CA2465735C - Flare stack safety system and method of use - Google Patents
Flare stack safety system and method of use Download PDFInfo
- Publication number
- CA2465735C CA2465735C CA 2465735 CA2465735A CA2465735C CA 2465735 C CA2465735 C CA 2465735C CA 2465735 CA2465735 CA 2465735 CA 2465735 A CA2465735 A CA 2465735A CA 2465735 C CA2465735 C CA 2465735C
- Authority
- CA
- Canada
- Prior art keywords
- flare
- line
- flare stack
- well
- source
- 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 - Fee Related
Links
- 238000000034 method Methods 0.000 title claims abstract description 6
- 239000007789 gas Substances 0.000 claims abstract description 52
- 238000010926 purge Methods 0.000 claims abstract description 50
- 239000012530 fluid Substances 0.000 claims 2
- 230000004913 activation Effects 0.000 abstract 1
- 238000013022 venting Methods 0.000 abstract 1
- 239000011261 inert gas Substances 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000002485 combustion reaction Methods 0.000 description 3
- 239000000446 fuel Substances 0.000 description 3
- 239000002737 fuel gas Substances 0.000 description 3
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000003780 insertion Methods 0.000 description 1
- 230000037431 insertion Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B41/00—Equipment or details not covered by groups E21B15/00 - E21B40/00
- E21B41/005—Waste disposal systems
- E21B41/0071—Adaptation of flares, e.g. arrangements of flares in offshore installations
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23G—CREMATION FURNACES; CONSUMING WASTE PRODUCTS BY COMBUSTION
- F23G7/00—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals
- F23G7/06—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of waste gases or noxious gases, e.g. exhaust gases
- F23G7/08—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of waste gases or noxious gases, e.g. exhaust gases using flares, e.g. in stacks
- F23G7/085—Incinerators or other apparatus for consuming industrial waste, e.g. chemicals of waste gases or noxious gases, e.g. exhaust gases using flares, e.g. in stacks in stacks
Landscapes
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Geology (AREA)
- Fluid Mechanics (AREA)
- Physics & Mathematics (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Incineration Of Waste (AREA)
- Filling Or Discharging Of Gas Storage Vessels (AREA)
Abstract
In the context of an oil or gas well site flare system, a safety system is provided so that in the event of a flammable gas release at the well, the safety system can be activated to extinguish the sources of ignition. Activation of the safety system does not prevent the continued venting or exiting of flare gases from the flare stack. In a system aspect, the safety system comprises a source of purge gas connected to a flare stack and actuator means. When the actuator means is actuated, a flow of purge gas commences from said source into said flare stack while allowing said flammable gases to continue to exit out said flare stack. Other system and method aspects are also provided.
Description
1 "FLARE STACK SAFETY SYSTEM AND METHOD OF USE"
4 The field of present invention relates generally to flare systems used at oil and gas drilling sites and, more particularly, to flare stack safety systems for 6 use during snubbing operations, well testing and other well completion operations.
9 During the insertion of piping and tools into live well bores, and the extraction of piping and tools from live well bores, known as "snubbing", it is 11 conventional that a flare stack is often burning nearby, to receive gases from the 12 well and thereby relief the well pressures that are present during the snubbing 13 operations.
14 However, at times failures occur in pressure control systems due to equipment malfunction or, more commonly, human error. During such an event, 16 large plumbs of flammable gas may escape from the pressure control equipment 17 and/or blow out from the well and drift towards the flare stack -occasionally with 18 disastrous results such as a well fire initiated by the flare system.
19 Flare stacks for oil and gas operations tend to be fairly simple systems that are devoid of anything but the simplest controls. Typically, an ignition source 21 such as a pilot flame is provided at the outlet of the flare stack and is left on 22 constantly so that, in the event that flammable gases are vented to the flare stack, 23 the ignition source will start combustion of such vented gases. Thus, during normal 1 operations, the flare stack or at least portions thereof towards the outlet end are 2 fairly warm. Additionally, even if the fuel for the pilot flame is shut off, the remaining 3 fuel (typically propane) in the line to the pilot still has enough pressure to keep the 4 pilot flame burning for a few minutes.
