Device for actuating pressure relief valve

A pressure relief valve including a housing having an inlet and a relief outlet connected by a fluid flow passageway, the inlet fluidly connectable to a work string. The pressure relief valve includes a head sealingly disposed within the passageway between the inlet and relief outlet closing the fluid flow passageway between the inlet and relief outlet. An elongate buckling rod supports the head and is bucklable at a predetermined load thereby permitting sliding of the head from between the inlet and a relief outlet and opening the fluid flow passageway. A projection within the housing is extendible to an extended configuration, wherein in the extended configuration the projection applies a lateral force perpendicular to the longitudinal direction of the buckling rod bending the rod from its axial center thereby decreasing the load at which the buckling rod collapses.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a national stage entry of PCT/US2014/052939 filed Aug. 27, 2014, said application is expressly incorporated herein in its entirety.

FIELD

The present disclosure relates generally to pumping systems involved in oil and gas exploration and production operations, and in particular to pressure control safety features.

BACKGROUND

Oil and gas operations involve drilling deep within subterranean formations to access hydrocarbon reserves. There are many phases during such operations including drilling, casing the wellbore, fracturing, removal of hydrocarbons, water flooding, as well as numerous other activities during the life and course of the wellbore. Involved in these phases is the need to pump various fluids down into the wellbore for a variety of reasons, depending on the phase and required needs of the project.

The pumping of these various fluids requires surface equipment including pumps, pipes, valves and other components used to complete the piping system, as well as downhole components. During pumping operations, inevitably high pressures are often reached within the system. Such high pressures can create life threatening safety hazards. For example if any of the pumping components fail as pressure exceeds safe levels, the contents under pressure or the failed components could cause harm to workers within the vicinity or result in damaged equipment.

In an effort to avoid such excessive pressure conditions, pressure relief valves have been employed, which upon reaching a particular pressure threshold provide a relief outlet for the fluid so as to prevent potentially dangerous pressure conditions.

It should be understood that the various embodiments are not limited to the arrangements and instrumentality shown in the drawings.

DETAILED DESCRIPTION

In the following description, terms such as “upper,” “upward,” “lower,” “downward,” “above,” “below,” “downhole,” “uphole,” “longitudinal,” “lateral,” and the like, when used in relation to orientation within a wellbore, shall mean in relation to the bottom or furthest extent of, the surrounding wellbore even though the wellbore or portions of it may be deviated or horizontal. Correspondingly, the transverse, axial, lateral, longitudinal, radial, and the like orientations shall mean positions relative to the orientation of the wellbore or tool.

Several definitions that apply throughout this disclosure will now be presented. The term “coupled” is defined as connected, whether directly or indirectly through intervening components, and is not necessarily limited to physical connections. The connection can be such that the objects are permanently connected or releasably connected. The term “communicatively coupled” is defined as connected, either directly or indirectly through intervening components, and the connections are not necessarily limited to physical connections, but are connections that accommodate the transfer of data between the so-described components. A “processor” as used herein is an electronic circuit that can make determinations based upon inputs. A processor can include a microprocessor, a microcontroller, and a central processing unit, among others. While a single processor can be used, the present disclosure can be implemented over a plurality of processors.

The term “outside” refers to a region that is beyond the outermost confines of a physical object. The term “inside” indicates that at least a portion of a region is partially contained within a boundary formed by the object. The term “substantially” is defined to be essentially conforming to the particular dimension, shape or other thing that “substantially” modifies, such that the component need not be exact. For example, substantially cylindrical means that the object resembles a cylinder, but can have one or more deviations from a true cylinder. The terms “comprising,” “including” and “having” are used interchangeably in this disclosure. The terms “comprising,” “including” and “having” mean to include, but not necessarily be limited to the things so described.

The term “radial” and/or “radially” means substantially in a direction along a radius of the object, or having a directional component in a direction along a radius of the object, even if the object is not exactly circular or cylindrical. The term “axially” means substantially along a direction of the axis of the object. If not specified, the term axially is such that it refers to the longer axis of the object. The term “formation” means the below ground level, geological structure in which hydrocarbons are located. The term “reservoir” refers to the pool of hydrocarbons within the formation. The term “overpressure condition” means pressure in excess of the maximum allowable pressure (rated working pressure) for a given component.”

