PARTICULATE SEPARATOR FOR PRODUCTION WELLS
Disclosed in a particulate separator for use with a petroleum production well that produces a fluid mixture including particulate matter. The separator includes an outer casing and an inner pipe disposed within the outer casing. The outer casing includes fluid intake slots extending through its sidewall near is upper end. Fluid entering the outer casing flows downward along a flow path between the outer casing and a lower open end of the inner pipe. A fin on a lower portion of the inner pipe imparts a radial motion to the downwardly flowing fluid, which forces particulates toward the inside surface of the outer casing. In an arrangement, the outer casing has an upper portion and a lower portion that overlaps the fin. In an arrangement, a sidewall thickness of the lower portion of the casing is greater than a sidewall thickness of the upper portion of the outer casing.
The present application claims the benefit of the filing date of U.S. Provisional Application No. 62/823,270 having a filing date of Mar. 25, 2019, the entire contents of which is incorporated herein by reference.
FIELDThe present disclosure is directed to oil and/or gas wells and more particularly to the removal of particulates, such as sand, from production streams of such wells.
BACKGROUNDOil and gas wells can be naturally flowing, injecting or can be produced by any means of artificial lift. Particulates within a production stream of such wells, which can include both liquid and gaseous products, can be both naturally occurring and manmade. Naturally occurring particulates can include sand, silt, and other solids, which may be natural byproducts of a producing well. As hydrocarbons and water flow through the formation, these particulates are carried in the flow stream and can be carried into the production tubing which can cause problems within the tubing and/or with an artificial lifting mechanism such as an electric submersible pump.
Manmade particulates are often introduced into a well via hydraulic fracturing (e.g., fracking), which is commonly utilized to increase well production. Such a procedure involves injecting large quantities of water, sand (e.g., fracture proppant), and chemicals under high hydraulic pressure into a bedrock formation (e.g., production formation) via the well bore. The process is intended to create new fractures in the formation as well as increase the size of any existing fractures. These fractures allow more production fluids to exit the formation increasing the production of the well. The sand, known as fracture proppant, flows into fractures under high hydraulic pressure and props these fractures open after removal of the high hydraulic pressure. That is, some of the fracture proppant remains trapped within the fractures to hold these fractures open. However, a portion of the introduced fracture proppant remains free within the well. Such fracture proppant may be included within the production stream of the well during production.
Natural or manmade particulates (e.g., fracture proppant) can cause a multitude of problems for oil and gas operators during production. For example, in flowing wells abrasive particulates can “wash through” metals in piping creating leaks and potentially hazardous conditions. Particulates can also fill-up or otherwise plug surface flow lines, vessels, and tanks. In wells using artificial lift, production of particulates can reduce of the life of the down-hole assembly (e.g., electric submersible pumps) and increase maintenance costs.
SUMMARYOne arrangement of the disclosure is directed to a particulate separator for use with a petroleum production well that produces a fluid mixture including particulate matter. The separator includes an outer casing and an inner pipe disposed within the outer casing. The outer casing is sized for receipt within a well bore and includes intake slots toward its upper end allowing a fluid mixture to enter the space between the outer casing and the inner pipe (e.g., from the well bore) and flow downward toward a pump intake formed by a lower end of the inner pipe. An upper end of the inner pipe may be fluidly attached to a pump (e.g. electric submersible pump). A lower outside portion of the inner pipe includes at least one fin (e.g., helical) to impart a radial motion to the downwardly flowing fluid, which forces particulates toward the inside surface of the outer casing. Fluid is drawn upward into an open bottom end of the inner pipe, which is typically disposed at or near an interior centerline of the outer casing. Drawing from at or near the centerline of the outer casing allows heavier particles disposed nearer to the inside surface of the outer casing (e.g., due to the radial motion of the fluid) to continue through a bottom end of the separator. In an arrangement, the properties of the outer casing varies over its length.
In one arrangement, a sidewall thickness of the outer casing varies over its length. More specifically, a portion of the outer casing that encases or overlaps the portion of inner pipe imparting radial motion on the fluid flow has a greater thickness than a portion of the casing that does not overlap this portion of the inner pipe. In a further arrangement, the outer casing includes an upper tube or barrel and a lower tube or barrel having a common inside diameter and different outside diameters. In such an arrangement, the lower tube having an increased outside diameter may overlap the portion of the inner pipe that imparts radial motion to the fluid flow.
In another arrangement, a sidewall property of the outer casing varies over its length such that a portion of the outer casing that encases or overlaps the portion of inner pipe imparting radial motion on the fluid flow has a different material type and/or hardness than a than a portion of the outer casing that does not overlap this portion of the inner pipe.
In a further arrangement, various components of the separator may be threadedly assembled. In such an arrangement, individual components may be replaced when worn without requiring the replacement of other components.
