TECHNICAL FIELD

[0001] The present invention relates to one or more of a flare system, a gas separator, and a flare and to methods involving use of said flare system, gas separator and flare, for example including to sense properties of a gas or fluid.

BACKGROUND ART

[0002] It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.

[0003] Flare systems are typically used for, but not limited to, well drilling and service operations and are utilised where a flammable gas returning to the surface is likely. A flare system is typically compact as it is designed to be moved from location to location by road transport.

[0004] Existing designs for flare systems can vary in view of different drilling practices and geology in different jurisdictions, which can result in differences in the composition of the fluid stream exiting a well. The fluid stream exiting a well can include a combination of formation fluid, fracturing proppants and other solids, gas and air. The composition can be highly variable. In some wells under normal conditions (saturated), the concentration of flammable gas (especially methane) exiting a well can be greater than 94% of the fluid stream, with the remaining components including ethane, carbon dioxide, nitrogen and water. However, water can be entrained in the fluid stream and in some cases the proportion of water in the fluid stream can be as high as 60%.

[0005] The composition can vary more considerably, depending on the operation performed on the well. For example, well servicing or workover operations can be conducted subsequent to a drilling operation. The servicing operation can use compressed air which is used to force the fluid and solids to return to the surface, thereby cleaning the well out. The fluid stream exiting a well during such operations can include a significant amount of air, as well as detritus from the well. If the gas exiting the well is only subterranean gas, then it may not contain much oxygen, hence combustion prior to the flare may not be a significant issue (this is why such gas is typically ignited with a flare). However, when air is pumped into the well oxygen is present which may create a danger with combustion within the system. Consequently, in these circumstances gas exiting the well is not typically ignited.

[0006] The fluid stream exiting the well can also do so at high speed and can be difficult to control. For example, Australian drilling practices often cater for higher volumes of fluid stream which is returned to the surface during well servicing operations. Moreover, the pressure of the gas exiting the well can go through peaks and troughs; for example when a well is not used for some time there is frequently an increase in pressure when the well is re-opened.

[0007] In some countries it may be possible to vent the fluid stream exiting a well directly to the atmosphere. However, this is frequently not an attractive option due to speed of the fluid stream, coupled with the liquids and solids entrained in the gas, and the flammable nature of many of the gases. These factors can mean that venting the fluid stream exiting a well directly to the atmosphere is not safe for personnel in the vicinity of the well. Furthermore, in many jurisdictions there are environmental regulations in relation to the handling and disposal of flammable gases such as methane which exit the well. Methane is a greenhouse gas, and as methane is capable of absorbing significantly more heat than carbon dioxide, methane emissions at a well can be highly regulated. The volume of methane which is capable of exiting a single well in a year can exceed one million tons.

[0008] Consequently, a separator (which can be a degasser) is often used to separate gases from the liquids and solids in the fluid stream. Operators also have the option of connecting a flare to gas line exiting the separator. However, typical separators are designed to work with a constant flow rate returning from an oil or gas well, and this flow rate is typically governed by either a choke valve or the flow rate of mud pumps (for example). A difficulty with this arrangement is that in operations common to Australian well servicing techniques there is frequently sudden high flow rates of gas which can force liquid that is trapped in the fluid flow or present in the separator through the gas line to the flare. If solids or liquid (for example water) enter a gas line to a flare, the flare operation can be dismpted.

SUMMARY OF INVENTION

[0009] The present invention is directed to a flare system, which may at least partially overcome at least one of the abovementioned disadvantages or provide the consumer with a useful or commercial choice.

[0010] With the foregoing in view, in a first aspect the present invention provides a flare system including: A gas separator including an inlet, at least one vacuum relief, at least one pressure relief, and a gas outlet;

A flare for igniting gas, wherein the flare is in fluid communication with the gas outlet of the gas separator; and

A flow driver for driving gas from the gas separator to the flare.

[0011] Advantageously, the gas separator may be capable of separating gas from other components (such as liquids and solids) in the fluid stream exiting a well. The gas separator includes at least one pressure relief, which may permit a release of gas from the gas separator if the pressure exceeds a certain amount (this may be especially important given the diameter of the gas outlet). As a volume of flammable gas may exit the gas separator through the pressure relief, the flare should not be located so close to the gas separator that such exiting flammable gas may be ignited. Consequently, the flare may be positioned some distance from the gas separator. To maintain pressure and consistent flaring at the flare, a flow driver is present to drive fluid from the gas separator to the flare. However, the use of the flow driver may create a partial vacuum (even if briefly) in the gas separator, and such a vacuum can result in liquids and solids (which were separated from the gas in the gas separator) being drawn into the gas separator gas outlet. To ameliorate this possibility, the at least one vacuum relief may permit ingress of gas into the gas separator if the pressure is below a certain amount.

[0012] The flare may be a flare assembly. The flare may include a gas inlet and a gas outlet. The flare may include a gas conduit between the gas inlet and the gas outlet. The flare may include a flare stack. The flare stack may be at the gas outlet. The flare may include a pilot flame. The pilot flame may form part of the flare stack or be located proximate to the gas outlet. The flare may include a deflagration arrestor (or flash back arrestor, or detonation arrestor), which may form part of the flare stack or be located proximate to the gas outlet.

[0013] The flare or flare assembly may include a separator for separating non-gaseous components from the gas flow. The separator may be a knock out pot. The separator may be proximate to, or in register with, the flare stack.