Disclosed herein is a pressure relief valve having a projection extendible to apply a lateral force to a buckling rod of an internal sealing mechanism, thereby actuating and releasing pressure from a piping system to which the pressure relieve valve can be coupled.

During oil and gas operations, pumping operations are often required in order to inject various fluids into a wellbore. The types of fluid depend on the particular needs or phase of the operation. For example, when installing a casing in a wellbore, cement is required to be pumped downhole between the casing and wall of the wellbore. Further, in fracturing operations, fluid containing gelling agents or proppant is pumped within the formation. Additionally, in post fracturing operations such as reservoir flooding, pumping of fluid downhole is conducted. There may be numerous operations requiring pumps and pressurized systems.

A surface work string is provided above ground on the surface, which includes pumping equipment, conveyances such as piping, tubing, lines, joints, or other components where various fluids and additives can be mixed and pumped into a downhole work string. During such pumping operations an overpressure condition can result in the surface work string. For example if there is a blockage downhole, this can result in sudden spikes of pressure throughout the system. Such increases in pressure, whether sudden or built up over time, can result in safety hazards. For example, the surface work string including the pumping equipment can have a maximum safe pressure level above which failure can occur.

The pressures which can cause such failure can depend on the equipment used, as well as the operation and pumping equipment. Accordingly, the pressure at which failure occurs or risk of failure may vary. Therefore, disclosed herein is a pressure relief valve which can be adjusted to accommodate different overpressure conditions and provide pressure release at varying predetermined pressures.

The pressure relief valve disclosed herein includes a housing having an inlet and a relief outlet connected by a passageway for a fluid. The housing also has a sealing mechanism including a head and a buckling rod which axially supports the head. The head is sealingly disposed between the inlet and outlet of the safety valve thus closing the fluid passageway. Accordingly, as fluid flows past the relief valve in the work string, fluid may enter a portion of the relief valve inlet and contact the head but be prevented from exiting the relief outlet, and thus continue on in the work string.

The buckling rod is configured to “buckle” or collapse at a particular predetermined pressure (i.e., load) imposed by fluid against the head. Ordinarily, the buckling rod is straight, withstanding the axial load imposed on the head and keeping it in place. However, as the pressure of the fluid increases against the head, the compressive load on the buckling rod increases. At some point the load rises to a critical level and the buckling rod bends, or bows, thus deforming. As a result of bending, the buckling rod can no longer support the axial load imposed on the head and the buckling rod then buckles, resulting in collapse. Upon buckling, the head then slides past the safety outlet thus opening the passage between the inlet and outlet. Accordingly, fluid can flow through the relief outlet and release pressure in the system. The load at which the buckling rod ceases to be able to bear a load and buckles and collapses can be referred to as the “buckling load” of the buckling rod.

The buckling rod can be configured to buckle and collapse at any particular predetermined load, (e.g. pressure or force) imposed in the axial direction. The buckling load depends on many features: material, length, diameter or cross section size, end configuration, and manufacturing tolerances of the buckling rod. However, with all features except length held constant, the buckling load varies in relation to its length.

The buckling rod therefore is under axial load as result of pressure on the head by fluid in a surface work string. As noted, when the load becomes sufficiently great, the rod buckles, which then results in axial movement of the head under the pressure of the fluid. The buckling of the rod however can be actuated by applying a lateral force against the buckling rod transverse to its axis. This has the effect of bending, or bowing, the buckling rod. The bowing adds eccentricity to the already loaded buckling rod. This causes immediate additional compressive stress as well as an immediate decrease in the load carrying capacity of the buckling rod. When this occurs, the buckling rod then “buckles” and collapses, thereby opening the passageway to relieve pressure in the system to which it is connected at the inlet. Accordingly, the pressure relief valve can be actuated to release pressure at will or predetermined detected pressure by extending a projection to impose lateral force on the buckling rod.

