Patent Application
20250025845
With the growth of worldwide demand for oil and the decline of the discovery rate of new oil fields, it is important to improve the oil production efficiency of current fields. Further, many of the world's reservoirs trap about two-thirds of the oil in place, which cannot be recovered by conventional production methods.
To increase oil recovery efficiency, enhanced oil recovery (EOR) processes are implemented to increase the ability of the oil to flow to a well by injecting water, chemicals, or gases into the reservoir or by changing the physical properties of the oil. There are three primary techniques of EOR. These include gas injection (GI), thermal injection (TI), and chemical injection (CI). GI technique utilizes gases including hydrocarbons, nitrogen, and carbon dioxide gas. TI technique includes heating a reservoir by injecting a heated fluid through a wellbore. CI includes using long-chained molecules such as polymers to increase the effectiveness of waterfloods.
GI technique or the process of injecting gases including carbon dioxide into existing oil fields is a well-known EOR technique and is conventionally used worldwide. The introduction of carbon dioxide gas in an oil reservoir can increase the overall pressure of the oil reservoir and can force the oil towards production wells. Another common approach for oil production, in general, is waterflooding technique. Waterflooding technique uses water injection to increase the oil production from oil reservoirs. There is another technique that combines water flooding with gas injection-which includes injecting gas-containing water into an oil reservoir. The use of carbonated fluids such as carbonated water or carbonated brine is also common in EOR, where the carbonated fluid is injected into an oil reservoir to increase the overall pressure of the oil reservoir. With the increased pressure, the oil in the reservoir can move towards production wells.
This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
In one aspect, embodiments disclosed herein relate to a microfluidic system that includes a set of replaceable microfluidic cartridges and a cooling system. In the set of replaceable microfluidic cartridges, each microfluidic cartridge may include a mechanically rigid box and a set of parallel microfluidic capillaries positioned inside the mechanically rigid box. A gas stream may be configured to flow through the set of parallel microfluidic capillaries. An aqueous fluid stream may be configured to flow through a space between an inner surface of the mechanically rigid box and an outer surface of the set of parallel microfluidic capillaries. The cooling system may be in thermal contact with the mechanically rigid box.
In another aspect, embodiments disclosed herein relate to a method of generating gas bubbles in an aqueous fluid stream. The method may comprise several steps including providing a microfluidic system that comprises a set of replaceable microfluidic cartridges comprising a set of parallel microfluidic capillaries positioned inside a mechanically rigid box, and a cooling system. The method may include introducing a gas stream through the set of parallel microfluidic capillaries and introducing an aqueous fluid stream to flow through a space in between an inner surface of the mechanically rigid box and an outer surface of the set of parallel microfluidic capillaries. The method may also include generating gas bubbles through the set of parallel microfluidic capillaries in the aqueous fluid stream to produce a gas containing aqueous fluid stream and fully saturating the aqueous fluid stream with gas bubbles under a temperature ranging from 1 to 25° C. and a pressure of 1 to 120 atm. The method may include then recirculating the remaining undissolved gas through a dedicated contour tube and transferring the gas containing the aqueous fluid stream to an external storage unit.
Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.
This specification describes technologies relating to a multipurpose microfluidic device for oil and gas applications. An example use of the described microfluidic device is conducting rapid on-site core flooding experiments. The highly carbonated water generated utilizing the disclosed microfluidic device can be used for injecting into an existing well to experiment with enhanced oil recovery with core flooding techniques. The disclosed microfluidic device allows the user to control the temperature and pressure at which this carbonated water is generated. Therefore, the microfluidic device can be used to generate carbonated water having pre-set properties that are required for core-flood experiments. Experimentally, fluid flow in porous rocks is commonly investigated by core-flood experiments-which are widely used in petroleum engineering to investigate miscible and immiscible fluid displacement and to understand subsurface flow in order to maximize oil recovery. Furthermore, the microfluidic device can be used for any experimental work or any application in an oil and gas operation, wherever highly carbonated water is needed.
In one aspect, one or more embodiments disclosed herein relate to a microfluidic system that includes a set of replaceable microfluidic cartridges, and a cooling circuit that includes a heat exchange unit in which liquified carbon dioxide is a heat carrier. The microfluidic cartridge includes a mechanically rigid box that has connecting holes for supplying water and carbon dioxide and at least one capillary. The microfluidic cartridge contains a set of steel and/or polymer capillaries with holes on the surface and is covered from the inside with a hydrophobic gas-permeable membrane. The hydrophobic gas-permeable membrane could be a track-etched membrane, that allows for precise control of the size distribution of the gas bubbles.
