Abstract:
Fracturing tools for use in oil and gas wells are disclosed. The fracturing tools have a run-in position and two operational positions. A sleeve disposed in the bore of the fracturing tool comprises a sleeve port alignable with a first port in the housing of the frac tool, i.e., the first operational position, during fracturing operations. A second port having a restriction member is disposed in the housing and is closed by the sleeve during fracturing operations. After fracturing operations are completed, a return member in the frac tool moves the sleeve from the first operational position to a second operational position for production operations. In this second operational position, the first port is closed and the sleeve port is aligned with the second port. Movement of the sleeve from the first operational position to the second operational position is performed without the need for an additional well intervention step.

Description:
BACKGROUND 
       [0001]    1. Field of Invention 
         [0002]    The invention is directed to fracturing tools for use in oil and gas wells, and in particular, to fracturing tools having a sleeve capable of being moved from a first operational position to a second operational position so that the fracturing tool can fracturing the formation in the first operational position and then be moved, without well intervention, to the second operational position to produce return fluids from the well. 
         [0003]    2. Description of Art 
         [0004]    Fracturing or “frac” systems or tools are used in oil and gas wells for completing and increasing the production rate from the well. In deviated well bores, particularly those having longer lengths, fracturing fluids can be expected to be introduced into the linear, or horizontal, end portion of the well to frac the production zone to open up production fissures and pores therethrough. For example, hydraulic fracturing is a method of using pump rate and hydraulic pressure created by fracturing fluids to fracture or crack a subterranean formation. 
         [0005]    In addition to cracking the formation, high permeability proppant, as compared to the permeability of the formation can be pumped into the fracture to prop open the cracks caused by a first hydraulic fracturing step. For purposes of this disclosure, the proppant is included in the definition of “fracturing fluids” and as part of well fracturing operations. When the applied pump rates and pressures are reduced or removed from the formation, the crack or fracture cannot close or heal completely because the high permeability proppant keeps the crack open. The propped crack or fracture provides a high permeability path connecting the producing wellbore to a larger formation area to enhance the production of hydrocarbons. 
         [0006]    One result of fracturing a well is that the return fluids, e.g., oil, gas, water, that are sought to be removed from the well are mixed with sand and other debris broken loose in the formation. As a result, after fracturing, an intervention step is performed to reorient a downhole tool such as a frac tool so that the return fluids are passed through a screen or other device to filter out the sand and debris. This intervention step usually involves dropping a ball or other plug element into the well to isolate a portion of the well or to actuate the frac tool to move an actuator to open a fluid flow path through the screen and closes a fluid flow path through which the fracturing fluid was previously injected into the well or well formation. 
       SUMMARY OF INVENTION 
       [0007]    After being run-in to the well in a non-operational “run-in” position and moved to a first operational position, the frac tools disclosed herein are capable of orienting themselves into a second operational position without the need for an intervention step to move the frac tools from a first operational position to the second operational position. The term “operational position,” means that the frac tool is oriented within a well in such a manner so that well completion, well production, or other methods can be performed to the well by the frac tool. In other words, “operational position,” means that the frac tool is oriented within in a well so that the frac tool can perform the function(s) for which it was designed. 
         [0008]    Broadly, the frac tools include a housing having a bore defined by an inner wall surface. The housing includes a series of ports, e.g., at least two ports, one of which may include a fluid flow control member such as a screen or filter used to prevent debris from entering the frac tool or a device for controlling the rate of fluid flow through the port. This “fluid flow controlled” port is disposed above the other port lacking the fluid flow control member. 
         [0009]    A sleeve is in sliding engagement with the inner wall surface of the housing and includes an actuator and a sleeve port in the side wall of the sleeve. A retaining member such as a shear screw or collet operatively associated with the inner diameter of the frac tool maintains the sleeve in the run-in position until actuated. While in the run-in position, both of the ports in the housing are closed. 
         [0010]    After the frac tool is disposed within the well at the desired location, an actuator, such as a ball seat, can be activated to release the sleeve from the retaining member and to force the sleeve into the first operational position so that the sleeve port is aligned with a first port in the housing of the frac tool. Meanwhile, the second port in the housing remains closed. This first port in the housing does not include a fluid flow restriction member so that fracturing fluid can be injected through the first port into the well or well formation without any fluid flow impedance. As a result of the alignment of the first port with the sleeve port, fracturing fluid is allowed to flow from the bore of the frac tool and into the well to fracturing the well or formation. 
