WO2007011812A1

WO2007011812A1 - Combined nitrogen generation system and well servicing fluid system in one power unit apparatus

Info

Publication number: WO2007011812A1
Application number: PCT/US2006/027548
Authority: WO
Inventors: James B. Crawford
Original assignee: P.E.T. International, Inc.
Priority date: 2005-07-16
Filing date: 2006-07-14
Publication date: 2007-01-25
Also published as: BRPI0612864A2; US20090151927A1; CN101248250A; JP2009501858A; CA2615633A1; EP1963621A1; MX2008000793A

Abstract

A combined system for treating an oil and/or gas well, comprising: a single transportation means having mounted thereon: a single prime mover for providing prime power for the operation of pumps and motors mounted on said transportation means; a nitrogen generator that can gather gaseous nitrogen from the earth's atmosphere; and a fluid pumping system for pumping fluids into a wellbore, said nitrogen generator and said fluid pumping system being interconnectable by plumbing and including a power transmission means responsive to the operation of said engine.

Description

COMBINED NITROGEN GENERATION SYSTEM AND WELL

SERVICING FLUID SYSTEM IN ONE POWER UNIT APPARATUS

FIELD

This invention relates, generally, to the treatment of oil and gas wells using nitrogen from the atmosphere to increase the production capability of the wells, and specifically, to providing in a single unit, all of the equipment and accessories to pump high pressure nitrogen and chemicals into the wells being treated.

BACKROUND

It is known in the art to provide work over operations using gaseous nitrogen to remove sand and/or water or other impediments to production. The prior art has not recognized that a single, relatively small unit can be provided with all of the equipment and accessories for running a nitrogen generation service and pressure pumping chemicals to treat such wells.

United States Patent 6,230,805 teaches a method of hydraulic fracturing in which at least two separate fracturing fluid components are pumped downhole, one of said components being pumped downhole within coiled tubing, but does not teach how to accomplish this with a single compact unit in which all equipment is powered by a common engine.

The prior art on land typically brings two or even three tractor-trailers to the well to be treated, one having either a liquid nitrogen tank or a large footprint nitrogen generation unit, and one having the nitrogen pumping unit, and one high pressure pumping unit for acids and other chemicals. The requirement for multiple tractor- trailers increases the transportation costs and personnel required to bring the units to the well and run this service.

United States Patent 6,273,188 teaches a trailer mounted coiled tubing rig.

United States Patent 6,702,011, also by the present inventors, teaches a combined nitrogen treatment system and coiled tubing system in one tractor/trailer apparatus. Like the present invention, a single tractor trailer unit is provided, in which the tractor itself drives a plurality of hydraulic motors that control the pumps and motors associated with a nitrogen system that is used for injecting nitrogen into a well, but unlike the present invention, no disclosure is made for the provision of well servicing fluid tanks, mixers, and pumps. Instead a crane unit and a coiled tubing injection unit are provided. Unlike the present invention, the preferred type of nitrogen system is tanks of liquid nitrogen, although an alternative mode is disclosed in which the liquid nitrogen system is replaced with one or more nitrogen generators that gather nitrogen from earth's atmosphere. However, it was not disclosed, as in the present invention, that the nitrogen could be mixed with well servicing fluids provided by the same tractor-trailer unit, but rather the nitrogen was pumped through the coiled tubing unit into the well being treated; or directly into the wellhead.

PCT Application US2004/034521, also by the present inventors, teaches a three-in- one nitrogen treatment system, fluid system, and coiled tubing system in one unit.

Like the present invention, a single tractor-trailer or marine unit is provided, in which a single engine drives a plurality of hydraulic motors that control the pumps and motors associated with a nitrogen system and a fluid system that is used for injecting nitrogen and fluid into a well, but unlike the present invention, a coil tubing system is also provided, which increases power requirements above those of the present invention. The only means disclosed for pumping fluid to the well is through the coil tubing system and no disclosure is made for the injection of well servicing fluids directly into the well. Also, no fluid blending tank is disclosed (a chemical tank, which is a tank inside a tank- double walled). The off-shore prior art that has the same functionality as the present invention, other than prior art from the present inventor, is large and expensive and requires either multiple trucks tractors and trailers, multiple barges or ships or a larger, more expensive barge or ship that has a deeper draft and can therefore depart from and reach fewer locations.