A further complicating factor is that during workover and completion 6 operations is it generally not desirable to shut off the flow of gases to the flare 7 system when the pressure control equipment has failed. Shutting off the flow of 8 vented gases, from the well to the flare stack, would only exaggerate the well 9 pressure that would be desirable to relieve. However, such a continued flow of gases through the flare stack would also allow the flare to continue burning, long 11 after the fuel to the pilot flame is shut off and the pilot flame itself has extinguished.
12 What is needed is a safety system which will eliminate the danger of 13 ignition of escaping flammable vapors, by the flare stack system, while still allowing 14 the flow of vented gases out through the flare stack.
18 Figure 1 is a schematic representation of one embodiment of a flare 19 stack safety system;
Figure 2 is a schematic representation of a second embodiment of a 21 flare stack safety system;
22 Figures 3a and 3b are perspective views of the embodiment of Figure 23 1; and 1 Figure 4 is a schematic representation of a third embodiment of a flare 2 stack safety system.
Figures 1, 3a and 3b show one embodiment of a flare stack safety 6 system 10. A main flare line 12 carries flammable gases from the well to a flare 7 stack 14 for combustion. The flare line 12 enters the flare stack 14 substantially 8 near the bottom. The flare stack 14 has an ignition source 16 to initiate the 9 combustion of the gases. The ignition source 16 can be electronic, a pilot light or pilot flame operated with a fuel gas, or any other equivalent ignition source.
In this 11 embodiment the ignition source 16 is a pilot flame created by a burner 18 supplied 12 with fuel gas through a pilot line 20 .
13 A purge line 22 connects a storage vessel 30 to the flare line 12 just 14 prior to the junction of the flare line 12 with the flare stack 14. The purge line 22 branches and also connects to the pilot line 20. Preferably, check valves 24, 16 are mounted in the purge line 22 such that when actuator or purge valve 32 is 17 opened, flow commences from storage vessel 30 into the flare line 12 and pilot line 18 20. Check valves 24, 26 are illustrated schematically as a spring-loaded balls and 19 prevent gas from entering purge line 22.
The purge valve 32 is preferably a quick opening valve. The purge 21 valve 32 is left in the normally closed position during normal operations.
A suitable 22 valve would be a butterfly valve or ball valve. Alternatively the purge valve 32 could 1 be a pressure activated valve that can be opened from a variety of locations on the 2 well site.
3 Storage vessel 30 typically carries a non-combustible pressurized 4 inert gas, preferably nitrogen. Another suitable non-combustible gas would be C02.
In this embodiment, storage vessel 30 further comprises bottles of nitrogen 34 6 connected to lengths of pre-charge piping 36. The pre-charged piping 36 stores the 7 desired volume of inert gas under pressure During normal well operations, the purge valve 32 is closed, keeping 11 the pressurized inert gas in the storage vessel 30. In the event of an emergency at 12 the well site involving a flammable gas or liquid release, purge valve 32 is actuated 13 to open. Flow of inert gas is immediately begun into the flare line 12 and pilot line 14 20 through the purge line 22 and past the check valves 24, 26. The flow of inert cool gases from the purge line 22 through the flare line 12 and then into the flare 16 stack 14 cools the flare stack 14 down and ensures that no oxygen can enter the 17 flare stack 14 as it is cooled down.
18 What results is a quick, within a few seconds, purging of flare stack 14 19 and pilot line 20 with inert gas from the storage vessel 30.
Advantageously, the ignition source 16 is also cut off from its fuel gas by the entry of inert gas into the 21 pilot line 20, and is thereby extinguished and cooled. The rapid cool down of both 22 the flare stack 14 and burner 18 precludes the availability of either as a further 23 source of ignition to escaping gas from the well. More advantageously, because the 1 vented gases are still able to flow from the well, through the flare Line 12, into the 2 flare stack 14, the well pressure can be relieved while having eliminated the danger 3 of igniting escaped flammable vapors from the well and causing a fire.
