U.S. patent application number 14/701012 was filed with the patent office on 2015-11-05 for bearing assembly cooling methods.
The applicant listed for this patent is Weatherford Technology Holdings, LLC. Invention is credited to James W. Chambers.
Application Number | 20150315874 14/701012 |
Document ID | / |
Family ID | 53175187 |
Filed Date | 2015-11-05 |
United States Patent
Application |
20150315874 |
Kind Code |
A1 |
Chambers; James W. |
November 5, 2015 |
BEARING ASSEMBLY COOLING METHODS
Abstract
The disclosure relates to apparatus and methods for cooling a
RCD at a wellbore including a bearing assembly configured for
operating in the RCD. A fixed latch with a heat exchanger system
and a volume of a cooling medium is configured for reducing heat
proximate the bearing assembly, an inner member, and one or more
seals between the bearing assembly and the inner member.
Inventors: |
Chambers; James W.;
(Houston, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Weatherford Technology Holdings, LLC |
Houston |
TX |
US |
|
|
Family ID: |
53175187 |
Appl. No.: |
14/701012 |
Filed: |
April 30, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61986661 |
Apr 30, 2014 |
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Current U.S.
Class: |
166/302 ;
166/57 |
Current CPC
Class: |
E21B 33/06 20130101;
E21B 36/001 20130101; E21B 33/085 20130101 |
International
Class: |
E21B 36/00 20060101
E21B036/00; E21B 33/06 20060101 E21B033/06 |
Claims
1. An apparatus for reducing heat in a pressure control device in a
wellbore, comprising: a fixed latch in the pressure control device,
wherein an interior surface of the fixed latch defines one or more
fluid passages; a heat exchanger system in fluid communication with
the fluid passage; and a volume of cooling medium housed within the
fixed latch and the heat exchanger system, wherein the volume of
cooling medium is configured for removing and absorbing heat from
the pressure control device.
2. The apparatus of claim 1, wherein the heat exchanger system
further comprises a heat exchanger in the heat exchanger system,
wherein the heat exchanger is configured for cooling the volume of
cooling medium; and one or more conduits in the heat exchanger
system, wherein the one or more conduits is configured for housing
the volume of cooling medium.
3. The apparatus of claim 2, further comprising an inlet port
connected to the fluid passage; and an outlet port connected to the
fluid passage.
4. The apparatus of claim 2, further comprising a condenser in the
heat exchanger system, wherein the condenser is configured to
condense the volume of cooling medium.
5. The apparatus of claim 4, wherein the heat exchanger system
further comprises a pump configured to circulate the volume of
cooling medium through the fluid passage and the conduit.
6. The apparatus of claim 5 further comprising a bearing assembly
housed within the fixed latch; and an inner member housed within
the bearing assembly, wherein the inner member is configured to
rotate relative to the bearing assembly, and further wherein the
inner member includes an insulating coating on an inner surface of
the inner member.
7. The apparatus of claim 6, wherein the insulating coating is an
insulating ceramic coating.
8. The apparatus of claim 7, further comprising a carrier mounted
to the pressure control device, wherein the fluid passages extend
to a surface of the carrier; and further wherein the surface of the
carrier has an insulating coating.
9. The apparatus of claim 8, further comprising one or more seals
situated between the inner member and the bearing assembly.
10. The apparatus of claim 1, wherein the fluid passages and the
heat exchanger system are a closed hydraulic system.
11. An apparatus for reducing heat in a bearing assembly and a RCD
at a wellbore, comprising: a piece of oilfield equipment; an inner
member housed within the bearing assembly, wherein the inner member
is configured to rotate relative to the bearing assembly; one or
more seals situated between the inner member and the bearing
assembly; a fixed latch configured to secure the bearing assembly
radially within the RCD; wherein the fixed latch defines a heat
exchanger profile located within the fixed latch configured to
allow a quantity of cooling medium to circulate through the fixed
latch thereby cooling the bearing assembly, the inner member, and
the seals during operation; and wherein the RCD is configured to
engage the piece of oilfield equipment as the piece of oilfield
equipment passes through the RCD, and further wherein the RCD is
configured to rotate with the piece of oilfield equipment.
12. The apparatus of claim 11, further comprising an insulating
coating on an inner surface of the inner member.
