Mud pump systems for drilling operations

Abstract

A system for pumping fluid (e.g., but not limited to, drilling fluid), the system having pump apparatus with a pumping section and a motor section, the pumping section having an inlet and an outlet, the motor section having a shaft for reciprocating in and out of the pumping section to alternately suck fluid into the inlet and pump fluid out the outlet, and the motor being a permanent magnet linear motor for moving the shaft in a reciprocating motion, e.g., but not limited to, vertically or horizontally; and methods for using such a system.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

This present invention is directed to drilling wellbores in the earth, to systems for providing drilling fluid (“mud”) for such operations, controls for such systems, and methods of the use of such systems.

2. Description of Related Art

The prior art discloses a wide variety of drilling systems, apparatuses, and methods including, but not limited to, the disclosures in U.S. Pat. Nos. 6,944,547; 6,918,453; 6,802,378; 6,050,348; 5,465,799; 4,995,465; 4,854,397; and 3,658,138, all incorporated fully herein for all purposes. The prior art discloses a wide variety of drilling fluid pumps (“mud pumps”) used in drilling operations and pump systems, for example, and not by way of limitation, those pumps and systems disclosed in U.S. Pat. No. 6,257,354; 4,295,366; 4,527,959; 5,616,009; 4,242,057; 4,676,724; 5,823,093; 5,960,700; 5,059,101; 5,253,987; and in U.S. application Ser. No. 10/833,921 filed Apr. 28, 2004 (all said U.S. references incorporated fully herein for all purposes).

By rotating a drill bit carried at an end of a drillstring wellbores are formed in the earth. Certain drillstrings include tubulars which may be drill pipe made of jointed sections or a continuous coiled tubing and a drilling assembly that has a drill bit at its bottom end. The drilling assembly is attached to the bottom end of the tubing or drillstring. In certain systems, to drill a wellbore, the drill bit is rotated by a downhole mud motor carried by the drilling assembly and/or by rotating the drill pipe (e.g. with a rotary system, power swivel, or with a top drive system). A drilling fluid, also referred to as “mud,” is pumped under pressure from a pit or container at the surface by a pumping system at the surface.

Drilling fluid or mud can serve a variety of purposes. It can provide downhole hydrostatic pressure that is greater than the formation pressure to control the pressure of fluid in the earth formation being drilled and to avoid blow outs. The mud drives a downhole drilling motor (when used) and it also provides lubrication to various elements of the drill string. Commonly used drilling fluids are either water-based or oil-based fluids. They can also contain a variety of additives which provide desired viscosity, lubricating characteristics, heat, anti-corrosion and other performance characteristics.

During drilling, the mud that is pumped downhole by the mud pump system is discharged at the bottom of the drill bit and returns to the surface via the annular space between the tubulars of the drillstring and the wellbore inside (also referred to as the “annulus”).

Certain prior, known mud pumps and mud pump systems have relatively complex and relatively heavy drive systems with typical connecting rods, eccentric shafts, and multiple rotating bearings, and many of these parts require constant lubrication. Certain prior “triplex” systems have a relatively large footprint.

BRIEF SUMMARY OF THE INVENTION

The present invention discloses, in certain aspects, a drilling fluid pumping system, also known as a mud pump system, for pumping drilling fluid or mud used in wellbore operations. In certain aspects a permanent magnet linear motor operates a pump apparatus to pump the fluid. In certain aspects of systems according to the present invention in which a linear motor applies power directly, increased efficiencies are possible.

A mud pump system according to the present invention may have one, two-ten, or more mud pump apparatuses, each with a permanent magnet linear motor. In one aspect, the present invention discloses a system for pumping fluid (e.g., but not limited to, drilling fluid), the system having pump apparatus with a pumping section and a motor section, the pumping section having an inlet and an outlet, the motor section having a shaft for reciprocating in and out of the pumping section to alternately suck fluid into the inlet and pump fluid out the outlet, and the motor being a permanent magnet linear motor for moving the shaft in a reciprocating motion, e.g., but not limited to, vertically or horizontally; and methods for using such a system.