SECOND EMBODIMENT
6 Figure 2 illustrates a second, slightly different embodiment, wherein 7 the ignition source 16 is an electronic igniter 50 maintained constantly in the on 8 position through use of switch or control labeled A. Accordingly there is no pilot line 9 nor does the purge line 22 connect to the ignition source. The purge valve 32 is controlled by switch B. When switch B is actuated, it accomplishes the following 11 tasks: the purge valve 32 is opened and the ignition source 16 is cut off.
12 Accordingly, in the event of an emergency at the well site switch B is 13 actuated which overrides the ignition source 16, closing it off while at the same time 14 opening the purge valve 32. Switch B can be manually activated or it can be tied into a flammable gas detector which will set off switch B automatically as well as 16 sound an audible alarm.
19 Figure 4 illustrates a third embodiment of the flare stack safety system 10, wherein a plurality of flare stacks 14a, 14b are shown, each connected to the 21 purge line 22 of the flare stack safety system 10.
9 During the insertion of piping and tools into live well bores, and the extraction of piping and tools from live well bores, known as "snubbing", it is 11 conventional that a flare stack is often burning nearby, to receive gases from the 12 well and thereby relief the well pressures that are present during the snubbing 13 operations.
14 However, at times failures occur in pressure control systems due to equipment malfunction or, more commonly, human error. During such an event, 16 large plumbs of flammable gas may escape from the pressure control equipment 17 and/or blow out from the well and drift towards the flare stack -occasionally with 18 disastrous results such as a well fire initiated by the flare system.
19 Flare stacks for oil and gas operations tend to be fairly simple systems that are devoid of anything but the simplest controls. Typically, an ignition source 21 such as a pilot flame is provided at the outlet of the flare stack and is left on 22 constantly so that, in the event that flammable gases are vented to the flare stack, 23 the ignition source will start combustion of such vented gases. Thus, during normal 1 operations, the flare stack or at least portions thereof towards the outlet end are 2 fairly warm. Additionally, even if the fuel for the pilot flame is shut off, the remaining 3 fuel (typically propane) in the line to the pilot still has enough pressure to keep the 4 pilot flame burning for a few minutes.
A further complicating factor is that during workover and completion 6 operations is it generally not desirable to shut off the flow of gases to the flare 7 system when the pressure control equipment has failed. Shutting off the flow of 8 vented gases, from the well to the flare stack, would only exaggerate the well 9 pressure that would be desirable to relieve. However, such a continued flow of gases through the flare stack would also allow the flare to continue burning, long 11 after the fuel to the pilot flame is shut off and the pilot flame itself has extinguished.
12 What is needed is a safety system which will eliminate the danger of 13 ignition of escaping flammable vapors, by the flare stack system, while still allowing 14 the flow of vented gases out through the flare stack.
18 Figure 1 is a schematic representation of one embodiment of a flare 19 stack safety system;
Figure 2 is a schematic representation of a second embodiment of a 21 flare stack safety system;
22 Figures 3a and 3b are perspective views of the embodiment of Figure 23 1; and 1 Figure 4 is a schematic representation of a third embodiment of a flare 2 stack safety system.
Figures 1, 3a and 3b show one embodiment of a flare stack safety 6 system 10. A main flare line 12 carries flammable gases from the well to a flare 7 stack 14 for combustion. The flare line 12 enters the flare stack 14 substantially 8 near the bottom. The flare stack 14 has an ignition source 16 to initiate the 9 combustion of the gases. The ignition source 16 can be electronic, a pilot light or pilot flame operated with a fuel gas, or any other equivalent ignition source.
In this 11 embodiment the ignition source 16 is a pilot flame created by a burner 18 supplied 12 with fuel gas through a pilot line 20 .
13 A purge line 22 connects a storage vessel 30 to the flare line 12 just 14 prior to the junction of the flare line 12 with the flare stack 14. The purge line 22 branches and also connects to the pilot line 20. Preferably, check valves 24, 16 are mounted in the purge line 22 such that when actuator or purge valve 32 is 17 opened, flow commences from storage vessel 30 into the flare line 12 and pilot line 18 20. Check valves 24, 26 are illustrated schematically as a spring-loaded balls and 19 prevent gas from entering purge line 22.
