METHOD AND SYSTEM FOR SOLID PARTICLE REMOVAL

Abstract

Disclosed is a system and method to separate solid particle components from a fluid. It can be used in close association with a hydrocarbon producing well and uses a novel combination of mechanical filtration, solids decantation, and real and apparent forces. Disclosed is a spherical vessel with a tangential inlet to introduce the fluid and a fluid exhaust and filter arranged on the center line of the interior of the vessel. A combination of pressurized fluid and solid particles enter at the tangential inlet and move primarily in a circular path around the interior of the vessel. The circular path results in the larger mass particles settling at the vessels lower region. Less massive particles may be entrained in the exiting fluid flow toward a filter element where they are removed from the exiting fluid. The vessel has an opening to remove the trapped separated particles.

Claims

1. A method for separating solid particles from a moving fluid comprising: entering solid particles entrained in a moving fluid into an interior volume of a vessel through an inlet port aligned tangential to an internal surface of the interior volume thereby: causing at least some of the solid particles to follow an uninterrupted trajectory that spirals downward along the internal surface from the inlet port to a drain port located below the inlet port; and causing at least some of the moving fluid to follow an uninterrupted trajectory from the inlet port up to an outlet opening defined by an outlet port located above the inlet port; allowing the moving fluid to flow out of the interior volume through the outlet opening; and removing the at least some of the solid particles through the drain port.

2. The method of claim 1 wherein a substantially horizontal cross-section of the internal surface is round.

3. The method of claim 2 wherein the internal surface extends continuously and uninterrupted from the inlet port to the drain port and from the inlet port to the outlet opening.

4. The method of claim 3 wherein the round horizontal cross-section and the uninterrupted extension of the internal surface and the tangential alignment of the inlet port causes the at least some of the solid particles to follow the uninterrupted trajectory that spirals downward along the internal surface from the inlet port to the drain port.

5. The method of claim 3 wherein the uninterrupted extension of the internal surface causes the at least some of the moving fluid to follow the uninterrupted trajectory from the inlet port to the outlet opening.

6. The method of claim 1 further comprising filtering the moving fluid as the moving fluid flows out of the interior volume through the outlet opening.

7. The method of claim 1 wherein the inlet port is positioned above a horizontal midplane of the vessel.

8. The method of claim 7 wherein the inlet port is closer to the horizontal midplane of the at least one vessel than to the outlet port.

9. The method of claim 1 wherein the inlet port is fluidly coupled to an inlet tube and the inlet tube is tangential to the internal surface.

10. The method of claim 9 wherein the inlet tube is substantially horizontal.

11. The method of claim 1 wherein the horizontal cross-section of the internal surface is substantially circular.

12. The method of claim 1 wherein the horizontal cross-section of the internal surface is substantially ellipsoidal.

13. The method of claim 1 wherein the horizontal cross-section of the internal surface is substantially oval.

14. The method of claim 1 wherein a horizontal diameter of the interior volume is greater at a horizontal midplane of the interior volume than near the drain port and the outlet port.

15. The method of claim 1 wherein a horizontal diameter of the interior volume is greater at a horizontal midplane of the interior volume than at a height of the inlet port.

16. The method of claim 1 wherein a horizontal diameter of the interior volume is greatest at a horizontal midplane of the interior volume.

17. The method of claim 1 wherein a horizontal diameter of the interior volume is variable along a height of the interior volume and diameter transitions of the interior volume are smooth.

18. The method of claim 1 comprising: opening a first valve fluidly connected to the drain port to allow the solid particles to flow through the drain port into a drain pipe while a second valve fluidly connected to the drain pipe is closed thereby blocking the solid particles from flowing downward out of the drain pipe; and subsequently closing the first valve to prevent the solid particles from flowing through the drain port into the drain pipe and opening the second valve fluidly connected to the drain pipe to thereby allow the solid particles to flow downward out of the drain pipe.

19. The method of claim 1 wherein the drain port defines a drain opening and the drain opening is flush with the internal surface.

20. The method of claim 1 wherein the outlet opening is flush with the internal surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The novel features believed characteristic of the present invention may be set forth in appended claims. The invention itself, however, as well as a preferred mode of use and further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:

[0034] FIG. 1 shows in schematic the invention with a single sphere.