Prior art units have components that are permanently attached to a transportation unit. This is a problem if there is a need to replace or upgrade any component. Because of improvements in nitrogen generation technology, the ability to upgrade this component is especially desirable, yet is not available in the prior art.

The primary object of the present invention is to provide a small unit that can be placed on a single tractor-trailer or a small barge or ship to provide a nitrogen generation system and pump a combination of high pressure nitrogen and acids or other chemicals into wells.

SUMMARY

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevated, pictorial view of a tractor unit and part of the trailer with nitrogen generation equipment that is connected to the discharge line at a tee;

FIG. 2 is an elevated, pictorial view of the other part of the trailer from FIG. 1, which shows storage, mixing, and pumping equipment for well servicing fluid, and shows that said equipment is connected to the discharge line at the same tee that the nitrogen generation equipment is connected to;

FIG. 3 illustrates, in block diagram, the various systems that are used in accordance with the present invention to treat a well with nitrogen;

FIG. 4 is a pictorial view of three nitrogen generators;

FIG. 5 is a pictorial view of a unit using membrane technology to pull gaseous nitrogen out of the atmosphere; and

FIG. 6 is a diagram of components that are removably attached to the transportation means.

DESCRIPTION

FIG. 1 shows a tractor 10 having a prime mover, such as a gasoline engine or a diesel engine, that is used to pull the trailer 20 illustrated in FIG. 1 and FIG. 2. The tractor's engine drives all of the components that are illustrated in FIG. 1. and FIG. 2, on the tractor 10, and the trailer 20, respectively. The chassis 11 of the tractor 10 may be, for example, a Freightliner. The tractor 10 also has a hydraulic tank 12 and a tank hold- down unit 13 which secures the hydraulic tank to the chassis. A hydraulic pump 14 has a coupling and a drive mechanism connected to its one end. The coupling 16 is connected into a transfer case and drive shaft mechanism 17. A hydraulic pump 18 is one of many hydraulic pumps in the tractor assembly 10 and also includes various hydraulic pumps within the assembly 19. It should be appreciated that all of the mechanisms illustrated with the trailer 20 in FIG. 2 are driven by hydraulic pumps located on the tractor chassis 10. The assembly 15 is a hydraulic pump that includes a clutch pulley being driven by the prime mover located within the tractor 10. The tractor bed 21 has an assembly 22 that is used to connect the tractor to the trailer as illustrated in FIG. 2.

Trailer bed 30 is connected to the tractor bed 21 by way of the mechanism 22. Mounted on the trailer bed 30, is a feed air system 32 that is connected to nitrogen membranes 33. Together, the feed air system 32 and nitrogen membrane 33 function as a nitrogen generator 31 (also shown in FIG. 5) that extracts nitrogen from the atmosphere to eliminate the need for (and the associated cost of) transporting and filling nitrogen tanks. The preferred embodiment nitrogen generator 31 uses a membrane 33 (also shown in detail in FIG. 6) that allows nitrogen-rich air from the earth's atmosphere to be continuously fed into bundle housing. The air reaches the center of the bundle of membrane fibers at which point the gas consists mostly of gaseous nitrogen. The nitrogen collects in the mandrel at the center of the bundle. As the air passes through the bundle of membrane fibers, the oxygen and other fast gases pass through the wall of the membrane fibers as they go through the fibers to be collected at the end. Oxygen, water vapor, and other fast gases are continuously collected and are moved from the bundle, thus leaving the nitrogen available for injection into the well being treated. This occurs at near ambient pressure and temperature. It is an advantage of this embodiment that large volumes of nitrogen can be provided at the well site to be pumped into the well, without the need to transport that entire volume in either liquid or gaseous form to the well site. The nitrogen generators of the preferred embodiment accomplish nitrogen generation with a smaller footprint than any prior art the inventor knows. The nitrogen then flows to the nitrogen booster compressor 38 that compresses the dry nitrogen to the desired pressure. The nitrogen will then be pumped to the tee 39 where is mixes with a fluid or a fluid mix, such as an acid, and then the resulting mixture enters the discharge line 40.

