Abstract:
A well servicing apparatus and method which facilitates servicing of a well without removal of the wellhead equipment, production tubing, or pump drive rod. One embodiment of the invention allows flexible tubing to be inserted into the production tubing string of a well. Fluid can then be pumped through the flexible tubing for purposes such as removing sand from the production tubing string. Another embodiment of the invention allows flexible tubing to be inserted into either the production tubing string or well casing or both. Fluid can then be pumped through the flexible tubing for purposes such as removing sand from either the production tubing string or well casing.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to apparatus and methods for servicing wells, particularly for servicing oil wells to remove sand.  
         BACKGROUND OF THE INVENTION  
         [0002]    In the production of a fluid such as hydrocarbons from a subsurface reservoir, a well is drilled down to provide a path for the fluid to flow to the surface. A well casing is used to keep the earth from collapsing the well. The casing is then perforated at a desired depth to allow the reservoir fluid (such as oil) to flow into the casing. A tubing string, extending from the surface to the bottom of the well, is provided for carrying the fluid to the surface. If the formation pressure is sufficiently high, the reservoir fluid flows naturally to the surface. However, when there is not sufficient pressure, lift must be provided, commonly by the use of downhole pumps. Such pumps may be operated from the surface by either a rotating or reciprocating drive rod.  
           [0003]    With many producing wells, the incursion of sand is a problem. Sand may accumulate in the casing or in the production tubing. When it becomes apparent that the incursion of sand is adversely affecting the production from the well to such an extent that the well is not economical, the well needs to be serviced to clean out the accumulated sand. Traditional procedures for removing sand from a well involve removing the casing spool or tubing spool from the wellhead and the use of a service rig to pull out the tubing string and drive rod. A sand line bailing unit or tubing bailing unit is then used to remove sand from the casing or the production tubing string. This is a costly and time-consuming procedure, and the opening of the well to the atmosphere can result in release of the reservoir fluids and gases, which can harm the environment and endanger those near the well. In addition, the open well can become contaminated or damaged by such items as wrenches, tools, dirt or bolts.  
           [0004]    U.S. Pat. No. 6,315,046 (Jack et al), which corresponds to Canadian Patent No. 2,268,223 describes a method and apparatus which provides for simplified and rigless servicing of a well casing. The apparatus includes a casing spool that allows flexible tubing to be inserted into the casing without removing the apparatus, tubing or drive rod. The flexible tubing can be extended down the well into the annular space between the production tubing string and the casing, and fluid can then be pumped through the flexible tubing to flush out sand in the well.  
           [0005]    Canadian Patent Application No. 2,310,236 (Komistek) describes a tubing clean-out spool having an entry port allowing flexible tubing to be inserted into the annular space between the production tubing and drive rod. A disadvantage of the Komistek apparatus is that due to the frictional contact between the flexible tubing and the tubing spool, both the tubing spool and the flexible tubing may be subject to rapid wear which could necessitate frequent replacement of the tubing spool, plus associated costs and lost well production.  
           [0006]    Accordingly, there is a need for well servicing apparatus and method which facilitate servicing and flushing of the annular space between the drive rod and the production tubing, without being prone to frequent and expensive replacement of components, and without requiring removal or disassembly. In addition, there is a need for such well servicing apparatus and method which also facilitate servicing and flushing of the annular space between the production tubing and the well casing without requiring removal or disassembly. The present invention is directed to these needs.  
         BRIEF SUMMARY OF THE INVENTION  
         [0007]    In general terms, the present invention relates to an improved well servicing apparatus and method utilizing a housing which includes a passage that allow flexible tubing to be inserted into the production tubing string in a helical orientation without the removal of the apparatus or the drive rod from the well. The present invention also relates to an improved well servicing apparatus and method utilizing a housing which includes passages that allow flexible tubing to be inserted into the well casing in a helical orientation without the removal of the apparatus or the production tubing.  
           [0008]    Accordingly, in one aspect, the invention is a well servicing apparatus comprising a housing having a lower end, an upper end, and an exterior surface, said housing further having:  
           [0009]    (a) a primary passage extending through the housing from the lower end to the upper end; and  
           [0010]    (b) a production tubing access passage extending generally upward from the primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the primary passage;  
           [0011]    wherein a drive rod may be disposed longitudinally through the primary passage.  
           [0012]    Preferably the well servicing apparatus further comprises a guide tube which may be detachably connected to the housing in association with the production tubing access passage. The well servicing apparatus may further comprise a flange attached to the housing near its upper end, said flange having an opening for supporting the guide tube.  
           [0013]    In the preferred embodiment, the exterior surface of the housing defines a shoulder, and the production tubing access passage extends from the primary passage to the exterior surface on the shoulder.  
