Radial Drilling in Horizontal Wells by Coiled-Tubing and Radial Drilling by E-Line and Slick-Line

Abstract

Methods and apparatus are disclosed to overcome problem that are encountered when using coiled-tubing to deploy radial drilling tools in certain wells. In addition, this disclosure provides means and tools by which radial drilling tools can be conveyed and powered by slickline or e-line. To advance the radial drilling tools and/or to apply and control weight on bit (WOB), a chamber is created and is then pressurized to generate a piston-affect. Furthermore, tools and methods are provided to monitor the radial drilling tools' operations and to convey this information to surface personnel. In addition, because the e-line, slickline and certain coiled-tubing strings lack adequate torsional stiffness, torque arresting mechanisms are disclosed. This disclosure further provides for a “zero-discharge drilling” system, a “drill-by-wire” system, and enables radial drilling solutions in horizontal wells using coiled-tubing, e-line or slickline.

1 . A coiled-tubing deployed system for radial drilling from a horizontal well comprising:
 a surface based pump capable of supplying fluid through coiled-tubing;   a whipstock placed in a wellbore on upset tubing;   the coiled-tubing serving as a control-line for a radial drilling tool-string positioned in the upset tubing;   the radial drilling tool-string comprising:
 a flexible tool-string and head wherein fluid can traverse the flexible tool-string and exit the head; 
 the head configured to penetrate casing and/or earthen formation; 
 a chamber formed by: the wellhead; the annulus in the upset tubing; and, a sealing apparatus between the upset tubing and the radial drilling tools-string; 
   said chamber able to be pressurized so as to create a piston-affect capable of driving the radial drilling tool-string and coiled-tubing down the horizontal well and/or of applying weight on bit.   
     
     
         2 . The sealing apparatus of  claim 1  either attached to the control-line, the radial drilling tool-string or to the upset tubing; and, selected as one from the following list:
 a labyrinth seal; 
 a ring or o-ring style seal; 
 a cup-seal; or, 
 a virtual seal created by the close proximity of the radial drilling tool-string to the inside of the upset tubing. 
 
     
     
         3 . The sealing apparatus of  claim 1  defining a cup-seal assembly attached to the radial drilling tool-string or the control-line and having one or more of the following characteristics:
 a cup which faces toward the top of the well; 
 a recess into which a portion of the cup can fold or collapse as it is moved in the upset tubing; or, 
 a cup-lip having a radius or chamber. 
 
     
     
         4 . The radial drilling tool-string of  claim 1  further comprising a torque arresting apparatus used to resist the reverse torque generated by a positive displacement motor powered by the coiled-tubing and used to rotate the flexible tool-string and head. 
     
     
         5 . The system of  claim 1  further comprising a sensor apparatus that can indicate at least one of the following radial drilling tool-string operating parameters:
 the torque load on a downhole motor; 
 the pressure generated by a downhole pump; 
 the weight on bit; 
 the pressure above the sealing apparatus; 
 the pressure below the sealing apparatus; or 
 the differential pressure across the sealing apparatus. 
 
     
     
         6 . The system of  claim 1  further comprising apparatus to communicate one or more radial drilling tool-string operating parameters to the surface via one of the following methods:
 an electrical conductor line running through the coiled-tubing; 
 a fiber-optic line running through the coiled-tubing; or, 
 via changes in the back-pressure of the fluid in the coiled-tubing. 
 
     
     
         7 . The radial drilling tool-string of  claim 1  further comprising a port-off apparatus, which directs a portion of the flow down the coiled-tubing into the chamber allowing for the creation of the piston-affect used to advance the radial drilling tool-string and/or apply weight on bit. 
     
     
         8 . The head on the end of the flexible tool-string in  claim 1  that is used to form the hole in the casing and/or in the earthen formation, selected from the following list:
 a rotating mechanical drilling bit; 
 a non-rotating jetting nozzle; 
 a cavitation or pulsating nozzle; 
 a rotating jetting nozzle; or, 
 a jet-assisted mechanical drilling head. 
 
