CA1299620C - Thermal protecting blanket for a well head control device - Google Patents
Thermal protecting blanket for a well head control deviceInfo
- Publication number
- CA1299620C CA1299620C CA000583157A CA583157A CA1299620C CA 1299620 C CA1299620 C CA 1299620C CA 000583157 A CA000583157 A CA 000583157A CA 583157 A CA583157 A CA 583157A CA 1299620 C CA1299620 C CA 1299620C
- Authority
- CA
- Canada
- Prior art keywords
- control device
- well head
- head control
- flexible
- heating element
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B33/00—Sealing or packing boreholes or wells
- E21B33/02—Surface sealing or packing
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH DRILLING; MINING
- E21B—EARTH DRILLING, e.g. DEEP DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B36/00—Heating, cooling, insulating arrangements for boreholes or wells, e.g. for use in permafrost zones
- E21B36/04—Heating, cooling, insulating arrangements for boreholes or wells, e.g. for use in permafrost zones using electrical heaters
Abstract
ROGERS, BERESKIN & PARR CANADA
TITLE: THERMAL PROTECTING BLANKET FOR
A WELL HEAD CONTROL DEVICE
INVENTORS: ROBERT A. ANDERSON
ABSTRACT
A thermal protecting blanket for a well head control device such as a blow out preventor. The blanket, is specially adapted for use in hazardous environments.It includes a flexible cover custom fitted to the shape of the well head control device, an electrical heating element disposed on the inside of the flexible cover, and which is detachable, and the cover having a closable opening so that, it may be closed to insulate the well head control device, and opened to permit access to the device during servicing.
The electrical heating element is detachable, and self regulating. External connections for the well head control device pass through openings in the flexible cover, and the openings are held tight against the external connections by a drawstring. The fabric cover is made of ail resistant, water resistant and fire resistant material.
TITLE: THERMAL PROTECTING BLANKET FOR
A WELL HEAD CONTROL DEVICE
INVENTORS: ROBERT A. ANDERSON
ABSTRACT
A thermal protecting blanket for a well head control device such as a blow out preventor. The blanket, is specially adapted for use in hazardous environments.It includes a flexible cover custom fitted to the shape of the well head control device, an electrical heating element disposed on the inside of the flexible cover, and which is detachable, and the cover having a closable opening so that, it may be closed to insulate the well head control device, and opened to permit access to the device during servicing.
The electrical heating element is detachable, and self regulating. External connections for the well head control device pass through openings in the flexible cover, and the openings are held tight against the external connections by a drawstring. The fabric cover is made of ail resistant, water resistant and fire resistant material.
Description
~L299~2~
This invention relates -to an apparatus for -the thermal protectlon of well head control devices such as blow out preventors (BOPs).
Well head control devices often operate in extremely cold environments where -temperatures reach below -40C. A11 of these well head control devices, such as BOPs, operate under high pressure and contain rubber parts which provide a sealing function for the well contents.
Extreme cold can affect the sealing function of the rubber parts and this can lead to failure of the seal, resulting in a dangerous environment. In addition, normal cold weather operation of the BOP can lead to a build-up of frost or rime in the bore of the BOP which impairs its safety.
In the past, methods of heating BOPs have involved: heating water in a boiler, and transferring the heat from the heated water to the BOP through a heat exchanger; or blowing air through a heated glycol filled radiator onto the surface of the BOP. These methods were inefficient due to a loss of heat to the environment.
Another method utilized a rigid box or container surrounding the BOP. While this improved heat retention, access to the BOP was restricted.
The present invention helps avoid the difficulties of the prior art and provides, in one aspect, a thermal protecting apparatus for a well head control device comprising:
`-- 1299620 a flexible cover fitted to the shape of the well head control devlcei an electrical heating element disposed on the inside of the flexible cover;
the cover being adjustable between a first position in which the well head control device is insulated from the environment and a second position in which the well head control device is exposed to and accessible from the environment;
means for fastening the cover in the first position; and an electrical power source connected to the electrical heating element.
Further summary of the invention may be found in the claims forming a part of this patent.