The purge valve 32 is preferably a quick opening valve. The purge 21 valve 32 is left in the normally closed position during normal operations.
A suitable 22 valve would be a butterfly valve or ball valve. Alternatively the purge valve 32 could 1 be a pressure activated valve that can be opened from a variety of locations on the 2 well site.
3 Storage vessel 30 typically carries a non-combustible pressurized 4 inert gas, preferably nitrogen. Another suitable non-combustible gas would be C02.
In this embodiment, storage vessel 30 further comprises bottles of nitrogen 34 6 connected to lengths of pre-charge piping 36. The pre-charged piping 36 stores the 7 desired volume of inert gas under pressure During normal well operations, the purge valve 32 is closed, keeping 11 the pressurized inert gas in the storage vessel 30. In the event of an emergency at 12 the well site involving a flammable gas or liquid release, purge valve 32 is actuated 13 to open. Flow of inert gas is immediately begun into the flare line 12 and pilot line 14 20 through the purge line 22 and past the check valves 24, 26. The flow of inert cool gases from the purge line 22 through the flare line 12 and then into the flare 16 stack 14 cools the flare stack 14 down and ensures that no oxygen can enter the 17 flare stack 14 as it is cooled down.
18 What results is a quick, within a few seconds, purging of flare stack 14 19 and pilot line 20 with inert gas from the storage vessel 30.
Advantageously, the ignition source 16 is also cut off from its fuel gas by the entry of inert gas into the 21 pilot line 20, and is thereby extinguished and cooled. The rapid cool down of both 22 the flare stack 14 and burner 18 precludes the availability of either as a further 23 source of ignition to escaping gas from the well. More advantageously, because the 1 vented gases are still able to flow from the well, through the flare Line 12, into the 2 flare stack 14, the well pressure can be relieved while having eliminated the danger 3 of igniting escaped flammable vapors from the well and causing a fire.
SECOND EMBODIMENT
6 Figure 2 illustrates a second, slightly different embodiment, wherein 7 the ignition source 16 is an electronic igniter 50 maintained constantly in the on 8 position through use of switch or control labeled A. Accordingly there is no pilot line 9 nor does the purge line 22 connect to the ignition source. The purge valve 32 is controlled by switch B. When switch B is actuated, it accomplishes the following 11 tasks: the purge valve 32 is opened and the ignition source 16 is cut off.
12 Accordingly, in the event of an emergency at the well site switch B is 13 actuated which overrides the ignition source 16, closing it off while at the same time 14 opening the purge valve 32. Switch B can be manually activated or it can be tied into a flammable gas detector which will set off switch B automatically as well as 16 sound an audible alarm.
19 Figure 4 illustrates a third embodiment of the flare stack safety system 10, wherein a plurality of flare stacks 14a, 14b are shown, each connected to the 21 purge line 22 of the flare stack safety system 10.
2 In one embodiment a method of operation of a flare stack safety 3 system comprises:
4 purging at least one flare stack with a non-combustible inert gas;
cutting off at least one ignition source; and 6 allowing waste gases to continue to exit out at least one flare stack.
4 purging at least one flare stack with a non-combustible inert gas;
cutting off at least one ignition source; and 6 allowing waste gases to continue to exit out at least one flare stack.
Claims (21)
1. A flare stack safety system, for connection to a flare line carrying flammable gases from a well, said well being under pressure, to a flare stack, the safety system comprising:
a source of purge gas connected to said flare line; and actuator means;
wherein said flare line provides for a flow of said flammable gases from the well to the flare stack at all times, thereby allowing for said well pressure to be relieved at all times; and wherein when the actuator means is actuated, a flow of purge gas commences from said source into said flare line while allowing said flammable gases to continue to exit out said flare stack.
a source of purge gas connected to said flare line; and actuator means;
wherein said flare line provides for a flow of said flammable gases from the well to the flare stack at all times, thereby allowing for said well pressure to be relieved at all times; and wherein when the actuator means is actuated, a flow of purge gas commences from said source into said flare line while allowing said flammable gases to continue to exit out said flare stack.