           [0014]    In another aspect, the invention is a well servicing apparatus comprising:  
           [0015]    (a) an upper housing having a lower end, an upper end, and an exterior surface, said upper housing further having:  
           [0016]    (i) an upper primary passage extending through the upper housing from the lower end to the upper end; and  
           [0017]    (ii) a production tubing access passage extending generally upward from the upper primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the upper primary passage;  
           [0018]    (b) a lower housing having a lower end, an upper end, and an exterior surface, said lower housing further having:  
           [0019]    (i) a lower primary passage extending through the lower housing from the lower end to the upper end;  
           [0020]    (ii) a casing access passage extending generally upward from the lower primary passage to the exterior surface;  
           [0021]    (c) tubing string suspension means, for supporting a production tubing string; wherein:  
           [0022]    (d) the upper housing is connected to the lower housing such that the upper and lower primary passages are substantially coaxial; and  
           [0023]    (e) a drive rod may be disposed longitudinally through the upper and lower primary passages and into the bore of the production tubing string.  
           [0024]    Preferably, at least a portion of the casing access passage has a helical orientation relative to the longitudinal axis of the lower primary passage. Ancillary wellhead components may be interposed between the upper housing and lower housing.  
           [0025]    Preferably, the well servicing apparatus further comprises a guide tube which may be detachably connected to the upper housing in association with the production tubing access passage. More preferably, the well servicing apparatus further comprises a flange attached to the upper housing near its upper end, said flange having an opening for supporting the guide tube.  
           [0026]    In the preferred embodiment, the exterior surface of the upper housing defines a shoulder, and the production tubing access passage extends from the upper primary passage to the exterior surface on the shoulder.  
           [0027]    Preferably, the well servicing apparatus further comprises a guide tube which may be detachably connected to the lower housing in association with the casing access passage.  
           [0028]    In the preferred embodiment, the exterior surface of the lower housing defines a shoulder, and the casing access passage extends from the lower primary passage to the exterior surface on the shoulder.  
           [0029]    Preferably, the tubing string suspension means is a bowl for a tubing hanger.  
           [0030]    In a further aspect, the invention is a method of servicing a well, comprising the steps of:  
           [0031]    (a) providing a well servicing apparatus comprising a housing having a lower end, an upper end, and an exterior surface, said housing further having:  
           [0032]    (i) a primary passage extending through the housing from the lower end to the upper end, through which said primary passage a drive rod may be longitudinally disposed; and  
           [0033]    (ii) a production tubing access passage extending generally upward from the primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the primary passage;  
           [0034]    (b) installing the well servicing apparatus on a wellhead in association with a production tubing string inside a well casing;  
           [0035]    (c) passing flexible tubing through the production tubing access passage, such that the flexible tubing enters the production tubing string; and  
           [0036]    (d) pumping a selected fluid through the flexible tubing.  
           [0037]    In another aspect, the invention is a method of servicing a well, comprising the steps of:  
           [0038]    (a) providing a well servicing apparatus comprising:  
           [0039]    (i) an upper housing having an upper end, a lower end, and an exterior surface, said upper housing further having an upper primary passage extending through the upper housing from the lower end to the upper end, and a production tubing access passage extending generally upward from the upper primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the upper primary passage;  
           [0040]    (ii) a lower housing having a lower end, an upper end, and an exterior surface, said lower housing further having a lower primary passage extending through the lower housing from the lower end to the upper end, and a casing access passage extending generally upward from the lower primary passage to the exterior surface;  
           [0041]    (iii) tubing string suspension means, for supporting a production tubing string; wherein:  
           [0042]    (iv) the upper housing is connected to the lower housing such that the upper and lower primary passages are substantially coaxial; and  
           [0043]    (v) a drive rod may be disposed longitudinally through the upper and lower primary passages and into the bore of the production tubing string;  
           [0044]    (b) installing the well servicing apparatus on a wellhead in association with a production tubing string inside a well casing;  
           [0045]    (c) passing flexible tubing through the production tubing access passage, such that the flexible tubing enters the production tubing string; and  
           [0046]    (d) pumping a selected fluid through the flexible tubing.  