In drawings which illustrate embodiments of the invention, by way of example:
Figure 1 is a perspective of a heating cover according to the invention for a ram type BOP heater in which the heating cover is in open posltion;
Figure 2 is a perspective of a heating cover according to the invention for an annular BOP heater in which the heatlng cover 1S in open position;
Flgure 3 lS a front view of a heating cover according to the lnventlon for a ram type BOP; and Figure 4 is a rear view of a heating cover according to the invention for a ram type BOP.
- . ~ . . . .
;. , . ~ . , :. - : . , ~zo , --4--~ l~wo ~yl~es of ~OI are widely used for well llecl-J
pressure conf:ro1. The embodiînen',s of ~,he inverll,iorl described here are cus~,om tailored to ~,he ~onfigura',iorl of the ram type and annul~r ~,ype of g~P. O~,her corlfigl1r-~,ion~
of well head con~:rol devices may be fi~,l,ed wil.h ~,he heal,incJ
cover of t,he invent,ion wi~,h appropria~,e modificat,ions to ~,he shape of t.he heat,ing cover.
Figure l shows a hea~,ing r-over cust,om con~oured for t.he ram ~.ype BOP. ~igure 2 shows a heat.ing cover custorn cont.oured for the annular ~ pe soP. In bo'.h designs, ~.he cover is made of an out.er shell 10, inner shell 12 and a layer of insulat,ion 14 sandwiched be~,ween t:he inner shell 10 and ou~,er shell 12. rlle ou~,er shel,l 10 is preferably rnade of a fire resist.an~,, oil resisl,an~,, and wat.er rcsistarl~
flexible fabric funct,ional from -40C ~.o ]00C SUCIl as Arct.ic Hyprene* available from Norseman Shel~,ers. Ihe inner shell 12 is made of woven glas fibre. 7lle in~ul;l'iorl ]4 ~i preferably a layer of solimide foam or ot.her fire resistan~
mat.erial. The layers of fabric and insula',ion are showll In the area generally loca~.ed c~: 16, and are sewn l:ogetller in known fashion about. t,he peri~et.er of t,he cover.
The flexibilit.y of ~.lle r-over perrni~s i~ o be wrapped around t.he BOP. Drawst.rings 20 on sleeve 21 are used t.o sea~ ':he cover agains~. ~.he ex~,ernal conrlecl,i ons and well head connect.ion of -.ne BOP by l.iglll,erling of ',he drawstrings 20. Out.let,s 18 are for t,he hydraulic connect.ions t,o t.he ram l.ype BOP. In Figure 2, openings 23 receive t.he ext,ernal connecl,ions of ~ e annular Iyl~e l30P.
*Trademark ~;~9~;~0 Overlapping fl.aps 22 and 24 have complementary VELCRO m stri.ps (VELCRO is a trade mark of Velcro Corpora~,i.on) on their inner and outer facing surfaces respect,ively. The flaps 22 and 24 and straps 26 wi,t,h complementary buckles 28 fasten the cover about t,he BOP. Straps 26 are preferably made of nylon.
The cover i.s substantially rectangular and is cust,om fit for the particular BOP and is provided wi.th enclosing ends 25 so tha~, when the cover is i,n its closed position, i.nsulating the BOP, it, i,s substantiall.y cylindrical. The flaps 22 and 24 are at the longitudinal ends of the cover.
Pouch 30, shown partially cut-away in figures 1 and 2, houses explosion proof connectors 32, which are readily commercially available. Connectors 32 connect 110v power cords 34 to the self regulating heating cable 36.
Self regulating heating cable 36 is rated at 110v x 10-20 watts/Ft, approved for hazardous environment (Class I, Div II Groups (ànd D) and may also be readiJ.y commercially obtained. Sel.f regulating heating cables 36 terminate in explosion proof termi.nat,ors 38, also readily commercially available. The self regulating heating cables 36 are preferably selected to ma.intain the BOP or o-ther well head control devlce within a range of temperatures speci.fi.ed by the manufacturers of the seals of the BOP, or other well head control~devi.ce, to be satisfactory for the performance of the rubber seals. For example, typical rubber seals operate in a -temperature range of -7C to +60C.
. . . ' . . ' ~ ~ :
. .
, . ' . ~ . . ,' ' :
.
,: , : . .