[0035] FIG. 2 shows in schematic the invention with two separators, operated in parallel, attached to a single wellhead and a plurality of valves.

[0036] FIG. 3 shows a side view of the separator with the inlet both above the center plane and tangential to the vessel interior.

[0037] FIG. 4 is an additional view of the entrance port showing its tangential entry and the location above the mid-plane of the separator including input flange with through holes and central opening port.

[0038] FIG. 5 is a top-down cross section view of the separator with the port shown to enter substantially tangentially to the interior region.

[0039] FIG. 6 is a is a schematic of a particle path internal to the separator.

[0040] FIG. 7 shows a bevel or chamfer to facilitate joining portions of the sphere together using butt welding.

[0041] FIG. 8 shows an idealized plot of angular momentum versus the radial distance from the chamber center.

[0042] FIG. 9 shows a detail of the filtration unit.

[0043] FIG. 10 is a detail of cross section of separator including location of recovered sand.

[0044] FIG. 11 shows detail of the filtration unit.

[0045] FIG. 12 is a schematic of potential real and apparent forces on a sample particle including gravitational, centrifugal and Coriolis.

[0046] FIG. 13 shows the separator, two external filters and a plurality of valves.

DESCRIPTION OF A PREFERRED EMBODIMENT

[0047] While the invention has been particularly shown and described with reference to preferred and alternate embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.

[0048] The apparatus of this invention is designed to separate particle solid components from high pressure, high velocity fluid streams. As used herein, fluid and fluids shall be understood to be the non-solid portion of the material entering a separator and can be comprised of liquids and flowback fluid like water, brine, solvents, surfactants and hydrocarbons and can be exiting gases like naturally occurring natural gas, or an added gas added to the well either in liquid phase or gas phase such as a fracking or flowback additive or aid or other material, and all such variations are contemplated to be found within the invention's operating specifications. As used herein, solid particle components shall be understood to be solid phase materials and aggregates that are entrained by the movement of the fluid entering the separator. Said fluid is comprised of water, chemicals, gases and solids. The device is designed to handle the high flow, high velocity and high-pressure fluid and solid streams while maintaining effectiveness at separation of solid particles. During continued operation, the composition of the fluid entering the separator may change from a fluid comprised of predominately liquid based constituents with minimal gas components to subsequently a fluid stream comprised of a predominately gas fluid with lower quantities of liquid entrained in the fluid transport.

[0049] Under high pressure or high fluid flow or both, solid particles components are entrained in the fluid flow, and travel substantially with the flow of the high pressure and high velocity fluid. The particles may have an overall velocity that is less than or greater than the average fluid flow velocity. This untreated and un-separated flow of fluid and solids can cause substantial damage and erosion on interior surfaces of equipment. One having ordinary skill will recognize that the majority of the entrained solids are fracking proppant and naturally occurring formation particles and all such variations of particle composition are contemplated to be found within the present inventions operating environment. The invention can work with all pressures conventionally encountered at wells but if future well pressures are found to be greater, the invention will be expected to work at greater pressures. In addition, the device can be expected to work at lower pressures as well. There is a general relation between incoming pressure and vessel size.

[0050] This invention comprises a vessel having an internal generally spherical region or cavity that will allow a high pressure and high velocity fluid and solid particle stream to enter said interior cavity. In an embodiment, the vessel is known as a separator. Unlike other solid particle separators, this device does not use any baffles or deflection plates or other additional means to reduce fluid and particle velocity. This separator uses natural fluid flow and the principles associated with angular momentum and other real and apparent forces to separate particles from a fluid stream.

[0051] Referring to FIGS. 1-12, the present invention comprises a solid particle component removing device that separates solid material from a fluid stream, herein called a separator, installed in proximity to and downstream to a wellhead and upstream from other support equipment such as a choke valve manifold, or other in-line equipment. The solid particle component separator causes solid particles and particle aggregates from a fluid stream including a high-pressure high-velocity fluid stream to migrate to substantially lower regions in the separator device. Particles with a mass greater than a threshold amount are collected in the bottom of the device and said collected particles can be removed or extracted by means of a removal port, valve, device or schema generally on the bottom of the device. Any particles that remain entrained in the fluid flow may be separated by means of a mechanical filter external to the body of the separator.