           [0047]    In another aspect, the invention is a method of servicing a well, comprising the steps of:  
           [0048]    (a) providing a well servicing apparatus comprising:  
           [0049]    (i) an upper housing having a lower end, an upper end, and an exterior surface, said upper housing further having an upper primary passage extending through the upper housing from the lower end to the upper end, and a production tubing access passage extending generally upward from the upper primary passage to the exterior surface at an angle towards the upper end, at least a portion of said production tubing access passage having a helical orientation relative to the longitudinal axis of the upper primary passage;  
           [0050]    (ii) a lower housing having a lower end, an upper end, and an exterior surface, said lower housing further having a lower primary passage extending through the lower housing from the lower end to the upper end; and a casing access passage extending generally upward from the lower primary passage to the exterior surface;  
           [0051]    (iii) tubing string suspension means, for supporting a production tubing string; wherein:  
           [0052]    (iv) the upper housing is connected to the lower housing such that the upper and lower primary passages are substantially coaxial; and  
           [0053]    (v) a drive rod may be disposed longitudinally through the upper and lower primary passages and into the bore of the production tubing string;  
           [0054]    (b) installing the well servicing apparatus on a wellhead in association with a production tubing string inside a well casing;  
           [0055]    (c) passing flexible tubing through the casing access passage, such that the flexible tubing enters the annular space between the production tubing string and the well casing; and  
           [0056]    (d) pumping a selected fluid through the flexible tubing.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0057]    Embodiments of the invention will now be described with reference to the accompanying figures, in which numerical references denote like parts, and in which:  
         [0058]    [0058]FIG. 1 is a sectional view of a first embodiment of the invention, shown with flexible tubing passing through the guide tube into the production string.  
         [0059]    [0059]FIG. 2 is a sectional view of the first embodiment of the invention, shown with the guide tube removed and a closure sealing the production tubing access passage.  
         [0060]    [0060]FIG. 3 is a side view, in partial cutaway section, of a second embodiment of the invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0061]    Referring to FIGS. 1 and 2, the apparatus of the present invention, in one embodiment, generally represented by reference numeral  10 , includes a housing  12  that has a lower end  16 , an upper end  14 , and an exterior surface  18 .  
         [0062]    A primary passage  24  extends through housing  12  from the lower end  16  to the upper end  14 . A production tubing access passage  36  extends generally upward from primary passage  24  to the exterior surface  18  at an angle towards the upper end  14  such that at least a portion of production tubing access passage  36  has a helical orientation relative to the longitudinal axis of primary passage  24 . A drive rod  26  may be disposed longitudinally through primary passage  24 .  
         [0063]    In the preferred embodiment, the exterior surface  18  defines a shoulder  20  protruding from the general outline of the housing  12 , and the production tubing access passage  36  extends from the primary passage  24  to the exterior surface  18  on the shoulder  20 . In the preferred embodiment, a guide tube  42  can be detachably connected to the housing  12  in association with the production tubing access passage  36 . Guide tube  42  may be supported at by a flange  44  positioned on housing  12  toward upper end  14 . Flexible tubing  38  may be inserted into production tubing access passage  36 .  
         [0064]    Flange  48  is provided at lower end  16  of housing  12  for the purpose of mounting well servicing apparatus  10 . Packing  30  may be used to seal the opening between rod  26  and housing  12  near the upper end  14  of housing  12 . Packing  30  is retained in place by packing retainer  32 .  
         [0065]    Referring to FIG. 2, a closure  40  closes production tubing access passage  36  when production tubing access passage  36  is not in use. To place closure  40  on production tubing access passage  36 , guide tube  42  (FIG. 1) must be detached.  
         [0066]    In an alternative embodiment of the invention, illustrated in FIG. 3, there is provided a well servicing apparatus  100 , which includes an upper housing  112  and a lower housing  162 .  
         [0067]    Upper housing  112  has a lower end  116 , an upper end  114 , and an exterior surface  118 . An upper primary passage  124  extends through upper housing  112  from lower end  116  to upper end  114 . A production tubing access passage  136  extends generally upwards from upper primary passage  124  to the exterior surface  118  at an angle towards upper end  114 , wherein at least a portion of production tubing access passage  136  has a helical orientation relative to the longitudinal access of upper primary passage  124 .  
         [0068]    In the preferred embodiment, the exterior surface  118  defines a shoulder  120  protruding from the general outline of the upper housing  112 , and the production tubing access passage  136  extends from the upper primary passage  124  to the exterior surface  118  on the shoulder  120 . In the preferred embodiment, a guide tube  142  can be detachably connected to the upper housing  112  in association with the production tubing access passage  136 . Guide tube  142  may be supported by flange  144  positioned on housing  112  toward upper end  114 .  
         [0069]    Flange  148  is provided at lower end  116  of housing  112  for the purpose of mounting the upper housing  112  of well servicing apparatus  100 . Packing (not shown) may be used to seal the opening between rod  26  and upper housing  112  near the upper end  114  of housing  112 . Packing (not shown) similar to packing  30  (FIGS. 1 and 2) is retained in place by packing retainer (not shown) similar to packing retainer  32  (FIGS. 1 and 2).  
