Patent Application
20180171999
Hydraulic fracturing is a well-stimulation technique in which a high-pressure fluid is injected downhole to fracture a subterranean rock. More particularly, hydraulic fracturing involves injecting a high-pressure fluid into a wellbore to create cracks in the rock through which hydrocarbons (e.g., natural gas, petroleum) may flow into the wellbore more freely. The injected fluid may be pressurized by a pump at the surface. The pump may be, for example, a reciprocating pump that includes a power end and a fluid end. The fluid end includes a housing that defines a chamber. One or more plungers may move in a first direction, allowing a lower pressure fluid to flow into the chamber. The one or more plungers may then move in a second, opposing direction, which reduces the volume of the chamber and causes the fluid to flow out to the wellhead. When the flow area in the well is saturated, higher pressure is needed to push the flow through the restrictions caused by the rock formations, thus causing the pressure of the fluid in the chamber to increase.
The cyclical hydraulic pressures in the chamber may strain the housing. This strain may lead to the initiation of cracks in the inner surface of the housing around the chamber. As the cracks propagate, the cracks may lead to the end of the useful life of the fluid end of the pump. In addition, the fluid that is pressurized in the chamber may include water, chemicals, and proppant that, while useful in the fracturing process, may accelerate the formation and propagation of the cracks in the housing. Thus, what is needed is an improved fluid end of a pump that is more resistant to cracks to increase the useful life of the fluid end of the pump.
This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
A fluid end of a pump includes a body that defines a suction bore, a discharge bore, and a plunger bore. A first central longitudinal axis extends through the suction bore, the discharge bore, or both. A second central longitudinal axis extends through the plunger bore. A chamber is defined at an intersection between the suction bore, the discharge bore, and the plunger bore. An interior surface of the body that at least partially defines the chamber comprises a first wall portion that is at least partially planar and oriented at an angle that is less than or equal to 15° from perpendicular to the first central longitudinal axis.
In another embodiment, the fluid end of the pump includes a body that defines a suction bore, a discharge bore, and a plunger bore. A first central longitudinal axis extends through the suction bore, the discharge bore, or both. A second central longitudinal axis extends through the plunger bore. A chamber is defined at an intersection between the suction bore, the discharge bore, and the plunger bore. An interior surface of the body that at least partially defines the chamber comprises a first wall portion that is at least partially planar and oriented at an angle that is less than or equal to 15° from perpendicular to the second central longitudinal axis.
In yet another embodiment, the fluid end of the pump includes a body that defines a suction bore, a discharge bore, and a plunger bore. A first central longitudinal axis extends through the suction bore, the discharge bore, or both. A second central longitudinal axis extends through the plunger bore. A chamber is defined at an intersection between the suction bore, the discharge bore, and the plunger bore. An interior surface of the body that at least partially defines the chamber comprises a first wall portion that is at least partially planar and oriented at an angle that is less than or equal to 15° from parallel to the first and second central longitudinal axes.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present teachings and together with the description, serve to explain the principles of the present teachings. In the figures:
Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying figures. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the system and method disclosed herein may be practiced without these specific details.
A first check valve 124 may be positioned in the suction bore 120. The first check valve 124 may allow fluid to flow therethrough in one direction but prevent the fluid from flowing therethrough in the opposing direction. More particularly, fluid may flow upward through the first check valve 124 and into the chamber 160 when a pressure differential across the first check valve 124 exceeds a predetermined amount.
A second check valve 132 may be positioned in the discharge bore 130. The second check valve 132 may also allow fluid to flow therethrough in one direction but prevent the fluid from flowing therethrough in the opposing direction. More particularly, the fluid may flow upward through the second check valve 132 to exit the chamber 160 when a pressure differential across the second check valve 132 exceeds a predetermined amount.
A nut 134 and discharge cover 135 may also be positioned at least partially in the discharge bore 130. The nut 134 and discharge cover 135 may retain the fluid and allow for access into the body 110. A nut 154 and access cover 155 may be positioned at last partially in the access bore 150. The nut 154 and access cover 155 may retain the fluid and allow for access into the body 110.
The plunger 144 may be positioned at least partially in the plunger bore 140. As described above, an end of the plunger 144 may be coupled to the power end of the pump, which may cause the plunger 144 to move axially back and forth (i.e., reciprocate) within the plunger bore 140. One or more seals 146 may be positioned (e.g., radially) between the plunger 144 and the body 110. A lower pressure fluid is available in bore suction 120, and when the plunger 144 moves away from the chamber 160 (e.g., to the right in
The planar portions of the suction wall portion 420 and/or the discharge wall portion 430 may be substantially perpendicular to the central longitudinal axis 122 and/or substantially parallel to the central longitudinal axis 142. For example, the planar portions of the suction wall portion 420 and/or the discharge wall portion 430 may be less than or equal to about 15°, less than or equal to about 10°, less than or equal to about 5°, or less than or equal to about 1° from perpendicular to the central longitudinal axis 122 and/or parallel to the central longitudinal axis 142
An average distance 421 between the central longitudinal axis 142 and the planar portion of the suction wall portion 420 may be from about 1 inch to about 6 inches, about 1.75 inches to about 4 inches, or about 2.5 inches to about 3.5 inches. Similarly, an average distance 431 between the central longitudinal axis 142 and the planar portion of the discharge wall portion 430 may be from about 1 inch to about 6 inches, about 1.75 inches to about 4 inches, or about 2.5 inches to about 3.5 inches. The average distance 421 plus (+) the average distance 431 may be referred to as a height H of the chamber 160. A ratio of the average distance 421 or the average distance 431 to a smallest diameter of the plunger bore 140 and/or the access bore 150 may be from about 2:5 to about 1:1.
