Fracturing pump assembly

Abstract

An improved fracturing pump is provided. The pump is reconfigurable on site. Internal components of the pump may be varied to meet the requirements of a specific operation. The reconfiguration gives the user the ability to increase or decrease the horsepower of the pump. A closed loop oil feed system provides constant and reliable lubrication even under heavy loads. The sealing system is enhanced to reduce leaks and thermal stresses. The pump also has an improved frame and chassis to reduce NVH and enhance reliability.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to pumps, and in particular, to an improved fracturing pump assembly.

2. Description of the Prior Art

Drilling and production systems are often employed to access and extract hydrocarbons from subterranean formations. These systems may be located onshore or offshore depending on the location of a desired resource. Further, such systems generally include a wellhead assembly mounted on a well through which the resource is accessed or extracted. These wellhead assemblies may include a wide variety of components, such as various casings, valves, pumps, fluid conduits, and the like, that control drilling or extraction operations.

Drilling and production operations, such as fracking, employ fluids referred to as drilling fluids to provide lubrication and cooling of the drill bit, clear away cuttings, and maintain desired hydrostatic pressure during operations. Drilling fluids can include all types of water-based, oil-based, or synthetic-based drilling fluids. Pumps can be used to move large quantities of fluid. Operations come to a halt if the pumps fail, and thus, reliability under harsh conditions, using all types of abrasive fluids, is of utmost commercial interest. Also, portability of these pumps is an issue, so having a versatile pump which can meet the needs of virtually any situation would be desirable.

An improved fracturing pump is provided. The pump is reconfigurable on site. Internal components of the pump may be varied to meet the requirements of a specific operation. The reconfiguration gives the user the ability to increase or decrease the horsepower of the pump. A closed loop oil feed system provides constant and reliable lubrication even under heavy loads. The sealing system is enhanced to reduce leaks and thermal stresses. The pump also has an improved frame and chassis to reduce NVH and enhance reliability.

SUMMARY OF THE INVENTION

It is a major object of the invention to provide an improved fracturing pump assembly.

It is another object of the invention to provide a fracturing pump assembly with interchangeable parts.

It is another object of the invention to provide a fracturing pump assembly with a variable power output.

It is another object of the invention to provide a fracturing pump assembly having an improved frame which utilizes partition support.

It is another object of the invention to provide a fracturing pump assembly where the pump frame is integrated into the skid chassis.

It is another object of the invention to provide a fracturing pump assembly with a closed loop lubricating system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 generally depicts a wellsite system, in accordance with one or more implementations described herein.

FIG. 2 shows a side cutaway view of a prior art pump.

FIG. 3 shows a perspective view of a first embodiment of a fracturing pump assembly.

FIG. 4 shows a perspective view of a frame and chassis configuration for the pump of FIG. 3.

FIG. 5. shows a side cutaway view of a second embodiment of the inventive system using different gearing.

FIG. 6 shows a side cutaway view illustrating the pistons and connecting rods.

FIG. 7 shows a detail of the fluid handling end.

FIG. 8 shows a detail of the bearing assembly.

FIG. 9 shows a perspective view of a third embodiment of a fracturing pump assembly.

FIG. 10 shows a perspective view of a frame and chassis configuration for the pump of FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Generally speaking, FIG. 1 illustrates a wellsite system in which the inventive fracturing pump can be employed. The wellsite system of FIG. 1 may be onshore or offshore. In the wellsite system of FIG. 1, a borehole 11 may be formed in subsurface formations by rotary drilling using any suitable technique. A drill string 12 may be suspended within the borehole 11 and may have a bottom hole assembly 100 that includes a drill bit 105 at its lower end. A surface system of the wellsite system of FIG. 1 may include a platform and derrick assembly 10 positioned over the borehole 11, the platform and derrick assembly 10 including a rotary table 16, kelly 17, hook 18 and rotary swivel 19. The drill string 12 may be rotated by the rotary table 16, energized by any suitable means, which engages the kelly 17 at the upper end of the drill string 12. The drill string 12 may be suspended from the hook 18, attached to a traveling block (not shown), through the kelly 17 and the rotary swivel 19, which permits rotation of the drill string 12 relative to the hook 18. A top drive system could alternatively be used, which may be a top drive system well known to those of ordinary skill in the art.