[0052] Valves throughout this invention are generally included in pairs to facilitate the efficient isolation of sections of the device to change filter elements, change separator devices, to remove sand and other particles and to facilitate the aforementioned changes and others without causing the well to be closed or shut-in or for high-pressure fluid or solids to exit the system in an uncontrolled fashion however in no way should they be inferred to be a limitation on invention and are simply included as one non-limiting embodiment.

[0053] FIG. 1. shows the separator device 10 including inlet port flange or connection surface 11, the inlet tube or pipe 12, with penetration into sphere 13. In addition, solids removal or outlet tube and port flange 14 and fluid exit flange 15.

[0054] Predominately following a wellhead and associated hardware, the solid particle component separator removes a large mass range of solids including those removed by means of mechanical and apparent forces, higher angular momentum and gravity, and those lighter solids removed by mechanical filtration.

[0055] FIG. 2 shows, schematically, multiple separators used in parallel and a plurality of connection and isolation valves. Two separators are indicated but one skilled in the art will recognize that any number of separators can be used. Incoming fluid and solids are introduced through inlet 20 and through manifold 21, allowing multiple separators to be used. Separators can be isolated by valves 22 and 22′, 23 and 23′ and also 24 and 24′, all of which can shut off the incoming or exiting materials to facilitate servicing, adjustment or replacement and further can isolate said separator allowing service or use of and alternate separator. Port 13 is substantially at or above the mid-plane 25. One will also recognize that any effective number of separators can be arranged in series, in parallel or a combination of series and parallel, and that the specific number in use is not a limitation as well as the valves, fittings and flanges are simply one embodiment and should not be construed as limiting

[0056] Prior to fluid entering said separator, there can be a plurality of valves, manifolds and associated equipment conventionally found at wellheads including schematically shown manifold 21, valves 22, exit valves 23 and exit manifold 25. The inclusion or omission of any associated equipment other than the invention herein should be recognized by one of ordinary skill in the art to not change the invention or use. Valve 22 serves to route or control flow of fluid to separator. One having ordinary skill in the art will recognize that valves 22 and 22′ are representative in nature and there are conventionally additional wellhead equipment between the wellhead and the separator and the valves 22 and 22′ is not intended to represent a complete installation but merely to illustrate that the separator can be isolated as required.

[0057] Solids can be removed by opening valves 24 and 24′, most often when valves 22 and 22′ and 23 and 23′ are closed to allow the removal of solids with no associated high well pressure. In addition, FIG. 2 shows upper filter isolation valves 27 and 27′, external filter 28 and lower filter isolation valves 29 and 29′. The inclusion of an external filter is one embodiment and should not be construed as limiting, as the invention can be used with or without a filter and the filter, if used can be internal or external.

[0058] FIG. 3 shows inlet port flange 11 which allows the connection of a source of fluid and solids into the interior of the separator via the inlet tube 12 and penetrating into interior of separator through inlet tube hole 13. Solid material that has been separated can be removed through separator sphere opening 32 and continuing through bolt surface 33. Separator sphere 34 has both an interior surface 35 and exterior surface 36. Separator has a mid-plane 37, of which the inlet port components 11, 12 and 13 are at or substantially above. Upper bolt surface 38 is a surface to mount additional manifolds and other apparatus through which the pressurized fluid may exit the device. The specific mounting schema may comprise a machined mounting surface and bolt holes, a tube and flange system or other connection methods and should not be construed as a limitation.

[0059] In addition, said separator comprises a high pressure, high fluid volume vessel. Said separator comprises an outer surface 36 and an inner surface 35 that can be spherical, nearly spherical, elliptical, oval or other geometries where the region near or about the midplane is of greater diameter than those areas closer to the upper and lower port penetrations. One skilled in the art will recognize that the surface geometry does not materially affect the separator function. Required penetrations comprise an inlet port system 11, 12 and 13 to introduce high pressure high volume fluid and solid particle components into the separator, a fluid exit bolt surface 38 and fluid exit penetration 39 as well as a collected particle extraction port 32 and mounting surface 33. Other penetrations could include but are not limited to pressure sensing ports, fluid velocity sensing ports, and particle level detection ports, none of which are material to the operation of the separator.