[0014] The flare may include a framework, skid or trailer for supporting the flare components, or for transporting the flare by road or rail. The framework, skid or trailer can have lifting fixtures for cranes or hoists. The framework, skid or trailer may have safety handrails, platforms, and the like. The framework, skid or trailer may include lifters for lifting the framework, skid or trailer for transport. For example, the lifters may be moveable legs, especially jack legs, more especially hydraulic jack legs. The flare stack may be separable for transport. The flare stack may include a joint for collapsing the flare stack for transport. The flare stack may include a hinge for folding the flare stack down for transport.

[0015] The flare system, flare or flare assembly may be configured to monitor or sense properties of the gas flowing from the gas separator, especially prior to ignition. The properties of the gas may include at least one of the gas composition, gas velocity, gas pressure, gas temperature, the mass or volume flow rate of the gas flowing from the gas separator, and the mass or volume flow rate of a specific gas (for example, methane, ethane) flowing from the gas separator. In one embodiment, the properties of the gas includes at least two, three, four, five or six of the gas composition, gas velocity, gas pressure, gas temperature, the mass or volume flow rate of the gas, and the mass or volume flow rate of a specific gas (for example, methane, ethane). In one embodiment, the properties of the gas includes the concentration or mass or volume flow rate of methane in the gas. The flare system, flare or flare assembly may include at least one sensor for sensing at least one of said properties of the gas. The flare system, flare or flare assembly may include at least two, three, four, five or six sensors for sensing at least two, three, four, five or six of said properties of the gas. The at least one sensor (or the at least two, three, four, five or six sensors) may sense the properties of the gas in the gas conduit. For example, an infra-red sensor may be used to sense the concentration of methane. An exemplary infra-red sensor may be BIOGAS 3000 by ThermoFisher Scientific. An ultrasonic flow meter may be used to measure velocity, pressure and temperature. An exemplary ultrasonic flow meter may be the PanaFlow Gas Meter System by Baker Flughes. Using the infra-red sensor and the ultrasonic flow meter the mass flow rate of methane in the system may be determined. This type of information may advantageously provide information about the cleanliness and efficiency of the well system. Typically, a well may be considered to be clean once the amount of solids exiting the well decreases, the amount of gas exiting the well increases and the amount of water exiting the well increases. The multiphase or gas separator may also include a sample line. The sample line may include a sensor, for example for measuring total suspended solids (TSS) and/or turbidity. It may be important to sense the temperature of the gas, as if a gas exceeds a predetermined temperature the flare system should be shut down to prevent combustion.

[0016] The flare system, flare or flare assembly may include a data processor for accepting input from the at least one sensor, especially input corresponding to the said at least one property of the gas. The data processor may be configured to calculate or determine measurements relating to the gas flowing from the gas separator (especially through the gas conduit), for example the mass or volume flow rate. The data processor may be configured to accept input from the at least one sensor corresponding to the said at least one property of the gas, and to generate a report (especially a composite report) in respect thereof. The report may include a digital file compatible with a program such as a word processor, spread sheet or database management software. Alternatively, the report may include a proprietary data format, encrypted data and/or ASCII data. The report may be in the form of an email. The flare system, flare or flare assembly may further include a telemetry system, and the data processor may utilize the telemetry system to form a web interface. The report may be a real time report.

[0017] The telemetry system may include a digital signal on the licensed spectrum for two- way radio such as HF/MF, VHF or UHF. The telemetry system may include an interface with a mobile telephony network such as CDMA, 3G, 4G, 5G GSM or GPRS networks. The telemetry system may include a subscription to a satellite phone system such as IRIDIUM and INMARSAT. The telemetry system may include two or more different telemetry systems to provide redundancy and coverage. For example, the data processor may select a digital mobile phone network where available, and the more expensive to use satellite phone/data system where necessary. The telemetry system may include an interface with a digital mobile phone network and/or a satellite phone/data system. The telemetry system may be operated by the data processor to transmit the report (or composite report) on either a continuous or intermittence basis. For example, the telemetry system may be configured to transmit a report periodically (e.g. once or twice a day). The report may be transmitted by the telemetry means by email, for example in SMTP packets. The data processor may include an accumulative log which may be periodically uploaded for audit purposes.

[0018] The flare system, flare or flare assembly may include a data store for storing data from the at least one sensor, or for storing data from the data processor. The flare system, flare or flare assembly may include a control system. The control system may include the data store, data processor, and telemetry system. An exemplary control system may include a programmable logic controller (PLC) or a computer.

[0019] The gas conduit may include at least a first and a second gas conduit. The first and second gas conduits may be in gaseous communication (or in register). The first gas conduit may include the at least one sensor. The first gas conduit may be proximate to the flare stack or pilot flame. The second gas conduit may be distal to the flare stack or pilot flame. The second gas conduit may be of larger diameter or larger cross-sectional area than the first gas conduit. The second gas conduit may be transverse to the first gas conduit. The first gas conduit and/or the second gas conduit may include a pressure relief, especially a pressure relief valve or a burst disk. The first and/or second gas conduits may be of any suitable cross-section, especially circular, square, rectangular or elliptical; especially circular.