     
     
         9 . A system for radial drilling in vertical, slant or horizontal wells deployed by e-line or slickline comprising:
 a whipstock placed in a wellbore on upset tubing;   the e-line or slickline serving as a control-line for a radial drilling tool-string positioned in the upset tubing;   the radial drilling tool-string comprising:
 a flexible tool-string and attached head configured to allow fluid to traverse the flexible tool-string and exit the head; 
 the head configured to penetrate casing and/or earthen formation; 
 an inlet port for fluid to enter from the upset tubing annulus into the radial drilling tool-string; 
   a pump capable of providing pressurized fluid to the radial drilling tool-string;   a chamber formed by: the wellhead; the annulus in the upset tubing; and, a sealing apparatus between the upset tubing and the radial drilling tools-string;   said chamber able to be pressurized so as to create a piston-affect capable of driving the radial drilling tool-string and coiled-tubing down the horizontal well and/or of applying weight on bit.   
     
     
         10 . The systems of  claim 9  further comprising a downhole filter that is part of the radial drilling tool-string and which filters fluid that moves from the upset tubing into the radial drilling tool-string. 
     
     
         11 . The system of  claim 9  further comprising one of the following:
 a surface-based pump system that moves fluid down the upset tubing, where it enters the radial drilling tool-string through the inlet port; 
 a downhole pump that is powered by the e-line and is part of the radial drilling tool-string; or, 
 a dual-purpose downhole assembly that is powered by the e-line and which both pumps fluid through the flexible tool-string and comprises a motor used to rotate the flexible tool-string. 
 
     
     
         12 . The system of  claim 9  further comprising a torque arresting apparatus used in conjunction with one of the following:
 an electric motor powered by the e-line and used to rotate the flexible tool-string and/or head; or, 
 a positive displacement motor powered by fluid pumped down the upset tubing from the surface and which enters the radial drilling tool-string via the inlet port, and is used to rotate the flexible tool-string and/or head. 
 
     
     
         13 . The sealing apparatus of  claim 9  either attached to the upset tubing; the control-line or the radial drilling tool-string; and, selected as one from the following list:
 a labyrinth seal; 
 a ring or o-ring style seal; 
 a cup-seal; or, 
 a virtual seal created by the close proximity of the radial drilling tool-string to the inside of the upset tubing. 
 
     
     
         14 . The sealing apparatus of  claim 9  defining a cup-seal assembly attached to the radial drilling tool-string or to the control-line and having one or more of the following characteristics:
 a cup that is oriented so as to expand outward when fluid is pumped into the chamber; 
 a recess into which a portion of the cup can fold or collapse as the cup-seal assembly is moved along the upset tubing; and/or, 
 a cup-lip having a radius or chamber. 
 
     
     
         15 . The upset tubing of  claim 9  having an intake port allowing fluid to pass from the annulus of the wellbore into the annulus of the upset tubing. 
     
     
         16 . The apparatus of  claim 9  further comprising a one-way valve that allows fluid to enter the upset tubing from the wellbore annulus, but prevents fluid from moving from the upset tubing to the wellbore annulus via this valve. 
     
     
         17 . The system of  claim 9  further comprising one or more sensor apparatus that indicate at least one of the following radial drilling tool-string operating parameters:
 the torque load on a downhole motor; 
 the pressure generated by a downhole pump; 
 the weight on bit; 
 the pressure above the sealing apparatus; 
 the pressure below the sealing apparatus; or 
 the differential pressure across the sealing apparatus. 
 
     
     
         18 . The system of  claim 9  further comprising apparatus to communicate one or more radial drilling tool-string operating parameters to the surface via one of the following methods:
 an electrical conductor line running through the e-line; or, 
 via changes in the pressure of the fluid in the annulus of upset tubing. 
 
     
     
         19 . The head on the apparatus of  claim 9  that is used to form the hole in the casing and/or in the earthen formation, selected as one from the following list:
 a rotating mechanical drilling bit; 
 a non-rotating jetting nozzle; 
 a cavitation or pulsating nozzle; 
 a rotating jetting nozzle; or, 
 a jet-assisted mechanical drilling head. 
 
