |
TASKINEN; John; (Nisku,
CA) ; LEBLANC; Troy; (Nisku, CA) ; McKINNON;
Shawn; (Nisku, CA) ; THORNELL; Lance; (Nisku,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TASKINEN; John
LEBLANC; Troy
McKINNON; Shawn
THORNELL; Lance |
Nisku
Nisku
Nisku
Nisku |
|
CA
CA
CA
CA |
|
|
Assignee: |
SNUBCO MANUFACTURING INC.
Nisku
CA
|
Family ID: |
53367798 |
Appl. No.: |
14/556325 |
Filed: |
December 1, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
13462446 |
May 2, 2012 |
8939219 |
|
|
14556325 |
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Current U.S.
Class: |
166/382 ;
166/77.1 |
Current CPC
Class: |
E21B 19/10 20130101;
E21B 44/00 20130101; E21B 19/16 20130101; E21B 47/00 20130101; E21B
19/07 20130101 |
International
Class: |
E21B 47/00 20060101
E21B047/00; E21B 19/07 20060101 E21B019/07; E21B 19/10 20060101
E21B019/10 |
Foreign Application Data
Date |
Code |
Application Number |
May 5, 2011 |
CA |
2739280 |
Claims
1. A system for monitoring and controlling a snubbing unit for
snubbing a pipe, the snubbing unit having first and second slips
operating in tandem to engage and move the pipe into or out of a
well, the system comprising: (a) a first actuation sensor
associated with the first slip and a second actuation sensor
associated with the second slip, wherein the actuation sensors
directly or indirectly detect engagement of the associated slip on
the pipe; and (b) a control system operatively connected to the
first and second actuation sensors and adapted to receive input
signals from the sensors, and configured to execute a method
comprising the step of confirming that either the first or second s
slip (the "unloaded slip") has engaged the pipe, before fully
releasing, or allowing the full release of the other one of the
slips (the "loaded slip"), when transferring the pipe load from the
loaded slip to the unloaded slip.
2. The system of claim 1 wherein the method comprises the further
step of confirming that the loaded slip has fully released the pipe
and has become unloaded.
3. The system of claim 1, wherein an actuation sensor comprises a
position sensor for detecting a position of the associated
slip.
4. The system of claim 1, wherein the position sensor comprises a
flow meter for measuring a volume of hydraulic fluid flowing into
or out of a hydraulic cylinder which actuates the associated
slip.
5. The system of claim 1 wherein the position sensor directly or
indirectly detects the position of a moving part of the associated
slip or a moving part of a component which actuates the associated
slip, which is indicative of the position of the associated
slip.
6. The system of claim 5 wherein the position sensor directly or
indirectly detects the position of a hydraulic cylinder rod which
actuates a slip of the associated slip.
7. The system of claim 6 wherein the position sensor directly or
indirectly detects a rotational position of a crankshaft that is
driven by the hydraulic cylinder rod and that drives the slip into
engagement with the pipe.
8. The system of claim 7 wherein the position sensor comprises a
cam rotated by the crankshaft, a linear cam follower that
translates rotational movement of the cam into linear movement, and
a linear differential transformer for measuring linear movement of
the cam follower.
9. The system of claim 1, wherein any one of the actuation sensors
comprises a load sensor for detecting a load on the associated
slip.
10. The system of claim 9, wherein the load sensor comprises an air
bladder, a hydraulic bladder, an electronic load cell, a hydraulic
load cell, or a strain gauge.
11. The system of claim 10, wherein the load sensor comprises a
pressure transducer.
12. The system of claim 1 wherein any one of the actuation sensors
comprises both a position sensor for detecting a position of the
associated slip and a load sensor for detecting a load on the
associated slip.
13. The system of claim 1 wherein the control system further
comprises a component which permits or blocks actuation of one of
the slips depending on the status of the other slip.