13. The apparatus of claim 11, further comprising: a seal element
mounted to the RCD; a pressure control device mounted to the RCD;
wherein the piece of oilfield equipment is proximate the RCD, and
wherein the seal element is configured to engage the piece of
oilfield equipment as the piece of oilfield equipment passes
through the pressure control device configured to seal against the
piece of oilfield equipment; a carrier mounted to the bearing
assembly, wherein the carrier is configured to secure the seal
element within the pressure control device; and wherein the carrier
defines a heat exchanger profile located within the carrier, and
wherein the heat exchanger profile is configured to allow a
quantity of cooling medium to circulate through the pressure
control device thereby cooling the seal element during
operation.
14. The apparatus of claim 13 wherein the carrier has an exterior
carrier surface; and further comprising a layer of insulating
coating on the exterior carrier surface.
15. A method for reducing heat proximate a bearing assembly of a
RCD at a wellbore, comprising the steps of: rotating an inner
member housed within the bearing assembly; circulating a quantity
of cooling medium through a heat exchanger system at the RCD; and
delivering the quantity of cooling medium through a heat exchanger
profile connected to the heat exchanger system, wherein the heat
exchanger profile is defined on an interior surface of a fixed
latch for exchanging heat generated by the inner member rotating
within the bearing assembly.
16. The method according to claim 15, further comprising the steps
of: removing the quantity of cooling medium from the heat exchanger
profile; and repeating the steps of circulating, delivering and
removing.
17. The method according to claim 15, further comprising the step
of insulating the inner member with a ceramic coating on an inner
surface of the inner member.
18. The method according to claim 15, wherein the heat exchanger
profile is further connected to a carrier supporting a seal
element, and further comprising the steps of insulating the carrier
with a layer of ceramic coating on a surface of the carrier;
reducing heat in the carrier; and reducing heat of a volume of
fluid applying pressure to the seal element.
19. The method according to claim 15 further comprising the step of
condensing the quantity of cooling medium.
20. The method according to claim 15 further comprising the step of
reducing a temperature experienced by a seal located between the
inner member and the fixed latch.
Description
BACKGROUND
Technical Field
[0001] The subject matter generally relates to systems and
techniques in the field of oil and gas operations. Reduction of
heat in rotating control devices (RCDs) improves the life of such
RCDs.
[0002] When a well site is completed, pressure control equipment
may be placed near the surface of the earth. The pressure control
equipment may control the pressure in the wellbore while drilling,
completing and producing the wellbore. The pressure control
equipment may include blowout preventers (BOP), rotating control
devices (RCDs), and the like. The RCD is a drill-through device
with a rotating seal that contacts and seals against the drill
string (drill pipe with tool joints, casing, drill collars, Kelly,
etc.) for the purposes of controlling the pressure or fluid flow to
the surface.
[0003] RCDs and other pressure control equipment are used in
underbalanced drilling (UBD) and managed pressure drilling (MPD),
which are relatively new and improved drilling techniques, and work
particularly well in certain offshore drilling environments. Both
technologies are enabled by drilling with a closed and
pressurizable circulating fluid system as compared to a drilling
system that is open-to-atmosphere at the surface. Managed pressure
drilling is an adaptive drilling process used to more precisely
control the annular pressure profile throughout the wellbore. MPD
addresses the drill-ability of a prospect, typically by being able
to adjust the equivalent mud weight with the intent of staying
within a "drilling window" to a deeper depth and reducing drilling
non-productive time in the process. The drilling window changes
with depth and is typically described as the equivalent mud weight
required to drill between the formation pressure and the pressure
at which an underground blowout or loss of circulation would occur.
The equivalent weight of the mud and cuttings in the annulus is
controlled with fewer interruptions to drilling progress while
being kept above the formation pressure at all times. An influx of
formation fluids is not invited to flow to the surface while
drilling. Underbalanced drilling (UBD) is drilling with the
hydrostatic head of the drilling fluid intentionally designed to be
lower than the pressure of the formations being drilled, typically
to improve the well's productivity upon completion by avoiding
invasive mud and cuttings damage while drilling. An influx of
formation fluids is therefore invited to flow to the surface while
drilling. The hydrostatic head of the fluid may naturally be less
than the formation pressure, or it can be induced.
