US20190072089A1

US20190072089A1 - Fluid end with curved internal cavity profile

Info

Publication number: US20190072089A1
Application number: US16/125,182
Authority: US
Inventors: Chris Buckley
Original assignee: Individual
Current assignee: ST9 Gas and Oil LLC
Priority date: 2017-09-07
Filing date: 2018-09-07
Publication date: 2019-03-07

Abstract

A fluid end assembly includes a fluid end and a plurality of valve assemblies each located within a cavity that has curved internal profiles. The curved internal profiles of the cavities are concaved outward. A plunger is included to provide variations in pressure within the fluid end so as to facilitate movement of the working fluid. A discharge plug is included in communication with the fluid end. The discharge plug may include a curved profile along an inner surface that corresponds with one of the cavities therein. A suction plug is releasably coupled to the fluid end and includes a curved profile along an inner surface. The suction plug also includes a recess for acceptance of a spring retainer. The spring retainer is included to support a suction valve assembly.

Description

CLAIM OF PRIORITY

This application claims the benefit of U.S. Provisional Application No. 62/555,546, filed 7 Sep. 2017. The information contained therein is hereby incorporated by reference.

BACKGROUND

1. Field of the Invention

The present application relates generally to a reciprocating pump, and in particular to a fluid end having a curved internal cavity profile for the reduction of turbulent flow and cavitation in the system.

2. Description of Related Art

It is difficult to economically produce hydrocarbons from low permeability reservoir rocks. Oil and gas production rates are often boosted by hydraulic fracturing, a technique that increases rock permeability by opening channels through which hydrocarbons can flow to recovery wells. During hydraulic fracturing, a fluid is pumped into the earth under high pressure (sometimes as high as 50,000 PSI) where it enters a reservoir rock and cracks or fractures it. Large quantities of proppants are carried in suspension by the fluid into the fractures. When the pressure is released, the fractures partially close on the proppants, leaving channels for oil and gas to flow.
Specialized pumps are used to deliver fracture fluids at sufficiently high rates and pressures to complete a hydraulic fracturing procedure or “frac job.” These pumps are usually provided with fluid ends having both reciprocating plungers that place fluids under pressure and valves that control fluid flow to and from the plungers. Fluid ends have many parts that are releasably fastened to one another so that they can be repaired or replaced. These fluid ends experience large amounts of internal stresses from turbulent flows and cavitation as the fracture fluids are passed through. Conventional designs where linear wall profiles and edges are prevalent contribute to this. By the nature of its operation a reciprocating pump or fluid end induces turbulent flow and cavitation into the system. These effects are detrimental to the whole pumping system. These stresses reduce the life of the fluid end and its internal components.
Although great strides have been made with respect to fluid end design, considerable shortcomings remain. An improved fluid end is needed that minimizes the internal stresses on the fluid end during operation.

SUMMARY OF THE INVENTION

It is an object of the present application to provide a fluid end assembly that reduces internal stresses through the incorporation of curved internal cavity profiles. This design is to reduce the internal stresses on the fluid end in operation by optimizing the internal profile of the cavities to produce a more laminar flow of the proppant. The addition of these profiles to the internal cavities and components mitigate the turbulent and cavitation present in the proppant.
It is a further object of the present application that the profiles of the suction port and discharge port in the fluid end are curved and consist of one or more radiuses. The radiuses are set at different diameters. The discharge plug may also include a curved profile to match that of the curved profile in the discharge cavity of the fluid end. The discharge curve profile in the discharge plug is profiled to continue the arc from the fluid end curved discharge port profile.
The suction plug is composed of a single member wherein the traditional plug and nut are combined together. The inner surface of the suction plug has a radiused profile. The discharge plug and the suction plug have mating faces and an adjacent recessed seal. As the plugs are threaded into location, the seal rides the chamfer thereby compressing the seal to the conforming diameter. The intersection of the chamfer start point and the seal groove is the same as the seal diameter. Therefore, no extrusion gap is created and the seal can not extrude so as to increase the feature life. Additionally, when fully seated, a gap is always present above the mating surfaces and seal.
Furthermore, it is a further object to provide a curved profile in the suction cavity of the fluid end. A spring retainer is seated in the suction cavity to hold the spring that operates the valve. A flat face is machined into the curved profile of the suction cavity to align the spring retainer in position and prevent the spring retainer from moving through the bore cavity. The suction plug includes the radiused features which help to guide the spring retainer into position during assembly and stops it from rotating circumferentially relative to the bore diameter.
Ultimately the invention may take many embodiments. This assembly overcomes the disadvantages inherent in the prior art. The more important features of the assembly have thus been outlined in order that the more detailed description that follows may be better understood and to ensure that the present contribution to the art is appreciated. Additional features of the system will be described hereinafter and will form the subject matter of the claims that follow.
Many objects of the present assembly will appear from the following description and appended claims, reference being made to the accompanying drawings forming a part of this specification wherein like reference characters designate corresponding parts in the several views.
Before explaining at least one embodiment of the system in detail, it is to be understood that the assembly is not limited in its application to the details of construction and the arrangements of the components set forth in the following description or illustrated in the drawings. The assembly is capable of other embodiments and of being practiced and carried out in various ways. Also it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the various purposes of the present system. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present system.

DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the application are set forth in the appended claims. However, the application itself, as well as a preferred mode of use, and further objectives and advantages thereof, will best be understood by reference to the following detailed description when read in conjunction with the accompanying drawings, wherein:

FIG. 1 is a perspective view of a fluid end assembly according to an embodiment of the present application.

FIG. 2 is a side view of the fluid end assembly of FIG. 1.

FIG. 3 is a section view of the fluid end assembly of FIG. 1.

FIG. 4 is an enlarged partial section view of the fluid end assembly of FIG. 3.

FIG. 5 is an enlarged partial section view of the fluid end assembly of FIG. 3.

FIG. 6 is an enlarged partial section view of the fluid end assembly of FIG. 3.

While the assembly and method of the present application is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific embodiments is not intended to limit the application to the particular embodiment disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the process of the present application as defined by the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Illustrative embodiments of the preferred embodiment are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developer's specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
In the specification, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of the present application, the devices, members, apparatuses, etc. described herein may be positioned in any desired orientation. Thus, the use of terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, as the assembly described herein may be oriented in any desired direction.
The assembly and method in accordance with the present application overcomes one or more of the above-discussed problems commonly associated with conventional fluid ends by reducing the internal stresses through the incorporation of curved internal cavity profiles. This design is configured to reduce the internal stresses on the fluid end during operation by optimizing the internal profile of the cavities to produce a more laminar flow of the proppant. The addition of these profiles to the internal cavities and components mitigate the turbulent and cavitation present in the proppant. These and other unique features of the device are discussed below and illustrated in the accompanying drawings.
The assembly and method will be understood, both as to its structure and operation, from the accompanying drawings, taken in conjunction with the accompanying description. Several embodiments of the assembly may be presented herein. It should be understood that various components, parts, and features of the different embodiments may be combined together and/or interchanged with one another, all of which are within the scope of the present application, even though not all variations and particular embodiments are shown in the drawings. It should also be understood that the mixing and matching of features, elements, and/or functions between various embodiments is expressly contemplated herein so that one of ordinary skill in the art would appreciate from this disclosure that the features, elements, and/or functions of one embodiment may be incorporated into another embodiment as appropriate, unless otherwise described.
The assembly and method of the present application is illustrated in the associated drawings. The assembly includes a fluid end with internal curved cavity profiles. The fluid end includes a plunger bore having a curved profile, a suction cavity with a curved internal profile, and a discharge cavity with a curved internal profile. A suction valve is located in the suction cavity. The suction cavity is concaved outward such that the diameter of the suction cavity is largest about its center. A discharge valve is located in the discharge cavity. The discharge cavity is concaved outward such that the diameter of the discharge cavity is largest about its center. A discharge valve may be located in communication with the discharge valve and the discharge cavity. The discharge plug may include a curved profile adjacent the cavity walls. The profile may be configured to match the curved diameter of the discharge cavity.
The assembly may also include a suction plug as a singular member that releasably communicates with the fluid end and is concentric with the plunger. The suction plug may have one or more curved profiles along an inner surface. The suction plug also includes a groove for acceptance of a spring retainer in communication with the suction valve. Additional features and functions of the device are illustrated and discussed below.