In the wellsite system of FIG. 1, the surface system may also include drilling fluid 26 (also referred to as fracturing) stored in a pit/tank 27 at the wellsite. A pump 29 supported on a skid 28 may deliver the drilling fluid 26 to the interior of the drill string 12 via a port in the swivel 19, causing the drilling fluid to flow downwardly through the drill string 12 as indicated by the directional arrow 8. The drilling fluid 26 may exit the drill string 12 via ports in a drill bit 105, and circulate upwardly through the annulus region between the outside of the drill string 12 and the wall of the borehole 11, as indicated by the directional arrows 9. In this manner, the drilling fluid 26 lubricates the drill bit 105 and carries formation cuttings up to the surface, as the drilling fluid 26 is returned to the pit/tank 27 for recirculation. The drilling fluid 26 also serves to maintain hydrostatic pressure and prevent well collapse. The drilling fluid 26 may also be used for telemetry purposes. A bottom hole assembly 100 of the wellsite system of FIG. 1 may include logging-while-drilling (LWD) modules 120 and 120A and/or measuring-while-drilling (MWD) modules 130 and 130A, a roto-steerable system and motor 150, and the drill bit 105.

FIG. 2 shows a cutaway side view of a prior art fracturing pump, illustrating various components of the power assembly, the portion of the pump that converts rotational energy into reciprocating motion. A pump as shown in FIG. 2 could be used as pump 29 of FIG. 1, although many other fracturing pumps, including those with designs described below in accordance with certain embodiments of the present technique, could instead be used as pump 29. Pinion gears 52 along a pinion shaft 48 drive a larger gear referred to as a bull gear 42 (e.g., a helical gear or a herringbone gear), which rotates on a crankshaft 40. Pinion shaft 48 is turned by a motor (not shown). The crankshaft 40 turns to cause rotational motion of hubs 44 disposed on the crankshaft 40, each hub 44 being connected to or integrated with a connecting rod 46. By way of the connecting rods 46, the rotational motion of the crankshaft 40 (and hub 44 connected thereto) is converted into reciprocating motion. The connecting rods 46 couple to a crosshead 54 (a crosshead block and crosshead extension as shown may be referred to collectively as the crosshead 54 herein). The crosshead 54 moves translationally constrained by guide 57. Pony rods 60 connect the crosshead 54 to a piston 58. In the fluid end of the pump, each piston 58 reciprocates to move fracturing in and out of valves in the fluid end of the pump 29.

Referring now to FIGS. 3 and 4, it can be seen that the pump 100 has a crankshaft 102, which drives connecting rods 104, which ultimately cause reciprocating action of the pistons 106 to create pumping action as in the prior art model discussed above. The pump 100 has an enhanced structural arrangement to increase pump reliability as can be seen most particularly in FIG. 4. It can be seen that the pump frame 105, has a series of partitioning structural dividing walls 107 which serve to separate the rods and pistons but is also configured to reduce NVH and increase pump reliability. In a key aspect of the invention, NVH reduction greatly increases pump reliability by reducing stresses on the pump 100. The dual chassis skid arrangement 114 is enhanced by adding multiple mounting points (for the pump 100 main body) for increased rigidity and to reduce deflection under load. In a key aspect of the invention, frame 105 and skid 114 are a single integrated structure, which greatly reduces noise, vibration, and harshness (NVH). The reduction in NVH enhances power output significantly.

