Abstract:
An alternative apparatus and pumping method for retrieving liquids from a wellbore without the use of a pumping unit as customarily used in oil field operations.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to an alternative apparatus and pumping method for retrieving liquids from a wellbore without the use of a pumping unit as customarily used in oil field operations. This unit is primarily targeted for gas well deliquification and/or low fluid volume oil or condensate wells. 
       BACKGROUND OF THE INVENTION 
       [0002]    In typical oil field operations, when liquids are recovered from oil and gas wells, the wells are equipped with a pumping unit which reciprocates sucker rods upwardly and downwardly in the well to activate a down-hole pump which pumps liquids, such as oil, water and mixtures thereof, to the surface. The maintenance of such equipment is relatively expensive, as is the equipment itself. Further in relatively low production wells it is continually necessary to adjust the speed and run time of the pumping unit, and the like to keep the level of the well liquids above the top of the pump. It is detrimental to operate a pump above the level of the liquid. 
         [0003]    In many instances, it is desirable to remove liquids from a wellbore by a different approach. The different approach is desirably one which does not require the use of the expensive equipment or the continued adjustments based upon the level of liquids in the well. 
         [0004]    Accordingly, a continuing search has been directed to a method for effectively removing liquids from such wells. 
       SUMMARY OF THE INVENTION 
       [0005]    According to the present invention, such liquids are readily recovered by an apparatus for recovering liquids from a well containing a tubular member having an inside and extending from an earth surface to penetrate a liquid producing subterranean formation, the apparatus comprising: a body having a body top and a body, a round exterior surface, openings in the body top and a valve in the body; a flexible support member extending from a system for raising and lowering the flexible support member in the wellbore and connected to the body top. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a schematic diagram of a prior art pumping system for recovering liquids from a subterranean liquid producing formation; 
           [0007]      FIG. 2  is a schematic diagram of an embodiment of the present invention; 
           [0008]      FIG. 3  is a schematic diagram of a further embodiment of the present invention; 
           [0009]      FIG. 4  is a schematic diagram of an embodiment of a body used to lift liquids according to the embodiment of the present invention; 
           [0010]      FIG. 5  is a schematic diagram of an alternate and larger embodiment of the body to use to lift liquids according to the embodiment of the present invention; 
           [0011]      FIG. 6  is a schematic diagram of a further alternate apparatus for producing liquids; and, 
           [0012]      FIG. 7  is a schematic diagram of a system useful for raising and lowering a slick line, wire line, copper tubing or the like into and retrieving the line from a well. 
       
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0013]    In the discussion of the Figures, the same numbers will be used throughout to refer to the same or similar components. 
         [0014]    In  FIG. 1  an embodiment of a prior art apparatus for the production of liquids from a subterranean formation is shown. A well  10  is shown extending from an earth surface  12  through an overburden  14  to a liquid bearing formation  16 . The well includes a casing  18  which is cemented into place by cement  20  with the casing having an inside  19 . Perforations  22  are positioned through casing  18  in the liquid producing formation and a pump  24  is positioned to pump fluids to the surface based upon reciprocal motion of sucker rods  26 . The fluids are produced through a production tubing  28  having an inside  30  through which the liquid is pumped and discharged through a production flow line  32 . A liquid level  34  is desirably maintained in well  10  above the top of pump  24  for operations. The well may include a tubing anchor catcher and centralizer at a position in the lower portion of the tubing. Such a tubing catcher and centralizer are shown at  39 . 
         [0015]    In  FIG. 2  an embodiment of the present invention is shown. The pump  24  and sucker rods  26  are no longer needed however a seal  38  is positioned in the top of production tubing  28  to permit the entry and movement of a flexible slick line  40  or the like through the seal. “Slick line” refers to a flexible solid wire which may be used to raise and lower apparatus in a production casing or in a production tubing. Other equipment which could be used for such purposes comprises wire lines, braided steel line, plastic line, and other various materials. The use of the term “wire line” is used to refer to a wire like flexible material which may comprise a plurality of strands. 
         [0016]    The present invention comprises a body  42 , which is shown positioned beneath the liquid level  34 . The body is connected via a slick line  40  to a system for raising the body in the production tubing. The body  42  includes a top  44  and a bottom  46 . The body is lowered to a position near the bottom  52  of the well. Desirably the body is lowered to a position beneath perforations  22  into subterranean formation  16 . Further it may be desirable that seals (not shown) be positioned around the outside surface of the body to minimize the amount of fluid that will leak between the body  42  and tubing  28 . 
         [0017]    In the operation of the apparatus shown in  FIG. 2 , liquids are shown to have accumulated to a level  34  in well  10 . These liquids may be petroleum, petroleum distillates, water, mixtures thereof and the like. It may be desirable from time to time to recover these liquids. Especially if the well is a relatively low production well, it may not be feasible to maintain a pumping unit at the well so alternate methods of producing these liquids are necessary if the well is to be produced at low, although profitable, levels. The body is positioned so that when raised by the slick line it moves liquids in production tubing  28  upwardly through the well for production through the production flow line  32 . 
         [0018]    The body in its raised position is shown in  FIG. 3  with the well having a reduced level  34 . The body may then be lowered into well  10  and is adapted to readily sink into production tubing  28  through the liquid for retrieval to remove additional liquid from the well. 
