Patent Application
20240199962
The invention relates to demulsification and separation of constituents in an emulsion, for example, apparatus and methods for demulsifying crude oil emulsions or other similar emulsions, using plasma treatment. The invention also relates to forming plasma enhanced treatment fluids such as plasma enhanced treatment water and/or plasma enhanced treatment gas(es).
In various situations, different fluids become emulsified together when it is not desired to produce an emulsion, thereby requiring demulsification. For example, crude oil is generally found in association with gas and saline formation water in the ground. The oil, brine and gases become emulsified during oil production processes. Further, as the reservoir becomes depleted, enhanced oil recovery (EOR) methods may use water or steam, or gas(es) for example, which are injected into an oil reservoir and then coproduced with oil. The oil emulsions may thus comprise a large or varying percentage of oil or water or depending on the production process, but in each case result in a highly stable emulsion. The oil emulsions present a significant problem for oil producers. These immiscible fluids are readily emulsified by the simultaneous action of shear and pressure drop at the wellhead, chokes and valves and other mechanisms during oil production. The need for demulsification has also expanded in significance due to the usage of water, steam and/or gases, for flooding operations or in situ recovery of heavy oils for example.
In general, crude oil emulsions are stabilized by rigid interfacial films that form a “skin” on water droplets and make it more difficult for the droplets to coalesce. The stability of these interfacial films, and hence, the stability of the emulsions, depends on a number of factors, including the heavy material in the crude oil (e.g., asphaltenes, resins, and waxes), solids (e.g., clays, scales, and corrosion products), temperature, droplet size and droplet-size distribution, pH, and oil and brine composition for example. Produced oil generally has to meet company and pipeline specifications. For example, the oil shipped from wet-crude handling facilities may be specified to not contain more than 1% basic sediment and water (BS&W) and 10 pounds of salt per thousand barrels of crude oil. Low BS&W and salt content is required to reduce corrosion and deposition of salts, which can damage or be detrimental effects to refinery or other equipment. Current separators and desalters have a high capital cost and also require high retention times, particularly with low API or heavy oils and in water or steam flooding operations. For example, enhanced oil recovery (EOR) uses water flooding, while oil sands may use steam-assisted gravity drainage (SAGD) operations in producing heavy oils. In such examples, in the field downstream of the well head, crude oil, water, and solids are produced together and flow in surface piping toward a facility tank resulting in severe emulsions. The heavier the crude oil, the worse the emulsion. Heavy oil operators currently experience retention times for heavy crude oil and water separation using traditional methods in the field of 3 days to up to a month. In another example, a typical SAGD operation may have a desalter with a 100,000 bpd throughput capacity, but this also results in ˜5% by volume developing into a rag layer where the operators are forced to purge off and inject to ensure steady production. This adds an operating expense and is wasteful, as this ˜5% by volume rag layer can contain up to half its volume in crude oil.
The breaking of emulsions during oil production is a costly problem, both in terms of chemicals or energy used, production lost and other problems. This process is generally accomplished by techniques including adding chemical demulsifiers, increasing the temperature of the emulsion, applying electrostatic fields that promote coalescence of water in the emulsion and/or reducing the velocity or stopping the flow of the emulsion that allows gravitational separation of oil, water, gases and solids. Some oil separators termed electrostatic coalescers apply an electric field to the emulsion, polarizing the oil and water droplets in the emulsion to attempt to cause flocculation and coalescence. However, the use of high voltages poses a danger as it may result in ignition of the hydrocarbon material or other problems. Additionally, existing traditional electrostatic coalescers, such as the Schlumberger NAPCO, are very large in scale and high in cost, and thus are only usable at large scale production sites. Further, current demulsification methods are application specific because of the wide variety of crude oils, brines, separation equipment, chemical demulsifiers, and product specifications. As emulsions and conditions generally change over time, this adds to the complexity of the demulsification treatment.
Oil emulsions can also occur in other situations, such as crude oil spills in bodies of water and/or washed up onto beaches. The longer the time the oil spill cleanup takes, the larger the impact on the environment. Though techniques have been developed to remove such contaminants, these have various associated problems. For oil impacted soils and solids, soil washing techniques are typically employed.
