US20130319220A1

US20130319220A1 - Fluid End Reinforced With Abrasive Resistant Insert, Coating Or Lining

Info

Publication number: US20130319220A1
Application number: US13/880,225
Authority: US
Inventors: Rajesh Luharuka; Laurent Coquilleau; Joe Hubenschmidt; Chris Fitzgerald
Original assignee: Schlumberger Technology Corp
Current assignee: Schlumberger Technology Corp
Priority date: 2010-10-19
Filing date: 2011-10-20
Publication date: 2013-12-05
Also published as: WO2012052842A3; WO2012052842A2

Abstract

A fluid end for use in a high-pressure, reciprocating, fluid pump assembly is provided having a bore therethrough in which a plunger reciprocates. The fluid end is provided with an insert to improve the fluid end washout life. In one embodiment, the insert is constructed of a ceramic material. In another embodiment, the insert includes an abrasive resistant coating or lining.

Description

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims benefit of priority to U.S. Provisional Patent Application No. 61/394,398, filed Oct. 19, 2010, which is incorporated herein by reference.

TECHNICAL FIELD

Embodiments described herein relate generally to abrasive resistant insert, coating or lining for pumps used in high pressure applications. More particularly, but not by way of limitation, an abrasive resistant insert, coating or lining for extending the life of the fluid end of a pump used in the field of oil and gas exploration and production.

BACKGROUND

The statements made herein merely provide information related to the present disclosure and may not constitute prior art, and may describe some embodiments illustrating the invention.
The fluid end of a positive displacement or reciprocating pump, such as a triplex pump, is the portion of the pump where a fluid is drawn in via a suction valve. A plunger then compresses the fluid and pushes it, with high pressure, through a release valve. These valves open when the pressure on the bottom side thereof is higher than the pressure on the top side thereof. An example of a triplex pump, is disclosed in commonly assigned PCT Application No. PCT/IB2010/053868, the entire contents of which are hereby incorporated by reference into the current disclosure.
In operation, the service life of the fluid end of a reciprocating pump is often susceptible to two types of failures: (i) wet fatigue, and (ii) washout. Wet fatigue is an engineering controlled mode of failure that primarily depends upon the design and material of the fluid end. Failures due to washout typically occur from abrasive wear near the sealing surfaces, which may ultimately result in bore enlargement.
Due to the high pressure applications and abrasive material required to be pumped during applications such as hydraulic fracturing operations, it is desirable to provide a reciprocating pump and fluid end with an improved wet fatigue and washout failure life cycle.

SUMMARY OF DISCLOSURE

According to an aspect of the present disclosure, one or more embodiments relates to a fluid end. The fluid end comprises a body portion having a bore therethrough and adapted to receive a reciprocating plunger. The bore has an internal surface and a recess portion defined therein. The fluid end further includes an elastomeric seal member and an insert disposed within the recess of the bore, wherein the insert separates the elastomeric seal member and the internal surface of the bore.

BRIEF DESCRIPTION OF THE DRAWINGS

To assist those of ordinary skill in the relevant art in making and using the subject matter hereof, reference is made to the appended drawings, which are not intended to be drawn to scale, and in which like reference numerals are intended to refer to similar elements for consistency. For purposes of clarity, not every component may be labeled in every drawing.

FIG. 1 depicts a schematic illustration of a pump body portion upon which the current application can be used according to an embodiment of the disclosure.

FIG. 2 depicts a schematic illustration of the pump body portion as in FIG. 1 from a different angle.

FIG. 3 depicts a schematic illustration of the pump body portion as in FIGS. 1-2 from yet a different angle.

FIG. 4 depicts a cross-sectional perspective view of the pump body portion as in FIGS. 1-3 upon which the current application can be used according to an embodiment of the disclosure.

FIG. 5 depicts a cross-sectional view of the pump body portion having an insert according to an embodiment of the disclosure.

FIGS. 6A-6B depicts a cross-sectional, partial view of the pump body portion having an insert according to embodiments of the disclosure.

FIGS. 7A-7B depicts a cross-sectional, partial view of the pump body portion having an insert according to alternative embodiments of the disclosure.

FIG. 8 depicts a cross-sectional, partial view of the pump body portion having an insert according to an embodiment of the disclosure.