[0020] The flare system, flare or flare assembly may include a flow driver for driving fluid from the gas separator to the flare. The flow driver may be at least one flow driver. The at least one flow driver may be at least one, two, three or four flow drivers; especially one, two, three or four flow drivers; more especially two, three or four flow drivers; most especially three flow drivers. Where there is more than one flow driver, the said flow drivers may be in series or parallel, especially parallel. Therefore, each said flow driver may include a gas inlet and a gas outlet. Each flow driver gas outlet may be in gaseous communication with (or in register with) the second gas conduit. The flare system, flare or flare assembly may include a manifold, and said manifold may be in gaseous communication with (or in register with) the flare or flare assembly gas inlet, and in gaseous communication with (or in register with) each said flow driver gas inlet. Each or at least one of said flow drivers and/or said manifold may include a pressure relief, especially a pressure relief valve or a burst disk. The flow driver may be located in a fluid line after the gas outlet of the gas separator, but before the gas is ignited.

[0021] The or each said flow driver may push or pull the gas from the gas separator. For example, the or each said flow driver may apply suction to suck the gas from the gas separator to the flare. In one embodiment, the flow driver is a suction source. An exemplary flow driver that operates by suction is provided in Australian Patent Application No. 2018902677 and Australian Patent No. 2019100796, the contents of which are incorporated by reference in their entirety. The flow driver may be a venturi system, eductor or ejector. The venturi system, eductor or ejector may be coupled to at least one source of compressed gas (or air), especially at least one air compressor. If the flow driver operates by suction it may be advantageously located proximate to the flare stack. In one embodiment, the ejector is located adjacent to a pilot flame in the flare. In another example, the or each flow driver may be a pump for pumping the gas from the gas separator to the flare, especially a blower for blowing the gas from the gas separator to the flare. Said blower may include a fan, such as a centrifugal or tangential fan. If the flow driver is a pump or a fan it advantageously may be located distal to the flare stack, or proximate to the flare or flare assembly gas inlet. In an exemplary embodiment, the flow driver, especially the blower(s) may be from 45- 100 kW. The flow driver(s) may be capable of driving 1-12 MMSCFD (million standard cubic feet per day), especially 3-10 MMSCFD or 4-8 MMSCFD, more especially 5-7 MMSCFD or about 6 MMSCFD. The flow driver(s) may be rated for use with flammable gases. [0022] The flare system, flare or flare assembly may include at least one filter for filtering solids or liquids from the gas. The at least one filter may be located upstream of the flow driver(s). The at least one filter may be located in the manifold.

[0023] The flare or flare system may further include a storage tank. The storage tank may be suitable for storing liquids or solids. The flare or flare system may include a door to enable personnel to access the storage tank.

[0024] The flare system may include a multiphase separator. The multiphase separator may include the gas separator. The multiphase separator may be for separating solids and liquids from gases.

[0025] The gas separator may be of any suitable size, shape and construction. The gas separator may be for separating gas from a fluid stream that has exited a well. The gas separator may separate gas from non-gaseous components (including solids, liquids, and substances such as mud and sand) of the fluid stream in any suitable way. For example, the gas separator may be an impingement separator. Non-gaseous components may be separated from gas by way of gravity segregation and/or centrifugal action, for example. The gas separator may be a poor boy separator. The gas separator may be an open-bottom vertical mud gas separator and the outlet for non-gaseous components may be sealed by way of a liquid seal.

[0026] The gas separator may include a vessel. The vessel may be of any suitable shape. The vessel may include at least one vessel wall. In one embodiment, the vessel wall(s) have a substantially rectangular, circular, square, elliptical or ovoid cross section; especially a circular cross section. The vessel wall may be substantially cylindrical. The vessel wall(s) may extend vertically. Preferably, the vessel may be cylindrical and vertically orientated, and may be of sufficiently large diameter so as to handle large volumetric flow rates.

[0027] The gas separator inlet may be of any suitable size, shape or construction. The gas separator inlet may be for introducing the fluid stream into the vessel. The gas separator inlet may include an inflow end connectable to a fluid stream line (especially a fluid stream line from a well, such as a blooey line) and an outflow end that is in fluid communication with or in register with the vessel. The gas separator inlet may be connected to the vessel and fluid stream line in any suitable way, for example, welding, bolting, clamping, screwing or other suitable connecting arrangement. The gas separator inlet may extend substantially horizontally between the inflow and outflow ends when the gas separator is in use.

[0028] The gas separator inlet may be configured to reduce the velocity of the fluid stream prior to entering the vessel. The gas separator inlet may be configured to reduce the velocity of the fluid steam relative to a velocity of the fluid stream within the fluid stream line (for example a blooey line). This may be achieved in any suitable way. In one embodiment, the gas separator inlet is of greater diameter or cross-sectional area than the fluid stream line. In another embodiment, the outflow end of the gas separator inlet has a greater diameter or greater cross- sectional area than the fluid stream inflow end or a diameter of the fluid stream line. This change to a larger diameter/cross-sectional area advantageously may result in the fluid stream velocity slowing to a suitable flow speed. The change in diameter or cross-sectional area may be sudden or gradual over any given length of the fluid stream inlet. The diameter/cross-sectional area can be square, circular, elliptical, oval or any other shape. The cross-sectional area of the inflow end may be of a different shape from the cross-sectional area of the outflow end.

[0029] The gas separator inlet may be extendable and/or retractable relative to the vessel. For example, the gas separator inlet, especially the inflow end, may include at least one telescopic adapter conduit. This arrangement may provide greater manoeuvrability when connecting to the fluid stream line. The inflow end may also be designed so as to connect to the fluid stream line other than along a shared central longitudinal axis. For example, the fluid stream line can extend to the inflow end at an angle up to about seven degrees relative to the central longitudinal axis of the inflow end.