[0060] Separator vessel 34 is constructed of such materials and by such processes that will provide suitable structural integrity to withstand the range of pressures expected, as well as in excess of those pressures at a wellhead, without requiring systems or equipment to reduce incoming pressure such as chokes and other means, which are frequently encountered on other types of separators and significantly limit their use and said pressure restriction can damage a well. Separator input system 11, 12 and 13 are substantially tubular and substantially horizontal with respect to the midplane of the separator. The separator input is more or less tangential to the interior of the sphere. Separator input is substantially arranged at or above the midplane 37 of the separator. The input tubular structure 12 extends from the body of the separator 34 to a distance that will allow convenient connection to associated well hardware. The input 11 is of a sufficient diameter to allow sufficient flow and material velocity within the separator to achieve separation. Tube 12 inside diameters can range from a fraction of an inch to several inches with an inside diameter of 2 inches being a common size.

[0061] Solids removal penetration 32 at the lower section of the separator allows solid particle components removal and disposal after a suitable quantity has been collected. Said solids collected may be comprised of dry particles or may be comprised of solids and liquids, a slurry or other collected materials prior to extraction. Collected solid material refers to those particles that have come substantially to rest in the lower portion of the separator and are not in substantial motion, though to one skilled in the art it will be clear that some degree of solids motion is possible and does not change the operation of the device. Alternately the lower portion of the vessel can comprise a schema for the continuous or semi-continuous removal of solids from the separator. To one skilled in the art, it will be apparent that the invention remains substantially unchanged in either embodiment and is not a limitation.

[0062] One preferred embodiment has dimensions as follows but one skilled in the art will recognize the dimensions can be changed with no adverse change in the functionality of the separator. In addition, one representative embodiment is described but should not be a limiting factor as other dimensions will be equally effective. The inlet port 11 from FIG. 3 is approximately 3 inches above the horizontal midplane. The exterior radius is substantially 23 inches and the internal radius is approximately 20 inches. The initial surface of the fluid inlet is 26 inches from the centerline. The separator is approximately 50 inches tall from surface 33 to surface 38 on the central vertical axis, including built up areas for fittings. The central bore of the inlet tube is about 19 inches from the midplane. The upper fixturing surface built up region is approximately 14 inches in diameter and the lower fixturing built up region is approximately 8 inches diameter.

[0063] The separator has materials and joining techniques suitable to withstand pressures encountered at wellheads. Nominal wall thickness is approximately 3 inches but this is not a limitation and the separator can be constructed with wall thickness to correspond to specific pressures encountered at point of use. The wall thickness will need to be in a range that can be sourced, manufactured and fabricated. The well pressure will range from what is commonly known as shut-in pressure as the highest to zero and can range from lower than 500 psi to more than 20,000 psi. The vessel wall thickness, joining specifications, fixturing and fitting will be sized to accommodate specific pressures and one skilled in the art will recognize that changes to accommodate pressure does not change the operation of the separator or the invention and that different use locations will correspond to different working pressures.

[0064] FIG. 4 provides an additional illustration of the exterior of separator vessel drawing attention to the tangentially arranged inlet system, that is comprised of connection surface 40, with connection points 42 through inlet tube interior 41, that is arranged substantially above the mid-plane 37 of the separator. This is only one embodiment of a large number of connection schema and should not be considered a limitation. The location and arrangement of the fluid inlet offset is determined by the separator dimensions, fluid characteristics, pressures and viscosities of a given well, and is not a limitation. Fluid and solid particle components are delivered to the separator vessel by apparatus, tubing and equipment conventionally used from a wellhead. Said separator can be supported directly on the valves, manifolds and fixtures below the separator or can be supported by a stand, by legs structurally attached to the separator or by chains or cables that support the separator or by other support means. The method of support does not change the function of the separator as one skilled in the art will recognize. The separator can be on a mobile skid, or other system designed to be transported from site to site as well as mounted in a mobile environment as a trailer or truck and one skilled in the art will recognize this is not a limitation on the function of the invention. One having ordinary skill in the art will understand that the fixturing and mounting does not change or augment the essentials of operation. Fluid is directed essentially from the wellhead to the separator. Manifolds, tubular structures and valves as well as other systems encountered at the well site may also be in-line or in conjunction with the separator, and one skilled in the art will understand those components will not change the operation of the separator. Solid particles are removed through port 33 at the lower portion of the vessel. During operation, the extraction area is sealed to allow the separator to operate at conventional operating pressures encountered at the wellhead.

