CA2865992C

CA2865992C - Closure for fluid ports in a production tank

Info

Publication number: CA2865992C
Application number: CA2865992A
Authority: CA
Inventors: John Lipinski
Original assignee: Trinity High Tech Products Ltd
Current assignee: Trinity High Tech Products Ltd
Priority date: 2014-09-26
Filing date: 2014-09-26
Publication date: 2015-06-16
Anticipated expiration: 2034-09-26
Also published as: CA2865992A1

Abstract

A production tank has a tank enclosure defined by a roof, a floor and a sidewall, at least one fluid inlet in fluid communication with the tank enclosure, and at least one fluid outlet in fluid communication with the tank enclosure. The at least one fluid outlet has a primary valve and a secondary valve with first and second actuators. The second actuator is biased toward a closed position. A fluid container is disposed below the at least one fluid outlet. A controller is connected to the at least one secondary valve and maintains the at least one secondary valve in an open position when activated. The controller permits the at least one secondary valve to close when deactivated. A sensor in communication with the fluid container is configured to deactivate the controller when a predetermined fluid condition is sensed.

Description

CLOSURE FOR FLUID PORTS IN A PRODUCTION TANK
TECHNICAL FIELD
[0001] This relates to a closure for fluid ports in a production tank, such as test cocks or fluid outlets.
BACKGROUND

[0002] Production tanks are used to store fluids produced from a well.
These wells include outlet, including larger outlets for transferring the produced fluids for transport, and other smaller outlets used for withdrawing samples of fluid, such as for testing purposes.
These outlets are often referred to as test cocks. Sometimes test cocks are not closed properly after use, in which case leaks can occur. If left uncorrected, the leak can result in significant environmental damage.
SUMMARY

[0003] According to an aspect, there is provided a production tank, comprising a tank enclosure defined by a roof, a floor and a sidewall, at least one fluid inlet in fluid communication with the tank enclosure, at least one fluid outlet in fluid communication with the tank enclosure comprising, a primary valve that has a first actuator for opening and closing the primary valve, and a secondary valve in line with the primary valve, the secondary valve having a second actuator for opening and closing the secondary valve, the second actuator being biased toward a closed position, a fluid container disposed below the at least one fluid outlet, a controller connected to the at least one secondary valve, the controller maintaining the at least one secondary valve in an open position when activated and the controller permitting the at least one secondary valve to move to the closed position when deactivated, a sensor in communication with the fluid container configured to deactivate the controller when a predetermined fluid condition is sensed within the fluid container.

[0004] According to another aspect, the controller may comprise a pressurized gas in fluid communication with the second actuator of the at least one secondary valve, the pressurized gas maintaining the at least one secondary valve in the open position, and the controller may be deactivated by releasing the gas pressure against the second actuator.

[0005] According to another aspect, the controller may comprise an electrical power source, the at least one secondary valve comprises a solenoid valve, and the controller may be deactivated by de-energizing the solenoid valve.

[0006] According to another aspect, the sensor may comprise a float that detects the presence of liquid in the fluid container.

[0007] According to another aspect, the production tank may further comprise a deactivation switch on an outer surface of the production tank and spaced from the at least one fluid outlet.

[0008] According to another aspect, the fluid container may comprise an outlet enclosure that encloses the at least one fluid outlets and is recessed within the tank enclosure relative to the sidewall.

[0009] According to an aspect, there is provided a production tank, comprising a tank enclosure defined by a roof, a floor and a sidewall. There is at least one fluid inlet in fluid communication with the tank enclosure and at least one fluid outlet in fluid communication with the tank enclosure. The at least one fluid outlet comprising a primary valve that has a first actuator for opening and closing the primary valve, and a secondary valve in line with the primary valve, the secondary valve having a second actuator for opening and closing the secondary valve. A fluid container is disposed below the at least one fluid outlet. A control arm is connected to the at least one secondary valve. The control arm moves between a raised closing position in which the at least one secondary valve is closed and a lowered opening position in which the at least one secondary valve is opened. A float carried by the control arm and positioned within the fluid container applies an upward force to the control arm when a predetermined level of fluid is in the fluid container such that the control arm closes the at least one secondary valve.