Pumping System

The pressure relief valve disclosed herein can be used with any pressurized system in order to provide safety pressure release. The pressure relief valve can be employed in connection with a work string on the surface related to an oil and gas operation. The pressure relief valve can be used in conjunction with any fluid transfer system susceptible to overpressure events, for example, this can be used in a boiler system, a compressor station, and other situations where pressure relief is potentially required. The pressure relief valve can be employed in a pumping system connected with a work string extending from the surface into a drilled borehole. The pumping system on the surface can be connected to discharge equipment and related components, also referred to as discharge manifold equipment (also in the field referred to informally as “iron”), for discharging fluid into a conveyance. The discharge manifold equipment affects the discharge of pressurized fluid from the one or more pumps.

In some oil and gas operations there can be containers or trucks, some containing a fluid such as water or salt water as well as others having additives, such as sand, other proppant or chemical additives. The fluid can be composed of liquids, gases, slurries, foams, multiphase or other phases. For example the fluid can include a fracturing fluid, a cement, a drilling mud, nitrogen, completion brine, acid, displacement fluid, steam water, treated water, hydrocarbons, CO2, or other fluid. The water and additives can be provided to a blender which mixes the water and additives together and then provided to one or more pumps. The pumps pressurize the fluid into a distribution manifold, which then discharges the pressurized fluid into a discharge line, and further into a conveyance which passes to the downhole work string. For ease of reference, the system together, including the pumps, discharge equipment, and subsequent conveyances can be referred to as the surface work string.

The pressure relief valve can be connected anywhere along the surface work string subsequent a pump. However, the pressure relief valve may be positioned closer to the pumps, for example in the discharge line or discharge manifold or a line exiting the pump.

As described, the pressure relief valve can be employed with any pressurized system. For example, the pressure relief valve disclosed herein can be provided in relation to fracturing operations. In such operations pressures can reach several thousands of psi, and thus safety can become a concern. Pressure can range from 600 to 20,000 psi, with pressure spikes reaching much higher than the operating range. Accordingly, the potential for equipment or systemic failure is possible. Although not restricted to such operations, one example of a pressurized system is an exemplary fracturing system10illustrated inFIG. 1.

In certain instances, the system10includes a fracturing fluid producing apparatus20, a fluid source30, a proppant source40, a blender45, a pump system50, surface work string55, and pressure relief valve200and resides at the surface at a well site where a well60is located. In certain instances, the fracturing fluid producing apparatus20combines a gel pre-cursor with fluid (e.g., liquid or substantially liquid) from fluid source30, to produce a hydrated fracturing fluid that is used to fracture the formation. The hydrated fracturing fluid can be a fluid for ready use in a fracture stimulation treatment of the well60or a concentrate to which additional fluid is added prior to use in a fracture stimulation of the well60. In other instances, the fracturing fluid producing apparatus20can be omitted and the fracturing fluid sourced directly from the fluid source30. In certain instances, the fracturing fluid may comprise water, a hydrocarbon fluid, a polymer gel, foam, air, wet gases and/or other fluids.

The proppant source40can include a proppant for combination with the fracturing fluid. Proppant can include sand or other hard particulate matter. The system may also include additive source70that provides one or more additives (e.g., gelling agents, weighting agents, and/or other optional additives) to alter the properties of the fracturing fluid. For example, the other additives70can be included to reduce pumping friction, to reduce or eliminate the fluid's reaction to the geological formation in which the well is formed, to operate as surfactants, and/or to serve other functions.

The fracturing fluid is then passed to a blender45to be combined with other components, including proppant from the proppant source40and/or additional fluid from the additives70and then received by pump system50. The resulting mixture may be pumped down the well60under a pressure sufficient to create or enhance one or more fractures in a subterranean zone, for example, to stimulate production of fluids from the zone. Notably, in certain instances, the fracturing fluid producing apparatus20, fluid source30, and/or proppant source40may be equipped with one or more metering devices (not shown) to control the flow of fluids, proppants, and/or other compositions to the pumping system50. Such metering devices may permit the pumping system50to source from one, some or all of the different sources at a given time, and may facilitate the preparation of fracturing fluids in accordance with the present disclosure using continuous mixing or “on-the-fly” methods. Thus, for example, the pumping and blender system50can provide just fracturing fluid into the well at some times, along with proppant at other times, and combinations of fluid and various components at other times.

