Abstract:
A method of treating and completing a well includes positioning a downhole tool within a well. The downhole tool includes an elongated body defining a central passageway and including a plurality of production openings and at least one frac opening, a frac mandrel disposed within the central passageway, and a packer disposed about the elongated body. The method further includes securing the downhole tool in the well by the packer, fracing a formation through the frac opening, and producing a fluid from the formation through the production openings.

Description:
BACKGROUND 
   The present invention relates generally to methods and apparatuses for treating and completing a well and, more particularly, to a system and method of production enhancement and completion of a well. 
   In preparing a subterranean formation for production after drilling a well, a packer or plug is often used to isolate zones of the wellbore. Packers and plugs are selectively expandable downhole devices that prevent or control the flow of fluids from one area of the wellbore to another. For example, during production enhancement operations, such as hydraulic fracturing (fracing), a packer may be used to direct acid, a fracturing fluid, or other process fluid into a desired zone while isolating the remaining zones of the wellbore from the process fluid. A well may also be cased or otherwise completed after drilling. For example, in low integrity formations or high productivity fields, wells may be lined with production liners. Other production enhancement operations may also be performed. These completion and production enhancement operations typically require multiple trips into the well. 
   SUMMARY 
   In a particular embodiment of the invention, a downhole tool system for single step completing, fracturing, and fracpacking a well is provided for use in completion and production enhancement of oil, gas, and other wells. 
   In accordance with a particular embodiment, a method of treating and completing a well includes positioning a downhole tool within the well. The downhole tool includes an elongated body defining a central passageway and including a plurality of production openings and at least one frac opening, a frac mandrel disposed within the central passageway, and a packer disposed about the elongated body. The method further includes securing the downhole tool in the well by the packer, fracing a formation through the frac opening, and producing a fluid from the formation through the production openings. 
   Technical advantages of one or more embodiments of the downhole tool system include completing, fracturing, and fracpacking a well in a single trip down the well. This saves considerable time and money when completing and/or preparing a well for production. The downhole tool system may be used for low integrity formations to prevent sluffing or collapse of the well near any fractures and/or may be used for high productivity fields to significantly enhance productivity and profitability. 
   Another technical advantage is securing the downhole tool system within the well using fluid inflatable packers, which may be inflated using frac fluids. In addition, the downhole tool may include a window sleeve that opens to allow fracing and closes to prevent sand and other particles from entering the inside of the downhole tool. 
   Other advantages include providing a tool that may be permanently set or retrievable from the well, and the use of a common setting tool for setting a liner hanger and controlling the window sleeve and packers. 
   Various embodiments of the downhole tool and method may include all, some, or none of the above or elsewhere described advantages. Moreover, other technical advantages may be readily apparent from the following figures, descriptions, and claims. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  illustrates a downhole tool disposed within a well according to one embodiment of the present invention; 
       FIG. 2A  is a cross-sectional view of one embodiment of a ported sub of the downhole tool of  FIG. 1 ; 
       FIG. 2B  is a cross-sectional view of another embodiment of a ported sub of the downhole tool of  FIG. 1 ; 
       FIG. 3A  is a flowchart illustrating a method of completing, fracturing, and fracpacking a well according to one embodiment of the present invention; 
       FIGS. 3B through 3G  schematically illustrate the method of  FIG. 3A ; and 
       FIG. 4  illustrates a downhole tool disposed within a horizontal well according to another embodiment of the present invention. 
   

   DETAILED DESCRIPTION 
     FIG. 1  illustrates a downhole tool  100  disposed within a well  102  according to one embodiment of the present invention. Well  102  may be any suitable well, such as an openhole well or a cased well cased with a casing  104 . Although illustrated in  FIG. 1  as being vertical, well  102  may also be horizontal, angled, or oriented in any suitable manner. 
   As described in further detail below, downhole tool  100  facilitates completing, production enhancing, fracturing, and/or fracpacking well  102  with only one trip, or a reduced number of trips, into well  102 . A single step process saves considerable time for the completion of a well, especially a deep well, resulting in considerable cost savings for the well&#39;s producer. As one example, in deep water applications, installing liner systems, activating packers for future well control, and placing multiple fractures in a wellbore using conventional processes may last many weeks, if not months. This is especially true for openhole fracturing and packing operations. In one embodiment, downhole tool  100  may deliver the above processes in one trip into the well, which completes the completion process in a matter of days. 
   In the illustrated embodiment, downhole tool  100  includes a liner hanger  105 , an elongated body  106  defining a central passageway  108  and having a plurality of production openings  110 , a plurality of ported subs  112 , a plurality of packers  114 , and a frac mandrel  116  disposed within central passageway  108 . The present invention contemplates more, less, or different components for downhole tool  100  than those shown in  FIG. 1 . 