Accordingly, it would be desirable to provide apparatus and methods for demulsification of emulsions, such as crude oil emulsions, which overcome the problems associated with current techniques. For example, it would be desirable to provide apparatus and methods for demulsification of emulsions at a faster rate or speed. It is also desired to achieve the desired separation of constituents in the emulsion to <1% BS&W, and to increase production throughput without needing large and high capital cost equipment and energy input, the cost of chemicals, or other costs or problems as compared to traditional apparatus and methods.
The apparatus, systems and methods of the invention are directed to overcoming limitations or problems with demulsification of crude oil emulsions or the like. The systems and methods of the invention reduce the need for long retention time to phase separate emulsions. The invention also reduces or eliminates the need for chemical demulsifiers, increasing the temperature of the emulsion or the like, though such techniques may be used in combination with the invention. For crude oil, the systems and methods also reduce the need for blending of condensate with the separated crude oil to satisfy pipeline specifications for example. The systems and methods of the invention provide the ability to produce more oil more quickly, while not requiring significant capital expenditure or space to achieve demulsification. The systems and methods of the invention also allow for enhanced production from oil reservoirs by forming plasma enhanced treatment fluids having synthesized surfactants and demulsification or other reactive molecules or species, that can be used in waterflooding, gas flooding, downhole applications or other oil recovery or related processes for example. The apparatus, systems and methods of the invention may also be used with other types of emulsions that may require demulsification, and the plasma enhanced treatment fluids useful for other processes or applications. These and other advantages are described in relation to various examples.
According to an example, the invention is directed to a method of demulsifying an emulsion comprising providing at least one plasma reactor with a reactor body defining a reaction chamber. The reaction chamber is filled with a carrier gas, and an emulsion is introduced into the chamber. At least one pair of electrodes are positioned in the reaction chamber and are energized to a voltage to ionize the carrier gas and produce plasma in the reaction chamber to cause flocculation and electrostatic coalescence in the emulsion for separation of the constituents in the emulsion. The separated constituents in the emulsion are removed from the reaction chamber. According to an example, the emulsion is introduced into the reaction chamber as a stream and continuously flows through the reaction chamber to at least one outlet port. Alternately, the treatment of the emulsion may be done in a semi-continuous/intermittent manner or in batches. The emulsion may be an oil emulsion with at least oil and water constituents, and the separated oil and water constituents are removed through at least one outlet port from the reaction chamber. For example, oil and plasma enhanced treatment water removed from the emulsified mixture may be pumped from separate outlet ports of the reactor body to separate storage tanks or otherwise. The oil may be pumped for further processing or sale, and the plasma enhanced treatment water may be reused in oil recovery or other processes for example. The plasma enhanced treatment gas(es) may be recirculated to the at least one reactor or removed for use in another process or application.
In another example, the invention is directed to a method of producing water treatment fluids for use in oil recovery methods comprising providing at least one plasma reactor with a reactor body defining a reaction chamber. The reaction chamber is filled with a carrier gas, and a crude oil/water emulsion is introduced into the chamber. At least one pair of electrodes are positioned in the reaction chamber and are energized to a voltage to ionize the carrier gas and produce plasma in the reaction chamber. The plasma energy reacts with the surface and volume of the emulsion, such as a crude oil/water emulsion, and transfers a charge to the crude oil/water emulsion to establish an electric field in the oil/water emulsion to cause flocculation and coalescence of constituents, as well as produce synthesized surfactants and demulsification molecules in association with the reactor fluids, to generate plasma enhanced treatment fluids. The plasma treatment of an oil emulsion for example produces plasma enhanced treatment water and/or plasma enhanced treated gas(es). The plasma enhanced treatment water or gas(es) are separated and removed from the reaction chamber for use in other processes. In an example, the plasma treated or enhanced treatment water may be recirculated into the at least one reactor of a demulsification system of the invention, injected into an oil reservoir in a waterflooding operation, or for another process or application. Similarly, the plasma enhanced treatment gas(es) may be used in other demulsification processes, gas lifting operations or other processes. The plasma enhanced treatment fluids may have