[0010] According to another aspect, the production tank may further comprise at least one deactivation lever connected to the at least one secondary valve and positioned outside the production tank and spaced from the at least one fluid outlet.

[0011] According to another aspect, the fluid container may comprise an outlet enclosure that encloses the at least one fluid outlets and is recessed within the tank enclosure relative to the sidewall.

[0012] According to another aspect, the at least one secondary valve may be biased to the closed position and is maintained in the open position until released by the controller.
BRIEF DESCRIPTION OF THE DRAWINGS

[0013] These and other features will become more apparent from the following description in which reference is made to the appended drawings, the drawings are for the purpose of illustration only and are not intended to be in any way limiting, wherein:
FIG. 1 is a side elevation view of a production tank.
FIG. 2 is a detailed front plan view of the outlets of a production tank.
FIG. 3 is a detailed front plan view of the outlets of a production tank after fluid has leaked.
FIG. 4 is a side elevation view of an alternative production tank.
FIG. 5 is a detailed front plan view of an alternative set of outlets.
DETAILED DESCRIPTION

[0014] A production tank generally identified by reference numeral 10, will now be described with reference to FIG. 1 through 5. While the description and drawings relate to a particular design, it will be understood that the shutoff valves described herein may be applied to other types and designs of production tanks as known in the art.

[0015] Referring to FIG. 1, production tank 10 has a tank enclosure 12 defined by a roof 14, a floor 16 and a sidewall 18. There is shown fluid inlet 20 in fluid communication with tank enclosure 12, although there may be more than one. Fluid inlet 20 is designed to be connected to a source of fluid, such as a well (not shown), and to receive the fluids produced from the well. When connected to a well, the produced fluids will include sand, water, liquid hydrocarbons, and possibly some gaseous hydrocarbons. Depending on the demands place on the well, there may be some initial separation prior to depositing the fluids into the production tank, although any separation steps taken at this time will not remove all of a single component. As shown in FIG. 1, there is a sand layer 22, a water layer 24, an oil layer 26, and a gas layer 28. Gas layer 28 may be ambient air, gaseous hydrocarbons from the production fluids, or more commonly, a mixture of both. The components of produced fluids and how the components are managed are well known in the art and will not be described further.

[0016] In the oil and gas industry, production tanks arc used to store fluids until the fluids can be transported. There may be more than one production tank on a site, and the production tanks will generally have more features than what is shown. In particular, there is generally a series of vents and access points on the top of a production tank, and there may be fluid level indicators or sensors, and the like. In the depicted example, production tank 10 is shown with a single vent 32 on roof 14, which may be, for example, a thief hatch. Thief hatches are used to provide internal access to tank enclosure 12, and generally include a two-way pressure relief valve to prevent over- or under-pressurization of production tank 10, as production tanks are generally designed to hold the necessary amount of fluid, but are not designed to be pressure vessels. Also shown in some embodiments is a smaller enclosure 34 that is recessed within sidewall 18 but is isolated from tank enclosure 12. One suitable type of enclosure is sold under the name Enviro-VaultTM. Generally, enclosure 34 is used to enclose connections, as shown in FIG. I, to protect them from damage and from the elements, as the fluids in enclosure 12 are generally heated, which will also heat enclosure 12.
Enclosure 34 may also be used as a liquid container, as shown in FIG. 3 and will be described in greater detail below.

[0017] As shown, production tank 10 has outlets 36 with corresponding risers 38 that extend to different heights. Outlets 36 allow an operator to withdraw fluids from different layers within enclosure 12. While three outlets 36 are depicted with risers 38 at three different heights, there may only be two, or any number as desired by the user. Referring to FIG. 1, outlets 36 are positioned within enclosure 34. Enclosure 34 acts as a fluid container for receiving overflow fluids and catching any drips or leaks that may occur while removing fluid from tank enclosure 12 through outlets 36.