14. A method of running a pipe into or out of a well with a
snubbing unit for snubbing a pipe, the snubbing unit having a first
slip and a second slip operating in a sequential manner to engage
and move the pipe into or out of the well, the method comprising
the steps of: (a) engaging the pipe with the first slip and moving
the second slip to a first position; (b) engaging the pipe with the
second slip; (c) confirming with a position sensor or a load
sensor, or both a position sensor and a load sensor, that the
second slip has adequately engaged the pipe before completely
releasing the first slip; and (d) moving the second slip to a
second position to move pipe either into or out of the well.
15. The method of claim 14 wherein the confirmation step comprises
the step of determining whether or not the second slip has reached
a closed position engaging the pipe, or determining whether or not
the second slip is bearing a substantial load, or both.
16. The method of claim 15 wherein a control system prevents
complete release of the first slip unless it is confirmed that the
slip has adequately engaged the pipe.
17. The method of claim 14 wherein the confirmation step comprises
the step of directly or indirectly measuring the rotational
position of the crankshaft that drives the second slip into
engagement with the pipe.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of U.S. patent
application Ser. No. 13/462,446 filed on May 2, 2012 entitled
"System and Method for Monitoring and Controlling Snubbing Slips",
the contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a system and method for
monitoring and controlling engagement and load transfer of load
bearing components in well intervention, completion, drilling, and
workover equipment, and snubbing units in particular.
BACKGROUND OF THE INVENTION
[0003] Well intervention, completion and drilling equipment are
used to feed pipe into and out of subterranean wells. As an
example, snubbing units are known in the oil and gas industry for
facilitating access to a well which is under pressure. A snubbing
unit manipulates various tubular components such as pipe, tubing,
and bottomhole assemblies into and out of a well while controlling
the well under pressure. A conventional snubbing unit includes
stationary and traveling slips which are operated sequentially to
shift tubulars into and out of the well through a wellhead, despite
the possibility of heavy tubular loads which urge the tubulars to
fall into the well ("pipe heavy"), or the reservoir
pressure-generated forces on the tubulars, which urge the tubular
out of the well ("pipe light").
[0004] While snubbing into or out of the well, a transition or
"balance point" occurs between pipe light and pipe heavy, where the
pipe weight and the lift force exerted by the well acting on the
cross-sectional area of the pipe string is substantially equal.
Subsequently, hundreds of feet of pipe can be moved with minimal
effort.
[0005] Snubbing is conventionally controlled manually by an
operator, who activates the traveling and stationary slips in
sequence when snubbing into or out of a well. The snubbing slips
are load bearing components and rely on friction to restrain the
tubulars or pipe string. However, it is not uncommon for an
operator to release one set of load bearing components
accidentally, before transferring the load to the other set of load
bearing components. Such an error may result in the pipe string
being dropped or ejected, placing personnel at risk and damaging
equipment.
[0006] Therefore, there is a need in the art for a method and
system which mitigates the difficulties of the prior art.
SUMMARY OF THE INVENTION
[0007] The present invention is directed to a system and method for
monitoring and controlling engagement and load transfer of load
bearing components in well intervention, completion, drilling, and
workover equipment. Without limitation, in one embodiment, the
equipment comprises a snubbing unit.
[0008] In one aspect, the invention comprises a system for
monitoring and controlling a snubbing unit for snubbing a pipe, the
snubbing unit having first and second slips operating in tandem to
engage and move the pipe into or out of a well, the system
comprising: [0009] (a) a first actuation sensor associated with the
first slip and a second actuation sensor associated with the second
slip, wherein the actuation sensors directly or indirectly detect
engagement of the associated slip on the pipe; and [0010] (b) a
control system operatively connected to the first and second
actuation sensors and adapted to receive input signals from the
sensors, and configured to execute a method comprising the step of
confirming that either the first or second slip (the "unloaded
slip") has engaged the pipe, before fully releasing, or allowing
the full release of the other one of the slips (the "loaded slip"),
when transferring the pipe string load from the loaded slip to the
unloaded slip.