~2~9~;20 Self regulatlng heating cables 36 are fastened by s-tltching between the detachable pads 42 and internal pads 46 are fastened to the inner shell 12 by snaps 44. Separated pads 42, as shown for the ram type BOP in Figure l, may be used to bridge openings for external connections to the BOP.
The pads 42 are preferably made of fire resistant, oil resistant, and water resistant material, such as woven glas fibre. The internal pads 46 are made of similar material and may be lined with metal wool to improve heat distribution.
The wire size in the self regulating heating cables 36 should be adjusted to meet temperature rating limitations set by the Canadian Standards Association according to the well bore fluids being used.
One or more RTDs (not shown) may be inserted into the pads 42 or 46 in contact with outside terminals for checking the inside temperature of the cover, without removal of the cover. Straps 48 are preferably strain relief detention straps, which are readily commercially available.
If desired, the self regulating heating cables 36 may be plugged into a breaker box (not shown). The breaker box may be wired to kick out if the ground connection is broken.
In use, the cover may be readily applied a~d fitted to the BOP. Straps 26, flaps 22 and 24 and drawstrlngs 20 are secured to provide a substantially airtight cover for the BOP. In the case of the annular type BOP, the openings 23 fit snugly against its external `''''~` ' - ' "
129g~D
connections. The temperature of the BOP 1s regulated by the self regula-tlng heating cable 36. Ready access to the BOP
for servicing is provided by the stxaps 26 and VELCROtm flaps 22 and 24.
Clearly, other methods of fastening the cover about the BOP may be used. For example, instead of VELCRO
flaps and buckles, rings and hooks, zips, buttons or straps only could be used. Overlapping flaps are desirable to improve the insulating capacity of the cover. Elasticized material at the edge of each opening may be used instead of drawstrings for fastening the opening of the cover about external connections to the well head control device.
Other alternative but e~uivalent devices may be constructed by persons skilled in the art, but these are intended to be covered by the claims which follow.
Well head control devices often operate in extremely cold environments where -temperatures reach below -40C. A11 of these well head control devices, such as BOPs, operate under high pressure and contain rubber parts which provide a sealing function for the well contents.
Extreme cold can affect the sealing function of the rubber parts and this can lead to failure of the seal, resulting in a dangerous environment. In addition, normal cold weather operation of the BOP can lead to a build-up of frost or rime in the bore of the BOP which impairs its safety.
In the past, methods of heating BOPs have involved: heating water in a boiler, and transferring the heat from the heated water to the BOP through a heat exchanger; or blowing air through a heated glycol filled radiator onto the surface of the BOP. These methods were inefficient due to a loss of heat to the environment.
Another method utilized a rigid box or container surrounding the BOP. While this improved heat retention, access to the BOP was restricted.
The present invention helps avoid the difficulties of the prior art and provides, in one aspect, a thermal protecting apparatus for a well head control device comprising:
`-- 1299620 a flexible cover fitted to the shape of the well head control devlcei an electrical heating element disposed on the inside of the flexible cover;
the cover being adjustable between a first position in which the well head control device is insulated from the environment and a second position in which the well head control device is exposed to and accessible from the environment;
means for fastening the cover in the first position; and an electrical power source connected to the electrical heating element.
Further summary of the invention may be found in the claims forming a part of this patent.
In drawings which illustrate embodiments of the invention, by way of example:
Figure 1 is a perspective of a heating cover according to the invention for a ram type BOP heater in which the heating cover is in open posltion;
Figure 2 is a perspective of a heating cover according to the invention for an annular BOP heater in which the heatlng cover 1S in open position;
Flgure 3 lS a front view of a heating cover according to the lnventlon for a ram type BOP; and Figure 4 is a rear view of a heating cover according to the invention for a ram type BOP.
- . ~ . . . .
;. , . ~ . , :. - : . , ~zo , --4--~ l~wo ~yl~es of ~OI are widely used for well llecl-J
pressure conf:ro1. The embodiînen',s of ~,he inverll,iorl described here are cus~,om tailored to ~,he ~onfigura',iorl of the ram type and annul~r ~,ype of g~P. O~,her corlfigl1r-~,ion~
of well head con~:rol devices may be fi~,l,ed wil.h ~,he heal,incJ
cover of t,he invent,ion wi~,h appropria~,e modificat,ions to ~,he shape of t.he heat,ing cover.
