Method and apparatus for jet-fluid abrasive cutting

A method to cut user programmable shapes or window profile(s) through down hole casing, cement, and formation rock using abrasive-jet-fluid flowing from a jet-nozzle, the method comprising the steps of:

• inserting an electric line unit and bottom trip anchor annulus an electric line operated top keyed in an annulus a predetermined depth below a bottom elevation depth where a shape or window profile(s) are to be cut and anchoring the bottom trip anchor to said casing;
• removing the electric line unit;
• inserting into the annulus an electrical line operated directional gyro, wherein the directional gyro is seated onto the bottom trip anchor and obtains directional references of the position of the bottom trip anchor;
• and
• removing the gyro from the annulus and inputting into a computer control unit the directional references of the bottom trip anchor.

A down hole jet-fluid cutting apparatus, the apparatus comprising:

• a jet-fluid nozzle;
• a high pressure pump, wherein the high pressure pump is capable of delivering a fluid abrasive mixture at high pressure to the jet-fluid nozzle;
• an abrasive fluid mixing unit, wherein the abrasive fluid mixing unit is capable of maintaining a coherent abrasive fluid mixture;
• a flexible tubing for delivering the coherent high pressure jet-fluid abrasive mixture to the jet-fluid nozzle;
• a jet-fluid nozzle jetting shoe, wherein the jetting shoe is adapted to receive the jet-fluid nozzle and flexible tubing and direct the coherent high pressure jet-fluid abrasive mixture towards a work piece;
• a flexible tubing controlling unit, wherein the controlling unit further includes at least one servomotor for manipulating the flexible tubing in a vertical and horizontal direction;
• a jetting shoe controlling unit, wherein the jetting shoe controlling unit further includes at least one servomotor for manipulating the jetting shoe along a vertical and horizontal axis;
• and
• a central processing unit, wherein the central processing unit includes;
• a memory unit, wherein the memory unit is capable of storing profile generation data for cutting a predefined shape or window profile in the work piece;
• software, wherein the software is capable of directing the central processing unit to perform the steps of;
• controlling the jetting shoe control unit to manipulate the jetting shoe along the vertical and horizontal axis to cut a predefined shape or window profile in the work piece;
• controlling the flexible tubing control unit to manipulate speed feed and the vertical and horizontal axial movement of the flexible tubing to cut a predefined shape or window profile in the work piece;
• controlling percentage of the abrasive fluid mixture to total fluid volume;
• and
• controlling pressure and flow rates of the high pressure pump.

A method for computer assisted milling of a well-bore structure, the method comprising the steps of:

• setting a bottom trip anchor into a well-bore at a predetermined depth below a milling site;
• inserting into the well-bore a directional gyro, wherein the directional gyro is positioned such that it rests on top of the inserted bottom trip anchor;
• transmitting directional telemetry from the directional gyro regarding the position of the bottom trip anchor to an above ground computer and retrieving the inserted directional gyro;
• coupling a profile generation system onto at least one of the well-bore well head or a blow out preventor stack and creating a communication link with the computer;
• connecting the computer to two axis drive servos;
• inserting a jetting-shoe assembly via a tubing string into an annulus of the well bore casing to the milling site depth;
• attaching rotating centralizers on an outer diameter surface of the tubing string to center the tubing string in the annulus;
• and
• milling of the site via an abrasive-jet fluid from the jetting-shoe assembly, wherein the computer implements a predefined shape or window profile at the milling site by controlling the vertical movement and horizontal movement through a 360 degree angle of rotation of the jetting-shoe assembly.