In another aspect, one or more embodiments disclosed herein relate to a method that includes assembling a microfluidic system, flowing a stream of gaseous carbon dioxide through the capillaries, and flowing a laminar flow of water in the outer space around the capillaries. Water can pass through the volume of the box and can be saturated with carbon dioxide gas supplied through the capillaries. The remaining undissolved carbon dioxide gas can be recirculated through a dedicated contour tube. Water/brine passing through a cascade of several cartridges may become completely saturated with the gas material/carbon dioxide and enter the storage tank in which the pre-set temperature and pressure are maintained. Carbon dioxide remaining after passing through the cascade of cartridges may re-enter the capillaries.
As used herein, the term “microfluidic technologies” refers to technologies that are used for studying fluid behavior flowing through micro-channels, and the technologies of manufacturing microminiaturized devices containing chambers and tunnels through which a fluid flows or confines.
A microfluidic system in accordance with one or more embodiments disclosed herein demonstrates the capability of creating and controlling monodisperse bubbles. Microfluidic capillaries with micrometer-sized inner diameters may be employed as micro channels for controlling microfluidic flow. The size of bubbles may be precisely controlled by tuning the frequency of breakup of the gaseous thread introduced in the microfluidic device. The ability to control the level of carbonation and size of the bubbles in the water/brine provides tunable carbonated solutions that may be used for a variety of fundamental studies in oil and gas applications.
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In one or more embodiments, the mechanically rigid box 202 is made of stainless alloy steel. The mechanically rigid box 202 may have a length ranging from 100 millimeters (mm) to 1 meter (m). The mechanically rigid box 202 may have a width ranging from 100 mm to 1 meter. For example, the mechanically rigid box 202 may have a length or a width in a range from a lower limit of any of 100, 200, 300, 400, 500, 600, 700, 800, and 900 mm to an upper limit of any of 200, 300, 400, 500, 600, 700, 800, 900, and 1000 mm where any lower limit can be used in combination with any mathematically-compatible upper limit. The mechanically rigid box 202 may have a height ranging from 1 mm to 500 mm. For example, the mechanically rigid box 202 may have a length in a range from a lower limit of any of 1, 5, 10, 20, 30, 40, 50, 100, 150, 200, 250, 300, 350, 400, and 450 mm to an upper limit of any of 5, 10, 20, 30, 40, 50, 100, 150, 200, 250, 300, 350, 400, and 500 mm where any lower limit can be used in combination with any mathematically-compatible upper limit. The mechanically rigid box may be capable of withstanding pressure ranging from 1 atm to 120 atm. For example, the mechanically rigid box may be capable of withstanding pressure in a range from a lower limit of any of 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, and 110 atm to an upper limit of any of 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, and 120 atm.
In one or more embodiments, the system is used for generating precisely controlled sizes of gas bubbles. The sizes of bubbles may be in the range of 1×10−9 and 5000×10−9 meters (m). For example, the sizes of gas bubbles in the aqueous fluid may be in a range from a lower limit of any of 1×10−9, 5×10−9, 10×10−9, 100×10−9, 500×10−9, 1000×10−9, 2000×10−9, 3000×10−9, and 4000×10−9 m, to an upper limit of any of 5×10−9, 10×10−9, 100×10−9, 500×10−9, 1000×10−9, 2000×10−9, 3000×10−9, 4000×10−9 and 5000×10−9 m, where any lower limit can be used in combination with any mathematically-compatible upper limit. The gas bubbles may include nano-bubbles having an average diameter of 1×10−9 to 10×10−9 m under a pressure in a range from 1 to 120 atm. For example, the sizes of gas bubbles in the aqueous fluid may be in a range from 1×10−9 to 10×10−9 m under a pressure in a range from a lower limit of any of 1, 2, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, and 115 atm to an upper limit of any of 2, 5, 10, 15, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, and 120 atm where any lower limit can be used in combination with any mathematically-compatible upper limit.
In one or more embodiments, the microfluidic system is used to produce highly carbonated water or highly carbonated brine. The microfluidic system may be used for producing water or brine saturated with precisely controlled sizes of gas bubbles that may be distributed and soluble in the water or brine. The gaseous bubbles in the water or brine may be primarily carbon dioxide gas bubbles.
In one or more embodiments, the water or brine entering a cartridge does not contain any gas. In one or more alternate embodiments, the water or brine entering a cartridge contains dissolved gas or a mixture of gases. The water or brine exiting a cartridge may be partially saturated with a gas flowing through the capillaries. The water or brine exiting a cartridge may be fully saturated with a gas flowing through the capillaries Water or brine passing through a cascade of several cartridges may be in thermal contact with a plurality of cooling systems.
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In one or more embodiments, the cooling system maintains the temperature of the gas flowing through the capillaries and water flowing through the channels at the same level. A cascade of cooling systems in thermal contact with a cascade of cartridges may be connected with each other via connectors and pipelines. The cooling system may exchange thermal energy with an aqueous fluid inside a cartridge via indirect contact. In one or more embodiments, the heat exchanger unit of the cooling system may be a coil heat exchanger. The cooling fluid may flow through the coil and exchange heat with its surrounding system.