2. The system of claim 1 wherein the source of purge gas comprises a storage vessel containing a purge gas.
3. The system of claim 1 further comprising a purge line connecting said source of purge gas to said flare line.
4. The system of claim 2 further comprising a purge line connecting said source of purge gas to said flare line.
5. The system of claim 1 wherein the actuator means comprises a normally closed purge valve.
6. The system of claim 4 wherein the actuator means comprises a normally closed purge valve.
7. The system of claim 3 further comprising at least one check valve mounted in the purge line.
8. The system of claim 6 further comprising at least one check valve mounted in the purge line.
9. The system of claim 1 further comprising at least one check valve mounted in the flare line.
10. The system of claim 8 further comprising at least one check valve mounted in the flare line.
11. A flare stack safety system, for connection to a flare stack receiving flammable gases from a well, said well being under pressure, the safety system comprising:
a source of purge gas connected to said flare stack; and actuator means;
wherein said flare stack safety system provides for a flow of said flammable gases from the well to the flare stack at all times, thereby allowing for said well pressure to be relieved at all times; and wherein when the actuator means is actuated, a flow of purge gas commences from said source into said flare stack while allowing said flammable gases to continue to exit out said flare stack.
a source of purge gas connected to said flare stack; and actuator means;
wherein said flare stack safety system provides for a flow of said flammable gases from the well to the flare stack at all times, thereby allowing for said well pressure to be relieved at all times; and wherein when the actuator means is actuated, a flow of purge gas commences from said source into said flare stack while allowing said flammable gases to continue to exit out said flare stack.
12. The system of claim 11 wherein the source of purge gas comprises a storage vessel containing a purge gas.
13. The system of claim 11 further comprising a purge line connecting said source of purge gas to said flare stack.
14. The system of claim 12 further comprising a purge line connecting said source of purge gas to said flare stack.
15. The system of claim 11 wherein the actuator means comprises a normally closed purge valve.
16. The system of claim 14 wherein the actuator means comprises a normally closed purge valve.
17. The system of claim 16 further comprising at least one check valve mounted in the purge line.
18. A method of flaring pressurized well gases while preventing well fires caused by gases or fluids inadvertently discharged around a well, comprising:
continuously directing the well gases out a flare stack, said flare stack having an adjacent ignition source;
sensing a gas or fluid leak at the well;
turning off said ignition source adjacent said flare stack;
purging said flare stack by injecting a purge gas into said stack; and allowing the well gases to exit out said flare stack at all times.
continuously directing the well gases out a flare stack, said flare stack having an adjacent ignition source;
sensing a gas or fluid leak at the well;
turning off said ignition source adjacent said flare stack;
purging said flare stack by injecting a purge gas into said stack; and allowing the well gases to exit out said flare stack at all times.
19. The system of claim 1 wherein the flare stack further comprises a pilot line and the source of purge gas is also connected to said pilot line.
20. The system of claim 11 wherein the flare stack further comprises a pilot line and the source of purge gas is also connected to said pilot line.
21. The method of claim 18 wherein the ignition source comprises a pilot light fed by a pilot line and the step of turning off the ignition source is accomplished by purging the pilot line with a purge gas.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2465735 CA2465735C (en) | 2004-04-29 | 2004-04-29 | Flare stack safety system and method of use |
| CA 2505536 CA2505536A1 (en) | 2004-04-29 | 2005-04-28 | Flare stack safety system and method of use |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2465735 CA2465735C (en) | 2004-04-29 | 2004-04-29 | Flare stack safety system and method of use |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2465735A1 CA2465735A1 (en) | 2005-10-29 |
| CA2465735C true CA2465735C (en) | 2011-08-02 |
Family
ID=35311204
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2465735 Expired - Fee Related CA2465735C (en) | 2004-04-29 | 2004-04-29 | Flare stack safety system and method of use |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2465735C (en) |
-
2004
- 2004-04-29 CA CA 2465735 patent/CA2465735C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2465735A1 (en) | 2005-10-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20170501 |