As shown inFIG. 1, the pressure relief valve200can be connected to the surface work string55, which includes pump system50and conveyances or lines exiting from the pump system50. The pressure relief valve200may be connected to the system at or subsequent the pump50. The pressure relief valve200can also be connected to the system prior to being passed down the well60. The work string includes conveyances such as tubular members, piping, coiled tubing, jointed pipe, and/or other structures that allow fluid to flow into the well60.

An environmental perspective of a pumping system is shown inFIG. 1A. As shown, a fluid source31(such as water or salt water) may be provided to an additive unit71, which can add gelling agents to the fluid from fluid source31. This can then be sent to a blender45which can blend the fluid with proppant from a proppant source42. The proppant source can be for example sand or hard particulate matter. The blended fluid can then be provided to distribution manifold equipment53on a low pressure side51. A series of pumps52can be provided on trucks which pressurize the system and pump the fluid from the high pressure side54of the distribution manifold53to the wellhead61, and into the well60. For purposes of this disclosure, the conveyances and lines from the pumps52to the distribution manifold53and to the wellhead can be referred to as a surface work string. The pressure relief valve200disclosed herein can be provided anywhere along the surface work string to provide pressure relief thereto.

FIG. 2shows the well60during a fracturing operation as shown inFIG. 1in a portion of a subterranean formation of interest102(usually having a hydrocarbon reservoir) surrounding a well bore104. The well bore104extends from the surface106, and the fracturing fluid in work string55is applied to a portion of the subterranean formation102surrounding the horizontal portion of the well bore. Although shown as vertical deviating to horizontal, the well bore104may include horizontal, vertical, slant, curved, and other types of well bore geometries and orientations, and the fracturing treatment may be applied to a subterranean zone surrounding any portion of the well bore. The well bore104can include a casing110that is cemented or otherwise secured to the well bore wall. The well bore104can be uncased or include uncased sections. Perforations can be formed in the casing110, any cement, and into the formation to allow fracturing fluids108and/or other materials to flow into the subterranean formation102. In cased wells, perforations can be formed using shape charges, a perforating gun, hydro-jetting and/or other tools.

The well is shown with a work string112depending from the surface106into the well bore104. The pump system50is coupled to surface work string55, for pumping the fracturing fluid108into well bore104via downhole work string112. The working string112may include coiled tubing, jointed pipe, and/or other structures that allow fluid to flow into the well bore104. The working string112can include flow control devices, bypass valves, ports, and or other tools or well devices that control a flow of fluid from the interior of the working string112into the subterranean zone102. For example, the working string112may include ports adjacent the well bore wall to communicate the fracturing fluid108directly into the subterranean formation102, and/or the working string112may include ports that are spaced apart from the well bore wall to communicate the fracturing fluid108into an annulus in the well bore between the working string112and the well bore wall.

The working string112and/or the well bore104may include one or more sets of packers114that seal the annulus between the working string112and wall of the well bore104to define an interval of the well bore104into which the fracturing fluid108will be pumped.FIG. 2shows two packers114, one defining an uphole boundary of the interval and one defining the downhole end of the interval. When the fracturing fluid108is introduced into well bore104(e.g., inFIG. 2, the area of the well bore104between packers114) at a sufficient hydraulic pressure, one or more fractures116may be created in the subterranean zone102. The proppant particulates in the fracturing fluid108may enter the fractures116where they may remain after the fracturing fluid flows out of the well bore. These proppant particulates may “prop” fractures116such that fluids may flow more freely through the fractures116.

Although a fracturing system is discussed above, the pressure relief valve200can be used in other operations that involved a pressurized work string or system. For example, as noted inFIG. 2, there is a casing110that may be cemented or otherwise secured to the well bore104. The pump50can pump cement mixture mixed in blender45, and then pumped via surface work string55into the annulus between the well bore104and the casing110. The pressure relief valve200can be connected to the surface work string55and pump system50for providing a safety pressure release. The pressure relief valve200can be used in other pressurized applications other than fracturing systems or cement operations as well.