         [0019]    An embodiment of the body  42  is shown in  FIG. 4  and, as shown, includes holes  72  in its top through which liquid can flow as shown by arrows  85 . Liquid flow into the body is shown by arrow  84 . A slick line wire is shown connected to a connector  70  on the top of body  42 . As the body  42  is lowered into the liquid, pressure under the ball  50  forces the ball to un-seat from the ball seat  48 . The action between ball  50  and seat  48  acts as a ball and seat valve. Liquid can thus flow into and through the body to permit readily lowering the body through a liquid level. If unusual or extreme conditions exist within well  10  rubber or plastic seals (not shown) would be placed in the machined grooves  78  on the outside of the tool  42 . The top  44  and bottom  46  of the body  42  are connected by the threaded section  47  at the top of part  46 . Machined channels  49  allow for wrenches to tighten part  44  to part  46  without affecting the close tolerance of the tool  42  and the tubing  28 .  FIG. 5  is an alternative embodiment of  FIG. 4  in that it is a larger diameter tool for use in larger diameter tubing. 
         [0020]    In  FIG. 6  an alternate embodiment of the body shown in  FIGS. 4 and 5  is shown. This embodiment is shown in a position for lowering the body into a liquid. Further, seals not shown in this embodiment are slightly different and comprise seals similar to o-rings seated in grooves  78  in a wall of the body  42   
         [0021]    A variety of seals of different configurations can be used with equal success. The seals shown are considered to be illustrative of the use of seals and it should be noted that the drawings are not drawn to scale. In a preferred embodiment, the mechanical clearance between the outside of body  42  and inside  30  of production tubing  28  is maintained at very close tolerances. This permits the withdrawal of the liquid effectively by the use of the body without respect to the seals. 
         [0022]    In some applications, it is desirable to have seals rather than closer tolerances since it is considered that the seals can be more effectively lowered into the liquid layer than can a very tightly toleranced body. Typically when no seals are used it is desirable that the clearance between an outer surface of the body  42  and the inside surface of the production tubing be such that a very small amount of liquid would flow past the body  42 . Somewhat larger tolerances between outer surface and the inside of the production tubing may be used when seals are used since the seals will facilitate prevention of leakage of liquids past the body. 
         [0023]    In  FIG. 7  a system is shown for lowering the slick line into the well. Slick line  40  is passed over a roller and mounting bracket  56  and accumulated on or discharged from a slick line drum  58 . As indicated previously, wire lines, polymer lines and the like may be used in lieu of the slick line. The wire line drum is supported on a support  60  and includes a pulley  62  which is driven by a belt  68  from a motor  64 , which is preferably an electric motor, which is supported on a stand  66 . The stand  66  is either mounted to a cement foundation or directly to the ground. Other configurations can be used for this operation as well known to those skilled in the art. 
         [0024]    The operation of the apparatus of the present invention is effective to lower the body into a well through a layer of liquid and to withdraw the body upwardly through the well to discharge liquids through a recovery line. This permits the recovery of significant amounts of liquids from wells which may not produce enough liquid to justify maintaining pumping unit equipment at the well. Further it does not require extensive control of the level since if the level rises too high it will simply be recovered through the recovery line  32  and the well can then be emptied using the slick line and the body at intervals as desired. The alternate pumping system of the present invention can also be used to operate wells of higher production but more frequent operation of the recovery cycle is necessary. Further the recovery cycle can be automated to run at selected intervals with only infrequent attention from the operator although it is anticipated that the operator of the well will periodically operate the well manually as required. This application also allows the operator of low liquid volume wells to set this application below perforations  16  if desired to further lower the bottom-hole pressure. Currently with most other forms of artificial lift, it is not recommended to set the pump intake below the perforations. 
         [0025]    A further application of the present invention is the removal of liquids which may accumulate in low pressure gas wells. In such wells, the gas may be produced at a pressure sufficiently low that it will not flow upwardly through the liquid layer. In such instances, lowering the liquid layer to a sufficiently low level is crucial to the production of the natural gas. Accordingly, it is clear that the apparatus of the present invention and the method of the present invention can be used for a variety of purposes such as the operation of recovery from a relatively high producing well to recovery of liquids from a relatively low producing well or for the removal of undesired liquids from low pressure gas wells. 
         [0026]    Furthermore this application lends itself to be powered by a standard electricity source such as power lines, or by alternative energy sources such as solar power, wind generators or any other alternative energy source that generates clean reliable energy. 
         [0027]    While not discussed above, it will be understood that the apparatus of the present invention could also be used inside a casing as it is used inside production tubing. In such instances, the body must be configured to suitably interact with the inside surface of the casing. In other respects the operation is the same as discussed above for operation of production tubing. This may also be desirable in some wells since it may be used in wells which are not fully completed or from which the tubing has been withdrawn. In some instances it may be desirable to limit the amount of liquid which is positioned for removal by the slick line withdrawal. Weight considerations may require that the amount of liquid which could be moved upwardly by the body be limited to the weight lifting capacity of the slick line. 
         [0028]    The liquids recovered are typically petroleum, petroleum distillates, water, brine, and mixtures thereof. The gas recovered typically comprises natural gas. The recovery of these valuable materials is facilitated by the use of the present invention in instances where it is not desirable or feasible to use a pumping unit with a submersible pump and the like. 
         [0029]    While the present invention has been described by reference to certain of its preferred embodiments, it is pointed out that the embodiments described are illustrative rather than limiting in nature and that many variations and modifications are possible within the scope of the present invention. Many such variations and modifications may be considered obvious and desirable by those skilled in the art based upon a review of the foregoing description of preferred embodiments.