enhanced wettability in relation to the formation and facilitate oil recovery operations. The enhanced wettability facilitates interactions between the solid rock or other solids and the liquids in a reservoir, such as the crude oil and brine that displace the oil to be produced. The carrier gas is ionized by the at least one pair of electrodes to produce plasma energy that causes chemical reactions with the reactor fluids, to produce synthesized surfactants and demulsification or other molecules in association with the reactor fluids. The amount of plasma energy can be varied, and use of a non-oxidative carrier gas may allow for higher electric fields to be produced in the emulsion, to generate plasma enhanced treatment fluids useable in other processes. The plasma energy chemically alters the emulsion mixture, and fluids such as water and/or gas(es) in the emulsion or introduced into the reactor. The plasma enhanced water and plasma enhanced gas(es) may thus have enhanced demulsifying characteristics, enhanced wettability and surfactant properties, and anti-microbial properties. The plasma energy causes reaction of the energy with the fluids, to synthesize larger surfactant and demulsification molecules to produce plasma enhanced water and plasma enhanced gas(es). The plasma energy may thus create plasma enhanced gas(es) with radicals and/or ions in the gas phase headspace above the emulsion and/or polymerization of gas(es), that go on to interact with the liquids and dissolve and become solvated, to enhance reactivity of electrons and/or ions in the liquids to facilitate flocculation and coalescence in the emulsion and create the plasma enhanced treatment fluids for example. The plasma energy results in chemically altering the liquids including the water to form plasma enhanced treatment water for example. The plasma enhanced treatment fluids, such as water and/or gas(es), may then be usable in other processes, with the plasma enhanced characteristics facilitating further demulsification processes, waterflooding or gas flooding processes or for many other possible processes and/or applications. With respect to an oil emulsion, the improved demulsification properties, enhanced wettability and surfactant properties, anti-microbial properties and other enhanced properties are useful in further oil recovery processes. These enhanced properties may also form treatment fluids that are specific to the particular oil reservoir and oil emulsion being demulsified, but may be usable with any oil reservoir or emulsion. The plasma enhanced treatment water and/or gas(es) with synthesized surfactant, wettability and demulsification molecules may then be beneficially used for EOR or downhole applications, lifting operations or other processes. For example, the plasma enhanced water and/or gas(es) may be used in flooding operations to promote removal and production of oil from a reservoir in which the treatment fluids are injected, to facilitate fracking operations, to facilitate gas lifting operations or for any other desired process or purpose.
In another example, the invention is directed to a method of demulsifying a rag layer formed in oil recovery operations, comprising providing at least one plasma reactor with a reactor body defining a reaction chamber. The reaction chamber is filled with a carrier gas, and a rag layer is introduced into the chamber. At least one pair of electrodes are positioned in the reaction chamber and are energized to a voltage to ionize the carrier gas and produce plasma in the reaction chamber that causes flocculation and electro-coalescence in the rag layer for separation of the oil and water constituents in the rag layer. The separated constituents in the emulsion are removed from the reaction chamber. According to an example, the rag layer is removed from a source and introduced into the at least one reaction chamber as a stream and continuously flows through the reaction chamber to at least one outlet port. The emulsion may be a crude oil emulsion with at least oil and water constituents, and the separated oil and water constituents are removed through at least first and second outlet ports from the reaction chamber. For example, oil and water removed from the emulsified mixture may be pumped from separate outlet ports of the reactor body. The oil may be pumped for further processing or sale, and the plasma enhanced treatment fluids may be reused in enhanced oil recovery (EOR) processes for example or other processes or applications.
A demulsifying system according to an example comprises at least one plasma reactor with a reactor body defining a reaction chamber. The reaction chamber includes a first gas inlet for supplying a carrier gas into the reaction chamber, and an emulsion inlet to introduce an emulsion into the chamber. At least one pair of electrodes are positioned in the reaction chamber, and a power supply is provided to supply a voltage to the at least one pair of electrodes to cause ionization of the gas and produce plasma in the reaction chamber. A separator is positioned in the reaction chamber to separate the produced constituents of the emulsion, and at least one outlet to remove the separated constituents of the emulsion from the reaction chamber. One or more outlet ports may be provided to remove the crude oil, water and any solids.