Actuable Pressure Relief Valve

The exemplary pressure relief valve200is illustrated inFIG. 3. As shown the relief valve200has a housing210with lower housing211and upper housing212. The upper housing212has an inlet245, a relief outlet250and an interior space213(seeFIG. 5). The inlet245is couplable to a surface work string and can receive fluid flow therein. The fluid can be any type of fluid flowing through the work string. For example, it can include fracturing fluid as discussed above, cement, water, salt water, or any other fluid. The internal contents of the upper housing212include a fluid flow passageway which connects the inlet245and outlet250, as well a head sealingly disposed in the passageway, as further described below.

The lower housing211comprises a portion of an elongate buckling rod240. The lower housing211can be made up of an open housing support, such as two or more support rods270on opposing lateral sides or surrounding the outer peripheral circumference. Alternatively, or additionally, the lower housing211may include a closed housing (with or without suitably sized access windows) where the internal contents are enclosed by a walled structure. The buckling rod240extends from within the upper housing212from its proximal end through upper frame276to the base frame275at the buckling rod240's distal end.

The support rods270extend from the upper frame276to the base frame275. The support rods270provide mechanical strength for supporting the buckling rod240and maintaining the structure of the lower housing211. For example, when fluid pressure is imposed at the inlet245, the force of the pressure transfers through the buckling rod240against the base275. Accordingly, with increased pressure at the inlet245, the buckling rod240is forced axially against the base275. With increased pressure the buckling rod is forced to carry a greater load and resulting force along its length. As discussed above, at some point the force or load imposed on the buckling rod240is so great that it begins to deform (bend, or bow) and then “buckles” or collapses, referred to herein as the buckling load. The occurrence is analogous to a column provided in a building between floors. The columns, like the buckling rod240, are under concentric axial load. If the load imposed on the column by the upper floors becomes great enough, the column begins to deform, eventually buckling and collapsing.

The buckling load of a buckling rod240can depend on a number of factors, including material, length, and diameter of the rod. Generally, the buckling rod is made up of solid steel or other metal. Conceivably, other materials could be employed such as a hard plastic or composite if sufficient strength and rigidity is provided. Further, with increased diameter the buckling load of the buckling rod240increases. With the type of materials and diameter held constant, the buckling load of the buckling rod240is related to its length.

While not held to any particular principle, the excess pressure, or axial force, that the buckling rod can accommodate may be determined by the Euler equation, namely formula (1) below:

F=π2⁢EI(KL)2(1)
Wherein F is the maximum or critical force (buckling load), E is modulus of elasticity, I is r- moment of inertia, L is unsupported length of column, and K is column effective length factor. Therefore, the buckling load is inversely proportional to the square of the length of the buckling rod.

As further illustrated inFIG. 3, the pressure relief valve200can have an extending device300for extending the projection310laterally against the buckling rod240(further shown inFIGS. 5-6). The extending device can be coupled to the lower housing211, and in particular one or more of the support rods270. The projection310in the illustrated embodiment is shown in a retracted configuration. In this configuration the projection310is retracted away from and not in contact with the buckling rod240. The projection310can be extended to engage and apply a lateral force transverse, or perpendicular, to the axis of the buckling rod240. The lateral force causes the buckling rod240to bend, or bow, from its axial center thus causing the load to be applied eccentrically. The buckling rod240will then buckle or collapse under the existing load being applied by the pressure of fluid at the inlet245thereby opening the passage and releasing fluid from relief outlet250.

FIG. 4illustrates another example wherein the extending device300is coupled to a support280. The support280is coupled to a buckling rod240. Accordingly, rather than being attached to a housing of the pressure relief valve200, the extending device300and projection310can be coupled to the buckling rod240.