[0011] In one embodiment, the first and second actuation sensors
each comprises a position sensor which determines the position of
the slip, wherein the slip may move between first position engaging
the pipe, and a second position disengaging the pipe. In another
embodiment, the first and second actuation sensors each comprise a
load sensor which determines the load status of the slip. If the
slip is loaded, that indicates the slip has engaged the pipe.
Conversely, if the slip is unloaded, the slip has not engaged the
pipe. Preferably, the system comprises both a position sensor and a
load sensor for each set of slips.
[0012] The control system is adapted to process the input signals
to provide measures of position and load status and comparing the
measures to predetermined values, wherein the positions and load
status of the traveling slips or the stationary slips are confirmed
if the measures are equal to the predetermined values.
[0013] In one embodiment, the position sensor detects the position
of a moving part of a slip, or a position of a hydraulic cylinder
rod which actuates the slip. In one embodiment, the position sensor
comprises a flow meter which measures the flow of a hydraulic fluid
used to energize a hydraulic cylinder. In one embodiment, the
position sensor directly or indirectly detects a rotational
position of a crankshaft that is driven by the hydraulic cylinder
rod and that drives the slip into engagement with the pipe. The
position sensor may comprise a cam rotated by the crankshaft, a
linear cam follower that translates rotational movement of the cam
into linear movement, and a linear differential transformer for
measuring linear movement of the cam follower.
[0014] In one embodiment, the load sensor comprises an air bladder,
a hydraulic bladder, an electronic load cell, a hydraulic load
cell, or a strain gauge. In one embodiment, the load sensor further
comprises a pressure transducer.
[0015] In another aspect, the invention comprises a method of
running pipe with a snubbing unit for snubbing a pipe, the snubbing
unit having first and second load bearing components, operating in
tandem to move the pipe into or out of a well, the method
comprising the steps of: [0016] (a) engaging the pipe with the
first slip, and moving the second slip to a first position; [0017]
(b) engaging the pipe with the second slip; [0018] (c) confirming
with a position sensor or a load sensor, or both a position sensor
and a load sensor, that the second slip has adequately engaged the
pipe before completely releasing the first slip; and [0019] (d)
moving the second slip to a second position to move pipe either
into or out of the well.
[0020] In one embodiment, the step of confirming slip engagement
with the pipe comprises a step of confirming that the slips have
reached a closed position, or determining whether or not the slips
are bearing a substantial load, or both.
[0021] In one embodiment of the method, at least step (d) is
automated to prevent complete release of the first slips without
confirmation that the second slips have adequately engaged the
pipe. The term "automated" means that a system, without any
operator intervention, prevents release of the stationary slips,
without the necessary confirmation.
[0022] In one embodiment, the confirmation step comprises the step
of measuring directly or indirectly measuring the rotational
position of the crankshaft that rotates the second slip into
engagement with the pipe.
[0023] Additional aspects and advantages of the present invention
will be apparent in view of the description, which follows. It
should be understood, however, that the detailed description and
the specific examples, while indicating preferred embodiments of
the invention, are given by way of illustration only, since various
changes and modifications within the spirit and scope of the
invention as defined by the appended claims, will become apparent
to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The invention will now be described by way of an exemplary
embodiment with reference to the accompanying simplified,
diagrammatic, not-to-scale drawings. In the drawings:
[0025] FIG. 1A is a schematic diagram showing an elevational view
of a pipe snubbing unit. FIG. 1B is a schematic diagram of one
embodiment of a system of the present invention.
[0026] FIG. 2 is a schematic block diagram of the method of one
embodiment of the present invention.
[0027] FIG. 3 is a schematic block diagram of the method of one
embodiment of the present invention.
[0028] FIGS. 4 and 5 are a perspective view and a side view,
respectively, of one embodiment of a position sensor of the present
invention that measures the rotational position of a crankshaft
driven by a hydraulic cylinder rod of a snubbing unit.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0029] The present invention is directed to a system and method for
monitoring and controlling engagement and load transfer of load
bearing components in well intervention, completion, drilling, and
workover equipment. When describing the present invention, all
terms not defined herein have their common art-recognized meanings.