Referring now to the Figures wherein like reference characters identify corresponding or similar elements in form and function throughout the several views. The following Figures describe the assembly of the present application and its associated features. With reference now to the Figures, an embodiment of the modular observation assembly and method of use are herein described. It should be noted that the articles “a”, “an”, and “the”, as used in this specification, include plural referents unless the content clearly dictates otherwise.
Referring now to FIGS. 1 and 2 in the drawings, a perspective view and side view of a fluid end assembly 101 is illustrated. Assembly 101 is configured to provide a reduction in internal stresses through the incorporation of curved internal cavity profiles which will be illustrated below. The curved internal cavity profiles may be provided through the fluid end and any of the associated plugs and valves. Assembly 101 includes a fluid end 103. Fluid end 103 includes a number of internal cavities and surfaces used in the movement of proppant. The surfaces of the cavities are curved to facilitate reduced stress. These will be depicted in the following figures. As seen in FIG. 1, a discharge plug 107 and a suction plug 105 are shown engaged with fluid end 103. A gauge port 104 is shown in communication with discharge plug 107. For purposes herein, discussion will be related to the combined plug 107 and gauge port 104 as a single discharge plug 107, as plug 107 may be used singly or as a combination with gauge 104.
Referring now also to FIG. 3 in the drawings, a section view of fluid end assembly 101 is illustrated. Internally, fluid end assembly 101 includes a plunger 109, a suction valve assembly 111, a discharge valve assembly 113, a suction plug 105, and discharge plug 107 (i.e. combined gauge 104 and plug 107). Plunger 109 passes through a plunger bore 117. Plunger bore 117 extends from surface 119 of fluid end 103 internally to suction plug 105. Suction valve assembly 111 resides in a suction cavity 121. Cavity 121 is adjacent to and in communication with plunger bore 117. Discharge valve assembly 113 resides in a discharge cavity 123. Cavity 123 is adjacent to and in communication with plunger bore 117 as well.
Plunger bore 117 has a varied internal diameter. Plunger bore 117 extends linearly away from surface 119 and then expands away from its axis and plunger 109 near the distal end of plunger 109. Diameter 125 a of plunger bore 117 is smaller than diameter 125 b of plunger bore. The surface of plunger bore between the diameters may be linear or may include a curved surface (i.e. be radiused). Plunger bore 117 may include one or more radiused curves along the curved surface wherein the curves are joined tangentially to one another.
Discharge cavity 123 and suction cavity 121 are shown in FIG. 3. The walls of each cavity are shown as nonlinear, whereas the walls are radiused outward such that the diameter of the cavity is widest away from the upper and lower ends. The walls of cavity 123 and 121 may include a plurality of radiused curves joined together tangentially such that the curve profile is varied. Each curve within the respective cavity 121 and 123 may be different from an adjacent curve such that together they form the curve profile for that particular cavity 121 and 123.
Referring now also to FIG. 4 in the drawings, a partial section view of fluid end assembly 101 is illustrated. In this view, suction plug 105 is partially unseated from fluid end 103 for illustrative purposes. As seen in the Figure, plunger 109 is located opposite from suction plug 105. Suction valve assembly 111 is located within cavity 121. Assembly 101 may include a spring retainer 127 that spans across the opening of cavity 121. Retainer 127 is configured to contact one side of spring 129, while suction valve assembly 111 is in contact with the opposing side. As plunger 109 reciprocates, the valve in suction valve assembly 111 opens and closes, being biased by spring 129. Retainer 127 is seated against the walls of cavity 121. As noted previously, the walls of cavity 121 consist of one or more curves tangentially adjacent one another to form a curved profile 131. Curved profile 131 of cavity 121 may include one or more parallel faces 133 tangential to the curve profile 131 for contact with retainer 127. Face 133 is configured to align and position spring retainer 127 within cavity 121.
Suction plug 105 is releasably coupled to fluid end 103 and is located linearly in alignment with plunger 109. Suction plug 105 is shown having an inner surface 135 with a curved profile having one or more curves. Where a plurality of curves exist, a “wave” effect may be realized along surface 135. Plug 105 includes a recess 137 along inner surface 135 that extends inward into plug 105. Recess 137 is configured to accept a portion of spring retainer 127. The outer edges of recess 137 about surface 135 are radiused to facilitate acceptance of retainer 127 and guide retainer 127 into position within recess 137. Recess 137 is configured to stop retainer 127 from rotating circumferentially to cavity 121.