The planar portions of the plunger wall portion 440 and/or the access wall portion 450 may be substantially parallel to the central longitudinal axis 122 and/or substantially perpendicular to the central longitudinal axis 142. For example, the planar portions of the plunger wall portion 440 and/or the access wall portion 450 may be less than or equal to about 15°, less than or equal to about 10°, less than or equal to about 5°, or less than or equal to about 1° from parallel to the central longitudinal axis 122 and/or perpendicular to the central longitudinal axis 142.
An average distance 441 between the central longitudinal axis 122 and the planar portion of the plunger wall portion 440 may be from about 1 inch to about 6 inches, about 2 inches to about 5 inches, or about 3 inches to about 4 inches. Similarly, an average distance 451 between the central longitudinal axis 122 and the planar portion of the access wall portion 450 may be from about 1 inch to about 6 inches, about 2 inches to about 5 inches, or about 3 inches to about 4 inches. The average distance 441 plus (+) the average distance 451 may be referred to as a width W of the chamber 160. A ratio of the average distance 441 or the average distance 451 to a smallest diameter of the suction bore 120 and/or the discharge bore 130 may be from about 1:4 to about 7:5.
A radius 480 may exist between the suction wall portion 420 and the plunger wall portion 440, between the suction wall portion 420 and the access wall portion 450, between the discharge wall portion 430 and the plunger wall portion 440, and/or between the discharge wall portion 430 and the access wall portion 450. The radius 480 may be the same or different between any two of these wall portions 420, 430, 440, 450. The radius 480 may be from about 0 inches to about 1.5 inches, about 0 inches to about 2 inches, or about 0.1 inches to about 2.5 inches.
A radius 481 may exist between the suction bore 120 and the suction wall portion 420 and/or between the discharge bore 130 and the discharge wall portion 430. The radius 481 may be from about 0 inches to about 0.8 inches, about 0 inches to about 1.0 inch, or about 0.1 inches to about 1.2 inches.
An average distance 461 between the central longitudinal axes 122, 142 and the planar portion of the first side wall portion 460 may be from about 1 inch to about 5 inches, about 2 inches to about 4 inches, or about 2.5 inches to about 3.5 inches. Similarly, an average distance 471 between the central longitudinal axes 122, 142 and the planar portion of the second side wall portion 470 may be from about 1 inch to about 5 inches, about 2 inches to about 4 inches, or about 2.5 inches to about 3.5 inches. The average distance 461 plus (+) the average distance 471 may be referred to as a depth D of the chamber 160. A ratio of the average distance 461 or the average distance 471 to a smallest diameter of the plunger bore 140 and/or the access bore 150 may be from about 1:2 to about 5:4.
The first side wall portion 460 and/or the second side wall portion 470 may include a radius 482 between the suction bore 120 and the discharge bore 130. The radius 482 may be from about 0.25 inches to about 5 inches, about 0.5 inches to about 4 inches, or about 1 inch to about 3 inches. A ratio of the radius 482 to the smallest diameter of the plunger bore 140 may be from about 1:16 to about 3:5. As discussed in greater detail below, in addition to including the radius 482, the first side wall portion 460 and/or the second side wall portion 470 may also be at least partially planar.
The radius 480 (from
The radius 481 (from
As discussed above, the planar portions of the suction wall portion 420 and the discharge wall portion 430 may be substantially perpendicular to the central longitudinal axis 122 and substantially parallel to the central longitudinal axis 142. The planar portions of the plunger wall portion 440 and the access wall portion 450 may be substantially parallel to the central longitudinal axis 122 and substantially perpendicular to the central longitudinal axis 142. The planar portions of the first side wall portion 460 and the second side wall portion 470 may be substantially parallel to the central longitudinal axes 122, 142.
Conventional fluid ends may experience greater levels of stress than the fluid end 100 proximate to the intersection of the bores 120, 130, 140, 150. For example, when the fluid is pressurized, a stress in the conventional fluid end is experienced. When the fluid reaches a similar pressure in the fluid end 100, however, the stress is only about 59% of the stress experienced by the conventional fluid end. This is due to the shape and size of the wall portions defining the chamber 160. This has reduced the stress concentration in the body 110. As a result, the fluid end 100 may be less likely to have cracks form and propagate therein when compared to a conventional fluid end. This may increase the useful life of the fluid end 100.
Simulated Stress Results
Table 1 below shows simulated stress results as the dimensions (e.g., variables) of the chamber 160 vary. The first simulation corresponds to a conventional chamber having a certain stress level (e.g., 100%) in response to a predetermined fluid pressure. The ninth simulation corresponds to the chamber 160 of the body 110, having a stress of level of about 59% of simulation 1, in response to the same predetermined fluid pressure. The other simulations illustrate how the stress levels vary in response to modifying different variables.
As used herein, the terms “inner” and “outer”; “up” and “down”; “upper” and “lower”; “upward” and “downward”; “above” and “below”; “inward” and “outward”; and other like terms as used herein refer to relative positions to one another and are not intended to denote a particular direction or spatial orientation. The terms “couple,” “coupled,” “connect,” “connection,” “connected,” “in connection with,” and “connecting” refer to “in direct connection with” or “in connection with via one or more intermediate elements or members.”
The foregoing description, for purpose of explanation, has been described with reference to specific embodiments. However, the illustrative discussions above are not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations are possible in view of the above teachings. Moreover, the order in which the elements of the methods described herein are illustrated and described may be re-arranged, and/or two or more elements may occur simultaneously. The embodiments were chosen and described in order to best explain the principals of the invention and its practical applications, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated.