In one or more embodiments, the cascade of cartridges has a temperature gradient from top to bottom or bottom to top. The cooling fluid may flow from a lower temperature to a higher temperature zone or vice versa.
In one or more embodiments, liquified carbon dioxide is used as a cooling fluid in the heat exchange unit for maintaining the temperature. The cooling fluid may be used to maintain the temperature of the system in the desired range. A supercritical fluid may be used as a cooling fluid. As used herein, the term “supercritical fluid” may refer to any substance at a temperature and pressure above its critical point, where distinct liquid and gas phases do not exist, but below the pressure required to compress it into a solid. A fluid may transition into the supercritical state when the fluid is heated and compressed beyond its critical point. In some embodiments, carbon dioxide may be used as a supercritical fluid coolant. For example, supercritical carbon dioxide fluid may be generated when the temperature is above 31° C. and the fluid pressure is equal to or greater than 1071 pounds per square inch area (PSIA). Non-limiting examples of other supercritical fluids as coolants may include water, methane, ethane, propane, ethylene, propylene, methanol, ethanol, acetone, and nitrous oxide.
The cooling fluid may recycle periodically from the topmost cartridge to the bottom-most cartridge of the microfluidic system having a cascade of cartridges. The recycling cooling fluid may pass through all intermediate cartridges between the topmost and bottom-most cartridges in the cascade of cartridges in the microfluidic system. The cooling fluid may recycle periodically from the bottom-most cartridge to the topmost cartridge of the microfluidic system having a cascade of cartridges. The recycling cooling fluid may pass through all intermediate cartridges between the topmost and bottom-most cartridges in the cascade of cartridges in the microfluidic system.
The present microfluidic system may include various controllers that are configured to control the temperature and pressure of the fluid passing through the system. Temperature controllers may be installed on a cartridge to monitor and control the temperature of the fluid within the cartridge. Pressure controllers may be installed at the gaseous mainline inlet 13 to monitor and control the pressure of the carbon dioxide being supplied into the microfluidic system 100. Temperature controllers and pressure controllers may also be installed at the water supply line 2 to monitor and control the temperature of the water being supplied into the microfluidic system 100. In one or more embodiments, piezoelectric sensors may be used to monitor the pressure.
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Both temperature and pressure can impact the carbonation of an aqueous fluid in the microfluidic system in accordance with one or more embodiments. When a gas is diffused through a hydrophobic membrane, the pressure difference between the gas bubbles and the aqueous fluid may be negligible, and therefore, the gaseous bubbles may be very small, such as on the order of microns in the diameter. As such, the bubbles may not create any visible bubbling in the aqueous fluid. The gaseous microbubbles may dissolve in the aqueous fluid, and therefore, the aqueous fluid may accumulate gas until saturation. The aqueous fluid is fully saturated with the gas at an equal overall pressure between the gaseous microbubbles and the aqueous fluid. By increasing the partial pressure of the gas being diffused through the hydrophobic membrane, greater carbonation of the aqueous fluid may be achieved. As used herein, “fully saturated fluid” refers to a fluid that contains the maximum amount of the specific gas that can be dissolved under the condition under which the fluid exists.
An example diagram of the solubility of carbon dioxide in water versus temperature is shown in
In one or more embodiments, the size of the bubbles generated by the microfluidic system depends on the pressure of the aqueous fluid. For a non-limiting example, the size of the bubbles generated by the microfluidic system under 1 atm pressure is larger than the size of the bubbles generated by the microfluidic system under 10 atm pressure considering the other parameters remain the same.
In one or more embodiments, increased carbonation of the aqueous fluid is facilitated by lowering the temperature of the microfluidic system. The solubility of certain gases, such as carbon dioxide gas in water increases with the lowering temperature of the water. The size of the bubbles generated by the microfluidic system may depend on the temperature of the aqueous fluid. For a non-limiting example, the size of the bubbles generated by the microfluidic system at a temperature of 25° C. is larger than the size of the bubbles generated by the microfluidic system at a temperature of 1° C. considering the other parameters remain the same.
In one or more embodiments, the solubility of a gas in an aqueous fluid may depend on the chemistry and physical parameters of the aqueous fluid. For a non-limiting example, the solubility of carbon dioxide gas in a brine solution may be less than the solubility of carbon dioxide gas in water under the same conditions. The solubility of carbon dioxide gas in the brine solution may be dependent on the total dissolved solids in the brine.