[0030] The gas separator inlet may be of unitary construction or may include two or more connected or connectable conduits or pipe (tubular) pieces. The gas separator inlet may be of adjustable length. If the gas separator includes two or more conduit or pipe (tubular) pieces, these may be connected together in any suitable way. Each piece of conduit or pipe may be of a differing diameter. One or more conduit or pipe pieces may be tapered so as to provide a gradual change in diameter or cross sectional area. If required, two or more of the conduit or pipe pieces may be telescopic such that the overall length of the gas separator inlet may be adjusted prior to or after connecting to a fluid stream line.

[0031] In one embodiment, the gas separator inlet may be in the form of a port or connector extending from the vessel for connection to the fluid stream line either directly or via an adaptor. A fluid stream line having a diameter that is standardly used for fluid stream lines (for example blooey lines; typical blooey lines may be of 6, 8 or 10 inch diameter for example) may be connected or connectable directly to such a port or connector. A fluid stream line having a diameter smaller than that of the port or connector may be connected to the port or connector via a diameter-increasing adaptor. In instances where a fluid stream line has been adapted with an adaptor to provide an enlarged diameter relative to a remainder of the line, that adaptor may form part of the gas separator inlet.

[0032] The gas separator may be configured to introduce the fluid stream into the vessel in any suitable way. In one embodiment, the gas separator inlet is located so that the fluid stream enters the vessel tangentially, especially so that centrifugal force separates the gas from the non- gaseous components of the fluid stream. In this embodiment, the non-gaseous components may fall by gravity to the outlet for non-gaseous components at the lower end of the vessel whilst gasses exit the vessel via the gas outlet.

[0033] The gas separator may include an outlet for non-gaseous components. The outlet may be of any suitable size, shape and construction. In one embodiment the outlet for non- gaseous components is an opening in the lower end of the vessel. In another embodiment the outlet for non-gaseous components is a pipe or port extending from the vessel. The outlet for non-gaseous components may be sealed by way of a liquid seal. In one embodiment the outlet for non-gaseous components is a pipe or conduit. The pipe or conduit may be located at a lower end of the vessel. Liquid in the vessel may be pumped from the vessel. Therefore, in one embodiment the gas separator may be fully enclosed.

[0034] The gas outlet may be of any suitable size, shape and construction. In one embodiment the gas outlet is a pipe or port extending from the vessel, especially from an upper end of the vessel.

[0035] The vessel may further include one or more impingement plates or baffles within the vessel for effecting separation of gas from non-gaseous components. If the gas separator is an impingement separator the plates or baffles may be positioned to interfere with the flow of non- gaseous components as these move toward the lower end of the vessel. If the gas separator employs centrifugal action, the plates or baffles may be positioned to disrupt the circular flow of non-gaseous components, especially in the lower end of the vessel. The plates or baffles may be configured to interfere with the flow of non-gaseous components descending to the lower end of the vessel. The vessel may include a replaceable impingement plate or baffle held in position within the vessel using locators. The gas separator may include a solids chute located at the lower end of the vessel. The solids chute may be angled to direct solids away from a liquid component outlet.

[0036] The gas separator may include a flushing system located at a lower region of the vessel. The flushing system may be used in conjunction with, but not limited to, the solids chute. The flushing system may include at least one jet. The at least one jet may be of any suitable size, shape and construction, and may be to force solids away from critical areas in the gas separator.

[0037] The at least one pressure relief may be for venting gas when gas pressure within the vessel exceeds an upper predetermined pressure. The at least one pressure relief may be of any suitable size, shape and construction, and can be made of any suitable material or materials. The at least one pressure relief may be at least one valve, vent or flap. The at least one vent or flap may be hinged to the vessel. The at least one vent or flap may be moveable between an open gas-release position (when the gas pressure within the vessel exceeds the upper predetermined pressure) and a closed vessel-sealed position (when the gas pressure within the vessel is below the upper predetermined pressure). Such a vent or flap may move to the closed position due to gravity. The at least one pressure relief may include a plurality of vents or flaps. The plurality of vents or flaps may be proximate to the gas outlet. The plurality of vents or flaps may be at least 6 vents or flaps, at least 10 vents or flaps, at least 20 vents or flaps, at least 30 vents or flaps or at least 40 vents or flaps. Advantageously it is believed that a larger number of smaller vents or flaps provides a gas separator that is more responsive when the predetermined pressure is exceeded. This is due to the smaller size of the openings to the vessel and the smaller weight of the vents or flaps. The at least one pressure relief may be mechanically or electronically actuated.

[0038] The at least one pressure relief may be configured to allow egress (or exit) of a gas when the pressure in the vessel is greater than 0.10 pounds per square inch gauge (psig), especially greater than 0.15 psig, more especially greater than 0.20 psig, or greater than 0.25 psig; most especially greater than 0.30 psig or greater than 0.35 psig.

[0039] In another embodiment, the pressure relief may include a vent pipe. The vent pipe may be for conveying vented gas to a secondary gas separator.

[0040] The at least one vacuum relief may be for allowing ingress of air or gas when gas pressure within the vessel is below a lower predetermined pressure. The at least one vacuum relief may be located towards or at an upper end or region of the vessel. The at least one vacuum relief may be located proximate to the at least one gas outlet. The at least one vacuum relief may be mechanically actuated (such as with a spring and weight) or electronically actuated. The at least one vacuum relief may be a valve, especially a proportional valve or a knife valve. The at least one vacuum relief may be a reverse valve or a vacuum breaker. Such valves are typically used in large scale production facilities rather in systems like those of the present specification.