To the extent that the following description is of a specific
embodiment or a particular use of the invention, it is intended to
be illustrative only, and not limiting of the claimed invention.
The following description is intended to cover all alternatives,
modifications and equivalents that are included in the spirit and
scope of the invention, as defined in the appended claims.
[0030] One embodiment of the invention is described in the context
of control of hydraulic snubbing units. As used herein, the term
"hydraulic snubbing unit" means a hydraulically actuated unit
including slips, a blowout preventer stack, and hydraulic jacks for
inserting or pulling pipe strings, or tubing, and bottomhole
assemblies from underbalanced or live well conditions. In the
hydraulic jacks, hydraulic pressures act on cylinders to produce a
force which is transmitted to the pipe string so that the snubbing
unit performs the operation of pushing pipe into or pulling pipe
from a well. Traveling slips transmit the lifting or snubbing force
from the hydraulic jack to the pipe string. However, it will be
understood by one skilled in the art that the method and system
described herein may be applied to any well intervention,
completion, drilling or workover equipment that utilizes load
bearing components that work in tandem to push pipe into or pull
pipe from a wellbore, referred to herein as a "service unit".
[0031] As used herein, the term "slip" means a load bearing
component that comprises a gripping element (for example, a
wedge-shaped piece of metal with teeth) used to hold the pipe
string in place. Typically, several opposing sets of slips are
included in a conventional snubbing unit, with particular slip sets
being designated for "pipe heavy" and "pipe light" operations.
Conventionally, the slips are "directional" in that they are
configured to better resist movement of the pipe in one direction.
Stationary heavy slips may be mounted on the blowout preventer
(BOP) stack and control the movement of heavy pipe. Traveling heavy
slips are conventionally attached to the top of a jack plate and
control the movement of heavy pipe. Stationary snubbing slips are
conventionally mounted on top of the BOP stack and hold tubing
which is in a pipe light or neutral state. Traveling snubbing slips
may be mounted in reverse orientation on a traveling jack plate and
control the movement of the pipe string into or from the well. The
traveling snubbing slips typically hold tubing only when tubing is
in the pipe light state.
[0032] The elements of the service unit or snubbing unit which are
used to actuate the load bearing components, and other conventional
elements of such units, are not part of the claimed invention. For
example, embodiments of the present invention may be implemented in
service units having rack and pinion actuation instead of hydraulic
cylinder actuation of the traveling components. The operation of a
conventional hydraulic snubbing unit is commonly known to those
skilled in the art and need not be described in detail herein.
[0033] In one embodiment, a snubbing unit (10) comprises a bottom
jack plate (12) and a top jack plate (14). The snubbing unit (10)
has a stationary heavy slip bowl (16), provided with an underlying
blowout preventer (BOP) (18), a stationary snubbing slip bowl (20),
and a number of hydraulic cylinder jacks (22) for moving a
traveling jack plate (24) vertically towards and away from the top
jack plate (14). The hydraulic cylinder jacks (22) each comprise a
hydraulic cylinder from which extends a cylinder rod (26), the
hydraulic cylinder being mounted between the bottom jack plate (12)
and the top jack plate (14), and the uppermost end of the cylinder
rod (26) being connected to a traveling jack plate (24). The
traveling heavy slip bowl (28) and the traveling snubbing slip bowl
(30) are mounted to the traveling jack plate (24). The pipe (32)
for snubbing passes through the traveling slip bowls (28, 30), the
stationary slip bowls (16, 20) and the BOP (18) as it continues
downward into the wellbore (not shown).
[0034] The present invention relates to a system and method for
monitoring engagement status of load bearing components in a
service unit. In one embodiment, the system and method further
controls or directs actuation of the load bearing components to
reduce the risk of dropping or ejecting the pipe string. In general
terms, the system and method provide confirmation to the control
system and/or operator that slips have closed and engaged the pipe,
and thus have actually been loaded with pipe. With this
information, the control system and/or operator will then allow the
opposing set of slips to fully release the load to the loaded
slips. In addition, the system and method may provide confirmation
that a set of slips have released its load.