[0018] In addition to outlets 36, production tank 10 also has testing outlets 40 with corresponding risers 42. Testing outlets 40 are smaller than outlets 36 and are used to 5 withdraw test samples. Outlets 40 may be referred to as test cocks. The shutoff system is described below with respect to test cocks 40. It will be understood that the system may also be applied to outlets 36.

[0019] Referring to FIG. 2, each outlet 40 has a primary valve 44 with a first actuator 46, which is a handle as shown that is manually operated to open and close primary valve 44.
Each outlet 40 that also has a secondary valve 48 in line along outlet 40 with primary valve 44. Secondary valve 48 has a second actuator 50 that opens and closes secondary valve 48.
As shown, second actuator 50 is a line that connects to secondary valve 48.
Second actuator 50 is biased toward a closed position. Secondary valve 48 may take various forms, and the actual details of secondary valve 48 and second actuator 50 are not shown. Two examples of secondary valves include a fluid-actuated valve, such as a pneumatic valve, hydraulic valve, or a solenoid valve. Each of these may be biased toward the closed position such that, when fluid pressure is released, in the case of a fluid-actuated valve, or the circuit broken, as in the case of a solenoid valve, the valve closes. In the depicted embodiment, line 51 is a pneumatic air line connected to a pressurized air cylinder 52, which acts as a controller for secondary valve 48. If secondary valve 48 were a solenoid valve, controller 52 would be a power source, such as a battery.

[0020] Under normal operation, controller 52 maintains secondary valve 48 in an open position. In the case of a pressurized air cylinder, this is done by maintaining air pressure to secondary valve 48, and in the case of a battery or power source, this is done by maintaining a current to the solenoid valve. Once the air pressure has been shut off or released, or the current turned off secondary valve 48 will close. A normally-closed valve is used in order to ensure that, if the system were to be in a failure condition, secondary valve 48 would close until repaired.

[0021] In order to determine when controller 52 allows secondary valves 48 to close, a sensor 54 is provided in communication with the fluid container configured to deactivate the controller when a predetermined fluid condition is sensed within the fluid container 34. As shown, sensor 54 is a float that is connected by an arm 56 to controller 52.
As the fluid level in fluid container 34 rises, float 54 will move upward until a certain level is reached, at which point controller 52 will allow secondary valves 48 to close. This may be done, for example, by having arm 56 open a valve that evacuates the pressurized air in controller 52, or it may turn a three way valve that closes controller 52 and vents line 51. When necessary to re-pressurize controller 52, this may be done using a compressor that is often present on well sites. In the case of an electric controller, the batteries may be recharged using solar or wind power, for example, or may be connected to a generator or other electrical equipment that is commonly used on well sites.

[0022] In addition to sensor 54, controller 52 may be signalled by a secondary deactivation switch 58 on an outer surface of production tank 10 and spaced from fluid outlets 40. Secondary switch 58 may be useful if a remote shutdown of secondary valves 48 is required, such as if there is a risk of fire or explosion. Referring to FIG.
4, secondary switch 58 may be on an outer surface of the production tank 10, or spaced from the production tank 10, or both. For example, secondary switch 58 may be on or close to a truck used to haul fluid from production tank 10. This allows an operator to shut secondary valves if a safety hazard were to occur requiring that the flow of fluid be shut down without the operator having to approach production tank 10. As will be understood, secondary switch 58 may be a push button, a lever, or other types of actuators as part of an air hose, hydraulic hose, a cable, push rod, etc. that are able to act on controller 52.

[0023] When secondary valves 48 are pneumatic valves, controller 52 may be connected by a hose to the pneumatic system of the vehicle. In this embodiment, when controller 52 is activated by either float 54 or secondary switch 58, it will also shut down the vehicle to further reduce the danger.