[0041] The at least one vacuum relief may be configured to allow ingress of a gas when the pressure in the vessel is less than -0.05 pounds per square inch gauge (psig), especially less than -0.10 psig, more especially less than -0.15 psig, or less than -0.25 psig; most especially less than -0.25 psig.

[0042] The at least one pressure relief and the at least one vacuum relief may be provided by a single device, such as a bidirectional valve. However, in one embodiment the at least one vacuum relief and the at least one pressure relief are separate components.

[0043] In one embodiment, the gas separator includes an assembly in register with the upper end of the vessel. The assembly may be a hood. The assembly may include: the gas outlet (which may be centrally located), at least one vacuum relief (which may be located proximate to the gas outlet), and a plurality of pressure reliefs (which may surround or be located proximate to the gas outlet).

[0044] The gas separator may include at least one pressure sensor. The at least one pressure sensor may be one pressure sensor. The pressure sensor may be located at the upper end or region of the vessel. As discussed above, the flare system may include a control system. The control system may be configured to modify operation of at least one of the flow driver, the flame or pilot flame, the at least one pressure relief and the at least one vacuum relief. For example, if the pressure sensor senses that the pressure in the vessel is below a lower predetermined pressure, the control system may slow or turn off at least one flow driver and/or turn off the pilot flame. This way pressure can rebuild in the vessel before reactivating these components. Similarly, if the pressure sensor senses that the pressure in the vessel exceeds an upper predetermined pressure, the pilot flame or flare may be turned off until it is safe to restart this component. An exemplary pressure sensor may be the VEGABAR 82 by VEGA (Germany).

[0045] In one embodiment the flow driver is at least one blower, especially at least two or three blowers. Each said blower may be rated to a maximum and minimum volume flow rate, and the flare system as a whole may be operable within a specific maximum and minimum volume flow rate. The control system may dynamically adjust the flow rate of each said flow driver to adjust the pressure in the gas separator. The control system may vary the operating speed of each of the said flow drivers (which may include switching a said flow driver off) based on the pressure sensed by the pressure sensor in the gas separator. For example, an exemplary flow driver is a blower made by Baratti Engineering GmbH (Germany; for example model number 8740-DWG-0040). When three of these blowers are present in the flare system, the minimum turndown rate of the system (with one blower operational) may be 810 m ³ per hour, and the maximum turndown rate (with all three blowers operational) may be 8400 m ³ per hour.

[0046] In another embodiment the flow driver may operate by suction, for example an ejector. In this embodiment no pressure sensor or control system may be needed to adjust the flow rate of the ejector. Instead the at least one pressure relief and the at least one vacuum relief may maintain the gas separator within a minimum and a maximum pressure.

[0047] In a similar way, the control system may operate the at least one vacuum relief and the at least one pressure relief in light of the pressure sensed by the pressure sensor. For example, the control system may control a vacuum relief in the form of a knife valve. The control system may be or include at least one PID controller (proportional integral derivative controller). The control system may include a PID controller to control each of the flow driver, the flame or pilot flame, the at least one pressure relief and the at least one vacuum relief. In one embodiment, the flow rate of the flow driver is configured to be adjusted based on the pressure sensed by the pressure sensor. In another embodiment, the flare includes a pilot flame, and the pilot flame is configured to be extinguished or lit depending on the pressure sensed by the pressure sensor.

[0048] The gas separator may include one or more filters (for example scrubbers). The filter(s) may be for filtering out non-gaseous components (including liquids and particulates) entrained in the gas, especially such that they cannot escape through the gas outlet. The filter may be of any suitable size, shape and construction, and may be made of any suitable material or materials. The filter may, for example, extend across the upper end of the vessel adjacent the gas outlet, pressure relief and/or vacuum relief. An example of a suitable filter/scrubber is reinforced copper or steel mesh (or wool mesh). The gas separator may include a noise suppressor. The noise suppressor may, for example, extend across the upper end of the vessel adjacent the gas outlet, pressure relief and/or vacuum relief. An example of a suitable noise suppressor is reinforced copper or steel mesh (or wool mesh).

[0049] The multiphase separator may further include a tank or container adapted to contain liquid. The lower end of the vessel may be located within the tank, especially so that the outlet for non-gaseous components may be sealed with liquid. This arrangement may encourage gas within the vessel to escape the vessel through the gas outlet.

[0050] The tank or container may be of any suitable size, shape and construction, and may be made of any suitable material or materials. The tank may include one or more compartments, such as a settling compartment within which the lower end of the vessel is located, and a suction compartment for collecting clarified liquid from the settling compartment (from which particulates have to some degree separated). The tank may include a weir, such as a v-weir for conveying liquid from the settling compartment to the suction compartment. The suction compartment may have a suction port for the removal of liquid from the suction compartment. At least one sensor may sense properties of the fluid passing through the weir. The properties may include one or more of: the flow rate, the volume of fluid, the mass or volume flow rate, turbidity, total suspended solids (TSS), the presence or absence of components in the liquid (for example pollutants), and the concentration of those components in the liquid. The at least one sensor may be or include an infra-red sensor (for example to sense TSS). An exemplary infra red sensor is a TSS EX1 sc Suspended solids probe, stainless steel, immersion style, ATEX by Hach (United Kingdom). The at least one sensor may be or include a radar, for example to sense the height of liquid at the weir. An exemplary radar sensor may be the VEGAPULS 61 by VEGA (Germany). From the height of the liquid at the weir it may be possible to calculate the flow rate of the liquid at the weir.