         [0011]    After the well is fraced, the flow pressure of the fracturing fluid is reduced. As a result, a return member, such as a spring, forces the sleeve to move from the first operational position to the second operational position so that the sleeve port is now aligned with the second port in the housing. Meanwhile the first port in the housing is now closed. As mentioned above, this second port in the housing can include a fluid flow control member. As a result of the alignment of the sleeve port with this second port, return fluids from the well or formation are allowed to flow into the bore of the housing and up to the surface of the well. In so doing, at least some of the debris in the return fluids is prevented by the screen from entering the bore of the housing and/or the return fluid flow rate is controlled. 
         [0012]    In one embodiment, a frac tool having a run-in position, a first operational position, and a second operational position is disclosed. The frac tool may comprise a housing having an inner wall surface defining a bore, a first port, and a second port disposed above the first port; a sleeve in sliding engagement with the inner wall surface of the housing, the sleeve having a sleeve port and an actuator for moving the sleeve from the run-in position to the first operational position; and a return member in sliding engagement with the inner wall surface and operatively associated with the sleeve, the return member having a biased member, the biased member being energized when the frac tool is in the first operational position and the biased member not being energized when the frac tool is in the second operational position, wherein the sleeve port closes the first and second ports in the housing when the frac tool is in the run-in position, the sleeve port is aligned with the first port in the housing and the second port is closed by the sleeve when the frac tool is in the first operational position, and the sleeve port is aligned with the second port in the housing and the first port is closed by the sleeve when the frac tool is in the second operational position. 
         [0013]    A further feature of the frac tool is that the actuator may comprise a seat disposed in a sleeve bore, the seat being actuatable by a plug element so that the sleeve can be moved from the run-in position to the first operational position by fluid pressure forcing the plug element into the seat. Another feature of the frac tool is that the seat may comprise a ball seat and the plug element may comprise a ball. An additional feature of the frac tool is that the inner wall surface may include a shoulder operatively associated with the biased member and a stop shoulder operatively associated with the return member. Still another feature of the frac tool is that the return member may comprise a return sleeve, the return sleeve having a head portion, a stem portion, and return member bore longitudinally disposed therethrough. A further feature of the frac tool is that the head portion, stem portion, inner wall surface, and shoulder may form a chamber in which the biased member is disposed. Another feature of the frac tool is that the biased member may comprise a coiled spring. An additional feature of the frac tool is that the sleeve may include a releasable retaining member for maintaining the sleeve in the run-in position. Still another feature of the frac tool is that the releasable retaining member may comprise a flange disposed on the sleeve, the flange be operatively associated with a recess disposed along the inner wall surface of the housing. A further feature of the frac tool is that the return member may be disposed below the sleeve and includes an engagement surface for engaging the sleeve in the first and second operational positions. 
         [0014]    In another embodiment, a frac tool has a run-in position, a first operational position, and a second operational position and comprises a housing have a bore, an inner wall surface, the inner wall surface defining the bore, an outer wall surface, a first port and a second port, each of the first port and the second port providing fluid communication with the bore through the inner wall surface and the outer wall surface, the first port being disposed below the second port and the second port having a screen disposed therein; a sleeve in sliding engagement with the inner wall surface of the housing, the sleeve having a sleeve port and a seat disposed within a sleeve bore, the seat having a seat engagement surface for receiving a plug element to restrict fluid flow through the sleeve bore so that the sleeve is movable from the run-in position to the first operational position by fluid pressure forcing the plug element into the seat; and a return member in sliding engagement with the inner wall surface and operatively associated with the sleeve, the return member having a biased member, the biased member being energized by movement of the sleeve from the run-in position to the first operational position, wherein the sleeve port closes the first and second ports in the housing when the frac tool is in the run-in position, the sleeve port is aligned with the first port in the housing and the second port is closed by the sleeve when the frac tool is in the first operational position, and the sleeve port is aligned with the second port in the housing and the first port is closed by the sleeve when the frac tool is in the second operational position. 