[0024] Referring to FIG. 5, in another embodiment, secondary valves 48 may be mechanically closed, such as by a lever. As shown, controller 52 is a lever that pivots as float 54 moves up and down and opens and closes valves 48. In this embodiment, secondary switch 58 is preferably a mechanical type of switch that either acts directly on controller 52 or acts directly against secondary valves 48 to close them. In this embodiment, secondary valves may be controlled by controller 52 and/or secondary switch 58 or may be biased to the closed position, where, when controller 52 or secondary switch 58 is activated, secondary valves 48 close and must be reset before resuming normal operation.

[0025] In this patent document, the word "comprising" is used in its non-limiting sense to mean that items following the word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article "a" does not exclude the possibility that more than one of the elements is present, unless the context clearly requires that there be one and only one of the elements.

[0026] The scope of the following claims should not be limited by the preferred embodiments set forth in the examples above and in the drawings, but should be given the broadest interpretation consistent with the description as a whole.

Claims

What is Claimed is:

1. A production tank, comprising:
a tank enclosure defined by a roof, a floor and a sidewall;
at least one fluid inlet in fluid communication with the tank enclosure;
at least one fluid outlet in fluid communication with the tank enclosure comprising:
a primary valve that has a first actuator for opening and closing the primary valve; and a secondary valve in line with the primary valve, the secondary valve having a second actuator for opening and closing the secondary valve, the second actuator being biased toward a closed position;
a fluid container disposed below the at least one fluid outlet;
a controller connected to the at least one secondary valve, the controller maintaining the at least one secondary valve in an open position when activated and the controller permitting the at least one secondary valve to move to the closed position when deactivated;
and a sensor in communication with the fluid container configured to deactivate the controller when a predetermined fluid condition is sensed within the fluid container.

2. The production tank of claim 1, wherein the controller comprises a pressurized gas in fluid communication with the second actuator of the at least one secondary valve, the pressurized gas maintaining the at least one secondary valve in the open position, and the controller is deactivated by releasing the gas pressure against the second actuator.

3. The production tank of claim 2, wherein the controller comprises an electrical power source, the at least one secondary valve comprises a solenoid valve, and the controller is deactivated by de-energizing the solenoid valve.

4. The production tank of claim 1, wherein the sensor comprises a float that detects the presence of liquid in the fluid container.

5. The production tank of claim 1, further comprising at least one deactivation switch outside the the production tank and spaced from the at least one fluid outlet.

6. The production tank of claim 1, wherein the fluid container comprises an outlet enclosure that encloses the at least one fluid outlets and is recessed within the tank enclosure relative to the sidewall.

7. A production tank, comprising:
a tank enclosure defined by a roof, a floor and a sidewall;
at least one fluid inlet in fluid communication with the tank enclosure;
at least one fluid outlet in fluid communication with the tank enclosure comprising:
a primary valve that has a first actuator for opening and closing the primary valve; and a secondary valve in line with the primary valve, the secondary valve having a second actuator for opening and closing the secondary valve;
a fluid container disposed below the at least one fluid outlet;
a control arm connected to the at least one secondary valve, the control arm moving between a raised closing position in which the at least one secondary valve is closed and a lowered opening position in which the at least one secondary valve is opened;
a float carried by the control arm and positioned within the fluid container, the float applying an upward force to the control arm when a predetermined level of fluid is in the fluid container such that the control arm closes the at least one secondary valve.

8. The production tank of claim 7, further comprising at least one deactivation lever connected to the at least one secondary valve and positioned outside the production tank and spaced from the at least one fluid outlet.

9. The production tank of claim 7, wherein the fluid container comprises an outlet enclosure that encloses the at least one fluid outlets and is recessed within the tank enclosure relative to the sidewall.

10. The production tank of claim 7, wherein the at least one secondary valve is biased to the closed position and is maintained in the open position until released by the controller.