Method for casing a wellbore

A method for encasing an open hole section of a well which has a cased section extending to a first depth, and the open hole section extending to a second depth, comprising:

• forming a metal tubular casing into a generally cylindrical upper end portion, a generally collapsed intermediate portion, and a generally cylindrical lower end portion, and inserting laterally spaced apart first and second strings of tubing into the casing during its forming;
• winding the intermediate portion of the casing onto a reel;
• mounting a cement shoe to the lower end portion of the casing, with the cement shoe being in fluid communication with the first string of tubing;
• placing in the lower end portion above the cement shoe an opening tool which has a piston and a conical forming head;
• providing a pressure chamber in the lower end portion below the piston and above the cement shoe, and placing the pressure chamber in communication with the second string of tubing;
• attaching a running tool to the upper end portion;
• deploying the intermediate portion of the casing from the reel and lowering the casing into the well until the cement shoe substantially reaches the second depth and the running tool is located in the cased section;
• pumping a cement slurry down the first string of tubing, and flowing the cement slurry back up the annulus between the open hole section and the casing;
• pumping a fluid down the second string of tubing into the pressure chamber, causing the piston to push the forming head upward relative to the casing and the strings of tubing, radially opening the intermediate portion of the casing into a cylindrical configuration;
• then
• releasing the running tool from the upper end portion of the casing and retrieving the opening tool and the strings of tubing with the running tool.

An apparatus for encasing a well, comprising:

• a string of tubing;
• a string of metal casing having an intermediate portion formed in a generally collapsed configuration with the string of tubing contained therein and wound onto a reel;
• an opening tool located in a lower end portion of the casing which has a piston, a forming head above the piston, and a pressure chamber in the lower end portion of the casing below the piston;
• the intermediate portion of the casing adapted to be deployed from the reel and lowered into the well;
• and
• the string of tubing adapted to be connected to a pump for pumping a fluid down the string of tubing into the pressure chamber, which acts against the piston to push the opening tool upward relative to the casing and the string of tubing, causing the head of the opening tool to radially open the intermediate portion of the casing from the collapsed configuration into a cylindrical configuration.

An apparatus for encasing a well which has an upper cased section and a lower open hole section, comprising:

• first and second strings of tubing;
• a string of metal casing having an intermediate portion formed in a generally flattened configuration with the first and second strings of tubing contained therein and laterally spaced apart, the intermediate portion of the casing being wound onto a reel;
• the casing having a generally cylindrical upper end portion and a generally cylindrical lower end portion;
• an opening tool located in the lower end portion which has a piston and a conical forming head;
• a cement shoe at the lower end portion below the piston which is in communication with the first string of tubing;
• a pressure chamber in the lower end portion of the casing below the piston and above the cement shoe, and which is in communication with the second string of tubing;
• a running tool attached to the upper end portion of the casing, the first and second strings of tubing having upper ends which terminate at the running tool;
• the running tool being secured to a running string for lowering the running tool and the upper end portion of the casing into the cased section of the well and the intermediate portion and the lower end portion of the casing into the open hole section of the well;
• wherein
• the first string of tubing is adapted to be connected to a source of cement for pumping cement down the first string of tubing and out the cement shoe to return up the annulus surrounding the casing;
• and
• the second string of tubing is adapted to be connected to a source of a fluid for pumping down the second string of tubing into the pressure chamber, which acts against the piston to push the opening tool upward relative to the casing and the string of tubing, causing the forming head of the tool to open the the intermediate portion of the casing into a cylindrical configuration;
• and
• the running tool is releasable from the upper end portion of the casing for retrieving the running tool and the first and second strings of tubing after the intermediate portion of the casing has been opened into the cylindrical configuration.

A well casing, comprising:

• a metal inner sleeve, having an outer wall surface;
• at least one metal outer sleeve surrounding the inner sleeve, the outer sleeve having an inner wall surface in contact with the outer wall surface of the inner sleeve;
• and wherein
• an intermediate portion of the casing has a running-in generally collapsed configuration which is subsequently openable while in the well to a generally cylindrical configuration.

An apparatus for opening a casing from a generally collapsed configuration to a generally cylindrical configuration, comprising:

• a forming head having a tapered exterior containing a plurality of flutes extending in straight lines from an upper end portion of the forming head to a lower end of portion of the forming head;
• pushing means for pushing the forming head through the casing;
• and
• a plurality of balls which roll downward on the flutes to engage an internal surface of the casing in rolling contact and bend the casing radially outward to the cylindrical configuration while the forming head is pushed through the casing.

A method for encasing a wellbore, comprising:

• (a) forming a metal tubular casing with an intermediate portion which is in a generally collapsed configuration and winding the intermediate portion of the casing onto a reel in the generally collapsed configuration;
• (b) deploying the intermediate portion of the casing from the reel and lowering the casing into the well;
• then
• (c) opening the intermediate portion of the casing from the collapsed configuration into a cylindrical configuration.

An apparatus for encasing a well, comprising:

• a string of metal casing having an intermediate portion formed in a generally collapsed configuration and wound onto a reel;
• an opening tool having a forming head and located in a lower portion of the casing;
• the intermediate portion of the casing adapted to be deployed from the reel and lowered into the well along with the lower portion;
• and
• the opening tool being upwardly movable from the lower portion through the intermediate portion, causing the head of to radially open the intermediate portion of the casing from the collapsed configuration into a cylindrical configuration.