[0065] Particles collected can be removed by opening to allow extraction of the solids when pressure is isolated from the sphere by valve 22 and through port 32. The upper region of the sphere comprises a fixturing system and mounting surface 38 to maintain and support the filter system and the fluid exit port 39. After the fluid and solid particles have entered the separator through port 11 and have been acted on by the separator the solid materials are predominately stationary in the lower region awaiting collection and removal through opening 32. Lighter particles that remain entrained in the fluid are removed by the filter element that can be located either internal to the sphere or external. The filter element is arranged to be removed for cleaning, servicing and replacement. The vessel fittings and fixtures for use in conjunction with the filter comprises a threaded opening that allows for installation and removal using threads or clamps or bolts or other fixturing schema. It will be recognized by one skilled in the art that the specific means for attaching a filter is not material to separator performance and a wide range of fixturing systems can be used with no change in the inventive concept.

[0066] FIG. 5 shows a top down view cross section of the vessel more or less above the midplane, highlighting the tangential inlet port flange 30, inlet tube 31 and separator penetration 13, that is arranged primarily above the horizontal mid-plane. A solid particle component that enters the separator will contact the internal surface of the separator, for example, in or around region 50. Said particle will move generally in path 51.

[0067] FIG. 6 shows a generalized section of the separator. Particle 60 moves both around the sphere and generally will be move to larger sphere radius during said transit. Because particle 60 is introduced generally above the midplane, the particle will move to regions of larger internal diameter. Particle 60 will travel through direction 61, in contact with vessel interior surface 35, as said particle moves at first to larger vessel diameters by means of traveling along expanding wall diameter 62, until particle is substantially at a midplane, said midplane is the region of maximum vessel diameter. As particle 60 moves to regions of larger diameter, the momentum of said particle will decrease and additional forces including but not necessarily limited to gravity will contribute to said particle moving to substantially lower regions of separator. As particle moves to lower regions of separator, progressively less energy from moving fluid is imparted to particle. Eventually a preponderance of particles will become more or less stationary and collected at the lower region of separator.

[0068] FIG. 7 schematically shows two halves of the sphere with a welding bevel 70 arranged substantially at the midplane of the separator comprised of one side from upper chamber half 71 and one half of the welding bevel from lower chamber portion 72. For manufacturing, the vessel is comprised of two or more sections that are welded or bolted or otherwise joined to provide an essentially featureless vessel interior. While FIG. 7 schematically indicated two halves7l and 72, and a welding bevel 70, one skilled in the art will recognize that more than two pieces can be assembled to create a separator vessel and that methods other than welding can suitably join the sub-systems including but not limited to bolting, threading, friction fitting, press fitting, riveting, or other methods of suitable joinery. In addition, fabrication methods may include construction from a substantially single piece of material. Method of fabrication is not a limitation and one skilled in the art will recognize that the invention is independent of method of construction and fabrication.

[0069] FIG. 8 shows a velocity profile where there is a region of low angular velocity A for fluid and particles close to the center of the chamber, a region B of greater angular velocity as the particles are less close to the center of the separator, a region of decreasing angular velocity C and a region of the greatest angular velocity D.