Referring now to FIG. 2, mounted on the trailer bed 30 are chemical storage tanks 42 that supply chemicals to blending tanks 44 where the chemicals are mixed. The mixed chemicals flow first to the centrifugal pump 46 and then to the well servicing fluid pump 48. The mixed chemicals flow to the tee 39 where the mixed chemicals mix with nitrogen and the resulting mixture flows into the discharge line 40. From the discharge line the resulting mixture can either flow through any coil tubing unit to the well head, or flow directly to the well head

Referring now to FIG. 3, there is illustrated in block diagram some of the components that are illustrated in FIGS. 1 and 2. The nitrogen air feed system 32 has its output connected into the input of a hydraulic pump 64. The prime mover 70, which may be a gasoline or diesel powered engine, has a return line 74. A hydraulic pump 90 is connected into a hydraulic motor 92 that is used to drive the return line 74.

Another hydraulic pump 96 drives a motor 98 to drive the crane 46 that is illustrated in FIG. 2.

Another hydraulic pump 100 drives a motor 102 to power the blending tanks that are illustrated in FIG. 2.

It should be appreciated that the prime mover 70 drives each of the hydraulic pumps 64, 90, 96 and 100 as shown by the line 106. Coming off of the prime mover 70, the hydraulic pump 64, 90, 96 and 100 are preferably driven by one or more belts that can be used with clutch pulleys as desired. A compressor unit 108 that is also driven by the prime mover 70 is run off of the drive line 106 to assist in keeping the liquid nitrogen down to its desired temperature.

It should be appreciated that while the prime mover 70 is obviously and desirably located on the tractor, and the nitrogen generation system and well servicing fluid system are preferably located on the trailer, most of the other items identified in FIG. 3 can be found on either the tractor and/or the trailer as desired. The important feature of this invention is to recognize that all of the items shown in FIG. 3 are located on a combined tractor/trailer configuration that does not require the use of either another tractor or another trailer.

Nitrogen generators, shown in FIG. 4, extract nitrogen from the atmosphere, which can eliminate the costs of transporting and filling nitrogen tanks. Some of such nitrogen generators utilize a membrane, shown in FIG. 5, which allows nitrogen-rich air from the earth's atmosphere to be continuously fed into bundle housing. The air reaches the center of the bundle of membrane fibers that at that point, consists mostly of gaseous nitrogen. The nitrogen collects in the mandrel at the center of the bundle. As the air passes through the bundle of membrane fibers, the oxygen and other fast gases pass through the wall of the membrane fibers as they go through the fibers to be collected at the end. Oxygen and the other fast gases are continuously collected and are moved from the bundle, thus leaving the nitrogen available to be used for injection into the well being treated. By stacking a plurality of such nitrogen generators, available volumes are provided that have an increased flow capability.

Referring now to FIG. 6, each component [blending tank 44, prime mover 70 (with fuel pump 400), nitrogen generator 31 with hydraulic compressor 38, and chemical storage tank 42] is removably connected to the transportation means 30 by connectors 300. This makes it possible to replace or upgrade any component. Because of improvements in nitrogen generation technology, the ability to upgrade this component is especially desirable. In the near future, more efficient compressors that use less fuel are expected to reach the market. It is also possible to swap a nitrogen generator for a nitrogen tank and vice versa.

The nitrogen generator 31 as a stand alone unit is available commercially. Combination of a nitrogen generator with fluid pumping and mixing on a single tractor-trailer and all powered by a single prime mover is not known in the prior art to the best of the inventor's knowledge, and as far the inventor knows, the preferred embodiment of the invention has a smaller footprint than any functional equivalent.

