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&#39;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:
FIELD 
       [0001]    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. 
       BACKGROUND 
       [0002]    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. 
         [0003]    U.S. Pat. No. 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. 
         [0004]    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. 
         [0005]    U.S. Pat. No. 6,273,188 teaches a trailer mounted coiled tubing rig. 
         [0006]    U.S. Pat. No. 6,702,011, also by the present inventors, teaches a combined nitrogen treatment system and coiled tubing system in one tractor/trailer apparatus. 
         [0007]    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&#39;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. 
         [0008]    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). 
         [0009]    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. 
         [0010]    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. 
         [0011]    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 
       [0012]    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&#39;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. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      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; 
           [0014]      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; 
           [0015]      FIG. 3  illustrates, in block diagram, the various systems that are used in accordance with the present invention to treat a well with nitrogen; 
           [0016]      FIG. 4  is a pictorial view of three nitrogen generators; 
           [0017]      FIG. 5  is a pictorial view of a unit using membrane technology to pull gaseous nitrogen out of the atmosphere; and 
           [0018]      FIG. 6  is a diagram of components that are removably attached to the transportation means. 
       
    
    
     DESCRIPTION 
       [0019]      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&#39;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 . 
         [0020]    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&#39;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 . 
         [0021]    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 
         [0022]    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 . 
         [0023]    Another hydraulic pump  96  drives a motor  98  to drive the crane  46  that is illustrated in  FIG. 2 . 
         [0024]    Another hydraulic pump  100  drives a motor  102  to power the blending tanks that are illustrated in  FIG. 2 . 
         [0025]    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. 
         [0026]    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. 
         [0027]    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&#39;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. 
         [0028]    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. 
         [0029]    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&#39;s knowledge, and as far the inventor knows, the preferred embodiment of the invention has a smaller footprint than any functional equivalent. 
         [0030]    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 &amp; 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).       
 
         [0042]    The preferred 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. 
         [0043]    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       
 
         [0052]    Connected to a separate coil tubing unit the preferred embodiment can:
       foam wash   jet with nitrogen   nitrify acid   nitrogen inhibitor       
 
         [0057]    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. 
         [0058]    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. 
         [0059]    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. 
         [0060]    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.