         [0015]    A further feature of the frac tool is that the return member may be disposed below the sleeve and includes an engagement surface for engaging the sleeve in the first and second operational positions. Another feature of the frac tool is that the inner wall surface may include a shoulder operatively associated with the biased member and a stop shoulder operatively associated with the return member and the return member comprises a return sleeve, the return sleeve having a head portion, a stem portion, and return member bore longitudinally disposed therethrough. An additional feature of the frac tool is that the head portion, stem portion, inner wall surface, and shoulder may form a chamber in which the biased member is disposed. Still another feature of the frac tool is that the biased member comprises an elastic element. A further feature of the frac tool is that the elastic element comprises a coiled spring. 
         [0016]    In an additional embodiment, a method of fracturing and producing fluids from a well is disclosed. The method may comprise the steps of: (a) disposing a frac tool in a string, the frac tool comprising a housing have a bore defined by an inner wall surface, an outer wall surface, a first port and a second port, each of the first port and the second port providing fluid communication with the bore through the inner wall surface and the outer wall surface, the first port being disposed below the second port, a sleeve in sliding engagement with the inner wall surface of the housing, the sleeve having a sleeve port, a run-in position, a first operational position, and a second operational position, wherein the sleeve port is aligned with the first port in the first operational position and the sleeve port is aligned with the second port in the second operational position, and a return member operatively associated with the sleeve and in sliding engagement with the inner wall surface of the housing; (b) lowering the string into the well; (c) moving the sleeve from the run-in position to the first operational position thereby energizing the return member; (d) fracturing the well in the first operational position by pumping a fracturing fluid through the bore, through the sleeve port, through the first port, and into the well; (e) reducing the flow of the fracturing fluid through the bore, through the sleeve port, and through the first port; (f) moving the sleeve from the first operational position to the second operational position by releasing energy stored in the return member to move the sleeve from the first operational position to the second operational position; and (g) producing fluids from the well by flowing fluids from the well, through the second port, through the sleeve port, and into the bore of the housing. 
         [0017]    A further feature of the method is that the sleeve may be moved from the run-in position to the first operational position by disposing a plug element on a seat disposed within a sleeve bore of the sleeve so that fluid pressure builds up above the plug element to force the sleeve from the run-in position to the first operational position. Another feature of the method is that the return member may be energized by compressing an elastic member. An additional feature of the method is that the return member may be energized by the return member being moved from a static position to an energized position by the sleeve engaging the return member and forcing the return member into a shoulder disposed along the inner wall surface of the housing. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0018]      FIG. 1  is a cross-sectional view of one specific embodiment of the fracturing tool disclosed herein shown in the run-in position. 
           [0019]      FIG. 2  is a partial cross-sectional view of the multi-position fracturing tool of  FIG. 1  shown in the first operational, or fracturing, position. 
           [0020]      FIG. 3  is a cross-sectional view of the multi-position fracturing tool of  FIG. 1  shown in the second operational, or producing, position. 
       
    
    
       [0021]    While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims. 
       DETAILED DESCRIPTION OF INVENTION 
       [0022]    Referring now to  FIGS. 1-3 , fracturing or frac tool  30  includes outer housing  32  having inner wall surface  34 , outer wall surface  36 , bore  38 , first or fracturing port,  40 , and second or production port  42 . Second port  42  may include a fluid flow control member or device shown as screen  43  that allows liquids to flow through second port  42 , but prevents certain sized particulate matter from flowing through second port  42 . Second port  42  may also include a second fluid flow control member such as a choke (not shown), that is capable of controlling the pressure drop and flow rate through second port  42 . In one particular embodiment, second port  42  includes screen  43  and a choke. 
         [0023]    Sleeve  50  is in sliding engagement with inner wall surface  34 . Sleeve  50  includes bore  52  and retaining member  53  shown as a flange  55  that is disposed within recess  35  in inner wall surface  35 . Sleeve  50  also includes sleeve port  54  and an actuator for moving sleeve  50  from the run-in position ( FIG. 1 ) to the first operational position ( FIG. 2 ). The actuator may be any device or method known to persons of ordinary skill in the art. As shown in  FIGS. 1-3 , the actuator is a seat such as ball seat  60  capable of receiving plug element such as ball  62 . Although  FIGS. 1-3  show ball seat  60  and ball  62 , it is to be understood that the seat is not required to be a ball seat and the plug element is not required to a ball. Instead, the seat can have any other shape desired or necessary for receiving a reciprocally shaped plug element. 