[0051] The gas separator or multiphase separator may be located on a framework, skid and/or trailer for supporting the gas separator, multiphase separator or components thereof and/or for transporting the gas separator or multiphase separator by road or rail. The framework, skid or trailer may have lifting fixtures for cranes and hoists. The framework, skid or trailer may also include safety handrails and platforms. The gas separator may include a detonation arrestor.

[0052] The flare system may include more than one gas separator, in which case the gas separators may be connected to one another in a series or in parallel. The gas separators maybe identical or different. The gas separators may each extend within a settling compartment of a tank.

[0053] The gas outlet of a first (primary) gas separator may extend to a gas inlet of a second (secondary) gas separator. The gas outlet of the primary gas separator may be a pipe or duct of any suitable length and cross-section and may feed the gas/fluid stream tangentially into the vessel of the second gas separator. The primary and secondary gas separators may be as described above.

[0054] Alternatively or additionally, a vent pipe of a pressure relief of a primary gas separator may extend to an inlet of a secondary gas separator. The vent pipe of the primary gas separator can be a pipe or duct of any suitable length and cross-section.

[0055] The gas outlet of the gas separator may be in fluid communication with the gas inlet of the flare. The gas outlet of the gas separator may be connected to the gas inlet of the flare via a fluid conduit. The fluid conduit may be a length of pipe or tubing. The fluid conduit may have a diameter of about 10 inches.

[0056] The components of the flare system may be made of any suitable material. In one embodiment, the components of the flare system are typically made from carbon steel or stainless steel.

[0057] In a second embodiment, the present invention provides a flare system. The flare system may include one or more features as described for the first aspect.

[0058] In a third aspect, the present invention provides a gas separator. The gas separator may include an inlet. The gas separator may include at least one vacuum relief. The gas separator may include at least one pressure relief. The gas separator may include a gas outlet. The gas separator may include at least one sensor. The sensor may be in fluid communication with, or in register with the gas separator gas outlet. In one embodiment, a gas separator includes an inlet, a gas outlet and at least one sensor, wherein the at least one sensor is configured to sense properties of the gas in the gas outlet

[0059] In a fourth aspect, the present invention provides a flare. The flare may be a flare assembly. The flare may include a flow driver for driving fluid to the flare. The flare may include a flare stack. The flare may include a pilot flame. The flare may include a gas conduit between the flow driver and the flare stack. The flare may include a gas inlet and a gas outlet.

[0060] In one embodiment of the fourth aspect, the flow driver may operate by suction. The flow driver may be a venturi system, eductor or ejector. In one embodiment, the flow driver may be located proximate to the gas outlet. In another embodiment the flow driver may be located adjacent to a pilot flame. Consequently, in one embodiment the fourth aspect of the present invention provides a flare including: a gas inlet, a gas outlet and a gas conduit extending between the gas inlet and the gas outlet; a pilot flame located proximate to the gas outlet; and an ejector located proximate to the pilot flame.

[0061] In a fifth embodiment, the present invention provides a method of igniting gas from a fluid stream, the method including: At least partially separating gas from a fluid stream with a gas separator, wherein the gas separator includes at least one vacuum relief, at least one pressure relief, and a gas outlet; wherein the at least partially separated gas exits the gas separator through the gas outlet; using a flow driver to drive gas from the gas separator to a flare, and igniting the gas at the flare.

[0062] In a sixth aspect, the present invention provides a method of igniting gas from a fluid stream, the method including using the flare system of the first or second aspect or the flare of the fourth aspect.

[0063] In a seventh aspect, the present invention provides a method of sensing at least one property of a gas, the method including:

At least partially separating gas from a fluid stream with a gas separator, wherein the gas separator includes at least one pressure relief, and a gas outlet; wherein the at least partially separated gas exits the gas separator through the gas outlet; and sensing at least one property of the gas with at least one sensor.

[0064] In one embodiment, the at least one property of the gas is sensed prior to ignition. The gas separator may include at least one vacuum relief. The method may include the step of using a flow driver to drive gas from the gas separator to a flare. The flare may include at least one sensor and a flame. The method may also include the step of igniting the gas with the flame.

[0065] In one embodiment, the gas separator is a multiphase separator, and wherein the multiphase separator includes at least one sensor for sensing properties of liquids or solids separated from the gas.

[0066] In an eighth aspect, the present invention provides a method of monitoring or sensing properties of a gas, the method including using the flare system of the first or second aspects, the gas separator of the third aspect or the flare of the fourth aspect of the present invention.

[0067] Features of the second to eighth aspects of the present invention may be as described, as appropriate, as for the first aspect.

[0068] Any of the features described herein can be combined in any combination with any one or more of the other features described herein within the scope of the invention. BRIEF DESCRIPTION OF DRAWINGS

[0069] Various embodiments of the invention will be described with reference to the following drawings, in which:

[0070] Figure 1 is a perspective view of a first exemplary flare system according to the present invention;

[0071 ] Figure 2 is a further perspective view of the system of Figure 1 ;

[0072] Figure 3 is a close-up perspective view of the flare of Figure 1;

[0073] Figure 4 is a close-up perspective view of the multiphase separator of Figure 1;

[0074] Figure 5 is a perspective view of a portion of the system of Figure 1;

[0075] Figure 6 is a perspective view of a portion of the multiphase separator of Figure 1;

[0076] Figure 7 is a perspective view of a portion of the flare of Figure 1; and

[0077] Figure 8 is a perspective view of a portion of the flare of Figure 1.