It is, therefore, an object of at least certain preferred embodiments of the present invention to provide new, useful, unique, efficient, nonobvious fluid pumping systems, methods of their use, drilling systems and methods, and mud pump systems for use in drilling operations.

Certain embodiments of this invention are not limited to any particular individual feature disclosed here, but include combinations of them distinguished from the prior art in their structures, functions, and/or results achieved. Features of the invention have been broadly described so that the detailed descriptions that follow may be better understood, and in order that the contributions of this invention to the arts may be better appreciated. There are, of course, additional aspects of the invention described below and which may be included in the subject matter of the claims to this invention. Those skilled in the art who have the benefit of this invention, its teachings, and suggestions will appreciate that the conceptions of this disclosure may be used as a creative basis for designing other structures, methods and systems for carrying out and practicing the present invention. The claims of this invention are to be read to include any legally equivalent devices or methods which do not depart from the spirit and scope of the present invention.

The present invention recognizes and addresses the problems and needs in this area and provides a solution to those problems and a satisfactory meeting of those needs in its various possible embodiments and equivalents thereof. To one of skill in this art who has the benefits of this invention's realizations, teachings, disclosures, and suggestions, other purposes and advantages will be appreciated from the following description of certain preferred embodiments, given for the purpose of disclosure, when taken in conjunction with the accompanying drawings. The detail in these descriptions is not intended to thwart this patent's object to claim this invention no matter how others may later attempt to disguise it by variations in form, changes, or additions of further improvements.

The Abstract that is part hereof is to enable the U.S. Patent and Trademark Office and the public generally, and scientists, engineers, researchers, and practitioners in the art who are not familiar with patent terms or legal terms of phraseology to determine quickly from a cursory inspection or review the nature and general area of the disclosure of this invention. The Abstract is neither intended to define the invention, which is done by the claims, nor is it intended to be limiting of the scope of the invention or of the claims in any way.

It will be understood that the various embodiments of the present invention may include one, some, or all of the disclosed, described, and/or enumerated improvements and/or technical advantages and/or elements in claims to this invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

A more particular description of embodiments of the invention briefly summarized above may be had by references to the embodiments which are shown in the drawings which form a part of this specification. These drawings illustrate certain preferred embodiments and are not to be used to improperly limit the scope of the invention which may have other equally effective or legally equivalent embodiments.

FIG. 1 is a schematic view, partially cutaway, of a system according to the present invention.

FIG. 2A is a perspective view of a pump apparatus according to the present invention.

FIG. 2B is a side view of a pump apparatus of FIG. 2A.

FIG. 3A is a perspective view of a pump apparatus according to the present invention.

FIG. 3B is a side view of a pump apparatus of FIG. 3A.

FIG. 4A is a perspective view of a pump apparatus according to the present invention.

FIG. 4B is a perspective view of a pump apparatus according to the present invention.

FIG. 4C is a perspective view of a pump apparatus according to the present invention.

FIG. 5A is a perspective view of a pump apparatus according to the present invention.

FIG. 5B is a top view of the pump apparatus of FIG. 5A.

FIG. 5C is a side view of the pump apparatus of FIG. 5A.

FIG. 6 is a schematic cutaway side view of a pump apparatus according to the present invention.

FIG. 7A is a front schematic view of a system according to the present invention.

FIG. 7B is a top view of the system of FIG. 7A.

FIG. 7C is a top view of a system according to the present invention.

FIG. 7D is a top view of a system according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The system 500 shown in FIG. 1 includes a derrick 502 from which extends a drillstring 504 into the earth 506. The drillstring 504, as is well known, can include drill pipes and drill collars. A drill bit 512 is at the end of the drillstring. A rotary system 514, top drive system 526, and/or a downhole motor 532 (“fluid motor”, “mud motor”) may be used to rotate the drillstring 504 and the drill bit 512. A typical drawworks 516 has a cable or rope apparatus 518 for supporting items in the derrick 502. A mud pump system 522 with one, two, three-to-ten, or more mud pumps 521 according to the present invention supplies drilling fluid 524 to the drillstring 504. Drilling forms a wellbore 530 extending down into the earth 506.