DETAILED DESCRIPTION

The description and examples are presented solely for the purpose of illustrating the different embodiments and should not be construed as a limitation to the scope and applicability. While any compositions or structures may be described herein as comprising certain materials, it should be understood that the composition could optionally comprise two or more different materials. In addition, the composition or structure can also comprise some components other than the ones already cited. Although some of the following discussion emphasizes fracturing, the compositions and methods may be used in any well treatment in which diversion is needed. Examples include fracturing, acidizing, water control, chemical treatments, and wellbore fluid isolation and containment. Embodiments will be described in terms of treatment of vertical wells, but is equally applicable to wells of any well orientation. Embodiments will be described for hydrocarbon production wells, but it is to be understood that they may be used for wells for production of other fluids, such as water or carbon dioxide, or, for example, for injection or storage wells. It should also be understood that throughout this specification, when a range is described as being useful, or suitable, or the like, it is intended that any and every value within the range, including the end points, is to be considered as having been stated. Furthermore, each numerical value should be read once as modified by the term “about” (unless already expressly so modified) and then read again as not to be so modified unless otherwise stated in context. For example, “a range of from 1 to 10” is to be read as indicating each and every possible number along the continuum between about 1 and about 10. In other words, when a certain range is expressed, even if only a few specific data points are explicitly identified or referred to within the range, or even when no data points are referred to within the range, it is to be understood that the inventors appreciate and understand that any and all data points within the range are to be considered to have been specified, and that the inventors have possession of the entire range and all points within the range.
Referring now to the figures of the current application, there is disclosed a pump body portion or fluid end, indicated generally at 100, of a plunger-type pump typically used for well service operations, such as hydraulic fracturing. In some cases, three pump body portions 100 are arranged to form a triplex pump assembly 102, best seen in FIG. 1. Those skilled in the art will appreciate that the pump assembly 102 may also be arranged in other configurations, such as a single, monoblock pump assembly or a quintuplex pump assembly comprising five pump body portions 100 or the like. Other pumps, such as water pumps, mud pumps, delta pumps, or the like can also implement embodiments of the current application.
In some embodiments, an end plate 118 is fitted on each of the outer or side pump body portions 100 to aid in assembling the body portions 100 into the pump assembly, such as the triplex pump assembly 102 shown in FIGS. 1 to 3. The end plates 118 are utilized, in conjunction with fasteners 104, to assemble the pump body portions 100 to form the pump assembly 102.
As best seen in FIGS. 4 to 5, the pump body 100 has an internal passage or piston bore 108 which may be a through bore for receiving a pump plunger 114. The plungers 114 reciprocate toward and away from a chamber 116 to pressurize the fluid therein. In this manner, the plunger 114 affects high and low pressures on the chamber 116. For example, as the plunger 114 is thrust toward the chamber 116, the pressure within the chamber 116 is increased.
At some point, the pressure increase will be enough to affect an opening of a discharge valve 118 to allow the release of fluid from the chamber 116, through a discharge channel 128, and out of the pump body 100. The amount of pressure required to open the discharge valve 118 as described may be determined by a discharge mechanism 120 such as valve spring which keeps the discharge valve 118 in a closed position until the requisite pressure is achieved in the chamber 116.
The plunger 114 may also affect a low pressure on the chamber 116. That is, as the plunger 114 retreats away from its advanced discharge position near the chamber 116, the pressure therein will decrease. As the pressure within the chamber 116 decreases, the discharge valve 118 will close, returning the chamber 116 to a sealed state. As the plunger 114 continues to move away from the chamber 116, the pressure therein will continue to drop, and eventually a low or negative pressure will be achieved within the chamber 116.
Similar to the action of the discharge valve 118 described above, the pressure decrease will eventually be enough to affect an opening of an intake valve 122. The opening of the intake valve 122 allows the uptake of fluid into the chamber 116 from a fluid intake channel 124 adjacent thereto. The amount of pressure required to open the intake valve 122 may be determined by an intake mechanism 126, such as spring which keeps the intake valve 122 in a closed position until the requisite low pressure is achieved in the chamber 116.
As described above, a reciprocating or cycling motion of the plunger 114 toward and away from the chamber 116 within the pump 102 controls pressure therein. The valves 118,122 respond accordingly in order to dispense fluid from the chamber 116, through the discharge channel 128, and eventually out of the pump 102 at high pressure. The discharged fluid is then replaced with fluid from within the fluid intake channel 124.
As mentioned above, the continued cycling of the plungers 114 into and out of the fluid end 100 of the pump 102 and the accompanied fluctuations between positive and negative pressure experienced by the inner surfaces of the fluid end 100 makes the fluid end 100 susceptible to failure.
As such, in one embodiment of the present disclosure, an insert 200/220 is provided having a surface that is less subject to abrasion, corrosion, erosion and/or wet fatigue than typical fluid end materials, such as carbon steel. Exemplary materials for the insert 200/220 include ceramic, zirconium, or a composite material. Alternatively, however, the insert 200/220 may be constructed of a material which may be less abrasive resistant (e.g., carbon steel, inconel, incoloy, or stainless steel), and the insert 200/220 may be coated or lined with an abrasive resistant coating. For example, a layer of tungsten carbide (WC) may be deposited on the insert 200/220 to provide the desired abrasion resistant qualities.
Referring again to FIGS. 4 to 5, the insert 200/220 constructed in accordance with the present invention may be disposed in regions of the pump body 100 which have been identified as being prone to washout failure. Such regions may include, but are not limited to, the area near the plunger packing assembly, the suction cover bore, discharge ports, and the discharge cover bore at the O-ring sealing locations, each of which will be described in more detail below.