Referring now toFIG. 5, a pressure relief valve200is coupled to a surface work string55having fracturing fluid108. The fracturing fluid108is pumped by pumping system50to a rig or wellhead125and into the downhole work string112. A pressure detector57, such as a transducer, can be coupled to the surface work string55to detect the pressure of fracturing fluid108. The relief valve200is shown having inlet245and relief outlet250. As shown the relief valve has a sealing mechanism220within its housing210. The sealing mechanism220has a head230and buckling rod240. The head230is sealingly disposed within the passageway between the inlet245and the relief outlet250thus closing the passageway to fluid flow. The head230can for example include a number of seals231and232which prevents the flow of fluid to the relief outlet250and into the interior space213of upper housing212. Further shown by the arrows, fracturing fluid108is under pressure and imposes force against the head230due to seals232being of larger area exposed to fluid flow108than the exposed area of seals231, thus placing axial force on the buckling rod240. The extending device300for extending the projection310against the buckling rod240is shown coupled to the housing210.

The action of the buckling rod240and the extension of projection310is illustrated inFIGS. 6-7.FIGS. 6 and 7illustrate the projection310in a retracted configuration and an extended configuration respectively. In each ofFIGS. 6 and 7, fracturing fluid is entering inlet245. However, inFIG. 6where the buckling rod240is straight, the head230having seals231is blocking the passageway to relief outlet250. The buckling rod240can be selected such that its resistance to buckling exceeds any potential column load created by the pressure of the fluid at inlet245, or just above an overpressure condition, or just above a particular predetermined relief pressure. An overpressure condition is where pressure spikes or rises to a potentially dangerous range where failure of equipment might occur. Selecting the buckling rod for above the overpressure condition or relieving pressure ensures that there is no premature buckling of the buckling rod240.

When a predetermined pressure is reached, detected for example by pressure detector57(seeFIG. 5), the projection310can be extended to an extended configuration, shown for example inFIG. 7. Alternatively, the projection310can be extended at any time by an operator by actuating the extending device300. In any case, the projection310can be extended to apply a lateral force on the side of the buckling rod240, thereby deforming the buckling rod240. The buckling rod240is then deformed from straight to bowed, thereby decreasing its load carrying capability, and decreasing its buckling load. Accordingly the increase in stress and decrease in load carrying capability of buckling rod240causes buckling as shown inFIG. 7.

Upon buckling of the buckling rod240, the head230then slides from relief outlet250thereby opening the passageway285. With opening of the passageway285, fluid can then exit the relief outlet250thus release fluid and relieving pressure of the system.

The manner in which projection310is extended is not particularity restricted. For example, extending device300may include an electromechanical device, for example a solenoid plunger. In such examples, the electromechanical device when actuated can produce an electromagnetic field which extends projection310laterally against the buckling rod240. The electromechanical device can be actuated for example by a push button on the outside of the housing211. Or alternatively, the electromechanical device can be communicatively coupled to pressure detector57(seeFIG. 5), which upon reaching a predetermined pressure actuates the electromechanical device to extend projection310.

A pressure monitoring system controller800(seeFIG. 5), having a processor, a storage device, and software coding instructions, can be implemented to monitor the pressure of the surface work string55and actuate the electromechanical device (the extending device300) when a predetermined pressure is reached. Further, one or more pressure detectors57and pressure relief valves200each having an electromechanical extending device300can be employed on various portions of the surface work string55or different work strings, and communicatively linked to the pressure monitoring system800. This would enable simultaneous operation of all safety valves from a central pressure monitoring system controller800. Accordingly, pressure could be monitored across work strings, and further, the communicatively coupled pressure relief valves may be actuated by extending a projection310in each of the connected pressure relief valves. By such system, two or more pressure relief valves200could be actuated at exactly the same time and predetermined pressure setting, thus enabling coordination of multiple pressure relief valves200.

In addition to electromechanical, extending devices300can also be actuated by hydraulic or pressurized fluid (liquid, gas or both). For example, pneumatic, or hydraulic cylinders may be configured to apply force to extend projection310. Moreover, the extending device300can be actuated manually directly or indirectly through linkages. For example, a lever can be attached to the external portion of housing211, and upon lifting or pushing a lever, the projection310can be extended.

