Abstract:
An apparatus and method is disclosed for insertion of a component into an oil or gas well. Typically, the well includes a cased hole section and may also include an uncased hole section. In some applications, the well deviates substantially from the vertical direction. The apparatus may include a tool member and an engagement mechanism mounted upon the tool member. The engagement mechanism is configured for selective frictional engagement to the cased hole section of the well. A piston is connected to the tool member and is configured for extension relative to the tool member. The component for insertion into the well may be a sand control screen, a perforating gun, or other device.

Description:
TECHNICAL FIELD 
       [0001]    The technical field of the invention is downhole tools and methods for employing downhole tools in oil and gas wells. 
       BACKGROUND 
       [0002]    Oil and gas wells are drilled at greater depths than in the past. Extended reach wells may be drilled several miles into the earth, with a large portion of the wellbore oriented in a direction that deviates substantially from the vertical direction. The operation of drill strings and other tubular devices with attached downhole tools at great distances within a deviated wellbore provides significant challenges in the drilling industry. 
         [0003]    Sand control screens are employed in wells such as extended reach wells to inhibit entry of sand and other solid particles into the wellbore while at the same time facilitating entry of oil and gas. Screens of this type comprise a considerably heavy mass. Screens may be employed in very long sections that extend as much as one mile in length. The total weight of a screen thousands of feet in length is substantial. The frictional forces generated between the screen and the wellbore during placement of such screens into extended reach horizontal wells poses a significant technical and mechanical challenge. In the placement of such screens, it is necessary to apply a force to the screen that overcomes the frictional forces resisting screen placement. When a wellbore deviates substantially from the vertical direction, it becomes a challenge to generate sufficient forces downhole to move the screen into the desired position within the well. 
         [0004]    This invention is directed to apparatus and methods useful for placing components of any type into a well. And, in one particular aspect of the invention, the invention is directed to apparatus and methods for placing sand control screens into wellbores. 
       SUMMARY 
       [0005]    In one aspect of the invention, an apparatus is adapted for insertion of a component into a well having a cased hole section. The apparatus comprises a tool member adapted for receiving a wellbore fluid and an engagement mechanism mounted upon the tool member. The engagement mechanism may be configured for selective frictional engagement to the cased hole section of the well. A piston is provided having a first end and a second end connected to the tool member. The piston is configured for axial extension relative to the tool member. A first choke may be attached to the piston, the first choke being configured for receiving pressurized fluid and transmitting fluid force to the piston to extend the piston axially relative to the tool member. 
         [0006]    In another aspect of the invention, the apparatus includes an engagement mechanism with a slip. The slip is configured for movement between an inboard disengaged position and an outboard engaged position, wherein the outboard engaged position affords frictional contact between the engagement mechanism and the cased hole section to secure the tool member relative to the cased hole section. The apparatus may include an attachment mechanism upon the second end of the piston. The attachment mechanism may be configured for releasably securing the component to the piston of the tool member. A first choke may be removably secured to the tool member. The tool member may be configured for receiving additional chokes with different fluid flow characteristics. In one embodiment of the invention, a force cone may be employed for receiving pressurized wellbore fluid and transferring force to the slip to actuate the slip to the outboard engaged position. 
         [0007]    The invention may be directed to a method for inserting a component into a well using a drill string with a tool member secured to the drill string. In the method, the well may have at least one cased hole section. A drill string is provided with an attached tool member and piston and a component secured to the distal end of the piston. The drill string is lowered into a cased hole section of a well. Then, a fluid is pumped through the drill string to the tool member. Fluid pressure is applied to the tool member that forces, with fluid pressure, an engagement mechanism of the tool member into frictional contact with the cased hole section. The tool member is secured relative to the cased hole section of the well. Fluid is forced through a choke attached to the piston to generate force upon the piston. Then, the piston is extended axially relative to the tool member, thereby inserting the component into the well. Once the component and piston are extended, the fluid pressure may be reduced, which releases the engagement mechanism from frictional engagement with the cased hole section. Subsequently, the drill string is lowered further into the well. This assists in returning the piston to a retracted position within the tool member. This procedure of raising pressure, followed by reducing pressure and lowering the drill string, may be repeated as many times as needed until the component (i.e. screen, perforating gun, or other device) is positioned correctly in the well. In the case of a screen, it is possible to release the screen from the piston in the proper position for well production through the screen. 
         [0008]    In one aspect of the method of the invention, fluid pressure may be applied to the cone, the cone being configured for receiving pressurized fluid and transmitting force to the slips. The slips are engaged against the cased hole section of the well. In some applications of the method, a spring is applied to the cone and the spring is compressed during the application of pressure to the cone. The spring is relaxed upon reduction of fluid pressure to the cone. 