Referring now to FIGS. 6A to 6B, a more detailed view of a washout prone region is shown having various alternatives of an insert 200 a/200 b constructed in accordance with the present disclosure. In both FIGS. 6A and 6B, a portion of the bore 108 is shown having the piston 114 disposed therein. In the illustrated embodiments, a series of elastomeric seal members, rings and structures are set forth between the plunger 114 and inner surface of the bore 108. Such rings and structures are generically referred to herein as a plunger packing assembly 300, and may specifically include a header ring 302, a pressure ring 304, a female adaptor 306 and spacers 308/310. The plunger packing assembly 300, which are generally made from rubber or elastomeric materials, may be arranged in various manners as can be readily perceived by a person skilled in the art and may include different types of seals and rings, some of which are referred to in the art as wiper rings and junk rings.
When the plunger 114 moves in and out of the fluid end 100, the internal pressure of the fluid end 100 fluctuates. As a result, the plunger packing assembly 300 engages in small movements in the radial and/or axial direction of the bore 108. A small space may appear between certain seals of the plunger packing assembly 300 and the internal surface of the bore 108. If the pumping fluids in the fluid end 100 contains abrasive materials, such as sands or other solids generally used in the oil field, typically referred to as ‘proppants,’ such abrasive material may lodge in the small space between the elastomeric seals and the internal surface of the plunger bore 108. Over time, the abrasive material may cause serious washout to the internal surface of the bore 108. As such, the sealing provided by the plunger packing assembly 300 between the plunger 114 and the fluid end 100 may become defective. Under severe conditions, the internal diameter of the bore 108 may be enlarged, which could be detrimental to the performance and lifespan of the fluid end 100.
As such, in an effort to address this problem, and in accordance with at least one embodiment of the present disclosure, the abrasive resistant insert 200 a/200 b is disposed in a recess portion of the bore 108 so as to separate the plunger packing assembly 300, or elastomeric seal members, from the internal surface of the bore 108. Advantageously, the insert may be replaceable and readily serviced.
Referring specifically to FIG. 6A, one embodiment of the present disclosure is shown wherein the bore 108 includes a recess portion 130, or an annular recess portion, adapted to accommodate the plunger packing assembly 300, the insert 200 a, as well as a carrier sleeve 400 a for holding the insert 200 a and the plunger packing assembly 300 into the pump body 100. The carrier sleeve 400 a, or seal carrier, may comprise a threaded end portion 402 a to be threadingly disposed on a portion of the fluid end body 100. The carrier sleeve 400 a is shown to include a shoulder 404 a for abutting against the insert 200 a and providing a sealing surface for the bore 108. Although the carrier sleeve 400 a is shown as being threadingly engaged into the fluid end 100, the carrier sleeve 400 a, insert 200 a and plunger packing assembly 300 may likewise be press fit into the fluid end 100 or against each other.
An alternative embodiment is shown in FIG. 6B, wherein an insert 200 b is formed to include a raised portion 202 b adapted to abut against a carrier sleeve 400 b. The carrier sleeve 400 b may also be threadingly engaged into the fluid end 100 to provide a proper seal in the bore 108. The insert 200 b may be press fit into the fluid end body 100 or alternatively installed with the plunger packing assembly 300. The carrier sleeve 400 b may be a standard packaging part, thereby functioning as a ‘packing nut’ to hold the insert 200 b in place.
Although specific geometries are shown in FIGS. 6A and 6B for the insert 200 a/200 b or the carrier sleeve 400 a/400 b, it will be readily appreciated by a person skilled in the art that the specific geometries may be changed while maintaining the desired function of each component. Likewise, additional seals may be provided between insert 200 a/200 b and the recess portion 130 of the bore 108.
Referring now to FIGS. 7A to 7B, an alternative embodiment of an insert 200 c/200 d is shown wherein at least a portion of the insert 200 c/200 d is coated or lined with an abrasive resistant material 201. As mentioned above, the insert may be lined with a layer of tungsten carbide (WC), for example. The tungsten carbide (WC) may be deposited by a High Velocity Oxygen Fuel (HVOF) thermal spray process or other coating processes known in the art. The deposited layer or coating may function as an abrasive resistant coating between the fluid end 100 and the elastomeric sealing members, or plunger packing assembly 300, therefore reducing the damaging effect of the abrasive material trapped between the bore 108 and the plunger packing assembly 300.
Referring now to FIG. 8, a more detailed view of another washout prone region is shown having an insert 220 constructed in accordance with the present disclosure. As previously discussed, a suction cover 140 is disposed on the fluid end 100 wherein a retaining member 150 is used to hold the suction cover in place. According to at least one embodiment of the present invention, the fluid end 100 includes a recess portion for accommodating an insert constructed as described herein. The insert may likewise be used to prevent washout failure and wet fatigue at the identified portion of the fluid end 100.
It is important to note that although fluid ends of reciprocating pumps are discussed above, the described insert 200 may be used for any pressure containing part, or any part that experiences a pressure fatigue cycle.
The preceding description has been presented with reference to some embodiments. Persons skilled in the art and technology to which this disclosure pertains will appreciate that alterations and changes in the described structures and methods of operation can be practiced without meaningfully departing from the principle, and scope of this application. For example, while the pump body 100 is shown to have a cross-bore configuration that is substantially perpendicular, those skilled in the art will appreciate that the pump body 100 may comprise bores formed in other configurations such as a T-shape, Y-shape, in-line, or other configurations. Accordingly, the foregoing description should not be read as pertaining only to the precise structures described and shown in the accompanying drawings, but rather should be read as consistent with and as support for the following claims, which are to have their fullest and fairest scope.