Suction plug 105 includes a mating surface 139 that is configured to mate with a fluid end mating surface 140. As seen in FIG. 4, the mating surfaces are separated as plug 105 is slightly unseated for illustrative purposes. When fully seated, mating surfaces 139 and 140 are configured to make full contact. Suction plug 105 also includes a seal groove 141. Seal groove 141 is located below the mating surface 139 and includes a seal 143. Seal 143 defines a diameter. The diameter at the intersection of the mating surface 139 and seal groove 141 is the same as the seal diameter to avoid extrusion gap. As seen in FIG. 5, a clearance gap 145 exists between plug 105 and fluid end 103 above mating surfaces 139 and 140 when plug 105 is fully seated.
Referring now also to FIG. 5 in the drawings, an enlarged section view of the fluid end assembly of FIG. 3 is illustrated. In FIG. 5, plug 105 is fully seated in fluid end 103. Mating surfaces 139 and 140 are in contact. Clearance gap 145 is shown as being maintained. Spring retainer 127 is located partially within recess 137. As noted previously, the curved profile 131 of cavity 121 has one or more radiused curves. Profile 131 expands outward in a concave manner such that diameter 147 a is larger than diameter 147 b
Referring now also to FIG. 6 in the drawings, an enlarged section view of the fluid end assembly of FIG. 3 is illustrated. Discharge cavity 123 is similar to that of suction cavity 121. Cavity 123 has a curved internal profile 149 wherein the walls of the profile expand outward in a concave fashion such that the diameter 151 a is larger than the diameter 151 b. The narrowest points of cavity 123 are at the upper and lower most points in the profile 149. Profile 149 may consist of one or more radiused curves that are joined together tangentially to form the overall profile 149. The radiused curves may have a different curve diameter.
Discharge plug 107 is configured to engage with and seat against fluid end 103 in a similar manner to that of suction plug 105. Discharge plug 107 includes a mating surface 153 that is configured to mate with a fluid end mating surface 154. As seen in FIG. 6, the mating surfaces are in contact with one another as plug 107 is shown in a seated position. When fully seated, mating surfaces 153 and 154 are configured to make full contact. Plug 107 also includes a seal groove 155. Seal groove 155 is located below the mating surface 153 and includes a seal 157. Seal 157 defines a diameter. The diameter at the intersection of the mating surface 153 and seal groove 155 is the same as the seal diameter to avoid extrusion gap. A clearance gap 159 exists between plug 107 and fluid end 103 above mating surfaces 153 and 154 when plug 107 is fully seated.
Plug 107 extends downward into cavity 123. A spring 161 is biased between plug 107 and discharge valve assembly 113, wherein the plug 107 and assembly 113 are on opposing ends of cavity 123. As plunger 109 reciprocates, pressure within plunger bore 117 pushes open the discharge valve to permit the discharge of proppant from bore 117. As the valve moves, spring 161 is actuated between a compressed and relaxed position. Spring 161 contacts surface 163 of plug 107.
Plug 107 has an inner surface 165. Surface 165 may include a nonlinear profile which extends from a central position in plug 107 toward the walls of cavity 123. As seen in FIG. 6, the curve profiled of surface 165 can be defined between length L1 and length L2. The curve profile of surface 165 may be configured to match that of profile 149, such that the curved profile of cavity 123 is continued along inner surface 165 of plug 107.
The current application has many advantages over the prior art including at least the following: (1) curved internal profiles of the plunger bore, valve cavities, and suction plug surface; (2) reduction of internal stresses; (3) singular body suction plug; and (4) minimized wear.
The particular embodiments disclosed above are illustrative only, as the application may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. It is therefore evident that the particular embodiments disclosed above may be altered or modified, and all such variations are considered within the scope and spirit of the application. Accordingly, the protection sought herein is as set forth in the description. It is apparent that an application with significant advantages has been described and illustrated. Although the present application is shown in a limited number of forms, it is not limited to just these forms, but is amenable to various changes and modifications without departing from the spirit thereof.