[0004] The thrust generated by the wellbore fluid pressure, the
radial forces on the bearing assembly within the RCD and other
forces cause a substantial amount of heat to build in the
conventional RCD. The heat causes the seals and bearings to wear
and subsequently require repair. The conventional RCD typically
requires an external cooling system that circulates fluid and
utilizes various valves and hose through the seals and bearings in
order to remove the heat. However, risers, used in many oilfield
operations, particularly subsea operations, may pose significant
obstacles to the use of external coolants, lubricants, lubricating
systems and/or cooling systems.
[0005] Therefore, an improved system for cooling radial seals and
the bearing section of an RCD is desired, particularly a system
which is able to function in environments with or without an
external control system. If the radial seals are not sufficiently
cooled, the localized temperature at the sealing surface will rise
until the temperature limitations of the seal material is reached
and degradation of the radial seal begins. High pressure, velocity
and temperature conditions at increasing lengths of time affect and
reduce the length of usable life for a seal. In order to obtain
sufficient life from radial seals, the rate of heat extraction
should be fast enough to allow the temperature at the sealing
surface to level off at a temperature lower than that of the seal
material's upper limit.
[0006] US Pub. No. 2006/0144622 proposes a system and method for
cooling a RCD while regulating the pressure on its upper radial
seal. Gas, such as air, and liquid, such as oil, are alternatively
proposed for use in a heat exchanger in the RCD. A hydraulic
control system is proposed to provide fluid to energize a bladder
of an active seal to seal around a drilling string and to lubricate
the bearings in the RCD.
[0007] The above discussed U.S. Pub. No. US 2006/0144622 is
incorporated herein by reference for all purposes in its entirety.
The above referenced patent publication has been assigned to the
assignee of the current invention.
BRIEF SUMMARY
[0008] The disclosure relates to apparatus and methods for cooling
a RCD at a wellbore including a bearing assembly configured for
operating in the RCD. A fixed latch with a heat exchanger system
and a volume of a cooling medium is configured for reducing heat
proximate the bearing assembly, an inner member, and one or more
seals between the bearing assembly and the inner member.
[0009] As used herein the term "RCD" or "RCDs" and the phrases
"pressure control equipment", "pressure control apparatus" or
"pressure control device(s)" shall refer to well related pressure
control equipment/apparatus/device(s) including, but not limited
to, rotating-control-device(s), active rotating control devices,
blowout preventers (BOPs), and the like.
BRIEF DESCRIPTION OF THE FIGURES
[0010] The exemplary embodiments may be better understood, and
numerous objects, features, and advantages made apparent to those
skilled in the art by referencing the accompanying drawings. These
drawings are used to illustrate only typical exemplary embodiments
of this invention, and are not to be considered limiting of its
scope, for the invention may admit to other equally effective
exemplary embodiments. The figures are not necessarily to scale and
certain features and certain views of the figures may be shown
exaggerated in scale or in schematic in the interest of clarity and
conciseness.
[0011] FIG. 1 depicts a schematic view of a well site having
pressure control devices for sealing an item or piece of oilfield
equipment.
[0012] FIG. 2 depicts a cross sectional view of a pressure control
device embodiment having a fixed latch with a heat exchanger
therein and a heat exchanger system.
[0013] FIG. 3 depicts a cross sectional view of half of a pressure
control device embodiment having a carrier having a pressure
reduction system and a heat exchanger profile.
DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT(S)
[0014] The description that follows includes exemplary apparatus,
methods, techniques, and instruction sequences that embody
techniques of the inventive subject matter. However, it is
understood that the described exemplary embodiments may be
practiced without these specific details.
[0015] FIG. 1 depicts a schematic view of a well site 100 having
pressure control devices 102 for sealing a rotating drill string or
other piece of oilfield equipment 122. The well site 100 may have a
wellbore 106 formed in the earth and lined with a casing 108. At
the Earth's surface or sea floor 110 (see, for example, US
publication no, 2014/0027129 FIGS. 1, 1A and 1B and accompanying
description depicting exemplary schematic views of fixed offshore
rig and land wellsites which is incorporated herein by reference)
the one or more pressure control devices 102 may control pressure
in the wellbore 106. The pressure control devices 102 may include,
but are not limited to, BOPs, RCDs, and the like. Risers 107 may be
positioned above, with and/or below the pressure control devices
102. The risers 107 may present challenges to introducing
lubricants, coolants, lubrication systems and/or cooling systems
for the pressure control devices 102. As shown, the top pressure
control device 102 is an RCD 114. A staged seal 116 may be part of
a bearing assembly 117a located in the RCD 114. The staged seal 116
may be a radial seal having a pressure reduction system 118. The
pressure reduction system 118 may be a closed piston system
configured to stage pressure across the staged seal 116. Further,
the staged seal 116 may be configured to engage and seal an inner
member 104 during oilfield operations. The inner member 104 may be
any suitable, rotatable equipment to be sealed by the staged seal
116.