[0035] In one embodiment, the invention comprises a system for
monitoring and controlling a service unit having first and second
load bearing components operating in tandem to engage and move pipe
into or out of a well, the system comprising: [0036] (a) a first
actuation sensor associated with the first load bearing component
and a second actuation sensor associated with the second load
bearing component, wherein the actuation sensors directly or
indirectly detect engagement of the load bearing component on a
pipe; and [0037] (b) a control system operatively connected to the
first and second actuation sensors and adapted to receive input
signals from the sensors, and configured to execute a method
comprising the step of confirming that either the first or second
load bearing components have engaged the pipe, before fully
releasing, or allowing the full release of the opposing load
bearing component, when transferring the pipe string load from one
load bearing component to the other.
[0038] In one embodiment, the first and second slip actuation
sensors each comprise a position sensor which determines the
position of the slip. In another embodiment, the first and second
slip actuation sensors each comprise a load sensor which determines
the load status of the slip. The presence of load on the slip is
indirect confirmation that the slip has engaged the pipe.
Preferably, the system comprises both a position sensor and a load
sensor for each set of slips.
[0039] In one embodiment, the position and load sensors detect
position of the slips and load on the slips, respectively, and each
generate signals representative of these parameters, and are
operatively connected to gauges or indicators which are visible to
the service unit operator, and which may also be associated to
visual, audible or tactile alarms which alert the operator to
condition that requires attention. In another embodiment, the
position and load sensors transmit the signals to a control system
(100). The control system comprises an interface (110), a memory
(120), and a processor (130). The interface (110) may be a
conventional interface that is used to receive and transmit data
for a controller, such as a micro-controller. The interface (110)
is configured to receive signals from the position and load
sensors.
[0040] The interface may be a conventional device for transmitting
and receiving data and may include multiple ports for transmitting
and receiving data. The ports may be conventional receptacles for
communicating data via various means such as, a portable memory
device, a PC or portable computer or a communications network. The
interface (110) is coupled to the memory (120) and the processor
(130).
[0041] The memory may be a conventional memory typically located
within a microcontroller that is constructed to store data and
computer programs. The memory may store operating instructions to
direct the operation of the processor when initiated thereby. The
memory is a non-volatile memory and includes a threshold value
section that is dedicated location of the memory configured to
store threshold values.
[0042] The processor may be a conventional processor such as a
microprocessor. The processor includes a comparison component (132)
that compares the measured position and load sensor values to a
threshold value. A signaling or actuation component (134) is
configured to allow or actuate further operation of particular
slips, depending on the comparison step. If the measured values do
not meet the predetermined values, then the control system signals
the operator accordingly, and may, in one embodiment, automatically
prevent further operation of the slips.
[0043] Thus, in one embodiment, operation of the slips (i.e.,
opening and closing) is thus driven by pre-programmed thresholds of
the respective physical quantities detected by the position sensors
and load sensors. The control system may then signal the operator
to actuate the slips, or may directly control the slip actuators in
an automated method. In a semi-automated process, the actuation of
the slips may be initiated by an operator, but the actuation may be
blocked by the control system unless satisfactory position and load
measurements are received by the system.
[0044] In one embodiment, load sensors (34A-D) are positioned so as
to be associated with each of the four sets of slips shown, for
example, in FIG. 1. Suitable load sensors include, but are not
limited to, an air bladder, a hydraulic bladder, an electronic load
cell, a hydraulic load cell, a strain gauge, or other appropriate
weight sensor. The load sensor may be incorporated assembled into
the slips, or attached between the slips and the load bearing
structure member to which the slips are mounted. When loaded, the
load sensor will provide a measurable value of the compressive or
tensile load applied to the slip. The value will be relayed to the
control system.
[0045] If the load sensor is a fluid-filled bladder, then a
pressure transducer within the bladder may measure the pressure and
send the information to the control system.