During drilling, the drilling fluid 524 is pumped by pump(s) 521 of the mud pump system 522 into the drillstring 504 (thereby operating a downhole motor 532 if such an optional motor is used). Drilling fluid 524 flows to the drill bit 512, and then flows into the wellbore 530 through passages in the drill bit 512. Circulation of the drilling fluid 524 transports earth and/or rock cuttings, debris, etc. from the bottom of the wellbore 530 to the surface through an annulus 527 between a well wall of the wellbore 530 and the drillstring 504. The cuttings are removed from the drilling fluid 524 so that it may be re-circulated from a mud pit or container 528 by the pump(s) of the mud pump system 522 back to the drillstring 506.

FIGS. 2A and 2B show a mud pump apparatus 10 according to the present invention which includes a typical single-action pump end 12 with a discharge port 14 through which drilling fluid is pumped out and a suction line 16 into which drilling fluid is sucked by action of a permanent magnet linear motor 20. A frame 21 supports the motor 20. A shaft 22 of the motor 20 reciprocates within a liner 23 and a body 24 of the pump end 12 to provide the pumping action for the drilling fluid. Appropriate check valves 15 and 17 are used for the port 14 and the line 16, respectively.

As with any permanent magnet linear motor in any system according to the present invention, the motor 20 may be a motor, with suitable power output as disclosed in U.S. Pat. Nos. 5,910,691; 5,175,455; 6,960,858; or 6,864,647 (or any permanent magnet linear motor disclosed in any reference cited in these patents), said patents incorporated fully herein for all purposes.

FIGS. 3A and 3B show a mud pump apparatus 30 according to the present invention like the apparatus 10 (and like numerals indicate like parts). A pump end 32 is a typical double-acting pump with a body 34 within which (shown schematically) is a typical double-acting mechanism 36. Drilling fluid is sucked in through a suction inlet 33 and pumped out through a discharge port 38. Known valving and seals are used (as is the case with all pump ends disclosed herein).

FIGS. 4A-4C illustrate mud pump systems according to the present invention with multiple pump apparatuses according to the present invention.

FIG. 4A shows a system 40 according to the present invention with three mud pump apparatuses 41, 42, 43 according to the present invention connected in parallel via connections 44, 45 with a main discharge port 47 and a common suction line 46 which provides fluid to all the apparatuses. The mud pump apparatuses 41, 42, 43 may be as any disclosed herein according to the present invention.

FIG. 4B shows a system 50 according to the present invention with six mud pump apparatuses 51, 52, 53, 54, 55, 56 according to the present invention connected in parallel via connection 59 with a main discharge port 57 and a common suction line 58 which provides fluid to all the apparatuses. The mud pump apparatuses 51, 52, 53, 54, 55, 56 may be as any disclosed herein according to the present invention.

FIG. 4C shows a system 60 according to the present invention with eight mud pump apparatuses 61a, 61b, 61c, 61d, 61e, 61f, 61g, 61h according to the present invention connected in parallel via connections 62, 63 with a main discharge port 67 and a common suction line 66 which provides fluid to all the apparatuses. The mud pump apparatuses 61a, 61b, 61c, 61d, 61e, 61f, 61g, 61h may be as any disclosed herein according to the present invention.

FIGS. 5A-5C show a system 70 according to the present invention which has six mud pump apparatuses 72 according to the present invention (which may be any mud pump apparatus according to the present invention disclosed herein). Via a suction line 71, a suction manifold 78 and individual suction lines 73, drilling fluid is sucked into each of the apparatuses 72. Via connections 74, 75 and lines 76 each apparatus 72 pumps fluid to a main discharge port 77. In certain aspects (and as compared to certain prior art systems) due to the pieces and parts of the system 70 (and systems according to the present invention with upright motors with motor shafts that reciprocate substantially veritically) which project vertically upwardly, such a system according to the present invention can occupy relatively less space than certain prior art systems, i.e., with certain systems according to the present invention a relatively smaller footprint is achieved.

It is within the scope of the present invention for any mud pump apparatus of the present invention to be single-acting or double-acting.