         [0024]    Sleeve  50  includes dynamic seals  56  (numbered only in  FIG. 1 ) to assist sleeve  50  in sliding along inner wall surface  34  and to reduce the likelihood of leaks between inner wall surface  34  and the outer wall surface of sleeve  50 . 
         [0025]    Also disposed along inner wall surface  34  is return member  70 . Return member  70  comprises a return sleeve  71  having bore  73  and biased member  74 . Although biased member  74  is shown as an elastic member such as a spring in  FIGS. 1-3 , it is to be understood that biased member  74  can be another elastic device that is capable of being energized to exert a force upward or against the flow of fluid against sleeve  50  when sleeve  50  is in the first operational position ( FIG. 2 ). Suitable elastic members for utilization as biased member  74  include belleville springs (also known as belleville washers), capillary springs, and deformable elastomers and polymers. 
         [0026]    Return sleeve  71  is in sliding engagement with inner wall surface  34 . As shown in  FIGS. 1-3 , inner wall surface  34  includes shoulders  33  and  35  and return sleeve  71  comprises a head portion  75  and a stem portion  76 . Dynamic seals  77  (numbered only in  FIG. 1 ) disposed on return sleeve  71  assist return sleeve  71  in sliding along inner wall surface  34  and to reduce the likelihood of leaks between inner wall surface  34  and the outer wall surface of return sleeve  71 . 
         [0027]    Head portion  75  and shoulder  33  form chamber  37  in which biased member  74  is disposed. Shoulder  35  provides a stop to prevent sliding of return sleeve  71  at a predetermined location along inner wall surface  34 . 
         [0028]    Biased member  74  is disposed within chamber  37  and on shoulder  33  so that biased member  74  can urge head portion  75  and, thus, return sleeve  71  upward. 
         [0029]    As illustrated in  FIG. 2 , ball  62  engages ball seat  60  to restrict fluid flow through bore  52 . Fluid pressure, such as by pumping fracturing fluid (not shown) down through bore  38 , is exerted onto ball  62  causing retaining member  53  to release from inner wall surface  34  so that sleeve  50  is forced downward into return member  70 . Sleeve  50  continues to be forced downward, energizing biased member  74 , until return sleeve  71  engages shoulder  35 . In this position, sleeve port  54  is aligned with first port  40  of housing  32  and, thus, frac tool  30  is in the first operational position as shown in  FIG. 2 . Accordingly, fracturing fluid can be pumped from bore  38 , through sleeve port  54 , through first port  40 , and into well or well formation to fracture the formation. 
         [0030]    As shown in  FIG. 3 , after sufficient fracturing fluid is injected into the well or open hole formation, ball  62  is removed from ball seat  60  through any method known to persons skilled in the art. For example, ball  62  may be removed from ball seat  60  by increasing the fluid pressure of the fracturing fluid being pumped downward through bore  38  until ball  62  is forced through ball seat  60  so that it can fall to the bottom of the well. Alternatively, ball  62  may be removed from ball seat  60  by decreasing the fluid pressure of the fracturing fluid being pumped downward through bore  38  so that ball can float back to the surface of the well. 
         [0031]    Reduction of the fluid pressure of the fracturing fluid, either after forcing ball  62  through ball seat  60 , or to allow ball  62  to float to the surface of the well, allows energized biased member  74  to overcome the downward force of the fluid being, or previously being, pumped downward through bore  38 . When the upward force of biased member  74  overcomes the downward force of the fluid being, or previously being, pumped downward through bore  38 , return member  70  begins to move upward and, thus, forces sleeve  50  upward from the first operational position ( FIG. 2 ) to the second operational position ( FIG. 3 ). In this position, sleeve port  54  is aligned with second port  42  of housing  32  and, thus, frac tool  30  is in the second operational position as shown in  FIG. 3 . Accordingly, return fluids, such as oil, gas, and water, are permitted to flow from the well or well formation and into bore  38  so that the return fluids can be collected at the surface of the well. 
