Methodolgy and apparatus for programmable robotic rotary mill cutting of multiple nested tubulars

Abstract

A methodology and apparatus for cutting shape(s) or profile(s) through well tubular(s), or for completely circumferentially severing a well through multiple tubulars, including all tubing, pipe, casing, liners, cement, other material encountered in tubular annuli. This rigless apparatus utilizes a computer-controlled, downhole robotic three-axis rotary mill to effectively generate a shape(s) or profile(s) through, or to completely sever in a 360 degree horizontal plane wells with multiple, nested strings of tubulars. This is useful for well abandonment and decommissioning where complete severance is necessitated and explosives are prohibited, or in situations requiring a precise window or other shape to be cut through a single tubular or plurality of tubulars.

1 . An apparatus for cutting shape(s) or profile(s) through well tubular(s), or for completely circumferentially severing a well through multiple tubulars, including all tubing, pipe, casing, liners, cement, other material encountered in tubular annuli and formation rock, comprising:
 a computer-control equipped control cabin;   a motorized reel with umbilical cord and distance or feed measurement counter, winch with cable, as required, enclosed electrical and communication wire(s) and hydraulic hose(s);   a downhole assembly body;   a computer-controlled profile generation system for generating and coordinating control signals sent to a three-axis, processor-controlled, downhole robotic rotary mill which simultaneously, and optimally, using sensor feedback adjustment, moves a powered rotary carbide milling cutter up and down in a vertical plane along a Z-axis of a well bore inside the downhole assembly and rotates in a 360 degree horizontal rotary W-axis of the wellbore inside of the downhole assembly,   a swing arm with a rotary milling spindle that moves in a Y-axis arc from the Y-axis body attached to the downhole assembly,   and the simultaneous movement of the Z-axis, W-axis, and Y-axis enabling cutting the tubulars, cement, other annular material or formation rock in any programmed shape(s) or window profile(s), including complete horizontal circumferential severance of all tubulars and annular material.   
   
   
       2 . The apparatus according to  claim 1 , the downhole assembly is deployable riglessly downhole into a wellbore with an umbilical cord or cable from the surface. 
   
   
       3 . The apparatus according to  claim 1 , the downhole assembly is deployable downhole into a well bore with a work string from the surface. 
   
   
       4 . The apparatus according to  claim 1 , wherein the tubulars that are to have shape(s) or profile(s) generated, or that are to be completely severed, are of metal. 
   
   
       5 . The apparatus according to  claim 1 , wherein the tubulars that are to have shape(s) or profile(s) generated, or that are to be completely severed, are of composite material. 
   
   
       6 . The apparatus according to  claim 1 , wherein the downhole assembly is adapted to be received into an innermost tubular with a minimum inside diameter of 5.75 inches and received into an innermost tubular with a maximum inside diameter of 19 inches. 
   
   
       7 . The apparatus according to  claim 1 , wherein the well is an oil well or a gas well, or a similar conductor or support structure comprised of multiple, nested tubulars. 
   
   
       8 . The apparatus according to  claim 1 , wherein the downhole assembly is lockable inside of the well bore with either cylinders, packers, or mechanical means and is capable of selectively locking itself into the tubular from a command from the computer processor. 
   
   
       9 . The apparatus according to  claim 2  has a quick-disconnect connection umbilical cord or cable that can be disconnected by a means controlled from the surface controls. 
   
   
       10 . The apparatus according to  claims 1 , wherein the Z-axis movement drive may be electrically or hydraulically driven, with a ball screw, cylinder, or rack and pinion. 
   
   
       11 . The apparatus, according to  claim 1 , wherein an inertia reference system is utilized for sensory positional data. 
   
   
       12 . The apparatus according to  claim 10 , wherein an encoder supplies Z-axis electrical position data to the computer processor. 
   
   
       13 . The apparatus according to  claim 10 , wherein a load cell measures Z-axis forces for adaptive feedback to the computer processor. 
   
   
       14 . The apparatus according to  claim 8 , wherein a W-axis motor is driven either electrically or hydraulically and rotates a cylinder inside the downhole assembly. 
   
   
       15 . The apparatus according to  claim 14 , wherein an encoder supplies W-axis electrical position data to the computer processor. 
   
   
       16 . The apparatus according to  claim 14 , wherein a load cell measures W-axis forces for adaptive feedback to the computer processor. 
   
   
       17 . The apparatus according to  claim 8 ,.wherein a Y-axis is attached to the bottom of the W-axis. 
   
   
       18 . The apparatus according to  claim 17 , wherein the W-axis body houses a motor driven milling spindle swing arm that is pivot mounted in the W-axis body. 
   
   
       19 . The apparatus according to  claim 18 , wherein the milling spindle swing arm motor may be housed in the pivoted milling spindle swing arm or driven by a motor in the W-axis body supplying power to the milling spindle swing arm through a swivel coupling, such as a C.V. joint. 
   
   
       20 . The apparatus according to  claim 18 , wherein the milling spindle swing arm motor has an encoder for supplying RPM data to the computer processor. 
   
   
       21 . The apparatus according to  claim 17 , wherein the Y-axis body has a hydraulic cylinder so arranged as to feed out the motor driven spindle in an arc, thereby enabling cutting of the tubular(s). 
   