Referring now to FIGS. 5 and 6 a second embodiment of the pump 200 is shown. It can be seen that the pump 200 has a crankshaft 202, which drives connecting rods 204, which ultimately cause reciprocating action of the pistons 206 to create pumping action as in the prior art model, and the previous embodiment discussed above. The pump 100 has the same enhanced structural arrangement to increase pump reliability as discussed above, modified to accommodate the different geometry of the pump 200 versus pump 100.

A closed loop oil feed system 118, (218) common to both pumps 100, 200 is part of an optimized lubrication system which reduces friction between crosshead 116 (216) and crosshead guides 117 (217). Low operating lube oil temperatures and high mechanical efficiency increase reliability.

A robust sealing system is provided to improve leak and thermal stresses handling during harsh high temperature fracturing operation in the field. As previously stated, the interior components of the pump, including the plunger 140 (240), can be interchangeably replaced to increase power output, a key aspect of the invention. In a preferred embodiment power generation for pumps 100, 200 range from 3000 HP to 4150 HP by way of interchangeable components. Also, the pumps 100, 200 allow variable high pressure output and high flow rate based on variance of plunger size and stroke length. Specifically, an 8 inch stroke creates a horsepower of about 3000 HP, with 9, 10, and 11 inch strokes creating 3400 HP, 3755 HP, and 4150 HP, respectively. (See attached spec sheet for additional details).

The enhanced fluid end assembly 123 is shown in FIG. 7. The cylindrical bearing assembly 127 is shown in FIG. 8. Both the fluid end assembly 123, and bearing assembly 127 are common to both pumps 100, 200.

FIGS. 9 and 10 shows another alternative embodiment of the pump assembly 300. The assembly 300 is a fracturing pump with gearbox drive horsepower capability that can handle ranges between 3000 Hp to 5000 HP E/T using drive power electric motor or turbine engine E/T based on a gear box ratio between 6.963:1 to 10.50:1 with optimized weight and drive stroke to meet demand for high power, pressure and less equipment.

It can be seen that the pump 300 has a crankshaft 302, which drives connecting rods, which ultimately cause reciprocating action of the pistons to create pumping action as in the prior art model discussed above. The pump 300 has an enhanced structural arrangement to increase pump reliability as can be seen most particularly in FIG. 10. It can be seen that the pump frame 305, has a series of partitioning structural dividing walls 107 which serve to separate the rods and pistons but is also configured to reduce NVH and increase pump reliability. In a key aspect of the invention, NVH reduction greatly increases pump reliability by reducing stresses on the pump 100. The dual chassis skid arrangement 314 is enhanced by adding multiple mounting points (for the pump 300 main body) for increased rigidity and to reduce deflection under load. In a key aspect of the invention, frame 305 and skid 314 are a single integrated structure, which greatly reduces noise, vibration, and harshness (NVH). The reduction in NVH enhances power output significantly.

The pump 300 uses the closed loop oil feed system 118, (218) common to pumps 100, 200, which is part of an optimized lubrication system which reduces friction between the crosshead and crosshead guides. Low operating lube oil temperatures and high mechanical efficiency increase long term reliability.

It is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims:

Claims

1. A fracturing pump assembly comprising: a frame having a plurality of bores formed therethrough; and a plurality of crossheads disposed in the plurality of bores, respectively, and adapted to reciprocate therein;

a crankshaft for imparting motive power to a plunger, said plunger situated in the fluid handling end of the pump, whereby rotation of said crankshaft causes reciprocating movement of said plunger which causes fluid to be expelled from the fluid handling end of the pump.

2. The pump assembly of claim 1 wherein said frame is mounted on a skid assembly, said skid assembly attached to said frame at multiple mounting points to distribute vibration.

3. The pump assembly of claim 1 wherein a plurality of pistons are connected to respective rods positioned within said frame, each of said rods coupled to said crankshaft for imparting rotating motive power thereto, said frame separated internally by partitioning walls.

4. The pump assembly of claim 1 wherein said pistons and rods are separated by said partitioning walls.