The demulsifying system may treat an emulsion in a continuous manner as a stream introduced into the reaction chamber, such as at a predetermined flow rate, with the separated constituents removed as they are produced. For example, the emulsion may be crude oil including water, or crude oil mixed with water and solids. The apparatus, systems and methods of the invention are usable to separate constituents of an emulsion, such as crude oil, water, and solid phases, such that re-emulsification is prevented. According to examples of the methods and apparatus, the voltage applied to the at least one pair of electrodes causes ionization of the gas to produce plasma, and may be at or in excess of the breakdown voltage of a carrier gas introduced into the reaction chamber through the first gas inlet. The carrier gas may be supplied to the reactor in a recirculating stream in association with at least one gas outlet, to maintain a predetermined pressure or pressure range in the reaction chamber. For oil emulsions, a non-oxidative gas may be used, which may be supplied from an oil well or any other source. The apparatus of the invention can run at standard conditions without inducing formation of a foam or rag layer. The separator may be any suitable separator to separate the immiscible liquids and solids formed in the reaction chamber. The apparatus and systems of the invention may be provided as relatively small, modular systems allowing easy transport and positioning in relation to a source of an emulsion, and require low maintenance.
These and other methods, processes, structures, apparatus, systems, characteristics, attributes, features and the like of the invention will be understood more fully upon a reading and understanding of various examples as set forth below.
Examples of the invention will be described in relation to the treatment of oil in water (O/W) and/or water in oil (W/O) emulsions, such as are encountered in crude oil production operations, whether primary, secondary and/or other environments or applications. It should be understood that other emulsions, such as wastewater emulsions, gaseous emulsions or the like, may be treated with the apparatus, systems or methods of the invention in a similar manner. Emulsions are formed when at least two immiscible liquid phases are present within a system. In O/W or W/O emulsions, these unmixable fluids are emulsified by the simultaneous action of shear and pressure reduction at the head of the well, clogs, controller valves or various other aspects of oil production or recovery. Turning to
In an example, an oil field generally will include a plurality of oil wells in relation to an oil reservoir or source. For processing of the production from each well, the invention contemplates that all production wells or a group of production wells will be pumped to one or more central distribution systems that would bring together the emulsions from each well. The emulsion may then be supplied in a controlled manner to at least one demulsification system of the invention. The demulsification system of the invention is configurable to handle demulsification of the expected production rate of the oil field, and shouldn't be a limiting factor in production from the field, as significant settling or dwell times to separate constituents of the emulsion are generally not required. The demulsification system of the invention includes at least one plasma reactor for treatment of the emulsion. In an example, a plurality of relatively small modular reactors may each be designed to operate together to accommodate a predetermined flow rate of emulsion in a continuous demulsification operation in relation to a particular oil field or reservoir or other source of emulsion. One or more modular reactors can be mounted on a base, such as a pallet vehicle, ship or the like, to allow for easy transport and delivery to any site, such as an oil field, off shore platform, or any other production site. Any number of reactors can thus be positioned in close proximity to a source of emulsion. Such modular reactors may thus be implemented easily to handle a particular oil field's requirements or to process another source of emulsion. As the modular reactors are also relatively small and thus have a relatively small footprint, this allows implementation in any desired location in an oil field or otherwise.
For example, at least one demulsification system may be provided, with at least one plasma reactor, and used in association with onshore or offshore oil and gas production. The modular configuration provides a system sized to be implementable on an offshore oil production platform for example. Compared with prior methods, the use of one of more plasma reactors designed to handle the production from the one or more wells may be implemented at a lower capital cost as well as lower ongoing operational and maintenance costs. The apparatus, system and methods avoid the high capital cost of some types of equipment, such as large electrostatic coalescers, and have a significantly smaller footprint. The modular configuration also allows for operation of a plurality of reactors in parallel or in series, such that depending on the characteristics of the emulsion, there can be multiple stages of reactors in series. It is also possible to operate reactors separately, such that depending on the characteristics of the emulsion, a first stage reactor may be used to initiate phase separation of an emulsion with a first flow rate, energy input, pressure and/or other operational characteristics, while a second or further stage may use a different flow rate, energy input, pressure and/or other operational characteristics, to ensure a <1% BS&W phase separation in the crude oil emulsion for example. As will be described, the plasma energy and plasma density produces desired demulsification of an emulsion, and also produces plasma enhanced treatment fluids, including plasma enhanced treatment water and plasma enhanced treatment gas or gases for example. The plasma causes chemical reactions in and between gas and liquid molecules, which may then react with other constituents and molecules in the emulsion to produce new species having enhanced characteristics.