[0078] Preferred features, embodiments and variations of the invention may be discerned from the following Description which provides sufficient information for those skilled in the art to perform the invention. The following Description is not to be regarded as limiting the scope of the preceding Summary of the Invention in any way.

DESCRIPTION OF EMBODIMENTS

[0079] Exemplary systems of the invention will now be discussed with reference to Figures 1 to 8. In the figures, like reference numerals refer to like features.

[0080] Figure 1 depicts a flare system 1, which includes a gas separator 10 and a flare or flare assembly 100 for igniting gas. The gas separator includes an inlet 20, at least one vacuum relief 30, at least one pressure relief 40 and a gas outlet 50. The flare or flare assembly 100 is in fluid communication with the gas outlet 50. The system 1 also includes a flow driver 110 for driving gas from the gas separator 10 to the flare 100.

[0081] The flare assembly 100 includes a gas inlet 120 and a gas outlet 130. The flare assembly 100 includes a flare stack 132 at the gas outlet 130. The flare assembly includes a pilot flame 134 located proximate to the gas outlet 130. The flare assembly 100 includes a deflagration arrestor 136 located proximate to the gas outlet 130.

[0082] The flare assembly 100 further includes a separator 138 in the form of a knock-out pot in register with the flare stack 132.

[0083] The flare assembly 100 includes a trailer and framework 140 for supporting the flare components and for transporting the flare by road. The trailer 140 includes lifters in the form of hydraulic jack legs 142 for raising the flare for transport. The flare stack 132 also includes a hinge 133 for folding down the flare stack 132 onto the top of the assembly for transport.

[0084] The flare assembly includes a first gas conduit 150 and a second gas conduit 152 which are in register. The first gas conduit 150 is proximate to the flare stack 132 and the second gas conduit 152 is distal to the flare stack 132. The second gas conduit 152 has a larger diameter than the first gas conduit 150 and is oriented transverse to the first gas conduit 150. The first and second gas conduits 150, 152 each include a pressure relief, in the form of a burst disk 154, 156.

[0085] The flare assembly 100 includes three flow drivers 110 for driving gas from the gas separator 10 to the flare 100. The three flow drivers 110 are in parallel, and each flow driver 110 includes a gas inlet 112 and a gas outlet 114. Each flow driver gas outlet 114 is in register with the second gas conduit 152. The flare assembly 100 includes a manifold 116 which is in register with each flow driver gas inlet 112. The manifold 116 includes a pressure relief, in the form of a vacuum breaker 118, and a filter 119. The inlet to the manifold 116 may include a valve which is shut when the pressure in the vessel 12 exceeds the predetermined amount. Each flow driver 110 is in the form of a 45-100 kW blower. Each flow driver in Figure 3 is a blower made by Baratti Engineering GmbH (Germany; model number 8740-DWG-0040). The flow drivers 110 are capable of driver about 6 MMSCFD and are rated for use with flammable gases. A burst disk 113 is located proximate to one of the flow driver gas inlets 112.

[0086] The first gas conduit 150 includes at least one sensor 160. The at least one sensor 160 is configured to monitor or sense properties of the gas flowing from the gas separator 10 prior to ignition. In the embodiment of Figure 3, the at least one sensor 160 includes an infra-red sensor to sense the concentration of methane (for example BIOGAS 3000 by ThermoFisher Scientific). The at least one sensor 160 also includes an ultrasonic flow meter to measure velocity, pressure and temperature (for example PanaFlow Gas Meter System by Baker Hughes). Using the infra-red sensor and the ultrasonic flow meter the mass flow rate of methane in the system may be determined. [0087] The flare assembly 100 further includes a control system 170 including a programmable logic controller (PLC) or a computer. The control system 170 may include a data processor, telemetry system, and data store. The control system 170 may monitor the parameters sensed by the sensors, and control operation of the flow drivers 110 and/or the gas separator 10 pressure relief 30 and vacuum relief 40.

[0088] The flare assembly 100 further includes a storage tank 180, and a door 182 to enable personnel to access the storage tank.

[0089] The flare system 1 includes a multiphase separator 6. The multiphase separator 6 incudes the gas separator 10. The multiphase separator 6 is suitable for separating gas from a fluid stream that has exited a well.

[0090] The gas separator 10 includes a vessel 12. The vessel 12 is substantially cylindrical. The gas separator inlet 20 is for introducing the fluid stream into the vessel 12. The inlet 20 includes an inflow end 22 connectable to a fluid stream line (for example a blooey line) and an outflow end 24 that is in register with the vessel 12. The gas separator inlet 20 extends substantially horizontally between the inflow end 22 and the outflow end 24 when the gas separator 10 is in use.

[0091] The gas separator inlet 20 is configured to reduce the velocity of the fluid stream prior to entering the vessel 12, or relative to the velocity of the fluid stream within the fluid stream line. As illustrated in Figure 4, the outflow end 24 is of greater diameter or greater cross sectional area than the inflow end 22. This change to a larger diameter / cross-sectional area results in a reduction in the velocity of the fluid stream. The inflow end 22 may be connectable to a 6 inch or 8 inch blooey line.