     
     
         20 . A method to performing radial drilling from a horizontal well by means of coiled-tubing comprising the steps of:
 positioning a whipstock in a horizontal well on upset tubing;   connecting the coiled-tubing to a radial drilling-tool-string comprised of:
 a flexible tool-string having a conduit for conveying fluid to a head; wherein, 
 the head is attached: to the flexible tool-string; allows for the ejection of fluid; and, is configured to form a hole in casing and/or earthen formation; 
   lowering the radial drilling tool-string through the upset tubing;   forming a chamber atop the upset tubing by means of a sealing apparatus situated between:
 the upset tubing and the radial drilling tool-string; or, 
 the upset tubing and the coiled-tubing; 
   activating a surface-based pump in fluid communication with and capable of powering the radial drilling tool-string;   generating a piston-affect used to advance the radial drilling string and/or apply weight on bit by virtue of pressurizing the chamber; and then,   advancing the radial drilling tool-string so as to form a hole in the wellbore casing and/or earthen formation by virtue of the head.   
     
     
         21 . The method of  claim 20  further comprising the steps of pressurizing the chamber to generate the piston-affect by:
 porting-off a portion of the fluid pumped down the coiled-tubing; or, 
 pumping fluid directly into the chamber from the surface. 
 
     
     
         22 . The method of  claim 20  further comprising the steps of supplying pressurized fluid to the radial drilling tool-string, thereby allowing the formation of the hole in the casing and/or earthen formation by virtue of one of the following types of head:
 a non-rotating nozzle; 
 a head defining a rotating nozzle; 
 a self-rotating mechanical drilling head; or, 
 a mechanical cutting-head that is rotated by a motor that rotates the flexible tool-string. 
 
     
     
         23 . The method of  claim 20  further comprising the steps of using a torque arresting apparatus to resist the reverse torque generated by a rotating head used to drill the casing and/or earthen formation. 
     
     
         24 . The method of  claim 20  further comprising an electrical cable or fiber optic cable;
 or changes in the fluid pressure within the coiled-tubing to report at least one of the following radial drilling tool-string operating parameters: 
 the torque on a downhole motor; 
 the weight on bit; 
 the pressure above the sealing apparatus; 
 the pressure below the sealing apparatus; and/or 
 the differential pressure across the sealing apparatus. 
 
     
     
         25 . A method for radial drilling into earthen formation with an e-line unit comprising:
 placing a whipstock in a wellbore on upset tubing;   connecting the e-line to a radial drilling tool-string comprising:
 an inlet port for fluid to enter from the upset tubing annulus into the radial drilling tool-string; 
 a flexible tool-string and attached cutting-head wherein fluid can traverse the flexible tool-string and exit the cutting-head; 
 an electric motor powered by the e-line and capable of rotating the flexible tool-string and cutting-head; and, 
 a torque-resisting apparatus to counter-act the reverse torque generated by the action of the cutting-head; 
   activating the electric motor to rotate the radial drilling tool-string;   activating a pumping system capable of supplying fluid through the flexible tool-string and out the cutting-head;   using the flexible tool-string and attached cutting-head to drill a hole in the wellbore casing and/or earthen formation; while engaging the torque-resisting apparatus to prevent any reverse torque generated by the cutting-head from twisting the e-line.   
     
     
         26 . A method for deploying radial drilling tools from vertical, deviated or horizontal wells by means of a slickline or e-line unit comprising:
 positioning a whipstock in a wellbore on upset tubing;   connecting the slick-line or e-line to a radial drilling tool-string comprising:
 a flexible tool-string capable of delivering fluid to a head, which is configured to form a hole in the casing and/or earthen formation; 
 an inlet port for fluid to enter from the wellbore into the radial drilling tool-string, wherein the fluid can traverse through the flexible tool-string and exit the head; 
   positioning a sealing apparatus between the radial drilling tool-string and the upset tubing so as to create a chamber atop the sealing apparatus;   activating a surface-based pumping system that pumps fluid down the upset tubing whereby it encounters the sealing apparatus and generates a piston-affect that is used to advance the radial drilling string and/or apply weight on bit; and, wherein at least some of the fluid enters the radial drilling tool-string and powers the head; and, then,   forming a hole in the casing and/or earthen formation by virtue of the flexible tool-string and head.   
     
     
         27 . The method of  claim 26  further comprising the steps of using the fluid to power a motor that is part of the radial drilling tool-string and which rotates the flexible tool-string and the head so as to mechanically drill the casing and/or earthen formation while engaging a torque-resisting apparatus that counter-act any reverse torque generated by the head. 
     
     
         28 . The method of  claim 26  further comprising the formation of the hole in the earthen formation by conveying pressurized fluid down the flexible drill-string and ejecting the pressurized fluid out a nozzle