         [0009]    In the specific embodiment of the invention that involves the placement of a screen, the screen may be released by rotating the drill string, thereby disengaging the screen. This may be accomplished, for example, by employing left-handed threads at threaded connection  58 , as further discussed herein. In other applications, it may be possible to release a component, such as a screen, by applying elevated fluid pressure to break a pressure activated rupture disk, thereby releasing the component from the tool member. Other methods known in the art for releasing a component from a drill string could be used as well. 
         [0010]    Essentially any commonly used oilfield fluid can be employed for the application of fluid pressure in the invention, including for example, brine, hydrocarbon, water based mud, oil based mud or pseudo-oil based mud. In some applications of the invention wherein excessive fluid loss into the formation is experienced, it may be useful to employ a fluid loss additive that is pumped with the fluid into the wellbore, through the choke, and into the formation. The fluid loss additive may be selected from essentially known and effective additive, including hydroxyethylcellulose (HEC) polymers, xantham gums derived from a strain of  Xanthomonus campestris  (XC), polymers having sized solids, and also degradable solid polymers. Such a fluid loss additive may include as well calcium carbonate or a calcium carbonate-containing additive. Thus, the invention may be particularly useful to resolve fluid loss problems by the use of fluid loss additives, which may be transported through the choke and into the subterrenean formation. The ability to pump fluid loss additives during the deployment of the component into the wellbore is a significant advantage in the use of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  shows the tool member in a wellbore; 
           [0012]      FIG. 2  illustrates a longitudinal cross-section of the tool member in the compressed or “run in” condition; 
           [0013]      FIG. 2A  shows a close-up cross-sectional view of the engagement mechanism in the disengaged position; 
           [0014]      FIG. 2B  shows a close-up cross-sectional view of the engagement mechanism in the engaged position; 
           [0015]      FIG. 3  illustrates the tool member as it is receiving fluid pressure, with the engagement mechanism contacting the casing of the wellbore and the piston beginning its axial extension (stroke) relative to the body of the tool member; 
           [0016]      FIG. 4  shows the piston of the tool member in the extended position; 
           [0017]      FIG. 5  illustrates the engagement mechanism in the disengaged position with the entire string being pushed further into the wellbore, thus contracting the piston to a return position within the tool member; and 
           [0018]      FIG. 6  shows a later step which occurs after multiple “jacking” procedures into the well, wherein the screen is now residing at the desired position for screen placement, and the tool member is uncoupled from the screen and ready for retraction from the wellbore. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    In one embodiment of the invention, an apparatus and method is disclosed for insertion of a component into a well. The component may be a gravel pack screen, perforating gun, or other mechanical device. Further, the invention may be applied to insertion of such a component into shallow reservoirs with relatively long well sections that deviate from vertical. 
         [0020]    In some applications of the invention, a swiveling tool (not shown) may be applied between the drill pipe and the tool member. Such a swiveling tool could function to facilitate the rotation of the deployment string without rotating the tool member and screen. One example of such a swiveling tool is the Caledus SwivelMASTER™, manufactured by Caledus UK Ltd of Aberdeen, Scotland, which is a drill pipe deployed tool to aid sand control screens or liners to be run at high angles or in tortuous wells to achieve the required depth. 
         [0021]    In the practice of the invention, it is possible to provide a pressure activated tool member that will anchor to the inner surface of the casing and then provide a downward stroke of a piston into the well, thereby driving a screen or other component into the well. A number of pressure cycles may be deployed until the component is located at the appropriate depth in the well. 
         [0022]    Referring now to  FIG. 1 , a drill pipe  26  is extended into a wellbore  24  inside a casing  22  below the ground  28  (or below the mudline in the case of a well drilled into a body of water). A tool member  20  is attached to the drill pipe  26 , and also includes a packer  30 . A component such as a screen  32  is connected to the tool member  20 . 
         [0023]      FIG. 2  shows a longitudinal cross-section of the tool member in the compressed or “run in” condition. The drill pipe  26  is secured by threaded connection  34  to the body  36  of the tool member  20 . A force cone  42  is held by spring  40  in an open position, which allows the slip  38  to remain in the disengaged position (i.e. not in contact with the casing  22 ). Fluid cavity  48  contains pressurized fluid which acts upon the force cone  42  as further described herein with reference to  FIG. 2A . A choke retaining nut  44  secures choke  46  within the piston  50 . Piston  50  is secured by threaded connection  52  to joint  56 , which in turn is connected by threaded connection  58  to screen  32 . Piston  50  rests against the stop  54  of the body  36 . The axial direction is indicated by direction  60  in  FIGS. 2-5 . The description set forth herein for numbered components in  FIGS. 2-5  apply equally to each of the  FIGS. 2-5 , and like numerals are used for like structures. 
