Apparatus and method for placing and for backwashing well filtration devices in uncased well bores

An expendable plug for inhibiting the unintentional application of fluid power into a flow bore comprising an internal C-shaped ring compressed within the bore of an external mounting collar and restrained therein by shearable means;

• said C-shaped ring comprising an outwardly biased ring having a slot therethrough said ring being compressed to approximate a circular shape and retained in said shape by confinement within a longitudinal bore in said exterior mounting collar and a plurality of resilient collet fingers formed by slots cut into said ring, said fingers being rigidly attached at one end to said ring and depending therefrom and having a resilient coating thereon;
• each of said collet fingers having a radially outwardly sloping shoulder at the unrestrained end of said finger and at least one of said collet fingers having a drill hole therethrough intermediate said catcher ring and said unrestrained end thereof;
• said external mounting collar comprising an essentially cylindrical tube having at least one bore hole intermediate the ends of said mounting collar said bore hole being alignable with said drill hole in said internal C-ring, and further said collar having at least one circumferential grooves in the exterior surface thereof on each side of said bore hole, each of said grooves being parallel to each other and being located intermediate said bore hole and an end of said mounting collar, each of said grooves confining an external sealing means within the boundaries thereof.

A ball catcher in combination with an extrudable drop ball which is resistant to unsealing as a result of the application of back pressure comprising:

• a. a first segment having a longitudinal flow conduit therethrough;
• b. a last segment having a longitudinal flow conduit therethrough, the internal diameter of said last segment flow conduit being smaller than the internal diameter of said first segment;
• c. said segments being connected by at least one radially inwardly sloping shoulder;
• d. a groove milled into the internal circumference of at least one of said longitudinal flow conduits;
• and
• e. an extrudable drop ball having a diameter larger than one of said grooved flow conduits and being sufficiently soft enough to extrude into said groove upon the application of sufficient pressure thereto.

An apparatus for backwashing downhole filtration means which are incorporated into a production string having a latch down collar proximate the terminal end thereof into position and for backwashing said downhole filtration devices comprising, in combination, from bottom to top,

• a. a float shoe having a longitudinal flow conduit therethrough, said flow conduit having a smooth bore at the one end thereof, a plurality of axially extending jet washing ports depending therefrom and a jet washing port at the terminal end thereof, said float show being rigidly attached at said terminal end to the end of said downhole filtration means so that said washing ports protrude from said filtration means;
• b. latch collet sub being stung into said float shoe and having a longitudinal flow passage therethrough and an external collet latch intermediate the ends of said sub, said collet latch comprising a lower radially outwardly stepped shoulder, said radially outwardly stepped shoulder being adapted to positively engage and latch together with a corresponding radially inwardly stepped shoulder in said latch down collar;
• c. ball catcher resistant to back pressure for sealingly and engagedly retaining a drop ball therein threadedly connected to said latch collet, said ball catcher sub having a flow passage therethrough said flow passage being in flow registration with the longitudinal flow passage of said latch collet sub connecting a first upper opening and a second lower opening and having a decreasing diameter therebetween, a ball retention groove milled into the inner wall of said flow passage intermediate said first opening and said second opening and a radially inwardly sloping ball seat intermediate said ball retention groove and said second opening;
• d. a cup packer threadedly connected to said ball catcher sub, said cup packer having a central mandrel with a longitudinal flow passage therethrough, a plurality of flow ports connecting said flow passage to the annular space between the exterior of said mandrel and the interior of said production string and two opposing essentially hollow bowl shaped sealing elements means, each of said elements extending from and being supported by said mandrel such that said plurality of flow ports are intermediate said element means and being oriented so that the bases of said cones face each other, the sides of said bowl shaped element means being in slidable and sealing engagement with the interior wall of said filtration means, and
• e. a shear sub having a first threaded end, a second swaged end and a flow passage connecting said first end with said second end, said shear sub being threadedly attached to said cup packer and being attached to the balance of the work string thereabove by shearable means.

A method for completing a partially cased, highly deviated or horizontal well bore comprising:

• a. assembling a production string consisting of a ported float shoe having a latch down collar incorporated therein threadedly connected to a plurality of threadedly interconnected well filtration devices, a sleeve valve, a hydraulically operated well packer and a sufficient number of lengths of tubing to reach the surface of said well;
• b. concentrically disposing within said production string a work string consisting of a latching collet in flow registration with the flow conduits of said float shoe and being threadedly connected to an anti-blow back ball catcher sub which is in turn threadedly connected to a cup packer having ports connecting the internal bore of said packer with the annulus between said packer and the inner wall of said production string and opposing conical elements disposed on either side of said ports, said cup packer being threadedly connected to a shear joint onto which is slidably and shearably attached a telescoping joint having concentric flow tubes, one being slidably mounted within the other and said tubes being lockable in a fully expanded condition, said expansion joint being threadedly connected to a collet-type ball catcher sub, said ball catcher sub being threadedly connected to a hydraulic setting tool, said setting tool being disposed in engageable relationship with said packer to effect the setting thereof and said setting tool having a ball actuated valve in sealing engagement with the flow ports of said setting tool and sufficient lengths of interconnected tubing to reach the earth's surface;
• c. running said production string and said work string into the well bore as a unit and pumping wash fluid through said work string into said well bore through said ports in said float shoe to remove debris from said well bore;
• d. positioning said production string at the desired location in said well bore while maintaining said packer within the cased portion of said well bore and thereafter ceasing the pumping of said wash fluid through said work string;
• e. dropping an extrudable ball into said work string and pumping fluid down said work string to force said ball into engagement with said ball actuated valve;
• f. increasing the pressure applied to said valve and said ball sufficiently to shear hollow shear pins therein thereby simultaneously expending an internal collet catcher from the external mounting collar of said valve and opening flow ports in the packer setting tool;
• g. further increasing the pressure applied to said ball to expend said ball from said internal collet catcher into sealing engagement with a second collet catcher;
• h. applying pressure sufficient to stroke a piston in said setting tool thereby moving the slips of said packer into binding engagement and the seals of said packer into sealing engagement with the casing of said cased portion of said well bore;
• i. further increasing the pressure within said work string to both expel the drop ball from said second collet catcher sub into sealing engagement with an anti-blow back ball catcher sub and to extrude said drop ball into a ball retention groove within said anti blow-back ball catcher sub thereby isolating the flow ports in said float shoe from the remainder of said work string;
• j. simultaneously pumping wash fluid down said work string and through the ports in said cup packer while manipulating said work string to reciprocate said cup packer within the bore of said well filtration devices until said wash fluid flows freely therethrough;
• k. pulling up on said work string until the upper shoulder of said cup packer is brought into engagement with a packer retention shoulder and continuing said upward pull until said telescoping joint is locked into its fully extended position;
• l. pushing down on said work string until said latching collet is restrainedly engaged by said latch down collar;
• m. applying sufficient upward force on said work string to shear the shearable means in said shear joint;
• n. withdrawing that portion of said work string above said cup packer from the bore of said production string;
• and
• o. attaching such accessory and surface equipment to said production string to place the well in production.