[0046] Although the load on any given slip may exceed many tens of
thousands of pounds in a snubbing operation, the load sensors need
not quantify the load above a threshold value which is a
substantial load. For example, any load over 5,000 lbs is a
substantial load, indicative of a positive grip on the pipe by the
slips. A substantial load may be any significant weight which is
indicative of adequate slip engagement.
[0047] The position sensor may sense or detect the position of a
slip either directly or indirectly. In one embodiment, the position
sensor detects the physical position of a moving component of the
slip, or a moving component of the actuator which opens or closes a
particular set of slips, which may be a hydraulic cylinder and rod
arrangement. The position of the moving component will be
indicative of the position of the slip. Position sensors are well
known in the art, and may include electronic proximity sensors,
linear or rotary differential transformers, string potentiometers,
or rotary or shaft encoders. In one embodiment, the position sensor
determines the position of the rod in an actuating hydraulic
cylinder arrangement.
[0048] In one embodiment as shown in FIGS. 4 and 5, the slips of
the snubbing unit (10) are actuated by a hydraulic cylinder and rod
arrangement (40). The hydraulic cylinder (42) is pivotally attached
to a connecting rod (44). One end of the connecting rod (44) is
pivotally connected to a first crank shaft (46), which is turn
connected to a first half (48) of the slip. The opposite end of the
connecting rod (44) is pivotally connected to a second crank shaft
(50), which is in turn connected to a second half (52) of the slip.
The connecting rod (44) translates horizontal movement of the
hydraulic cylinder rod (42) into rotational moment of the crank
shafts (46, 50), which rotate the halves (48, 52) of the slip into
engagement with a pipe (not shown). A cam (54) attached to the
first crankshaft (46) translates rotational movement of the first
crankshaft (46) into linear movement of a cam follower (56) that is
biased by a spring against the cam (54). A linear differential
transformer (58) measures the movement of the cam follower (56) and
transmits data indicative of this position to the processor. Based
on the geometric relationships between the foregoing parts, the
processor of the system correlates the position of the cam follower
(56) to the position of either the half (48) of the slip or of the
hydraulic cylinder rod (42), to confirm whether the first half (48)
of the slip has engaged the pipe. In one embedment, the engagement
of the second half (52) of the slip with the pipe can be confirmed
in the same manner.
[0049] In another embodiment, the position sensor may comprise a
flow meter which measures the volume of hydraulic oil which was
used to either extend or retract the hydraulic cylinder rods from
or into their corresponding hydraulic cylinders. The volume
required to open the slips is calibrated by opening the slips from
the closed position. The volume is recorded for use in confirming
that the slips have fully opened. The volume required to close the
slips is calibrated by closing the slips from the open position and
recorded for use in confirming that the slips have fully
closed.
[0050] The volume required versus the position of the cylinder rod
is a directly linear relationship. A volume measurement may thus be
used to indirectly determine the position of the slips during
closing and opening. For example, if the volume used to close the
slips was 75% of the calibrated volume, then it may be inferred
that the slip hydraulic cylinder rod moved only 75% of the distance
required to fully close the slips on the pipe string. Such
information provides the control system and/or operator with
confirmation that the slips did not completely close as
required.
[0051] In one embodiment, the system may further comprise a
measurement system for measuring the movement of the hydraulic
valves which fill or empty the hydraulic cylinders which actuate
the slips. The hydraulic valves move into either an open position
to allow the flow of pressurized hydraulic oil, or a closed
position to prevent the flow of the hydraulic oil. The hydraulic
oil in turn powers the hydraulic cylinders to open and close the
slips. By measuring the opening or closing of the hydraulic valves,
the control system may determine if the hydraulic valves have
successfully completed the desired action, and are properly
functioning.
[0052] In operation, the system monitors the slip position and load
sensors to determine if a specific slip actuation has been
completed successfully. If the sensors indicate that the required
actions have been completed, the control system will emit a signal
to operate, or allow operation of the opposing set of slips to
which the load is being transferred. If the position sensors and/or
load sensors do not generate successful (i.e., pipe engagement)
signals, then the control system will not release the opposing set
of slips, or the operator is warned not to release the opposing set
of slips.