Reference will now be made to the accompanying drawings, which at least assist in illustrating the various pertinent features of the presented inventions. The following description is presented for purposes of illustration and description and is not intended to limit the inventions to the forms disclosed herein. Consequently, variations and modifications commensurate with the following teachings, and skill and knowledge of the relevant art, are within the scope of the presented inventions. The embodiments described herein are further intended to explain the best modes known of practicing the inventions and to enable others skilled in the art to utilize the inventions in such, or other embodiments and with various modifications required by the particular application(s) or use(s) of the presented inventions.
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The change in direction of the production fluid from downward movement in the annulus between the outer casing and inner pipe to an upward movement into the pump intake 128 in the bottom of the inner pipe works to separate some particulates from the intake. That is, the downward moving particulates have a momentum that may allow them to proceed past the pump intake despite suction forces existing at the pump intake. To further effect separation of particulates, a fluid directing fin 125 is attached to an outside surface of a lower portion of the inner pipe 120. The fin 125 extends into a spacing (e.g., annulus) between the outer casing 100 and the lower portion of the inner pipe 120. This fin 125 (e.g., helical fin) directs the fluid mixture radially as it moves downward.
The downward velocity of the production fluids and the radial movement caused by the fin 125 works to force particulates in the fluid flow toward the inside surface of the outer casing 100. That is, centrifugal forces move the heavier particulates to the outside edge of the fluid flow moving these particulates away from the opening of pump intake 128. The momentum of the heavier solid particulates in the fluid mixture and their disposition nearer to the inside surface of the outer casing 100 prevents most of the particulates/particles 180 from reversing direction and entering the pump intake 128, thereby allowing the particles 180 to continue through the bottom of the separator into, for example, a mud anchor below the separator. It should also be noted that flow into the pump intake 128 can be managed by altering the speed of the pump depending on, for example, an operator's parameters or constraints from other parameters in the system. By way of example, by altering the relative diameters of the outer casing 100 and the inner pipe 120 the downward velocity of flow path and the upward, or suction velocity of flow path at the pump intake (which may dependent on pump speed) can be controlled better optimizing velocity for the fluid mixture to reduce any vacuum effect at pump intake that would draw particulates into the intake. Generally, it is desirable to insure that the downward velocity of the gas, liquids, and particulates is greater than the upward intake velocity. Once the liquid and gas now mostly or entirely free of particulates have entered pump intake, the mixture is able to move into the inner pipe and travel up to the surface of the well.
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As previously noted, the threaded connection between all of the components facilitates the assembly and repair of the separator. More specifically, the threaded connection allows for disassembly in the field as well as replacement and/or redressing of any of the components of the separator. That is, the separator may be removed from a well, disassembled, redressed and reused. The ability to redress the separator is of additional importance when the separator is utilized with wells that have undergone hydraulic fracking and are experience high fluid flow, either naturally or by way of artificial lift (e.g., submersible pumps). In such instances, the production streams typically include significant amounts of particulate and the high flow rates result in considerable abrasion due to the particulates. Such abrasion is of particular concern in the lower portion of the separator where the internal fin 125 of the inner pipe 120 imparts a radial flow on the production fluid and particulate mixture. More specifically, centrifugal force imparted due to the radial motion of the fluid disposes the heavier particulates to the outside surface of the flow path. Stated otherwise, the particulates move outward against the inside surface of the outer casing. This results in considerable abrasive wear to the inside surface of the outer casing where the outer casing overlaps the lower portion of the inner pipe 120 having the radial flow inducing fin 125. This portion of the separator typically wears out prior to any other component of the separator.
In an embodiment, the separator is configured to ameliorate effects caused by high production flows having significant particulate content. More specifically, use of a two-piece outer casing design, different materials, and/or a non-uniform thickness of the outer casing provides a separator the may be easily repaired and/or provides improved resistance to abrasive wear. As shown in
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Though discussed as utilizing an upper barrel and lower barrel that are connected, it will be appreciated that the outer casing may be formed from a single tube. In such an arrangement, the sidewall thickness may vary over the length of the single tube while an internal diameter of the single tube may be uniform over its length.
The foregoing description has been presented for purposes of illustration and description. Furthermore, the description is not intended to limit the inventions and/or aspects of the inventions to the forms disclosed herein. Consequently, variations and modifications commensurate with the above teachings, and skill and knowledge of the relevant art, are within the scope of the presented inventions. The embodiments described hereinabove are further intended to explain best modes known of practicing the inventions and to enable others skilled in the art to utilize the inventions in such, or other embodiments and with various modifications required by the particular application(s) or use(s) of the presented inventions. It is intended that the appended claims be construed to include alternative embodiments to the extent permitted by the prior art.