         [0032]    In operation, frac tool  30  is disposed on a tubing or casing string through attachment members (not shown) disposed at the upper and lower ends of housing  32 . The string is then lowered into the well to the desired location. During this run-in step, sleeve  50  and, thus frac tool  30  is in the run-in position ( FIG. 1 ) so that first and second ports  40 ,  42  are closed. 
         [0033]    Bore  52  is restricted and sleeve  50  is moved from the first operational position to the second operational position. In one specific embodiment, bore  52  is restricted by dropping a plug element such as ball  60  into bore  38  and landing the plug element on a seat. Fracturing fluid is pumped down bore  38  to release sleeve  50  and force sleeve  50  downward. Sleeve  50  engages return member  70  and forces return member  70  downward until return member  70  engages a stop disposed along inner wall surface  34 , e.g., stop shoulder  35 . In so doing, return member  70  becomes energized. 
         [0034]    When return member  70  is energized, sleeve  50  and, thus, frac tool  30 , is in the first operational position ( FIG. 2 ) such that sleeve port  54  is aligned with first port  40  of housing  32 . Fracturing fluid, therefore, is allowed to flow from bore  38  into well or well formation to fracturing the formation. After an amount of time as passed to fracture the formation as desired or necessary to stimulate hydrocarbon production from the well, fracturing fluid is no longer pumped downward through bore  38 . In one embodiment, bore  52  is completely opened, i.e., no longer restricted, prior to or during movement of sleeve from the first operational position ( FIG. 2 ) to the second operational position ( FIG. 3 ). Due to the reduction in fluid pressure acting to force sleeve  50  into return member  70 , the energized return member  70  moves sleeve  50  upward from the first operational position ( FIG. 2 ) to the second operational position ( FIG. 3 ). As a result, sleeve port  54  is now aligned with second port  42  in housing  32  and first port  40  is closed off. 
         [0035]    Once oriented in the second operational position ( FIG. 3 ), return fluids are allowed to flow from the well or well formation through second port  42  and into bore  38  so that the return fluids can flow to the surface of the well for collection. 
         [0036]    As will be recognized by persons of ordinary skill in the art, movement of frac tool  30  from the first operational position ( FIG. 2 ) to the second operational position ( FIG. 3 ) did not require any well intervention using another tool or device. All that was required was the reduction of fluid pressure forcing sleeve  50  into return member  70  either to facilitate both removal of the restriction in bore  52  and movement of sleeve  50  from the first operational position ( FIG. 2 ) to the second operational position ( FIG. 3 ), or to facilitate movement of sleeve  50  from the first operational position ( FIG. 2 ) to the second operational position ( FIG. 3 ) after the restriction in bore  52  has been removed by other non-intervention means, e.g., forcing ball  62  through ball seat  60 . In another embodiment, restriction of bore  52  is not required during fracturing operations, i.e., when frac tool  30  is in the first operational position ( FIG. 2 ). In an additional embodiment, bore  52  can remain restricted during production operations, i.e., when frac tool  30  is in the second operational position. 
         [0037]    In the embodiments discussed herein with respect  FIGS. 1-3 , upward, toward the surface of the well (not shown), is toward the top of  FIGS. 1-3 , and downward or downhole (the direction going away from the surface of the well) is toward the bottom of  FIGS. 1-3 . In other words, “upward” and “downward” are used with respect to  FIGS. 1-3  as describing the vertical orientation illustrated in  FIGS. 1-3 . However, it is to be understood that frac tool  30  may be disposed within a horizontal or other deviated well so that “upward” and “downward” are not oriented vertically. 
         [0038]    It is to be understood that the invention is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. For example, return member may include a belleville spring (also known as belleville washers) or a deformable elastomer or rubberized element. Moreover, return member may be an actuator energized by hydraulic pressure, hydrostatic pressure or electrical power such as from battery packs having electrical timers. Additionally, the actuator for moving the sleeve from the first operational position to the second operational position may be a piston that is actuated using hydrostatic or other pressure. Accordingly, the invention is therefore to be limited only by the scope of the appended claims.