Turning to
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In another example, one or more demulsification systems may be used to assist in cleaning up a crude oil spill in water or on land such as from underwater or land based pipelines, well blowouts, barge or carrier accidents or otherwise. At the location of such a spill, a slurry pump or the like may be used to gather the oil/water emulsion from the water or oil in earthen materials combined with water and supply it to one or more demulsification systems of the invention. Turning to
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In a further example, this type of reactor is formed in a modular configuration, such as shown in
In this example, at a position downstream of the reaction chamber 204, a separator 212 is positioned to separate the oil after demulsification. At least one outlet is provided to remove separated constituents from the reactor. In this example for an oil emulsion, an outlet 214 is provided at a point past the separator 212 for the separated oil, and an outlet 216 is provided to remove the separated water and solids constituents of the emulsion from the reaction chamber 204. Individual outlets for the separated water and solids constituents may also be provided. In this manner, after an emulsion is introduced via inlet 208, the separated constituents can be removed in a continuous manner. Alternatively, for a batch processing arrangement, only one inlet/outlet may be provided if desired. The separator 212 may be a weir, flume or other suitable separator. For example, separator 212 may be a weir plate designed to run the full width of the reaction chamber 204. This helps to minimize unwanted surges which would be deleterious to separation of the oil or cause water to overflow into the oil outlet compartment. The height of the weir plate may be adjustable, to adjust the static and operating levels of emulsion in the reaction chamber 204, and may allow for automatic adjustment based on changing conditions to further enhance and optimize performance of the system. The separator 212 may be operated to adjust and vary the height of the emulsion in the chamber 204 by any suitable mechanism.
In the example of
In this example of a reactor 200, a non-thermal plasma is generated at about atmospheric pressure in the chamber 204 to create a plasma zone in reactor 200. The emulsion is made to flow through the plasma zone in the chamber 204 and into the inter-electrode gap within the chamber 204. An applied voltage between the electrodes which is equal to or greater than the breakdown voltage of the carrier gas in the inter-electrode discharge gap generates plasma. The current between the electrodes at a voltage potential sufficient to cause a spark discharge and the plasma zone in chamber 204.
In an example, for a crude oil emulsion, methane gas or natural gas may be available at the site of the emulsion to be processed and can be used as the carrier gas in the reactor 200. The use of methane, as a non-oxidative gas, may allow higher energy input in operation of the reactor 200. The carrier gas may also be a flue gas from a nearby source or any other suitable gas or source. In the modular system, it may also be worthwhile to use the carrier gas from one modular reactor in other reactors that may be in use in an overall system, as well as the plasma enhanced treatment water produced. Alternatively, the plasma enhanced treatment gas can be recirculated from an outlet valve 218, to facilitate continued formation of the synthesized surfactants and demulsification molecules in association with the water and other gases in the emulsion. The carrier gas may be supplied to form a slightly pressurized reaction chamber 204 during operation.