Figure l shows a hea~,ing r-over cust,om con~oured for t.he ram ~.ype BOP. ~igure 2 shows a heat.ing cover custorn cont.oured for the annular ~ pe soP. In bo'.h designs, ~.he cover is made of an out.er shell 10, inner shell 12 and a layer of insulat,ion 14 sandwiched be~,ween t:he inner shell 10 and ou~,er shell 12. rlle ou~,er shel,l 10 is preferably rnade of a fire resist.an~,, oil resisl,an~,, and wat.er rcsistarl~
flexible fabric funct,ional from -40C ~.o ]00C SUCIl as Arct.ic Hyprene* available from Norseman Shel~,ers. Ihe inner shell 12 is made of woven glas fibre. 7lle in~ul;l'iorl ]4 ~i preferably a layer of solimide foam or ot.her fire resistan~
mat.erial. The layers of fabric and insula',ion are showll In the area generally loca~.ed c~: 16, and are sewn l:ogetller in known fashion about. t,he peri~et.er of t,he cover.
The flexibilit.y of ~.lle r-over perrni~s i~ o be wrapped around t.he BOP. Drawst.rings 20 on sleeve 21 are used t.o sea~ ':he cover agains~. ~.he ex~,ernal conrlecl,i ons and well head connect.ion of -.ne BOP by l.iglll,erling of ',he drawstrings 20. Out.let,s 18 are for t,he hydraulic connect.ions t,o t.he ram l.ype BOP. In Figure 2, openings 23 receive t.he ext,ernal connecl,ions of ~ e annular Iyl~e l30P.
*Trademark ~;~9~;~0 Overlapping fl.aps 22 and 24 have complementary VELCRO m stri.ps (VELCRO is a trade mark of Velcro Corpora~,i.on) on their inner and outer facing surfaces respect,ively. The flaps 22 and 24 and straps 26 wi,t,h complementary buckles 28 fasten the cover about t,he BOP. Straps 26 are preferably made of nylon.
The cover i.s substantially rectangular and is cust,om fit for the particular BOP and is provided wi.th enclosing ends 25 so tha~, when the cover is i,n its closed position, i.nsulating the BOP, it, i,s substantiall.y cylindrical. The flaps 22 and 24 are at the longitudinal ends of the cover.
Pouch 30, shown partially cut-away in figures 1 and 2, houses explosion proof connectors 32, which are readily commercially available. Connectors 32 connect 110v power cords 34 to the self regulating heating cable 36.
Self regulating heating cable 36 is rated at 110v x 10-20 watts/Ft, approved for hazardous environment (Class I, Div II Groups (ànd D) and may also be readiJ.y commercially obtained. Sel.f regulating heating cables 36 terminate in explosion proof termi.nat,ors 38, also readily commercially available. The self regulating heating cables 36 are preferably selected to ma.intain the BOP or o-ther well head control devlce within a range of temperatures speci.fi.ed by the manufacturers of the seals of the BOP, or other well head control~devi.ce, to be satisfactory for the performance of the rubber seals. For example, typical rubber seals operate in a -temperature range of -7C to +60C.
. . . ' . . ' ~ ~ :
. .
, . ' . ~ . . ,' ' :
.
,: , : . .
~2~9~;20 Self regulatlng heating cables 36 are fastened by s-tltching between the detachable pads 42 and internal pads 46 are fastened to the inner shell 12 by snaps 44. Separated pads 42, as shown for the ram type BOP in Figure l, may be used to bridge openings for external connections to the BOP.
The pads 42 are preferably made of fire resistant, oil resistant, and water resistant material, such as woven glas fibre. The internal pads 46 are made of similar material and may be lined with metal wool to improve heat distribution.
The wire size in the self regulating heating cables 36 should be adjusted to meet temperature rating limitations set by the Canadian Standards Association according to the well bore fluids being used.
One or more RTDs (not shown) may be inserted into the pads 42 or 46 in contact with outside terminals for checking the inside temperature of the cover, without removal of the cover. Straps 48 are preferably strain relief detention straps, which are readily commercially available.