In one or more embodiments, pure water with zero total dissolved solids (TDS) may be used as the aqueous fluid. In other embodiments, brine may be used as the aqueous fluid. The brine may comprise dissolved salts such as sodium, potassium, calcium, and magnesium-based salts, and any combinations thereof. The salts may have anions selected from the group consisting of chlorides, sulfates, carbonates, and iodides. The total dissolved solids (TDS) of the brine may be between 0.1 to 500,000 ppm. For example, the total dissolved solids (TDS) of the brine may be in a range from a lower limit of any of 0.1, 1, 10, 50, 100, 500, 1000, 5000, 10000, 50000, 100000, 200000, 300000, and 400000 ppm to an upper limit of any of 10, 50, 100, 500, 1000, 5000, 10000, 50000, 100000, 200000, 300000, 400000 and 500000 ppm, where any lower limit can be used in combination with any mathematically-compatible upper limit.
In one or more embodiments, the aqueous fluid flowing through the space in between the inner surface of the mechanically rigid box and the outer surface of the set of microfluidic capillaries is laminar. The water may flow through the space in a similar or opposite direction to the gas flowing in capillaries. As used herein, “laminar flow” is defined as a fluid that flows in parallel layers, with minimal disruption between the layers. The fluid flows through paths in layers, with each layer moving smoothly past the adjacent layers with little or no mixing. At low velocities, in laminar flow, fluid tends to flow without lateral mixing. In one or more embodiments, the aqueous fluid flowing through the space in between the inner surface of the mechanically rigid box and the outer surface of the set of microfluidic capillaries is turbulent.
In one or more embodiments, water or brine, passing through a cascade of several cartridges, is completely saturated with a gas such as carbon dioxide using the microfluidic system disclosed herein. Once the water or brine is saturated, it may be transferred to a storage tank which may have a maintained pre-set temperature and pressure.
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In one or more embodiments, a manufacturing process to make track-etched membranes includes exposing a thin polymer film to charged particles in a nuclear reactor in a controlled manner. The charged particles may pass through the film, leaving behind sensitized tracks. The density of these tracks in the film may depend on the amount of time that the film may be exposed to the reactor. The energetic ions may create changes in a material along their trajectory when they travel through the material. These changes, including structural, chemical, and both may alter the material properties. The energetic ions may deposit energy in a material, and they may also cause radiation damage. The etchant (an acid or a corrosive chemical) may break down the polymer material starting at the weakest points of the polymer material, such as the tracks. The etchant may widen the tracks into full-fledged pores, therefore, the size of which may be controlled by carefully monitoring the exposure time, concentration, and temperature of the etchant. During chemical etching, the damaged zone of a latent track may be removed and transformed into a hollow channel.
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In one or more embodiments, the remaining undissolved gas is recirculated through a contour tube, where the undissolved gas may re-enter the microfluidic system at a lower temperature after passing through the tube. The temperature of the gas passing through the contour recycling tube may be maintained at the same level as the temperature of the fluid in the cartridge, ranging from 1 to 25 degrees Celsius (° C.).
In one or more embodiments, a certain pressure range is required for saturating water with carbon dioxide gas. The pressure range may assist the kinetics of the saturation process. The cooling system may maintain the temperature of the carbon dioxide-containing water at a given range where the carbon dioxide concentration may reach the highest values, therefore the water may become fully saturated with carbon dioxide.
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In one or more embodiments, microfusion of half parts, side end walls, and upper and lower cover plates may include using polymers as the main material of the cartridges.
Embodiments of the present disclosure may provide at least one of the following advantages. The disclosed microfluidic system uses capillaries with high-surface areas that allow for quick saturation of the water with carbon dioxide gas compared with conventional methods. The disclosed microfluidic system utilizes a method that can precisely control the gas bubble sizes, and their distribution in water under a certain range of pressure and temperature to efficiently achieve maximum carbon dioxide saturation in water. Usage of the cooling circuit allows for maintaining temperature all throughout the system. The generated, highly carbonated water could be used for core flooding experiments for the purpose of increasing oil recovery. Moreover, the disclosed system allows the user to control the temperature and pressure at which this carbonated water is generated.
According to the limitation of microfabrication technologies, generating microbubbles on a large scale using automatic equipment for industrial applications is still a challenge for common chip-based microfluidic platforms. Scaling up the process may be achieved by increasing the number of cartridge units in the assembly. Highly carbonated water may be intended to be applied in laboratory testing for core plugging experiments to analyze the efficiency of the enhanced oil recovery.
Another advantage of the disclosed system is that it can be useful for greenhouse effect reduction. For example, gases and volatile liquids that are widely known for their greenhouse effect may be utilized as a cooling fluid for the disclosed system. Therefore, the disclosed system may use carbon dioxide and other greenhouse gases for generating highly carbonated or other greenhouse gas saturated liquid, and thus, reducing the amount of greenhouse gases in the atmosphere. The disclosed system may be useful in developing decarbonization processes.
Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112 (f) for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/RU2022/000303 | 10/3/2022 | WO |