[0092] The gas separator 10 is configured to introduce the fluid stream into the vessel 12 tangentially, so that centrifugal force separates the gas from the non-gaseous components of the fluid stream. The gas separator 10 includes a filter (not shown) for filtering out non-gaseous components entrained in the gas. The filter extends across the upper end of the vessel 12 adjacent the gas outlet 50 or assembly 70. The filter may be steel mesh.

[0093] The multiphase separator 6 includes an outlet for non-gaseous components 60 in the form of an opening in the lower end of the vessel 12. In use, the outlet for non-gaseous components 60 is sealed by way of a liquid seal. The lower end of the vessel 12 is located with a tank 62 adapted to contain liquid, so that the outlet for non gaseous components 60 is sealed with liquid. [0094] The tank 62 includes a settling compartment 64 and a suction compartment 66 for collecting clarified liquid from the settling compartment 64. The tank 62 includes a v-weir 68 for conveying liquid from the settling compartment 64 to the suction compartment 66. At least one sensor is used to sense properties of the fluid passing through the weir 68. In the system of the Figures, an infra-red sensor is present to sense TSS (the TSS EX1 sc Suspended solids probe, stainless steel, immersion style, ATEX by Hach (United Kingdom)), and a radar is used to sense the height of liquid at the weir 68 (the VEGAPULS 61 by VEGA (Germany)). The height of the liquid at the weir can be used to calculate the flow rate of the liquid at the weir.

[0095] The gas outlet 50 is a pipe extending from an upper end of the vessel 12. The gas separator 10 includes an assembly 70 in register with the upper end of the vessel 12. The assembly includes the gas outlet 50 (which is centrally located), a vacuum relief 30 (located proximate to the gas outlet 50) and a plurality of pressure reliefs 40 (which surround the gas outlet 50).

[0096] The at least one pressure relief 40 is for venting gas when gas pressure within the vessel exceeds an upper predetermined pressure. In the system of the Figures, the upper predetermined pressure is 0.35 psig. The at least one pressure relief 40 in the Figures is in the form of a plurality of vents which are hinged to the vessel 12 (or to the assembly 70). The vents are in the system of the Figures is moveable between an open gas-release position (when the gas pressure within the vessel 12 exceeds 0.35 psig) and a closed vessel-sealed position (when the gas pressure within the vessel 12 is below 0.35 psig).

[0097] The at least one vacuum relief 30 in the Figures is one vacuum relief 30. The vacuum relief allows ingress of air or gas when gas pressure within the vessel is below a predetermined pressure (in the system of the Figures this is -0.25 psig). The vacuum relief 30 in the Figures is a proportional valve which is mechanically actuated.

[0098] The gas separator 10 includes at least one pressure sensor for sensing the pressure within the vessel 12. The pressure sensor is located within the upper region of the vessel 12.

[0099] In the system of the Figures, the control system 170 is configured to modify operation of the flow drivers 110 and the pilot flame 134, based on the pressure sensed by the pressure sensor (the pressure relief 40 and the vacuum relief 30 are mechanically actuated in the Figures). For example, if the pressure sensor senses that the pressure in the vessel 12 is below - 0.25 psig, the control system 170 may slow or turn off at least one blower 110 and/or turn off the pilot flame 134. Similarly, if the pressure sensor senses that the pressure in the vessel 12 exceeds 0.35 psig, the pilot flame 134 may be turned off until it is safe to restart this component. In the system of the Figures, the pressure sensor is the VEGABAR 82 by VEGA (Germany). The control system 170 includes at least one PID controller to control the flow drivers 110 and the pilot flame 134.

[00100] In the system of the Figures, the multiphase separator 6 includes a sample line (not shown), extending from assembly 70. The sample line includes a sensor for measuring total suspended solids (TSS) and/or turbidity.

[00101] The multiphase separator 6 is located on a trailer 80 for transporting the separator 6 by road. The gas separator 10 also includes a detonation arrestor 90.

[00102] The gas outlet 50 of the gas separator is connected to the gas inlet of the flare 120 via a fluid conduit, in the form of a pipe with a diameter of about 10 inches.

[00103] The components of the flare system 1 are typically made from carbon steel or stainless steel.

[00104] In use, fluid from a fluid stream travel along a blooey line and into the gas inlet 20 of a multiphase separator 6 which includes gas separator 10. Gas is at least partially separated from liquids and solids in the separator 10 and the gas exits the separator 10 via gas outlet 50. If the pressure in the vessel 12 of the gas separator 10 is too low, air enters the vessel 12 via vacuum relief 30. If the pressure in the vessel 12 of the gas separator 10 is too high, gas exits the vessel 12 via pressure relief 40. Gas from the gas outlet 50 is then driven to the flare 100 using flow drivers 110. The gas then flows to a flare stack 132 for ignition. The system 1 includes sensors to sense and/or monitor the properties of the gas flowing to the flare stack 132, and the properties of the liquid exiting the multiphase separator 6. In this way, an operator can determine for example how a well cleanout operation is progressing, or the cleanliness or performance of the well.

[00105] In the present specification and claims (if any), the word ‘comprising’ and its derivatives including‘comprises’ and‘comprise’ include each of the stated integers but does not exclude the inclusion of one or more further integers.

[00106] Reference throughout this specification to‘one embodiment’ or‘an embodiment’ means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases ‘in one embodiment’ or ‘in an embodiment’ in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more combinations.

[00107] In compliance with the statute, the invention has been described in language more or less specific to structural or methodical features. It is to be understood that the invention is not limited to specific features shown or described since the means herein described comprises preferred forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims (if any) appropriately interpreted by those skilled in the art.