[0053] The control system will provide the operator with
confirmation that the load has been transferred to the slips which
have been actuated. The operator will thus be aware that the slips
have a sufficient hold on the pipe string, so as to be confident in
releasing the opposing slips. The load and position sensors may
also provide confirmation that previously loaded slips have
released its hold on the pipe string, and thus has been relieved of
its load.
[0054] The control system may have features for recording events or
maintenance including, but not limited to, event logging with real
time clock for data time stamping, and logging of system
configuration changes to track the system configuration history and
the identity of the operator performing the configuration changes.
Display means which are either connected to or integral with the
control system display indication signals (for example, system
status, errors, alarms, output messages, instructions, audible
buzzers) to inform an operator whether a particular slip is opened
or closed.
[0055] The following is a specific example of one embodiment of the
present invention. This example demonstrates how the system of the
present invention can be used for monitoring and controlling slips
of a snubbing unit to reduce the risk of dropping or ejecting the
pipe string. This example is offered by way of illustration and is
not intended to limit the claimed invention in any manner.
[0056] A method of the present invention may be implemented in the
operation of any service unit, where load bearing components
operating in a sequential manner for running pipe into or out of a
well, comprising the steps of: [0057] (a) engaging the pipe with a
first load bearing component and moving a second load bearing
component to a first position; [0058] (b) engaging the pipe with
the second load bearing component; [0059] (c) confirming with a
position sensor or a load sensor, or both a position sensor and a
load sensor, that the second load bearing component has adequately
engaged the pipe before completely releasing the first load bearing
component; and [0060] (d) moving the second load bearing component
to a second position to move pipe either into or out of a
wellbore.
[0061] Exemplary steps are presented schematically in FIG. 2 for
removing pipe string from the well, in a pipe heavy situation, by
transferring the load from the stationary heavy slip to the
traveling heavy slip. This may be achieved by the operator closing
the traveling heavy slips on the pipe string by actuating the slip
hydraulic cylinders. As the hydraulic cylinders move the cylinder
rods downwardly, the positioning sensor detects and senses the
movement, generates a signal representative of the position of the
cylinder rod, and transmits the signal to the control system.
[0062] If the traveling heavy slips have not yet completely closed,
the control system may provide a signal (for example, audible,
visual or electronic) to the operator notifying of the incomplete
action, and the paired slips may be disabled. If the traveling
heavy slips have completely closed, the control system interprets
the signal as a completed, successful action, and the paired slips
may be enabled or actuated.
[0063] With the traveling heavy slips fully closed to restrain the
pipe string, the operator may then begin to transfer the pipe
string load from the stationary heavy slips to the traveling heavy
slips, by moving the traveling heavy slips slightly upward. The
load sensors associated with the traveling heavy slips will sense
and detect the load, generate a signal representative of the load,
and transmit the signal to the control system for processing and
analysis. In one embodiment, if the load reaches a minimum
threshold level, for example 5,000 pounds, the control system will
interpret the signal as a completed, successful action. Before the
load reaches the minimum threshold level, the control system will
provide a signal to the operator, and may block release of the
stationary slips.
[0064] If the traveling heavy slips are not loaded, the control
system emits a signal to the operator notifying of the incomplete
action, and may automatically prevent the stationary heavy slips
from disengaging. If the traveling heavy slips are loaded, the
control system interprets the signal as a completed, successful
action.
[0065] If the signals from either or both of the positioning
sensors and load sensors are not indicative of successful
travelling slip engagement with the pipe, the control system will
signal the operator accordingly, and may not permit disengagement
of the stationary slips. Once the traveling heavy slips are both
properly loaded and restraining the pipe string, the control system
then signals the operator and permits actuation of the stationary
heavy slips which can be released from the pipe string to allow its
removal from the well.