Claims
1. A particulate separator for disposition within a well casing of a petroleum production well producing a fluid mixture including particulate matter, the separator comprising:
- an outer casing including intake apertures, proximate an upper end of the outer casing, allowing the fluid mixture to enter the outer casing;
- an inner pipe disposed within the outer casing, wherein an upper outlet of the inner pipe exits through the upper end of the separator and a lower end of the inner pipe is disposed proximate to a lower end of the outer casing;
- a fin disposed on a lower portion of the inner pipe, wherein fluid flows downward between the interior of the outer casing and an exterior of the inner pipe, wherein the fin imparts a radial path to the fluid as it moves toward a pump intake defined by the lower end of the inner pipe,
- wherein, a lower portion of the outer casing that encases the fin on the lower portion of the inner pipe has at least a first material property that is different than a material property of an upper portion of the outer casing that encases an upper portion of the inner pipe that free of the fin.
2. The separator of claim 1, wherein the material property comprises one of:
- a sidewall thickness;
- a hardness; and
- a material type.
3. The separator of claim 1, wherein a sidewall thickness of the outer casing varies over its length.
4. The separator of claim 3, wherein the sidewall thickness of the lower portion of the outer casing is greater than a sidewall thickness of the upper portion of the outer casing.
5. The separator of claim 3, wherein the outer casing comprises:
- an upper barrel forming the upper portion of the outer casing; and
- a lower barrel forming the lower portion of the outer casing.
6. The separator of claim 5, wherein the lower barrel and the upper barrel are threadedly connected.
7. The separator of claim 1, further comprising:
- an elongated hollow connector having: a first set of threads configured to connect to mating threads on an upper end of the inner pipe; and a second set of threads configured to connect to mating threads on an upper end of the outer casing.
8. The separator of claim 7, wherein the first set of threads and the second set of threads are disposed on a first end of the elongated hollow connector, the elongated hollow connector further comprising:
- a third set of threads disposed on a second end of the elongated hollow connector.
9. The separator of claim 1, further comprising:
- a hollow bottom fitting having: a first set of threads on a first end of the hollow bottom fitting configured to connect to mating threads on a lower end of the outer casing; and a second set of threads on a second end of the hollow bottom fitting.
10. The separator of claim 9, internal periphery of the upper interior end of the hollow bottom fitting comprises a chamfered surface.
11. A particulate separator for disposition within a well casing of a petroleum production well producing a fluid mixture including particulate matter, the separator comprising:
- an outer casing having: an upper barrel having at least a first intake aperture disposed through a sidewall of the upper barrel proximate an upper end of the upper barrel; a lower barrel having an upper end attached to a lower end of the upper barrel, wherein hollow interiors of the upper barrel and lower barrel are aligned to define a hollow interior the outer casing;
- an inner pipe disposed within the hollow interior of the outer casing, the inner pipe extending from an upper end disposed proximate to an upper end of the outer barrel to an open lower end disposed within a lower portion of the lower barrel, wherein a space between the inside surface of the outer casing and an outside surface of the inner pipe defines a flow path between the intake aperture and the open lower end of the inner pipe; and
- a fin disposed on a lower portion of the inner pipe, wherein the fin imparts a radial path to the fluid as it moves along the flow path toward the open end of the inner pipe, wherein the lower barrel overlaps the lower portion of the inner pipe and the fin.
12. The separator of claim 11, wherein a sidewall thickness of the lower barrel is greater than a sidewall thickness of the upper barrel.
13. The separator of claim 12, wherein an inside diameter of the upper barrel is substantially equal to an inside diameter of the lower barrel.
14. The separator of claim 11, wherein the lower barrel is formed from a first material and the upper barrel is formed form a second material, wherein the first and second materials are different.
15. The separator of claim 11, further comprising:
- an elongated hollow connector having: a first set of threads configured to connect to mating threads on an upper end of the inner pipe; and a second set of threads configured to connect to mating threads on an upper end of the upper barrel of the outer casing.
16. The separator of claim 17, wherein the first set of threads and the second set of threads are disposed on a first end of the elongated hollow connector, the elongated hollow connector further comprising:
- a third set of threads disposed on a second end of the elongated hollow connector.
17. The separator of claim 1, further comprising:
- a hollow bottom fitting having: a first set of threads on a first end of the hollow bottom fitting configured to connect to mating threads on a lower end of the lower barrel of the outer casing; and a second set of threads on a second end of the hollow bottom fitting.
18. The separator of claim 17, internal periphery of the upper interior end of the hollow bottom fitting comprises a chamfered surface.
19. The separator of claim 11, wherein an upper outlet of the inner pipe exits through an upper end of the separator.
20. The separator of claim 11, further comprising:
- a plurality of intake apertures disposed about a periphery of the sidewall of the upper barrel.
Type: Application
Filed: Mar 20, 2020
Publication Date: Oct 1, 2020
Inventor: Andy Fires (Midland, TX)
Application Number: 16/826,029