   
       22 . The apparatus according to  claim 20 , wherein the hydraulic cylinder has been gun-drilled for an inductive positioning system to supply electrical position data to the computer processor. 
   
   
       23 . The apparatus according to  claim 20 , wherein the hydraulic cylinder presses on a load cell to provide adaptive feedback to the computer processor. 
   
   
       24 . The apparatus according to clam  1 , wherein the three-axis robotic downhole rotary mill will completely sever through multiple nested, non-concentric, cemented tubulars of any thickness that can be machined with carbide, out to and through an outermost tubular of 42-inch diameter, initiating the severance from the smallest tubular in  claim 6 . 
   
   
       25 . A method for downhole three-axis rotary milling utilizing a downhole assembly that is 360-degree rotatable, with extendable, pivotal, motor-driven, swing arm(s) with rotary milling cutter(s) to generate shape(s) or profile(s) through well tubular(s), or to completely circumferentially sever a well, with cutting and severance beginning from the innermost tubular of the well and including severance of all tubulars, including tubing, pipe, casing and liners and also cement or other material in the annuli of said tubulars, comprising the steps of:
 transporting to the well abandonment site the downhole assembly, a computer control-equipped operator cabin, a motorized reel with umbilical cord, winch with cable, or work string, or, as required, enclosed electrical and communication wire(s) and hydraulic hose(s) attached to the downhole assembly;   lowering an electronic or mechanical device into the wellbore for the purpose of verifying drift and clearance for the downhole assembly and subsequently retrieving this device after it has provided data down to the depth where the downhole assembly is to be locked in place and at which cutting or severance operations will take place;   lifting the downhole assembly by on-site crane and inserting it, as well as attached umbilical cord or cable, into the wellbore;   monitoring a distance measurement counter to ensure that as the downhole assembly is lowered into the well it reaches the correct depth in the area at which cutting or severance operations will take place;   locking the downhole assembly in place, by means of a packer or hydraulically or electrically operated locking mechanism, thus maintaining the vertical position of the downhole assembly inside the innermost tubular of the installed multiple, nested casing;   utilizing a programmable, computerized central processing unit (CPU) from the control cabin to communicate electronically to send and receive digital sensor data from components of the downhole assembly and from a digital inertial reference system, algorithmically engaging robotic axial and milling actuation based upon received data, or, alternatively, embedding a CPU in the downhole unit to send and receive digital sensor data from components of the downhole assembly and an inertial reference system, algorithmically engaging robotic axial and milling actuation based upon received data;   engaging robotic axial and milling actuation specifically to include up and down movement along the Z-axis in the downhole assembly; W-axis rotation of the downhole assembly permitting 360 degree circumferential horizontal rotation; Y-axis arc feed of the extendable, pivotal, motor-driven, swing arm(s) with rotary milling cutter(s); rotation of the milling spindle assembly measured in RPM; torque adjustment due to torque encountered by the milling spindle swing arm assembly; and other combinations of Z-axis, W-axis and Y-axis adjustment that may be required to generate a specific shape or profile of specific shape or location based on digital inertia or encoder reference system data.   
   
   
       26 . The method of  claim 25 , in order to achieve complete severance of all tubulars, including tubing, pipe, casing and liners and also cement or other material in the annuli of said tubulars, comprising the steps of:
 rotating the downhole assembly in a 360-degree horizontal plane on the W-axis and moving the Z-axis vertical movement up or down, while feeding out along the Y-axis radially and rotating the extendable, pivotal, motor-driven, swing arm(s) with rotary milling cutter(s);   increasing progressively the circumference or extension of the cut; and   utilizing combinations of X-, Y-, and Z-axis movement of the downhole assembly and extendable, pivotal, motor-driven, swing arm(s) with rotary milling cutter(s) to generate optimal mill cuts, create proper space for cutting and ensure sufficient extension of said arm(s), especially initiating cuts at a lower point and moving upward along the Z-axis;   thereby cutting completely through and severing the multiple, nested tubulars, cement or other encountered material in tubular annuli, freeing the tubulars for removal to the surface;   producing a visually detectable drop of the tubulars (conductor) at the surface.   
   
   
       27 . The method of  claim 25 , not used in order to achieve complete 360 degree circumferential severance of all tubulars, but rather to generate other desired cut(s) shape(s) or profile(s) in or through tubular(s) comprising the steps of:
 generating a 360 degree circumferential cut(s) through a single tubular; or generating a 360 degree circumferential cut(s) through a plurality of tubulars, but not through all tubulars in the well of multiple, nested tubulars; or   generating a cut(s), shape(s) or profile(s) in a single tubular; or   generating a cut(s), shape(s) or profile(s) in a plurality of tubulars, but not through all tubulars in the well of multiple, nested tubulars; or   generating a cut(s), shape(s) or profile(s) through all tubulars in the well of multiple, nested tubulars and through any cement or other encountered material in the annuli of said tubulars, such cut(s), shape(s) or profile(s) to include windows.   
   
   
       28 . The method of  27 , used in particularity with the inertia reference system to verify a cut(s), shape(s) or profile(s) in a specific location in the multiple, nested tubulars.