         [0024]      FIG. 2A  reveals a closer view of the slip  38  in the disengaged position (as in  FIG. 2 ). Fluid from fluid cavity  48  enters inlet  62  into vesicle  64  where it may apply force upon force cone  42 . In  FIG. 2A , the pressure is low, so that the force cone  42  is held in its relaxed position by spring  40 . The base  66  butts against force cone  42 . A spring  68  is also in the relaxed (not sprung) position against grip plate  70 . Grip plate  70  is not engaged with casing  22  in the configuration of  FIG. 2A , which facilitates the run in of the tool member  20  into the wellbore  24 . 
         [0025]    When the screen  32  has reached the appropriate place in the wellbore  24 , the fluid in fluid cavity  48  has entered inlet  64  (as shown in  FIG. 2B ) to apply pressure to force cone  42  which places spring  40  in full compression. When this occurs, the force cone  42  applies force to base  66 , to place spring  68  into compression, pushing grip plate  70  against casing  22  to form a frictional engagement of the grip plate  70  of the tool member  20  with the casing  22 . At this point in the procedure, as shown in  FIG. 2B , the tool member  20  is reversibly fixed axially relative to the casing  22  (as shown in  FIG. 2B  and  FIG. 3 ). 
         [0026]    As the circulating pressure of the fluid cavity  48  is further increased, force is applied upon choke  46  and upon the piston  50 . Fluid pressure causes piston  50  to move in the axial direction  60  into the wellbore  24 , which carries the screen  32  into the wellbore.  FIG. 3  shows the position of the piston  50  as the piston  50  begins its descent into the wellbore  24 , as exhibited by space  55  (see  FIG. 3 ) which begins to form between the piston  50  and the stop  54 . 
         [0027]      FIG. 4  shows further descent of the piston  50  and screen  32  into the wellbore  24 . In  FIG. 4 , the piston of the tool member  20  is in the fully extended position, with piston  50  resting against stop  54 . The screen  32  has been pushed with considerable force into the wellbore  24  in  FIG. 4 . 
         [0028]      FIG. 5  illustrates a further step in the sequence, wherein the fluid pressure has been reduced, causing the force of the spring  40  to relax, pulling the base  66  from the grip plate  70 , facilitating the release of frictional engagement of the grip plate  70  from the casing  22 . Then, in a next step, the drill pipe  26  is lowered into the wellbore  24  by a distance that approximates the length of the piston  50 , which pushes the piston  50  back into the body  36  of the drill pipe  26 , as shown in  FIG. 5 . 
         [0029]    The step sequence of (1) elevating fluid pressure, (2) engaging the casing  22 , (3) hydraulically pushing the piston  50  and screen  32  into the wellbore  24 , (4) lowering fluid pressure and then (5) moving the drill pipe  26  into the wellbore  24  to reset the piston  50  is repeated as many times as is required to place the screen  32  into the desired position in the wellbore  24 . 
         [0030]    Once the screen  32  (or other component) is positioned in the wellbore  24 , a packer  30  may be set against the casing (see  FIGS. 5 ,  6 ), and then the threaded connection  52  may be rotated to release the screen  32  as shown in  FIG. 6 . 
         [0031]    In the application wherein the component is a perforating gun (not shown), the perforating gun would not be released, but would be retracted from the well with the drill pipe  26  once perforation operations are completed. 
         [0032]    In the specific application of placement of a screen, the screen may be released by rotating the drill string, thereby disengaging the screen, as shown in  FIG. 6 . This may be accomplished, in one embodiment of the invention, by employing left-handed threads at threaded connection  58 , wherein the rotation of the drill pipe  26  facilitates the release of screen  32 . In other applications, it may be possible to release a component, such as a screen, by applying elevated fluid pressure to break a pressure activated rupture disk (not shown), thereby releasing the component from the tool member. Other methods known in the art for releasing a mechanical component from a drill pipe  26  could be employed in the practice of the invention. 
         [0033]    If a fluid loss additive is deployed, the fluid loss additive may be added to the fluid and provided through the choke  46  for deployment into the formation. This may assist in blocking fluid loss into the formation. It is one advantageous feature of the invention that a fluid loss additive may be provided through the apparatus and into the formation during the deployment of the apparatus into the wellbore. The additive may be selected from essentially known and effective additive for oilfield use. Such additives may include hydroxyethylcellulose (HEC) polymers, xantham gums derived from a strain of  Xanthomonus campestris  (XC), polymers having sized solids, and also degradable solid polymers. Such sized solids may include calcium carbonate or salts. HEC is a known polymer that is used in gravel pack fluid systems. XC polymers are known for having good gel strength. 
         [0034]    All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.