In this example, the at least pair of electrodes 210 include an upper electrode and lower electrode that each project into the discharge chamber 204, and define an inter-electrode discharge gap. The inter-electrode discharge gap can be adjustable and set to optimize desired plasma generation. The electrodes 210 are connected to a power supply and control system 220 (shown schematically), to allow electrodes 210 to be energized to a varying voltage potential difference between electrodes sufficient to ionize the carrier gas and create plasma. In an example, an operating voltage of 1-60 kV with a current of 0.1 to 4 mA may be provided for example, but the operating voltage and/or current may be set in any desired manner to achieve plasma formation, and may vary dependent on the inter-electrode discharge gap, emulsion characteristics, density of the medium or other factors. Insulation or other suitable arrangements to prevent unwanted discharges may be provided. The power of the plasma generated in the reactor 200 may depend on the required production rate and specific energy input to the treated emulsion to achieve the desired results from a particular reactor 200 in association with a particular emulsion. Different reactors 200 in a modular system can be operated differently to achieve the desired results. The use of higher voltages and/or currents to control plasma generation may enhance mobility of the constituents in the emulsion, and/or the use of higher currents may provide more water extraction. The energy of the plasma may be controlled to adjust for particular characteristics of the emulsion or other factors. The plasma caused flocculation and coalescence allow extraction of water at lower initial currents and voltages because the plasma produces resistive and/or conductive pathways for charge species, differently charged ions and electrons in the emulsion. The plasma energy it thus transferred to and through the emulsion and gases and liquids therein, creating additional reactive species or molecules to produce the plasma enhanced treatment fluids with the enhanced characteristics. The inter-electrode discharge gap, and plasma energy is designed to optimize the efficiency of the demulsification process, and may be based on factors such as the emulsion being treated, the injected carrier gas, and the applied voltage and/or current or other factors. For example, the inter-electrode discharge gap may be from 1 to about 100 millimeters, but can vary. The energization of the electrode may be equal to, or greater than, the breakdown voltage of the carrier gas, which may vary depending on various factors and conditions in the reactor. The dielectric breakdown of the carrier gas varies according to the particular gas(es), the gas pressure, density of the reactor medium, the geometry of the electrode, the inter-electrode distance and/or other factors, and the voltage applied to the electrodes may be varied accordingly to produce desired plasma energy and/or density. The breakdown voltage of the carrier gas will be less than the breakdown voltage of the emulsion or separated liquids produced, providing a large surface area in reaction chamber 204 of direct contact between the plasma discharge and emulsion, and pathways therethrough. The discharge occurs between the electrodes 210 in association with the carrier gas and moves through the emulsion to ground at the other electrode 210. Depending on the arrangement, the discharge may be continuous or pulsed. The power supply and control system 220 required will depend on the number of electrode pair gaps for processing of an emulsion, the inter-electrode discharge gap, the continuous energy requirements or pulse repetition rate, emulsion flow rate through the reactor, the gas flow in the chamber or other factors for example.
At least one control system 220 may be provided to operate the various systems or functions of the apparatus 200 or parts thereof. The control system 220 may be a suitable computer control for example, including a computing device that may comprise one or more processor(s), PLC controllers or any other suitable system, configured to execute computer-executable instructions, such as instructions composing operation of one or more components of the reactor 200 and/or modular reactors as a part of a system. A computer typically includes a variety of computer readable media and can be any available media that can be accessed by computer. The system memory may include computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM) and/or random access memory (RAM). By way of example, and not limitation, there may be provided an operating system, application programs, other program modules, and program data. A user or operator is enabled to enter commands and information into the computer. In this example, the control system 220 may include a suitable interface to allow setting and selection of operation of the reactor(s) 200 and/or other associated systems. The control may thus operate the power supply, the pumps for supply and/or extraction of emulsion or constituents, drives for adjusting the separator such as a weir, adjusting the inter-electrode gap, controlling the gas injection and circulation, removal device for any solids constituents or other equipment or components as described, which may be performed by an unskilled operator. The control system 220 may include the use of sensors to monitor all aspects of operation of the reactor(s) 200, such as level sensors, pressure sensors, flow sensors, temperature sensors or any other suitable sensor for monitoring operating functions of the reactor(s) 200.
In an example, the treatment of an emulsion would be performed as a continuous process in the reactor system for an emulsion or slurry. The emulsion or slurry is supplied to the reactor 200 to predetermined height controlled by the control system 220. The emulsion is made to flow through the reactor chamber 204 at a predetermined flow rate continuously at a predetermined or variable rate controlled by the control system 220. The rate corresponds with the demulsification characteristics in association with a particular emulsion, the configuration of the modular reactor system or reactor 200, or other factors. The flow rate will determine the dwell time the emulsion interacts with the plasma to result in demulsification to a desired degree. The emulsion may be recirculated to continue plasma treatment for a predetermined energy input to the emulsion or treatment time for the particular emulsion. The separated constituents are then continuously removed from the reactor 200 or modular reactor system after separation. Alternatively, in batch process, the reactor 200 may be designed to accommodate a volume of emulsion and expose the volume to plasma for a dwell time in a similar manner, with the demulsified constituents removed thereafter.