   Liner hanger  105  may be any suitable liner hanger that functions to hang elongated body  106 . Liner hanger  105  may be set at any desired location by using any suitable setting tool that is coupled to frac mandrel  116 . In the illustrated embodiment, liner hanger  105  is disposed at the bottom of casing  104 . A liner packer (not explicitly shown) may be utilized to secure and seal liner hanger  105  in place. 
   Elongated body  106  may be any suitable liner, such as a slotted liner or a screen liner that functions to produce a suitable fluid from subterranean formation  103  through production openings  110  formed therein. Production openings  110  may be any suitable size and any suitable shape. Elongated body  106  may be any suitable shape and may be formed from any suitable material. Elongated body  106  couples to liner hanger  105  in any suitable manner. Elongated body  106  may also function to prevent collapsing of well  102 , especially for a horizontal well. 
   Ported sub  112 , which is described in greater detail below in conjunction with  FIGS. 2A and 2B , generally functions to facilitate the fracturing of formation  103  at desired locations within well  102 . Ported subs  112  are also known in the industry as hydrajet fracturing subs or jetting subs. Ported subs  112 , which may either be coupled to elongated body  106  or formed integral therewith, have one or more frac jets associated therewith that allows a suitable frac fluid to fracture formation  103 . This is described in greater detail below. Ported subs  112  may be spaced apart with any suitable spacing. For example, a spacing between ported subs  112  may be approximately three hundred feet. 
   Packers  114  may be any suitable packers, such as mechanical packers or inflatable packers. Packers  114  are disposed about elongated body  106  and function to secure downhole tool  100  within well  102  and to separate well  102  into desired sections. Any suitable spacing may be used for packers  114 ; however, in a particular embodiment, packers  114  are disposed on either side of each ported sub  112  to isolate particular zones of well  102 . 
   Frac mandrel  116  is disposed within central passageway  108  and facilitates the activation and deactivation of packers  114  in addition to facilitating the fracturing of formation  103  by controlling the flow of a frac fluid through frac jets of ported subs  112 . Frac mandrel  116  may also function to set liner hanger  105  with a suitable setting tool, as described above, or function to facilitate other suitable production enhancement operations, such as acidizing. Frac mandrel  116  may be formed from any suitable material. Further details of the functions of frac mandrel  116  are described below in conjunction with  FIGS. 2A and 2B . 
     FIGS. 2A and 2B  are cross-sectional views of two different embodiments of ported sub  112  of downhole tool  100 . Generally,  FIG. 2A  illustrates a single-use ported sub  112  and  FIG. 2B  illustrates a multiple-use ported sub  112 . 
   Referring to  FIG. 2A , ported sub  112   a  includes an outer body  200  and a window sleeve  202  disposed within outer body  200  and coupled to outer body  200  with one or more shear pins  204 . Outer body  200  includes a pair of frac openings  206  that each include a frac jet  207 . Window sleeve  202  includes a pair of openings  208  that coincide with frac openings  206 . Therefore, when frac mandrel  116  is positioned in such a manner that frac openings  206  are aligned with openings  208  and openings  117  in frac mandrel  116 , then window sleeve  202  is considered in an “open” position. This open position facilitates the fracturing of formation  103  by flowing a suitable frac fluid down through the passageway within frac mandrel  116  and out openings  117 , through openings  208  in window sleeves  202 , through frac openings  206 , and out frac jets  207  in outer body  200 . 
   Shear pins  204  hold window sleeve  202  in place during the fracturing process. A pair of gaskets  211  may be disposed around an outer perimeter of window sleeve  202  to seal an annular space between window sleeve  202  and outer body  200 . This prevents any frac fluid or other process fluid from interfering with the function of frac jets  207 . In order to ensure that the frac fluid is directed correctly through frac jets  207 , a valve ball  212  is disposed at the end of frac mandrel  116  on a shoulder  213  that is formed by the coupling of a setting tool  214  to the bottom of frac mandrel  116 . Details of setting tool  214  are described below. Valve ball  212  forces frac fluid to enter frac openings  206  and flow out through frac jets  207 . 
   After the fracturing process is completed, the circulation of the frac fluid is stopped and window sleeve  202  is moved to a “closed” position. In order to move window sleeve  202  into the closed position, shear pins  204  need to be sheared. This is facilitated by setting tool  214 , which in the illustrated embodiment is a drag block type setting tool. Other suitable setting tools, such as a ball type setting tool may also be utilized. Setting tool  214  includes a drag block  216  disposed around an outer perimeter thereof. An outer surface of drag block  216  essentially drags along the inside surface of window sleeve  202 . 
