Turbulence cementing sub

Claim 1

A turbulence-generating cementing sub adapted to be connected into a well casing and pass downwardly into a portion of a a second well casing and be positioned therein, said sub comprising: a short tubular body member, casing thread means at each end of said body member for connecting said body member in end-to-end axial alignment between two sections of a well casing, a plurality of first rigid flow-directing means formed on the outer surface of said tubular body member and extending outwardly therefrom and fixedly and integrally arranged on said body member in spaced-apart parallel relationship in a direction to cause a cement slurry flowing thereby to swirl around said body member in one direction toward one end of said body member and at an angle to one side of the axis thereof, and a plurality of second rigid flow-directing means formed on the outer surface of said tubular body member in spaced-apart relationship and extending outwardly therefrom adjacent to and axially displaced from said first flow-directing means and fixedly and integrally arranged on said body member in a second direction at an angle to the other side of the axis thereof to cause cement slurry flowing thereby to swirl around said body member is said second direction toward the same end of said body member to cause a zone of turbulence in said flowing cement slurry, said flow directing means extending outwardly from the body member an overall distance less than the inner diameter of the well casing into which it is passed and positioned.

Claim 17

A method of preventing channeling in a cement sheath and seal in the annular space between a well liner made of pipe sections and a well casing positioned in a well drilled into earth formations, said well liner being run into the well by a lowering and cementing pipe string and hung in said well casing at least 50 feet above the lower end thereof by means of a liner hanger and then pumping cement down the pipe string and into the annular space between the well liner and the well casing, wherein the improvement comprises, coupling a reverse-turbulence rigid tubular cementing pipe sub of a diameter less than the inner diameter of the well casing and in axial screw-threaded engagement between two sections of the well liner below the hanger thereof, providing first and second sets of cement-slurry flow-directing rigid ribs axially displaced one from the other and fixedly and rigidly carried by and spaced around the circumference of the sub on the outer surface thereof, said ribs having channels therebetween, one set of ribs slanting at an angle to the right of the axis of the sub, the other set of ribs slanting at an angle to the left of the axis of the sub, running said well liner and hanger and cementing pipe sub down a well casing to a selected position therein to form an annular space between said liner and well casing, setting the liner hanger to fixedly secure the top of the liner to the inner wall of the well casing with at least 50 feet of the top said liner concentrically arranged within the lower end of said well casing with the cementing pipe sub located above the lower end of the well casing and with the remaining lower length of said well liner extending below said casing, pumping cement slurry down said pipe string, through said liner, up the outside thereof and substantially vertically and axially upwardly into and through the annular space between the liner and the casing, creating in the annular space between the well liner and the well casing at least a first zone of turbulence in the substantially axially-flowing cement slurry by channeling at least a portion of the cement slurry stream at an angle to the liner axis to cause said slurry portion to start to swirl around said well liner in one direction and substantially immediately interrupting the flow of said slurry portion to cause it to swirl around said well liner in the other direction, continuing the pumping of cement slurry past said zone of turbulence and upwardly past said liner hanger to prevent channeling in the cement slurry that remains in the annular space, and allowing said cement slurry in said annular space to harden to a solid sheath in the annular space to form a fluid impervious seal prior to producing said well.

Claim 18

A method of preventing channeling in a cement sheath and seal in the annular space between a well liner made of pipe sections and a well casing positioned in a well drilled into earth formations, said well liner being run into the well by a lowering and cementing pipe string and hung in said well casing at least 50 feet above the lower end thereof by means of a liner hanger and then pumping cement down the pipe string and into the annular space between the well liner and the well casing, wherein the improvement comprises, coupling a reverse-turbulence rigid tubular cementing pipe sub of a diameter less than the inner diameter of the well casing and in axial screw-threaded engagement between two sections of the well liner below the hanger thereof, providing first and second sets of cement-slurry flow-directing rigid ribs axially displaced one from the other and fixedly and rigidly carried by and spaced around the circumference of the sub on the outer surface thereof, said ribs having channels therebetween, one set of ribs slanting at an angle to the right of the axis of the sub, the other set of ribs slanting at an angle to the left of the axis of the sub, running said well liner and hanger and cementing pipe sub down a well casing to a selected position therein to form an annular space between said liner and well casing, setting the liner hanger to fixedly secure the top of the liner to the inner wall of the well casing with at least 50 feet of the top said liner concentrically arranged within the lower end of said well casing with the cementing pipe sub located above the lower end of the well casing and with the remaining lower length of said well liner extending below said casing, pumping cement slurry down said pipe string, through said liner, up the outside thereof and substantially vertically and axially upwardly into and through the annular space between the liner and the casing, creating in the annular space between the well liner and the well casing at least a first zone of turbulence in the substantially axially-flowing cement slurry by channeling at least a portion of the cement slurry stream at an angle to the liner axis to cause said slurry portion to start to swirl around said well liner in one direction and substantially immediately interrupting the flow of said slurry portion to cause it to swirl around said well liner in the other direction, continuing the pumping of cement slurry past said zone of turbulence and upwardly past said liner hanger to prevent channeling in the cement slurry that remains in the annular space, and allowing said cement slurry in said annular space to harden to a solid sheath in the annular space to form a fluid impervious seal prior to producing said well.