In this example, the electrodes 210 are connected to a power source to supply AC or DC voltage to between the electrodes 210 which pass through the reactor body 202, and connect to one or more conductive sheets or plates 205. A plurality of plates 205 may be used in association with one or both electrodes in spaced apart relation for example. The electrodes 210 or one or more plates 205 may be provided with a resistive material, such as a coating or otherwise, to facilitate plasma generation. The electrical power for generating plasma between the select pairs of electrodes 210 may be less than 20 kW, such as from about 100 W to about 10 kW for example, but other power supplies may be used. The sheets 205 may be provided with several pins or points 207 extending toward the other electrode 210 if desired. The pins 207 may be attached or formed with plates 205 to extend toward the other electrode. In operation, plasma will be generated and discharge into the circulated gas to the surface of the emulsion flowing or provided in the reactor 200. The lower (and upper) sheets 205 may be mesh to allow solids in the emulsion to settle toward the bottom of chamber 204. The position of the upper and lower plates or sheets 205 are variable, and may be modified based on different expected heights of the emulsion as controlled, to provide optimized conditions for treatment and demulsification. Any suitable arrangement for varying the position of plates 205 or electrodes 210 may be used. The sheets 205 may also have plasma catalytic properties. The sheets 205 in association with lower electrodes 210 may also be configured to promote separation of the constituents as they are separated as the emulsion flows through the reactor, as well as the bottom and/or sides of the reactor body 202. The lower electrodes 210 designed for submersion in the emulsion may be configured accordingly. The emulsion as it is demulsified will separate into a layer of oil at the top, a rag layer of oil/water still mixed and a bottom layer of water with any solids falling out to the bottom. A system for moving any settled solids toward outlet 216, such as a conveyor system or other suitable arrangement may be provided.
Other design and/or operational alternatives may be provided, such as for example, the plasma energy or density is constant or varied along the length of the reactor chamber 204. The inter-electrode discharge gap may be constant or varied along the length or width of the reaction chamber. For example, as constituents are separated towards the outlet of the reactor chamber 204, the configuration may be altered accordingly. The electrode configurations may facilitate production of a more uniform plasma within the reactor chamber 204 above and in interaction with the emulsion in the chamber 204, but alternative electrode configurations or other characteristics of reactor 200 are contemplated, and would be evident to a person of ordinary skill in association with plasma reactors. For example, the electrodes 210 may be shaped as flat sheet or blade electrodes, and/or as tube-shaped electrodes or in other suitable forms. Again, different configurations of plasma reactor may be used to treat an emulsion according to the invention.
The modular reactor 200 may thus be easily transported and deployed at the source site of an emulsion, such as oil production wells. An oil field generally will include a plurality of oil production wells, and the modular demulsification system 200 may be configured with other systems 200 to handle a group of production wells. All the crude oil emulsions produced from each well would flow into at least one demulsification system 200 for phase separation, as will be described in relation to a further example. The ability to easily transport and deploy one or more modular demulsification systems 200, that can be mounted on a base, such as a pallet, allow for any number of reactors 200 used to accommodate a particular source of emulsion. The modular demulsification system 200 also allows the methods as described to be easily implemented, such as to assist in cleaning up a crude oil spills in water or land, such as from underwater pipelines, well blowouts, barge accidents or otherwise. At the location of such a spill, a slurry pump or the like may be used to gather the oil/water emulsion from the water and supply it to one or more demulsification systems 200. After demulsification, the oil can be salvaged, and supplied to an oil barge or other suitable storage, while the water is storable for further processing if needed. The use of one or more demulsification systems 200 aboard a vessel would be easily implemented for remediation of such spills, and reduce the environmental impact. Similarly, the invention could be used in clean up of oil from beaches or soil affected by a spill, with the contaminated sand or soil formed into a slurry with water, and supplied to one or more demulsification systems 200. Heavy oil sands may also be produced in a similar manner. One or more demulsification systems 200 may be used to demulsify a rag layer for recovery of additional crude oil that is not generally cost effective to recover.