   One or more steel balls  217  are positioned within a circular groove of drag block  216 . Steel balls  217  are resting on a first surface  219  of setting tool  214  such that steel balls  217  are engaging an end  222  of window sleeve  202 . In this manner, when one pulls up on frac mandrel  116 , the engagement of steel balls  217  with end  222  of window sleeve  202  will cause shear pins  204  to shear and thereby move window sleeve  202  upward, as denoted by arrow  224 , until resting on a shoulder  225  of outer body  200 . This causes openings  208  to be misaligned with frac jets  207 , thereby closing any pathway from the inside of frac mandrel  116  to frac jets  207 . In order to move drag block  216  within window sleeve  202 , an operator merely turns frac mandrel  116  either right or left such that steel balls  217  drop within a longitudinal groove  227  on setting tool  214  so that steel balls  217  engage a second surface  220 . This essentially moves steel balls  217  radially inward so that drag block  216  may slide within window sleeve  202 . 
   Thus, ported sub  112   a  as illustrated in  FIG. 2A  is a single-use ported sub that may be used only once to fracture a formation, such as formation  103 . Ported sub  112   a  is installed in the open position and, when fracturing is completed, is permanently moved to the closed position, as described above. 
   Referring to  FIG. 2B , ported sub  112   b  is similar to ported sub  112   a  in  FIG. 2A  except that ported sub  112   b  may be used to fracture a formation more than one time. This is facilitated by having window sleeve  202  slidably disposed within outer body  200 . 
   Window sleeve  202  is illustrated in  FIG. 2B  in a “closed” position. Window sleeve  202  is movable between open and closed positions as follows. Steel balls  217  of setting tool  214  engage a shoulder  230  near end  222  of window sleeve  202 . As described above, an operator that pulls on frac mandrel  116  may move window sleeve  202  upward until openings  117  and openings  208  are aligned with frac jets  207 . Thereafter, a frac fluid may be pumped through the internal passageway of frac mandrel  116  and out through frac jets  207 , as described in conjunction with the embodiment of  FIG. 2A . After the fracturing operation, window sleeve  202  needs to be closed. Thus, an operator merely turns frac mandrel  116  either to the right or left in order to allow steel balls  217  to fall within groove  227  so that drag block  216  may slide within window sleeve  202 . Frac mandrel  116  is pulled up far enough to where steel balls  217  engage a shoulder  232  of an end  234  of window sleeve  202  that is opposite end  222 . Frac mandrel  116  is then turned back to its original position so that steel balls  217  may pop back out in order to engage shoulder  232 . Frac mandrel  116  is then pushed downward thereby pushing window sleeve  202  into the closed position, as illustrated in  FIG. 2B . If further fracturing is required through frac jets  207 , the process above is merely repeated. 
     FIG. 3A  is a flowchart illustrating an example method of completing, fracturing, and fracpacking a well according to one embodiment of the present invention.  FIGS. 3B through 3G  schematically illustrate this example method. 
   The example method begins at step  300  where downhole tool  100  is positioned within well  102 , as illustrated in  FIG. 1 . Although not required, a liner hanger  105  may be set within well  102 , as denoted by step  302 . The setting of liner hanger  105  is illustrated in  FIG. 3B . Liner hanger  105  may be sealed with a packer  318 . Any suitable liner packer may be utilized for packer  318 . In a particular embodiment, packer  318  may be an inflatable packer. 
   Downhole tool  100  is then secured and sectionalized in well  102  by packers  114 , as denoted by step  304 . This is illustrated in  FIG. 3C  in which three separate packers  114   a ,  114   b , and  114   c  are illustrated. As described above, packers  114  may be any suitable mechanical or inflatable packers. As an example of setting packers  114 , downhole tool  100  is run in hole to a first desired position for packer  114   a . During the run in hole, an operator will feel a resistance when first ported sub  112   a  is reached. When the operator reaches ported sub  112   a , a slight turn of downhole tool  100  to the right or to the left will “bypass” ported sub  112   a . The next resistance felt will be the position for packer  114   a . Packer  114   a  is then set using frac mandrel  116 . 
   After packer  114   a  is set, downhole tool  100  is run in hole until reaching a second position for packer  114   b . Again, the operator will feel a resistance when reaching a ported sub  112   b . The operator would again either turn downhole tool  100  to the right or to the left to bypass ported sub  112   b . Packer  114   b  would then be set before downhole tool  100  is run in hole until reaching a third desired position. Along the way, downhole tool  100  will reach a ported sub  112   c . Again, downhole tool  100  will be turned either to the right or to the left to bypass ported sub  112   c  until reaching the desired position for packer  114   c . Packer  114   c  is then set. This process continues until the final packer  114  is set. 