FIG. 6 shows schematically a diagram of a system 100 according to the present invention which includes a drillstring 115 with tubulars 116 that have a drill bit 118 at its bottom end. A drilling fluid 120 is pumped by a mud pump system 110 from a source (container or mud pit) 140 into the drillstring 115 by one or more mud pumps 110a-110c according to the present invention in the mud pump system 110. The drill bit 118 is rotated (by any system or apparatus as described herein) by rotating the drillstring 115. The drill bit 118 cuts the earth formation into fragments 124 (referred to in as “cuttings”). The drilling fluid 120 discharges at the drill bit bottom 118a and returns to the surface 102 via an annulus 122 carrying the cuttings 124. The returning drilling fluid 126 passes into a riser 128, and then into a return line 130. The fluid 126 returning from the wellbore may be a three phase fluid: liquid, gas and solids. Optionally, the fluid 126 from the return line 130 passes to a shaker that removes the cuttings 124. Optionally, the fluid 126 is then processed in a processor 145. The fluid 120 flows to the pit 140 for pumping down the drillstring 115.

Each of the mud pump apparatuses 110a, 110b, and 110c includes a motor 131 (like any permanent magnet linear motor disclosed herein) with a shaft 132 (like the shaft 22, FIG. 2A) extending into a pump end 133 (like any pump end disclosed or referred to herein). A control system 160 controls the operation of the pump apparatuses 110a, 110b, 110c. In one aspect, the control system automatically insures that the flow of drilling fluid into the drillstring 115 is at a constant rate (gals/min) and, in certain aspects, at a variable pressure with a constant stroke speed. Within limits pressure may be held constant by varying speed and flow rate. A typical range for certain mud system flow is between 500 and 2200 gallons per minute and typical pressures range between 1000 and 7500 psi.

The control system 160 receives flow and pressure information from sensors: sensors for position/direction/location of shaft; sensors for fluid discharge pressure; sensors for shaft velocity calculations for flow and pressure control; and sensors indicating number of strokes (in one aspect, parameters sensed by the sensors used to inhibit or eliminate pulsations). For example, in one aspect sensors 161 sense position of the motor shafts; sensors 162 sense pressure; and sensors 163 count piston strokes.

The control system 160 has computing apparatus, e.g. computer(s), and/or PLC's; and/or there may be a separate control system for pump(s) (e.g. for turning pumps on and off as needed) and/or which can manage the pumping system.

In one aspect with a system 100 unwanted pulsation can be inhibited or eliminated. As one piston (pump) is about to stroke out and is slowing down, another piston (pump) increases in speed. These are controlled by controlling the linear motion speed of the pumps.

Systems according to the present invention are useful for pumping, among other things, any fluid pumpable by a reciprocating pump.

FIGS. 7A and 7B show a system 200 according to the present invention which includes a pump system 202 according to the present invention which is mounted on a support 204 (e.g., but not limited to, a wall or support member of a structure or a wall, beam, or mast portion of a drilling rig).

As shown in FIG. 7B the pump system 202 is mounted flush against the support 204. As shown in FIG. 7C the pump system 202 may be supported by and spaced-apart from the support 204 by members 206.

FIG. 7D shows a system 220 according to the present invention with multiple pump systems 222 according to the present invention each secured to a support 224 (like the support 204, FIG. 7A). The pump systems 222 may be upright (as shown in FIG. 7D) or they may be positioned generally horizontally. A motor of a pump in system according to the present invention may be on a support that is substantially flat (e.g. frame 21, FIG. 2B) or the motor may be supported upright so that the motor shaft moves up and down in a substantially vertical movement.

The present invention, therefore, provides in at least some embodiments, a system for pumping fluid having a pump apparatus with a pumping section and a motor section, the pumping section with a body with an inlet and an outlet, the motor section with a shaft for reciprocating in and out to alternately suck fluid (e.g., but not limited to, drilling fluid) into the inlet and pump fluid out the outlet, and the motor being a permanent magnet linear motor. Such a system according to the present invention may have one or some (in any possible combination) of the following: wherein the pump apparatus is single acting; wherein the pump apparatus is double acting; a control system for controlling the pump apparatus; wherein the control system maintains a flow at a constant rate from the pump apparatus; wherein the control system maintains a constant pressure of fluid output from the pump apparatus; wherein the pump apparatus includes a plurality of pump apparatuses each with a pumping section and a permanent magnet linear motor; and/or wherein the or each permanent magnet linear motor is supported by a substantially flat support so that the shaft is reciprocal substantially horizontally or the or each permanent magnet linear motor is supported so that the shaft is reciprocal substantially vertically.