An example system for recovery of crude oil from an oil reservoir is shown in
These may be modular plasma reactors 312 that can easily used in conjunction with one another to provide the desired configuration of a demulsifying system 310. The modular reactors 312 may be provided as relatively small, modular systems allowing easy transport and positioning in relation to a source of emulsion, and require low maintenance. Modular reactors 312 can be easily assembled to work either independently or work together within a particular or existing processing system as a step in handling the emulsion 303. The number of reactors 312 can be varied easily according to the production requirement. Each reactor 312 can be operated independently using its own flow control, pressure control, power supply control and the like, or a plurality of reactors can be operated together by a common control system. Alternatively, a reactor 312 may be particularly configured and designed to accommodate a particular flow rate or volume of emulsion based on a particular application for example. In this example, the demulsification system may be relatively easily implemented at the site of a waterflood operation for an oil reservoir 300. The crude oil emulsion is plasma treated with the at least one plasma reactor 312 in the demulsification system to form crude oil, water and solids constituents. The separated constituents are removed from the at least one plasma reactor system and supplied to a retention tank 314 if needed for a short retention time after processing. A continuous flow of the crude oil emulsion 303 may be supplied to the demulsification system 310 for processing, or batch processing may be used. After processing in the demulsification system, the separated crude oil 305 is supplied for sale, and the plasma enhanced treatment fluids 307, such as plasma enhanced treatment water and/or plasma enhanced treatment gas is supplied to at least one storage tank 316 for an injection well 304 in the waterflooding operation. If needed, make up water 318 may be supplied for waterflooding using the plasma enhanced treatment water from demulsification system 310. A plasma enhanced treatment gas from demulsification system 310 may be used in injection for gas flooding or pumped to another location for use, such as in further demulsification processes in demulsification system 310 or other demulsification system, a gas lifting operation or any other process. The plasma enhanced treatment fluids may allow enhanced recovery while requiring reduced injection pressure and pressure in the formation. Depending on the particular oil field, the ability to supply production from a plurality of wells to the demulsification system 310 through the distribution system 306 allows significant flexibility in designing the demulsification system 310 for a predetermined flow rate and volume for processing in a particular situation. The demulsification system can be optimized to enhance production of crude oil for a particular oil field. The use of one or more distribution systems 306, such as a distribution manifold to accommodate the predetermined or expected production of crude oil emulsion, allows flow control of the oil emulsion 303 to the at least one plasma reactor 312. The at least one reactor 312 may be used to treat an amount of emulsion and to recirculate the emulsion for additional treatment until a desired energy input and/or separation of constituents is achieved if desired. Alternatively or in addition, a plurality of reactors in parallel or in series may be provided to receive the flow of the crude oil emulsion 303 from the distribution system 306, and may be operated separately or as a unit. The ability to treat the production from a plurality of wells simultaneously may provide cost efficiencies. The provision of plasma enhanced treatment fluids back into the at least one injection well 302 should enhance oil recovery by the synthesized surfactants and demulsification molecules formed during plasma treatment of the emulsion. The demulsification system 310 and plasma reactor 312 also facilitate removing bacteria or other microbes and may have anti-microbial properties when reinjected into the oil reservoir 300 to help prevent souring of the reservoir.
The demulsification system 310 phase separates severe emulsions of crude oil and water, to minimize any rag layer, leading to additional revenue. The demulsification system 310 further allows the operator to continuously produce crude oil and sell it quickly for increased revenue with little or no retention time. The ability to integrate with waterflooding during enhanced oil recovery (EOR) provides significant advantages in relation to traditional methods of phase separation of heavy crude oils, oil sands or the like for example. The ability to transport and employ a demulsification system 310 at or close to the site of the source of emulsion allows for transportation and production efficiencies. The demulsification system 310 may also include a reactor 312 for processing rag layer specifically, in a primary or later demulsification process. Any rag layer remaining after processing can be separated for further demulsified for recovery of additional crude oil that has previously not been cost effective to recover.
Turning now to
While specific examples of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details are contemplated in the invention. These examples are thus meant to be illustrative only and not limiting as to the scope of the invention as set forth in the appended claims and any and all equivalents thereof.