[0070] In general, the greater the radial location of a solid particle the greater the angular velocity and the greater the angular momentum of each solid particle. Small scale deviations to this general notion does not change the operation of the separator and one skilled in the art will recognize these variations do not change the operation of the separator and are not a limitation. The angular velocity will be determined by the inside diameter of the sphere, the pressure differential between inlet pressure and vessel pressure, the velocity of the entering fluid and solid particle components, and the viscosity of the mixture of fluid and particles. Perturbations to parameters comprising the said diameter, inlet pressure, fluid velocity, and pressure differential will be apparent to one skilled in the art to not be a limitation and to not change the inventive concept. The angular velocity will in general cause all parts of the fluid and particles to be subjected to forces including a centrifugal force that will generally cause a migration to the larger radius trajectory closer to the wall of the interior sphere. In addition, because the inlet is above the horizontal mid plane, particle solids will move lower in the chamber due to gravity and because of other apparent and real forces. As the particles drop due to gravitational effects, the inside of the sphere diameter will increase due to the inlet being above the mid-plane and the fluid velocity will decrease and this in turn will increase the likelihood of a particle settling at the bottom of the chamber. Particles that are not substantially entrained by the fluid will migrate to the lower region of the sphere and will collect. Less massive particles will remain entrained by the fluid flow and those that are not separated by the action of other forces including gravity and centrifugal force, can be mechanically separated by a mechanical filter.

[0071] In addition, FIG. 8 also shows the angular velocity is lower for small radii and greater for large radii. The lower angular velocity is found toward the middle of the chamber.

[0072] FIG. 9 shows one embodiment of a mechanical filter element. Detail of said filter include connecting threads 90, exterior screen 91, end tube plate 92 and internal frame 93.

[0073] FIG. 10 shows the interior of the vessel 100 as being comprised of an essentially continuous, essentially spherical and essentially uninterrupted interior surface. FIG. 10 also indicates the fluid entrance aperture 101 on the separator interior surface. Said interior surface comprises a regular surface and openings for functionality. Openings include but are not limited to a fluid entrance, a material removal system aperture 102 and an exiting fluid penetration 103 to allow the material to exit the separator. There may be other penetrations including but not limited to pressure sensors, fluid velocity sensors, additional inlets, additional solids removal ports and additional filter fixtures. One skilled in the art will recognize that additional port openings will not substantially affect the separator function. FIG. 10 also shows a schematic of collected solid particle components 104 substantially at the bottom of the separator. The figure also shows the exterior surface 105 that may be spherical but may be other geometries as well. The figure also shows a possible particle path of motion 106 indicating among other motions a path to the lower portion of the separator. Various coupling and connection methods 107 may be used but is not a limitation to the function of this invention. The exit for fluid 108 is essentially at the top of the device and may be parallel to the midplane to allow for connection to subsequent apparatus.

[0074] FIG. 11 shows detail of the filtration unit 112 including a filter element 110 and particles 113.

[0075] FIG. 12 shows a representative particle 60 proximate to interior surface 34 with representative actual and apparent forces indicated comprised of gravity, the Coriolis force, centrifugal, and centripetal forces. During operation, high pressure fluid and solid particles components enter the separator interior tangentially and substantially above the horizontal midplane and begin a generally circular and essentially discotic path in the separator interior, caused by the essentially spherical shape of the separator interior. A particle 60 will follow a trajectory 61, influenced by the interior surface 34 of the separator and the previously named forces. This more or less discotic trajectory is substantially parallel to the device midplane, and more or less parallel to the earths local surface. The rotational motion of said particle causes angular momentum as represented in FIG. 8 to be imparted to the particles and fluid. Forces comprised of gravitational force and apparent forces centrifugal and Coriolis are indicated schematically, in order to represent some of the potential actions on the solid particle component. In this case, a particle has mass m, and the weight is the product of mass and gravitational constant g. In this schematic illustration, F.sub.g is the force due to gravity and is commonly the negative product of mass and gravitational constant or −mg, F.sub.107 is the centrifugal force and is the vector multiplicative product of the mass and square of the velocity vector divided by the radial distance or mv.sup.2/r where bold case indicates a vector quantity, and F.sub.c is the Coriolis force and is the vector cross product of the angular velocity vector ω and linear velocity v, increased by the negative of twice the mass, (−2 m) or −2 m(ω x v) where x is the vector cross product.

[0076] FIG. 13 shows the separator 130, two external filters 131 and a plurality of valves 132, 132′.

[0077] While the invention has been particularly shown and described with reference to preferred and alternate embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention. By way of example, the fixturing and fitting to support the vessel may be changed without changed the invention. The filter element fixturing and fitting as well does not change the basic inventive nature.

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