If desired, the self regulating heating cables 36 may be plugged into a breaker box (not shown). The breaker box may be wired to kick out if the ground connection is broken.
In use, the cover may be readily applied a~d fitted to the BOP. Straps 26, flaps 22 and 24 and drawstrlngs 20 are secured to provide a substantially airtight cover for the BOP. In the case of the annular type BOP, the openings 23 fit snugly against its external `''''~` ' - ' "
129g~D
connections. The temperature of the BOP 1s regulated by the self regula-tlng heating cable 36. Ready access to the BOP
for servicing is provided by the stxaps 26 and VELCROtm flaps 22 and 24.
Clearly, other methods of fastening the cover about the BOP may be used. For example, instead of VELCRO
flaps and buckles, rings and hooks, zips, buttons or straps only could be used. Overlapping flaps are desirable to improve the insulating capacity of the cover. Elasticized material at the edge of each opening may be used instead of drawstrings for fastening the opening of the cover about external connections to the well head control device.
Other alternative but e~uivalent devices may be constructed by persons skilled in the art, but these are intended to be covered by the claims which follow.
Claims (14)
1. A thermal protecting apparatus for a well head control device comprising:
a flexible outer cover fitted to the shape of the well head control device;
an electrical heating element disposed on the inside of the flexible outer cover;
the flexible outer cover being adjustable between a first position in which the well head control device is insulated from the environment and a second position in which the well head control device is exposed to and accessible from the environment;
means for fastening the flexible outer cover in the first position; and an electrical power source connected to the electrical heating element.
a flexible outer cover fitted to the shape of the well head control device;
an electrical heating element disposed on the inside of the flexible outer cover;
the flexible outer cover being adjustable between a first position in which the well head control device is insulated from the environment and a second position in which the well head control device is exposed to and accessible from the environment;
means for fastening the flexible outer cover in the first position; and an electrical power source connected to the electrical heating element.
2. The thermal protecting apparatus of claim 1 in which the well head control device includes rubber seals for sealing the well head control device, and in which the electrical heating element is self regulating at a range of temperatures in which the rubber seals function.
3. The thermal protecting apparatus of claim 1 in which the flexible outer cover is made from water resistant, fire resistant and oil resistant material.
4. The thermal protecting apparatus of claim 1, 2 or 3 in which the flexible outer cover is made from water resistant, fire resistant and oil resistant material which is functional between -40° and +100°C.
5. The thermal protecting apparatus of claims 1, 2 or 3 in which the electrical heating element is detachably attached to the flexible outer cover.
6. The thermal protecting apparatus of claims 1, 2 or 3 in which the flexible outer cover is a substantially rectangular pad having a plurality of openings for the well head control device external connections, and having, for each opening, means for tightening and substantially sealing the flexible outer cover against the external connections, the substantially rectangular pad being fastened in the second position by fastening means at its longitudinal ends.
7. The thermal protecting apparatus of claims 1, 2 or 3 in which the flexible outer cover is custom fit for a particular well head control device, having a plurality of openings for the well head control device external connections, and having, for each opening, means for tightening and substantially sealing the flexible outer cover against the external connections.
8. The thermal protecting apparatus of claims 1, 2 or 3 in which the electrical heating element is disposed between inner and outer fabric pads, and the outer fabric pad is detachably attached to the flexible outer cover.
9. The thermal protecting apparatus of claims 1, 2 or 3 in which the electrical heating element is disposed between inner and outer fabric pads, and the outer fabric pad is detachably attached to the flexible outer cover and further including conducting material lining the inside of the inner fabric pad facing the well head control device.
10. A thermal protecting apparatus for a well head control device, having external connections, the thermal protecting apparatus comprising:
a flexible outer cover having a plurality of openings fitted to the shape of the well head control device external connections;
means for tightening and substantially sealing the flexible outer cover against the well head control device external connections;
an outer pad detachably attached to the inside of the flexible outer cover;
an inner pad attached to the outer pad;
a self regulating electrical heating element disposed between the inner and outer pads;
the flexible outer cover being adjustable between a first position in which the well head control device is insulated from the environment and a second position in which the well head control device is exposed to and accessible from the environment;
means for fastening the flexible outer cover in the first position; and an electrical power source connected to the self regulated electrical heating element.
a flexible outer cover having a plurality of openings fitted to the shape of the well head control device external connections;
means for tightening and substantially sealing the flexible outer cover against the well head control device external connections;
an outer pad detachably attached to the inside of the flexible outer cover;
an inner pad attached to the outer pad;
a self regulating electrical heating element disposed between the inner and outer pads;
the flexible outer cover being adjustable between a first position in which the well head control device is insulated from the environment and a second position in which the well head control device is exposed to and accessible from the environment;
means for fastening the flexible outer cover in the first position; and an electrical power source connected to the self regulated electrical heating element.