With reference toFIG. 8, an exemplary system and/or pressure monitoring system controller800includes a processing unit (for example, a central processing unit (CPU) or processor)820and a system bus810that couples various system components, including the system memory830, read only memory (ROM)840and random access memory (RAM)850, to the processor820. The system controller800can include a cache822of high-speed memory connected directly with, in close proximity to, or integrated as part of the processor820. The system controller800can copy data from the memory830and/or the storage device860to the cache822for access by the processor820. These and other modules can control or be configured to control the processor820to perform various operations or actions. The memory830can include multiple different types of memory with different performance characteristics.

Multiple processors or processor cores can share resources such as memory830or the cache822, or can operate using independent resources. The processor820can include one or more of a state machine, an application specific integrated circuit (ASIC), or a programmable gate array (PGA) including a field PGA. The system bus810can be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. A basic input/output (BIOS) stored in ROM840or the like, may provide the basic routine that helps to transfer information between elements within the system controller800, such as during start-up.

The system controller800can further include storage devices260or computer-readable storage media such as a hard disk drive, a magnetic disk drive, an optical disk drive, tape drive, solid-state drive, RAM drive, removable storage devices, a redundant array of inexpensive disks (RAID), hybrid storage device, or the like. The storage device860can include software modules862,864,866for controlling the processor820. The system controller800can include other hardware or software modules. Although the exemplary embodiment(s) described herein employs a hard disk as storage device860, other types of computer-readable storage devices which can store data that are accessible by a computer, such as magnetic cassettes, flash memory cards, digital versatile disks (DVDs), cartridges, random access memories (RAMs)850, read only memory (ROM)840, a cable containing a bit stream and the like may also be used in the exemplary operating environment. Tangible computer-readable storage media, computer-readable storage devices, or computer-readable memory devices, expressly exclude media such as transitory waves, energy, carrier signals, electromagnetic waves, and signals per se.

The basic components and appropriate variations can be modified depending on the type of device, such as whether the system controller800is a small, handheld computing device, a desktop computer, or a computer server. When the processor820executes instructions to perform “operations”, the processor820can perform the operations directly and/or facilitate, direct, or cooperate with another device or component to perform the operations.

To enable user interaction with the system controller800, an input device890represents any number of input mechanisms, such as a microphone for speech, a touch-sensitive screen for gesture or graphical input, keyboard, mouse, motion input, speech and so forth. An output device870can also be one or more of a number of output mechanisms known to those of skill in the art. In some instances, multimodal systems enable a user to provide multiple types of input to communicate with the system controller800. The communications interface880generally governs and manages the user input and system output. There is no restriction on operating on any particular hardware arrangement and therefore the basic hardware depicted may easily be substituted for improved hardware or firmware arrangements as they are developed.

One or more parts of the example system controller800, up to and including the entire system controller800, can be virtualized. For example, a virtual processor can be a software object that executes according to a particular instruction set, even when a physical processor of the same type as the virtual processor is unavailable.

Numerous examples are provided herein to enhance understanding of the present disclosure. A specific set of examples are provided as follows. In a first example, a pressure relief valve is disclosed including a housing having an inlet and a relief outlet connected by a fluid flow passageway, the inlet fluidly connectable to a work string; a head sealingly disposed within the passageway between the inlet and relief outlet closing the fluid flow passageway between the inlet and relief outlet; an elongate buckling rod supporting the head and bucklable at a predetermined load thereby permitting sliding of the head from between the inlet and the relief outlet and opening the fluid flow passageway; and a projection within the housing extendible to an extended configuration, wherein in the extended configuration the projection applies a lateral force transverse to a longitudinal direction of the buckling rod bending the rod thereby decreasing the load at which the buckling rod collapses.

In a second example, a pressure relief valve according to the first example is disclosed, wherein the projection further has a retracted configuration, wherein in the retracted configuration the projection does not apply a lateral force to the buckling rod.

In a third example, a pressure relief valve according to the first or second examples is disclosed, wherein the projection is extended by an electric extending device or fluid extending device.

In a fourth example, a pressure relief valve is disclosed according to any of the preceding examples first to the third, wherein the projection is manually extendible.

In a fifth example, a pressure relief valve is disclosed according to any of the preceding examples first to the fourth, wherein the projection is coupled to and extendible from the housing.

In a sixth example, a pressure relief valve is disclosed according to any of the preceding examples first to the fifth, wherein the projection is communicatively coupled to a pressure detector.