   A fracture is then created in formation  103 , as denoted by step  306 . This is illustrated in  FIG. 3D . As illustrated, a first fracture  330  is created in formation  103 . The process to create fracture  330  is described above in conjunction with  FIGS. 2A  and/or  2 B. Once the desired length of fracture  330  is obtained, the fracture is packed, as denoted by step  308 , with a frac material  332  by reducing a flow of process fluid or fracing fluid through an annulus between elongated body  106  and the wall of well  102 . This initiates the tip screenout and starts the packing process. Frac material  332  then fills the fracture  330  and the corresponding annulus between the packers disposed on either side of fracture  330 , namely  114   b  and  114   c  in  FIG. 3D . After the packing process, the process fluid is reverse circulated, as denoted by step  310  to clean the inside of frac mandrel  116 . This reverse circulation is an optional step. 
   As denoted by decisional step  312 , it is determined whether or not the creation of all fractures is finished. If fracing is not finished, then a new fracture  334  is created in formation  103 . This is illustrated in  FIG. 3E . The process of completing the fracture  330  and packing the fracture  330  as described above applies to fracture  334  also. Again, process fluid may be reverse circulated to clean out frac mandrel  116  before another fracture is created. 
   Once the final fracture is created, as illustrated in  FIG. 3F , then frac mandrel  116  is removed from elongated body  106  so that the production of fluids from formation  103  may proceed. This is illustrated in  FIG. 3G  in which frac mandrel  116  is shown above liner hanger  105  as it is being removed. In particular embodiments of the invention, frac mandrel  116  may be designed in such a manner to double up as the production string if so desired. In any event, frac mandrel  116  is removed, as denoted by step  314  and fluids may be produced from well  102 , as denoted by step  316 . This ends the example method as outlined in  FIG. 3A . 
   Thus, the example method described above illustrates that downhole tool  100  may be used for completing, fracturing, and fracpacking well  102  in a single step during one trip down well  102 . This eliminates multiple tripping operations, which saves considerable time and money. 
     FIG. 4  illustrates a downhole tool  400  disposed within a horizontal well  402  according to another embodiment of the present invention. In the illustrated embodiment, well  402  is an openhole well oriented horizontally within a subterranean formation  403 . Formation  403  is meant to illustrate a somewhat less competent formation. Downhole tool  400  facilitates convenient placement of a liner system, fracturing of formation  403 , packing the fracture, and leaving the liner system in place to prevent sluffing or collapse of well  402  near the fracture. 
   Accordingly, downhole tool  400  includes an elongated body  406 , a pair of inflatable packers  408 , and a frac mandrel  410 . Elongated body  406  is the liner system that is left in place after the fracturing and fracpacking process is completed to prevent the collapse of well  402 , as described above. Any suitable elongated body  406  may be utilized, such as a screened or slotted liner. 
   Inflatable packers  408  may be any suitable mechanical or inflatable packers. In a particular embodiment, and as illustrated in  FIG. 4 , packers  408  are sand bags, which are made of a chemically resistive fabric material that allows filtered fluid to move out of the sand bags and leave sand or other suitable proppant behind in the sand bags to inflate them and anchor the elongated body  406  within well  402 . The interior of inflatable packers  408  are coupled to an inside passageway  411  of frac mandrel  410  through conduits  412  formed in a wall of elongated body  406 . Conduits  412  may be any suitable size and typically consume the pressure energy at rates of less than ten gallons per minute. 
   Frac mandrel  410  is coupled to the inside surface of elongated body  406  by a shear pin  414  so that downhole tool  400  may be disposed within well  402  in a convenient manner. Frac mandrel  410  may be formed from any suitable material and may be any suitable shape. 
   In operation of one embodiment of downhole tool  400  illustrated in  FIG. 4 , downhole tool  400  is run in hole into a desired location. A frac fluid is circulated, as denoted by arrow  416  through passageway  411  of frac mandrel  410  and directed through openings  417  in frac mandrel  410  and frac jets  418  to create a fracture  420  in formation  403 . During the fracturing of fracture  420 , some of the frac fluid travels through conduits  412  and into packers  408 . As described above, the fluid of the frac fluid filters through the sand bags while leaving the proppant behind to fill inflatable packers  408  to anchor elongated body  406  within well  402 . Once the desired length of fracture  420  is obtained, the fracpacking process begins by reducing the flow of the frac fluid within annulus  424  between the outside of elongated body  406  and well  402 . 
   When the fracpacking process is finished, an operator pulls frac mandrel  410  upward in order to shear shear pin  414  to release frac mandrel  410  from elongated body  406 . Frac mandrel  410  may then be removed from well  402  while leaving elongated body  406  in place adjacent fractures  420 . Fluids may then be processed from formation  403 . 
   Although the present invention has been described in several embodiments, various changes and modifications may be suggested to one skilled in the art. It is intended that the present invention encompass such changes and modifications as fall within the scope of the appended claims.