Claims

What is claimed is:

1. A fluid end assembly, comprising:

a fluid end;

a plunger for reciprocation through a plunger bore in the fluid end;

a suction valve located within a suction cavity in the fluid end, the suction cavity having a curved internal profile; and

a discharge valve located within a discharge cavity in the fluid end, the discharge cavity having a curved internal profile;

wherein the curved internal profiles of the suction cavity and the discharge cavity are concaved outward.

2. The assembly of claim 1, wherein the plunger bore is radiused so as to open or expand away from the plunger adjacent to the suction cavity and the discharge cavity.

3. The assembly of claim 1, wherein the plunger bore has a plurality of radiused curves, the plurality of radiused curves having at least two different curve diameters joined together tangentially and cause the diameter of the plunger bore to vary.

4. The assembly of claim 1, wherein the suction cavity has a plurality of radiused curves joined together tangentially.

5. The assembly of claim 4, wherein the plurality of radiused curves in the suction cavity each have a different curve diameter.

6. The assembly of claim 1, wherein the discharge cavity has a plurality of radiused curves joined together tangentially.

7. The assembly of claim 6, wherein the plurality of radiused curves in the discharge cavity each have a different curve diameter.

8. The assembly of claim 1, further comprising:

a suction plug releasably coupled to the fluid end and located linearly with the plunger, the suction plug including a curved profile along an inner surface.

9. The assembly of claim 8, wherein the suction plug includes a recess along the inner surface, the recess being radiused adjacent the inner surface.

10. The assembly of claim 9, further comprising:

a spring retainer in communication with the suction valve, the spring retainer configured to pass into the recess.

11. The assembly of claim 8, wherein the suction plug includes a mating surface and a seal groove, the seal groove located below the mating surface and includes a seal having a diameter, the mating surface configured to engage a corresponding mating surface of the fluid end upon installation; and

wherein the diameter at the intersection of the suction plug mating surface and the seal groove is the same as the seal diameter to avoid extrusion gap.

12. The assembly of claim 11, wherein a clearance gap is maintained between the suction plug and the fluid end above the mating surface.

13. The assembly of claim 1, further comprising:

a spring retainer in communication with the suction valve, the suction cavity including one or more parallel faces tangential to the curved profile of the suction cavity, the parallel faces configured to align and position the spring retainer.

14. The assembly of claim 1, further comprising:

a discharge plug in communication with both the discharge valve and the discharge cavity, the discharge valve and the discharge plug are on opposing ends of the discharge cavity.

15. The assembly of claim 14, wherein the discharge plug includes a discharge plug curve profile adjacent the discharge cavity.

16. The assembly of claim 15, wherein the curve of the discharge plug curve profile is configured to match that of the discharge cavity curved profile, such that the curved profile of the discharge cavity is continued along the discharge plug curve profile.

17. The assembly of claim 14, wherein the discharge plug includes a mating surface and a seal groove, the seal groove located below the mating surface and includes a seal having a diameter, the mating surface configured to engage a corresponding mating surface of the fluid end upon installation; and

wherein the diameter at the intersection of the discharge plug mating surface and the seal groove is the same as the seal diameter to avoid extrusion gap.

18. The assembly of claim 18, wherein a clearance gap is maintained between the discharge plug and the fluid end above the mating surface.

19. A fluid end assembly, comprising:

a fluid end;

a plunger for reciprocation through a plunger bore in the fluid end;

a suction valve located within a suction cavity in the fluid end, the suction cavity having a curved internal profile;

a discharge plug in communication with both the discharge valve and the discharge cavity, the discharge valve and the discharge plug are on opposing ends of the discharge cavity, the discharge plug includes a discharge plug curve profile adjacent the discharge cavity;

a suction plug releasably coupled to the fluid end and located linearly with the plunger, the suction plug including a curved profile along an inner surface, the suction plug includes a recess along the inner surface, the recess being radiused adjacent the inner surface; and

a spring retainer in communication with the suction valve, the spring retainer configured to pass into the recess of the suction plug;

20. The assembly of claim 19, wherein the curve of the discharge plug curve profile is configured to match that of the discharge cavity curved profile, such that the curved profile of the discharge cavity is continued along the discharge plug curve profile.