[0066] Exemplary steps are presented schematically in FIG. 3 for
inserting the pipe string into the well, in a pipe light
configuration, by transferring the load from the traveling snubbing
slip to the stationary snubbing slip. Once the traveling snubbing
slip has reached the bottom of its stroke, the operator then closes
the stationary snubbing slips on the pipe string by actuating the
hydraulic cylinders. As the hydraulic cylinders move the cylinder
rods, the positioning sensor detects and senses the movement,
generates a signal representative of the position of the cylinder
rod, and transmits the signal to the control system for processing
and analysis.
[0067] If the stationary snubbing slips have not completely closed,
the control system emits a signal to the operator notifying of the
incomplete action, and may automatically prevent the traveling
snubbing slips from actuating. If the stationary snubbing slips
have completely closed, the control system interprets the signal as
a completed action.
[0068] With the stationary snubbing slips fully closed to restrain
the pipe string, the operator may then begin to transfer the pipe
string load from the traveling snubbing slips to the stationary
snubbing slips, by moving the traveling snubbing slips slightly
upward. The load sensors sense and detect the resulting load on the
stationary snubbing slips, generate a signal representative of the
load, and transmit the signal to the control system.
[0069] If the stationary snubbing slips are not sufficiently
loaded, the control system emits a signal to the operator notifying
of the incomplete action, and may automatically prevent the
traveling snubbing slips from disengaging. If the stationary
snubbing slips are loaded, the control system interprets the signal
as a completed action.
[0070] If the signals from either or both of the positioning
sensors and load sensors are not indicative of successful
stationary slip engagement with the pipe, the control system will
signal the operator accordingly, and may not permit disengagement
of the travelling snubbing slips. Once the stationary snubbing
slips are both properly loaded and restraining the pipe string, the
control system then emits a signal to actuate the traveling
snubbing slips which can be released from the pipe string to allow
the hydraulic cylinders to jack up the traveling snubbing slips.
The sensors and method of transferring the pipe from the stationary
snubbing slips to the traveling snubbing slips is initiated and
completed to allow the traveling snubbing slips to insert the pipe
string into the well.
[0071] The functionality and features associated with the control
system as described above and in accordance with the embodiments
may be implemented in the form of one or more software objects,
components, or computer programs or program modules in the server
and/or the client machines. The control system and methods
described above may be implemented in software, firmware or
hardware, or combinations thereof. The system components shown in
the Figures or described above may be or may include a computer or
multiple computers. The components may be described in the general
context of computer-executable instructions, such as program
modules, being executed by a computer. Generally, program modules
include routines, programs, objects, components, data structures,
etc., that perform particular tasks or implement particular
abstract data types. Further, at least some or all of the software
objects, components or modules can be hard-coded into processing
units, programmable devices, and/or read only memories or other
non-volatile storage media. The specific implementation details of
the software objects and/or program modules will be within the
knowledge and understanding of one skilled in the art.
[0072] Thus, the control system may comprise a processing unit
which operates under stored program control, for example, software
or firmware stored in memory or other non-volatile storage media,
may utilize any of a wide variety of other technologies including a
special purpose computer, a microcomputer, mini-computer, mainframe
computer, programmed microprocessor, micro-controller, peripheral
integrated circuit element, a CSIC (Customer Specific Integrated
Circuit), ASIC (Application Specific Integrated Circuit), a logic
circuit, a digital signal processor, a programmable logic device
such as an FPGA (Field Programmable Gate Array), PLD (Programmable
Logic Device), PLA (Programmable Logic Array), RFID processor,
smart chip, or any other device or arrangement of devices that is
capable of implementing the steps of the processes of the
invention.
[0073] The computer system may include a general purpose computing
device in the form of a computer including a processing unit, a
system memory, and a system bus that couples various system
components including the system memory to the processing unit.
Although many internal components of the computer or microprocessor
device are not shown or described, those of ordinary skill in the
art will appreciate that such components and the interconnections
are well known.
[0074] As will be apparent to those skilled in the art, various
modifications, adaptations and variations of the foregoing specific
disclosure can be made without departing from the scope of the
invention claimed herein.
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