Claims

What is claimed is:

1. A fluid end of a reciprocating pump, comprising:

a body portion having a bore therethrough and adapted to receive a reciprocating plunger, the bore having an internal surface;

an elastomeric seal member disposed within a recess of the bore; and

an insert disposed in the recess of the bore and separating the elastomeric seal member and at least a portion the internal surface of the bore.

2. The fluid end of claim 1, wherein the insert comprises a ceramic material.

3. The fluid end of claim 1, wherein at least a portion of the insert comprises a coating or layer of abrasive resistant material.

4. The fluid end of claim 3, wherein the abrasive resistant material comprises tungsten carbide.

5. The fluid end of claim 1, wherein the insert is in the shape of a sleeve.

6. The fluid end of claim 1, wherein the fluid end further comprises a seal carrier for holding the insert and the elastomeric seal member into the body portion of the fluid end.

7. The fluid end of claim 6, wherein the seal carrier comprises a threaded portion for threadingly engaging a corresponding threaded portion of the body portion of the fluid end.

8. The fluid end of claim 6, wherein the insert is press fit against the seal carrier.

9. A fluid pump assembly, comprising:

a power end; and

a fluid end comprising:

a body having a horizontal passage, a vertical passage intersecting the horizontal passage, and a discharge passage intersecting the vertical passage;

the horizontal passage providing an annular recess portion having a circumferential, internal surface, and a bore to receive a reciprocating plunger;

an elastomeric seal member disposed within the annular recess portion of the horizontal passage; and

an insert disposed in the annular recess portion and separating the elastomeric seal member and the circumferential, internal surface of the horizontal passage.

10. The fluid pump assembly of claim 9, wherein the insert comprises a ceramic material.

11. The fluid pump assembly of claim 9, wherein at least a portion of the insert comprises a coating or layer of abrasive resistant material.

12. The fluid pump assembly of claim 9, wherein the fluid pump assembly is a triplex pump.

13. A method of preventing washout in a pump body, comprising:

providing a body portion having a bore therethrough to receive a reciprocating plunger, and wherein the bore comprises a recess portion to receive an elastomeric seal member; and

disposing an insert in the recess portion of the bore so as to separate the elastomeric seal member and at least a portion of an internal surface of the bore.

14. The method of claim 13, wherein the insert comprises a ceramic material.

15. The method of claim 13, wherein at least a portion of the insert comprises a coating or layer of abrasive resistant material.

16. The method of claim 15, wherein said abrasive resistant material comprises tungsten carbide.