[0016] A pressure control device 102 is located directly below the
RCD 114 (as shown) and may be a sealing device 119. The sealing
device 119 may have stripper rubbers 120 for sealing against the
rotating drill string or piece of oilfield equipment 122, and a
bearing assembly 117b. The bearing assembly 117b may have a fixed
latch (or RCD body) 126 configured to engage a bearing 128. The
stripper rubbers 120 may engage the rotating drill string 122 as
the drill string 122 is inserted into the wellbore 106. The fixed
latch 126 may have a heat exchanger 130 (see FIG. 2) built into the
latch in order to cool the latch as will be discussed in more
detail below. The RCD 114 with the staged seal 116 does not
necessarily, although can be, used above or with the RCD 114 with
the sealing device 119.
[0017] FIG. 2 depicts a cross sectional view of the pressure
control device 102 having the fixed latch 126 with a heat exchanger
profile 400 therein. The fixed latch 126 may secure a bearing
assembly 402 within the pressure control device 102. The fixed
latch 126 and bearing assembly 402 may allow the inner member 104
to rotate relative to the fixed latch 126 and bearing assembly 402
as the drill string 122 is run through the pressure control device
102. As the inner member 104 rotates with or relative to the drill
string 122, the motion creates friction between the inner member
104 and an inner surface 407 of the bearing assembly 402. The
friction may cause heating in both the bearing assembly 402 and the
seals or shaft seals 406, which lie between the bearing assembly
402 and the inner member 104. The increased heat decreases life
span of the seals 406 and the bearing assembly 402. The bearing
assembly 402 and the seals 406 may respectively be any suitable
bearing assembly and seals used in the pressure control device 102
including those described herein.
[0018] The heat exchanger profile 400 may cool the fixed latch 126,
and bearing assembly 402 during operation thereby extending the
life of the seals 406 and bearing assembly 402. This may further
allow the bearing assembly 402 to operate or be operational with a
self-contained lubricant (i.e. an integral bearing assembly 402
with lubricant without any external lubrication system or without
any lubrication system running through a riser 107 to the surface).
The heat exchanger profiles 400 may be fluid passages 401 through
the interior surface area 403 of the fixed latch 126. The fluid
passages 401 may be configured to maximize the interior surface
area 403 that is cooled in the fixed latch 126. Any suitable heat
exchanger shape or channel way for paths/fluid passages 401 may be
used for the heat exchanger profile 400 so long as the fixed latch
126 is cooled. By way of example only, in the embodiment shown,
there is one inlet 415a and one outlet 415b, to the path/fluid
passages 401.
[0019] The heat exchanger profile 400 may be coupled to or integral
with a heat exchanger system 408 and may cool through or from
either side of the RCD 114. The heat exchanger system 408 may
include, but is not limited to, a heat exchanger 410, a tank 411
for containing a volume of cooling medium or coolant 405, a pump
412, an optional separate condenser 409, and one or more conduits
414. The heat exchanger 410 may be any suitable device for cooling
the fluid, a quantity or volume of cooling medium 405, circulating
through the conduit 414 including, but not limited to, the exposed
sea temperature on the conduit 414, a shell and tube exchanger, and
the like. The pump 412 may be any suitable device for circulating
the quantity of cooling medium 405 from the tank 411 through the
conduit 414. The optional separate condenser 409 may be included to
condense any gases or fluids after having circulated the fluid
passages 401 and conduits 414. By way of example only, the optional
separate condenser 409 may be located near the outlet 415b but
could also be located near the inlet 415a or intermediate thereto.
The pump 412 may be any suitable device for delivering the quantity
of cooling medium 405 through the heat exchanger system 408
including, but not limited to, a centrifugal pump, a reciprocating
pump, and the like. The quantity of cooling medium 405 may be any
suitable medium for cooling the heat exchanger system 408
including, but not limited to, water, sea water, refrigerant,
refrigerant mixtures, liquids (including those that remain in a
liquid state during the heat exchange process) or gases, air, oil
and/or the like.