The preferred embodiment of the present invention can be used for any application that requires pressure pumping various chemicals, including but not limited to:

- completions workovers underbalanced drilling - well servicing enhanced oil recovery

- industrial plant degassing and purging mining

- purging pipelines with nitrogen - deepwater marine applications

- LNG & LPG tanks and facilities

- nitrogen lifting, the lifting of fluids from wells when the well does not have sufficient pressure (insufficient bottom hole pressure for production). The present embodiment can operate as a stand-alone unit or operate with a separate coil tubing unit and is also compatible with any coil tubing unit. When working with a separate coil tubing unit, connecting discharge line 40 of the preferred embodiment to the coil tubing unit allows the coil tubing unit to pump nitrogen and chemical mixtures into the well.

As a stand alone unit, without a coil tubing unit, the preferred embodiment can do well servicing:

- nitrified acid - nitrogen displacement pipeline testing

- tubing testing

- acidizing

- cleanouts fix sanding up

- parafins

Connected to a separate coil tubing unit the preferred embodiment can: foam wash - jet with nitrogen

- nitrify acid nitrogen inhibitor

One advantage of the preferred embodiment is that it makes it possible to do with one tractor-trailer what previously required three tractor-trailers: a liquid nitrogen tank transport truck, a second tractor trailer with a high pressure pumping system for other chemicals and acids, and a third tractor trailer with a nitrogen pumping unit. Because this embodiment allows one tractor-trailer to do what once require several connected together with the requisite hoses and plumbing, the time and expense of plumbing the separate units together is avoided. Plumbing all three systems together before rigging up to the well is avoided. Disconnecting and stowing all of the plumbing after completion is also avoided, saving additional time and labor. Where the prior art took three tractor-trailers and three days (one day each for set-up, well treatment, and disassembly), the preferred embodiment can do the same job with one tractor-trailer in one day. The danger of transporting liquid, which is an explosion hazard, is also avoided. Tripping hazards associated with the plumbing and hoses are also avoided.

The preferred embodiment is even more advantageous in remote locations where liquid nitrogen is rare and expensive, or extremely difficult to transport to the well head.

It should be noted that while the embodiment described so far is mounted on and uses the engine of a tractor-trailer, the invention can also be mounted on skids and powered by a prime mover such as a marine engine and is equally suited for off shore use. Because of its small footprint, this invention allows replacement of large, expensive barges or ships with much smaller and cheaper barges or ships that have shallower drafts.

Although the present invention has been described by reference to its preferred embodiment as is disclosed in the specification and drawings above, many more embodiments of the present invention are possible without departing from the invention. Thus, the scope of the invention should be limited only by the appended claims.

Claims

1. A combined system for treating an oil and/or gas well, comprising: a. a transportation means having mounted thereon: i. a single prime mover for providing prime power for the operation of pumps and motors mounted on said transportation means; ii. a nitrogen generator that has a gaseous nitrogen gathering capability for gathering nitrogen from the earth's atmosphere; and iii. a fluid pumping system for pumping fluids into a wellbore, b. said nitrogen generator and said fluid pumping system each being interconnectable by plumbing and responsive to the operation of said prime mover.

2. The system according to claim 1 wherein said transportation means comprises a tractor-trailer.

3. The system according to claim 1 wherein said transportation means comprises a marine vessel.

4. The system according to claim 1 wherein said transportation means comprises a skid.

5. The system according to claim 1 further comprising attachments for connecting said fluid pumping system to a coil tubing unit.

6. The system according to claim 1 further comprising acid tanks and wherein said fluid pumping system comprises high pressure pumps.

7. The system according to claim 1 further comprising a fluid blending tank, said fluid blending tank, said nitrogen generator, and said fluid pumping system each being interconnectable by plumbing and responsive to the operation of said prime mover.

8. The system according to claim 1 wherein all components are controlled by a single control panel.

9. The system according to claim 1 wherein said components, including said nitrogen generator, are removably attached to said transportation means so that individual components may be replaced.

10. The system according to claim 1 wherein said nitrogen generator is no larger than a standard liquid nitrogen tank.