In a seventh example, a pressure relief valve is disclosed according to any of the preceding examples first to the sixth, wherein the projection is extended upon detection of a predetermined detected pressure.

In an eighth example, a pressure relief valve is disclosed according to any of the preceding examples first to the seventh, wherein the projection is coupled to a portion of a support coupled to the buckling rod.

In a ninth example, a work string is disclosed, including a tubular conveyance having a pump and a pressure relief valve; the pressure relief valve having a housing having an inlet and a relief outlet connected by a fluid flow passageway, the inlet fluidly connected to the tubular conveyance; a head sealingly disposed within the passageway between the inlet and relief outlet closing the fluid flow passageway between the inlet and relief outlet; an elongate buckling rod supporting the head and bucklable at a predetermined load thereby permitting sliding of the head from between the inlet and the relief outlet and opening the fluid flow passageway; and a projection within the housing extendible to an extended configuration, wherein in the extended configuration the projection applies a lateral force transverse to a longitudinal direction of the buckling rod bending the rod thereby decreasing load at which the buckling rod collapses.

In a tenth example, a work string is disclosed according to the ninth example, wherein the tubular conveyance includes a fracturing fluid.

In an eleventh example, a work string is disclosed according to the ninth or tenth examples, wherein the tubular conveyance includes cement for a borehole casing.

In a twelfth example, a work string is disclosed is disclosed according to any of the preceding examples ninth to the eleventh, wherein the projection is extended by an electric or hydraulic device.

In a thirteenth example, a work string is disclosed is disclosed according to any of the preceding examples ninth to the twelfth, further including a pressure detector coupled to the work string for detecting a pressure of a fluid within the work string.

In a fourteenth example, a work string is disclosed according to any of the preceding examples ninth to the thirteenth, wherein the electric or hydraulic extending device extends the projection to the extended configuration upon detection of a predetermined pressure by the pressure detector.

In a fifteenth example, a work string is disclosed is disclosed according to any of the preceding examples ninth to the fourteenth, wherein the projection further has a retracted configuration, wherein in the retracted configuration the projection does not apply a lateral force to the buckling rod.

In a sixteenth example, a work string is disclosed according to any of the preceding examples ninth to the fifteenth, wherein the projection is manually extendible.

In a seventeenth example, a work string is disclosed according to any of the preceding examples ninth to the sixteenth, wherein the projection is coupled to and extendible from the housing.

In an eighteenth example, a work string is disclosed is disclosed according to any of the preceding examples ninth to the seventeenth, wherein the projection is coupled to a portion of a support coupled to the buckling rod.

In a nineteenth example a system is disclosed, including a tubular conveyance having a pump and a plurality of pressure relief valves; a controller communicatively coupled to the plurality of pressure relief valves; and the plurality of pressure relief valves each having a housing having an inlet and a relief outlet connected by a fluid flow passageway, the inlet fluidly connected to the tubular conveyance, a head sealingly disposed within the passageway between the inlet and relief outlet closing the fluid flow passageway between the inlet and relief outlet, an elongate buckling rod supporting the head and bucklable at a predetermined load thereby permitting sliding of the head from between the inlet and the relief outlet and opening the fluid flow passageway, a projection within the housing extendible to an extended configuration, wherein in the extended configuration the projection applies a lateral force transverse to a longitudinal direction of the buckling rod bending the rod thereby decreasing the load at which the buckling rod collapses, and wherein the controller is configured to extend the projection to the extended configuration.

In a twentieth example, a system according to the nineteenth is disclosed, further including one or more pressure detectors coupled to the work string for detecting a pressure of a fluid within the work string, and wherein the controller is configured to extend the projections of each of the plurality of relief valves upon detection of a predetermined pressure by the one or more pressure detectors.

The embodiments shown and described above are only examples. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present technology have been set forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes may be made in the detail, especially in matters of shape, size and arrangement of the parts within the principles of the present disclosure to the full extent indicated by the broad general meaning of the terms used in the attached claims. It will therefore be appreciated that the embodiments described above may be modified within the scope of the appended claims.