In conclusion, therefore, it is seen that the present invention and the embodiments disclosed herein are well adapted to carry out the objectives and obtain the ends set forth. Certain changes can be made in the subject matter without departing from the spirit and the scope of this invention. It is realized that changes are possible within the scope of this invention and it is further intended that each element or step recited herein is to be understood as referring to the step literally and/or to all equivalent elements or steps. This specification is intended to cover the invention as broadly as legally possible in whatever form it may be utilized. All patents and applications identified herein are incorporated fully herein for all purposes.

Claims

1. A system for pumping fluid, the system comprising

a pump apparatus including a pumping section and a motor section,

the pumping section having a body with an inlet and an outlet,

the motor section having a shaft for reciprocating in and out of the pumping section to alternately suck fluid into the inlet and pump fluid out the outlet, and

the motor comprising a permanent magnet linear motor for moving the shaft in a reciprocating motion.

2. The system of claim 1 wherein the pump apparatus is single acting.

3. The system of claim 1 wherein the pump apparatus is double acting.

4. The system of claim 1 further comprising

a control system for controlling the pump apparatus.

5. The system of claim 4 wherein the control system maintains a flow at a constant rate from the pump apparatus.

6. The system of claim 4 wherein the control system maintains a constant pressure of fluid output from the pump apparatus.

7. The system of claim 1 wherein the pump apparatus includes a plurality of pump apparatuses each with a pumping section and a permanent magnet linear motor each with a shaft.

8. The system of claim 1 wherein the permanent magnet linear motor is supported by a substantially flat support so that the shaft is reciprocal substantially horizontally.

9. The system of claim 1 wherein the permanent magnet linear motor is supported so that the shaft is reciprocal substantially vertically.

10. The system of claim 7 wherein each permanent magnet linear motor is supported by a substantially flat support so that the shaft of each of said motors is reciprocal substantially horizontally.

11. The system of claim 7 wherein each permanent magnet linear motor is supported so that the shaft of each of said motors is reciprocal substantially vertically.

12. A system for pumping drilling fluid for wellbore operations, the system comprising

a pump apparatus including a pumping section and a motor section,

the pumping section having a body with an inlet and an outlet,

the motor section having a shaft for reciprocating in and out of the pumping section to alternately suck drilling fluid into the inlet and pump drilling fluid out the outlet,

the motor comprising a permanent magnet linear motor for moving the shaft in a reciprocating motion.

12. The system of claim 12 wherein the pump apparatus is single acting.

13. The system of claim 12 wherein the pump apparatus is double acting.

14. The system of claim 12 further comprising a control system for controlling the pump apparatus.

15. The system of claim 14 wherein the control system maintains a flow at a constant rate from the pump apparatus.

16. The system of claim 14 wherein the control system maintains a constant pressure of fluid output from the pump apparatus.

17. The system of claim 12 wherein the pump apparatus includes a plurality of pump apparatuses each with a pumping section and a permanent magnet linear motor.

18. The system of claim 12 wherein the permanent magnet linear motor is supported by a substantially flat support so that the shaft is reciprocal substantially horizontally, or wherein the permanent magnet linear motor is supported so that the shaft is reciprocal substantially vetrically.

19. A method for pumping fluid, the method comprising comprising

sucking fluid into an inlet of a pumping section of a system, the system comprising a pump apparatus including a pumping section and a motor section, the pumping section having a body with an inlet and an outlet, the motor section having a shaft for reciprocating in and out of the pumping section to alternately suck fluid into the inlet and pump fluid out the outlet, the motor comprising a permanent magnet linear motor for moving the shaft in a reciprocating motion and

with the pump apparatus, pumping fluid out the outlet.

20. The method of claim 19 wherein the fluid is drilling fluid.