         [0070]    The lower housing  162  has a lower end  166 , and upper end  164 , and an exterior surface  168 . A lower primary passage  172  extends through the lower housing  162  from the lower end  166  to the upper end  164 . A casing access passage  174  extends generally upward from the lower primary passage  172  to the exterior surface  168 . In the preferred embodiment, at least a portion of casing access passage  174  has a helical orientation relative to the longitudinal access of the lower primary passage  172  of lower housing  162 .  
         [0071]    In the preferred embodiment, the exterior surface  168  defines a shoulder  170  protruding from the general outline of the lower housing  162 , and the casing access passage  174  extends from the lower primary passage  172  to the exterior surface  168  on the shoulder  170 . In the preferred embodiment, a guide tube  176  can be detachably connected to the lower housing  162  in association with the casing access passage  174 .  
         [0072]    Flange  178  is provided at upper end  164  of lower housing  162 , and flange  182  is provided at the lower end  166  of lower housing  162 , for the purpose of mounting lower housing  162  of well servicing apparatus  100 .  
         [0073]    The upper housing  112  is connected to the lower housing  162  such that upper primary passage  124  and lower primary passage  172  are substantially coaxial. The connection may be direct, or ancillary wellhead components  180  may be interposed between the upper housing  112  and the lower housing  162 . A drive rod  26  may be disposed longitudinally through the upper primary passage  124  and lower primary passage  172  and into the bore of the production tubing string  156 .  
         [0074]    Tubing string suspension means (not shown) is provided for supporting production tubing string  156 . In the preferred embodiment, a bowl (not shown) for a tubing hanger (not shown) is provided as the tubing suspension means.  
         [0075]    A closure (not shown) similar to closure  40  (FIG. 2) may be used to close production tubing access passage  136  and casing access passage  174  when the well servicing apparatus  100  is not in use.  
         [0076]    With reference to FIGS. 1 and 2, the use and operation of the well servicing apparatus generally identified by reference numeral  10  will now be described.  
         [0077]    Referring to FIG. 1, the well servicing apparatus  10 , as described above, has been developed to facilitate the servicing of a well with flexible tubing  38 . Production tubing access passage  36  allows for flexible tubing  38  to be passed through production tubing access passage  36  into primary passage  24  and into the production tubing string (not shown) without removing well servicing apparatus  10  or drive rod  26  from primary passage  24  of well servicing apparatus  10 . The helical orientation of the production tubing access passage  36  facilitates introduction of the flexible tubing  38 , thereby reducing abrasion and wear of the flexible tubing  38  and the internal walls of the production tubing access passage  36 . Detachable guide tube  42  may be attached to production tubing access passage  36  for the purpose of guiding flexible tubing  38  into production tubing access passage  36 . A selected fluid, for example water, is then pumped through flexible tubing  38 .  
         [0078]    When production tubing access passage  36  is not in use, closure  40  may be used to close production tubing access passage  36 .  
         [0079]    With reference to FIG. 3, the use and operation of the well servicing apparatus generally identified by reference numeral  100  will now be described.  
         [0080]    Referring to FIG. 3, the well servicing apparatus  100 , as described above, has been developed to facilitate the servicing of a well with flexible tubing  38 . Production tubing access passage  136  allows for flexible tubing  38  to be inserted through production tubing access passage  136  into upper primary passage  124  to a desired depth within the well without removing well servicing apparatus  100 , production tubing string  156 , or drive rod  26 . The helical orientation of the production tubing access passage  136  facilitates introduction of the flexible tubing  38 , thereby reducing abrasion and wear of the flexible tubing  38  and the internal walls of the production tubing access passage  136 . Guide tube  142  may be attached to production tubing access passage  136  for the purpose of guiding flexible tubing  38  into production tubing access passage  136 . A selected fluid, for example water, is then pumped through the flexible tubing  38 .  
         [0081]    Casing access passage  174  allows for flexible tubing  38  to be inserted through casing access passage  174  into casing  60  to a selected depth within the well without removing well servicing apparatus  100 , tubing string suspension means (not shown), production tubing string  156 , or drive rod  26 . A selected fluid, for example water, is then pumped through the flexible tubing  38 .  
         [0082]    In this patent document, the word “comprising” is used in its non-limiting sense to mean that items following that word are included, but items not specifically mentioned are not excluded. A reference to an element by the indefinite article “a” does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one such element.  
         [0083]    It will be readily seen by those skilled in the art that various modifications of the present invention may be devised without departing from the essential concept of the invention, and all such modifications are intended to be included in the scope of the claims appended hereto.