[0020] The inner member 104 may further include an insulating
coating 416 on the inner surface 142 of the inner member 104. The
insulating coating 416 may be configured to reduce heat transfer
from the inner surface 142 of the inner member 104 caused by heated
wellbore fluids to the seals 406. This additional cooling may
prevent the wear on the seals 406. By way of example only, in one
embodiment, the insulating coating 416 may be made of ceramic,
refractory, hard rubber, fiberglass, composite, elastomer, and/or
thermal/electrical materials of suitable thickness for insulating a
passage of inner member 104. In addition, the insulating coating
416 may extend to one or more surfaces on the stripper rubber mount
132 to which the stripper rubber(s) 120 are attached to.
[0021] FIG. 3 depicts a cross sectional view of half of a pressure
control device 102 embodiment having a carrier 500 (see U.S.
Provisional Appl. No. 61/986,544, filed on Apr. 30, 2014, which is
herein incorporated by reference) having the pressure reduction
system 118 and in the heat exchanger profile 400. The carrier 500
as shown is configured to support a seal element 502 for engaging
the drill string 122. The seal element 502 may be configured to
seal drill string 122 as the drill pipe is run into or out of the
wellbore 106 (as shown in FIG. 1). The carrier 500 may be located
below, above or within the bearing assembly 117 of an RCD 114. In
one embodiment, the pressure reduction system 118 may operate in
the same manner as described in U.S. Provisional Appl. No.
61/986,544, in order to apply pressure to the outer radial surface
504 of the seal element 502. In another embodiment, the pressure
reduction system 118 may be controlled by a hydraulic unit or
controller in order to maintain the pressure on the outer radial
surface 504 of the seal element 502.
[0022] The heat exchanger profile 400 may operate in the same
manner as described in conjunction with FIG. 2. To this end, the
heat exchanger profile 400 may be a part of the heat exchanger
system 408 and have the heat exchanger 410, the pump 412 and the
conduit 414 (as shown in FIG. 2). A carrier inlet 510 and a carrier
outlet (not pictured) may continue or extend the heat exchanger
profiles 400 from the fixed latch 126 into the carrier 500 (or from
another heat exchanger profile 400 independent of the fixed latch
126), allowing the cooling medium 405 to circulate through the
carrier 500. The heat exchanger profile 400 in the carrier 500 may
reduce the heat in the carrier 500 and thereby reduce the
temperature of the volume of fluid 303 applying pressure to the
seal element 502. Further, the carrier 500 may have a layer of
insulating coating 506 on the carrier's surfaces 508 (by way of
example on the outer or exterior surface) to help reduce heat
transfer caused by heated wellbore fluids. The decreased
temperature applied to the seal element 502 may reduce wear and
increase the life of the seal element 502.
[0023] In addition, the heat exchanger system 408, heat exchanger
profile 400, and carrier 500 may be a closed hydraulic control
system 420, thereby eliminating the need for an external cooling
system to control the temperature of the pressure control device
102. A closed hydraulic system 420 may relieve demand on limited
resources, and further, addresses difficulty in installing and
maintaining an external cooling system in extreme environments.
Risers 107, used in subsea operations, may also pose significant
obstacles to the use of external cooling systems.
[0024] While the exemplary embodiments are described with reference
to various implementations and exploitations, it will be understood
that these exemplary embodiments are illustrative and that the
scope of the inventive subject matter is not limited to them. Many
variations, modifications, additions and improvements are possible.
For example, although the exemplary embodiments have thus far been
depicted and described with a closed hydraulic control system 420,
the exemplary embodiments described within may also be utilized in
conjunction with an open or external hydraulic control system.
Further, the implementations and techniques used herein may be
applied to any strippers, seals, or packer members at the well
site, such as the BOP, and the like.
[0025] Plural instances may be provided for components, operations
or structures described herein as a single instance. In general,
structures and functionality presented as separate components in
the exemplary configurations may be implemented as a combined
structure or component. Similarly, structures and functionality
presented as a single component may be implemented as separate
components. These and other variations, modifications, additions,
and improvements may fall within the scope of the inventive subject
matter.
* * * * *