11. A thermal protecting apparatus for a blowout preventer, having external connections, the thermal protecting apparatus comprising:
a flexible cover having a plurality of openings fitted to the shape of the blowout preventor external connections;
an outer pad detachably attached to the inside of the flexible cover;
an inner pad having first and second sides, the first side being attached to the outer pad;
a self regulating electrical heating element disposed between the inner and outer pads;
the flexible cover being adjustable between a first position in which the blowout preventor is insulated from the environment and a second position in which the blowout preventor is exposed to and accessible from the environment;
a conductive lining attached to the second side of the inner pad and disposed on the inside of the electrical heating element such that the conductive lining is disposed between the electrical heating element and the blowout preventor when the flexible cover is in the first position.;
means for fastening the flexible cover in the first position; and an electrical power source connected to the self regulated electrical heating element.
a flexible cover having a plurality of openings fitted to the shape of the blowout preventor external connections;
an outer pad detachably attached to the inside of the flexible cover;
an inner pad having first and second sides, the first side being attached to the outer pad;
a self regulating electrical heating element disposed between the inner and outer pads;
the flexible cover being adjustable between a first position in which the blowout preventor is insulated from the environment and a second position in which the blowout preventor is exposed to and accessible from the environment;
a conductive lining attached to the second side of the inner pad and disposed on the inside of the electrical heating element such that the conductive lining is disposed between the electrical heating element and the blowout preventor when the flexible cover is in the first position.;
means for fastening the flexible cover in the first position; and an electrical power source connected to the self regulated electrical heating element.
12. A thermal protecting apparatus for a blow out preventor, having external connections, comprising:
a flexible cover having a plurality of openings fitted to the shape of the blow out preventor external connections;
an electrical heating element disposed on the inside of the flexible cover;
the flexible cover being adjustable between a first position in which the blowout preventor is insulated from the environment and a second position in which the blow out preventor is exposed to and accessible from the environment;
means for fastening the flexible cover in the first position;
an electrical power source connected to the electrical heating element; and in which the flexible cover comprises an outer layer, a middle layer made of flexible insulating material and an inner layer made of fire, oil and water resistant material.
a flexible cover having a plurality of openings fitted to the shape of the blow out preventor external connections;
an electrical heating element disposed on the inside of the flexible cover;
the flexible cover being adjustable between a first position in which the blowout preventor is insulated from the environment and a second position in which the blow out preventor is exposed to and accessible from the environment;
means for fastening the flexible cover in the first position;
an electrical power source connected to the electrical heating element; and in which the flexible cover comprises an outer layer, a middle layer made of flexible insulating material and an inner layer made of fire, oil and water resistant material.
13. The thermal protecting apparatus of claim 12 further including a conductive lining disposed on the inside of the electrical heating element such that the conductive lining is disposed between the electrical heating element and the blowout preventor when the flexible cover is in the first position.
14. The thermal protecting apparatus of claim 13 in which the electrical power source is connected to the electrical heating element by explosion proof connectors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000583157A CA1299620C (en) | 1988-11-15 | 1988-11-15 | Thermal protecting blanket for a well head control device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000583157A CA1299620C (en) | 1988-11-15 | 1988-11-15 | Thermal protecting blanket for a well head control device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1299620C true CA1299620C (en) | 1992-04-28 |
Family
ID=4139102
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000583157A Expired - Lifetime CA1299620C (en) | 1988-11-15 | 1988-11-15 | Thermal protecting blanket for a well head control device |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1299620C (en) |
-
1988
- 1988-11-15 CA CA000583157A patent/CA1299620C/en not_active Expired - Lifetime
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |