Method and apparatus for lateral well drilling utilizing a rotating nozzle

Abstract

Apparatus and method for drilling into strata adjacent to a well casing through an existing hole in a side of the well casing at a desired elevation therein, including a flexible tube for passage through the hole having a first end, an opposite second end, and an internal cavity extending therethrough between the first end and the second end, a nozzle for passage through the hole on the first end of the flexible tube, the nozzle having at least one aperture therethrough in communication with the internal cavity of the flexible tube, and structure suspendable in the well casing and connected to the second end of the flexible tube for supporting the flexible tube and the nozzle in the well casing at the desired elevation for passage through the hole, the structure including an element for rotating the flexible tube and the nozzle when extending through the hole relative to the structure, and the structure including an internal passage connected in communication with the internal cavity of the flexible tube and connectable to a source of fluid under pressure for delivering the fluid under pressure to the flexible tube such that the fluid under pressure will pass through the flexible tube and be discharged through the at least one aperture of the nozzle to drill an extension of the hole into the strata as the flexible tube and the nozzle are rotated.

What is claimed is:  
     
         1 . Apparatus for drilling into strata adjacent to a well casing through an existing hole in a side of the well casing at a desired elevation therein, comprising: 
 a flexible tube for passage through the hole having a first end, an opposite second end, and an internal cavity extending therethrough between the first end and the second end;    a nozzle for passage through the hole on the first end of the flexible tube, the nozzle having at least one aperture therethrough in communication with the internal cavity of the flexible tube; and    structure suspendable in the well casing and connected to the second end of the flexible tube for supporting the flexible tube and the nozzle in the well casing at the desired elevation for passage through the hole, the structure including an element for rotating the flexible tube and the nozzle when extending through the hole relative to the structure, and the structure including an internal passage connected in communication with the internal cavity of the flexible tube and connectable to a source of fluid under pressure for delivering the fluid under pressure to the flexible tube such that the fluid under pressure will pass through the flexible tube and be discharged through the at least one aperture of the nozzle to drill an extension of the hole into the strata as the flexible tube and the nozzle are rotated.    
     
     
         2 . The apparatus of  claim 1 , wherein the structure comprises a sheath containing the flexible tube, the sheath being engageable with an element in the well casing having an elbow therethrough aligned with the hole in the side of the well casing, the element for rotating the flexible tube comprising a fluid driven motor, and the flexible tube and the structure including threadedly engaged members which support the flexible tube in the sheath, the motor being operable for rotating the flexible tube for threadedly disengaging the flexible tube from the structure to allow the flexible tube to be lowered from the sheath to enter the hole in the side of the well casing through the elbow.  
     
     
         3 . The apparatus of  claim 2 , wherein an elongate rigid tube is connected between the motor and the flexible tube.  
     
     
         4 . The apparatus of  claim 2 , wherein the fluid motor is connected to the internal passage of the structure for receiving the fluid under pressure for operating the motor, the motor including at least one port communicating with the internal cavity of the flexible tube for discharging the fluid under pressure from the motor to the flexible tube.  
     
     
         5 . A method for drilling into strata adjacent to a well casing through an existing hole in the side of the well casing at a desired elevation therein, comprising the steps of: 
 providing a flexible tube extendible through the hole having a first end, an opposite second end, and an internal cavity extending therethrough between the first end and the second end, a nozzle extendible through the hole on the second end of the flexible tube, the nozzle having at least one aperture therethrough in communication with the internal cavity of the flexible tube;    providing structure for supporting the flexible tube and nozzle for entry into the hole in the side of the well casing, the structure including a fluid drivable motor drivingly connected to the flexible tube for rotating the flexible tube relative to the structure when fluid under pressure flows through the motor, the structure including an internal passage connecting a source of fluid under pressure to the motor and connecting a fluid discharge port of the motor with the internal cavity of the flexible tube for flow of the fluid under pressure thereto;    positioning the structure in the well casing with the nozzle of the flexible tube in position for entering the hole in the side of the well casing; and    lowering the flexible tube while supplying fluid under pressure to the motor for drivingly rotating the flexible tube and the nozzle and for directing the fluid under pressure discharged from the motor through the flexible tube and the nozzle so as to impinge the strata adjacent to the well casing for drilling an extension of the hole into the adjacent strata.    
     
     
         6 . The method of  claim 5 , wherein the structure for supporting the flexible tube includes an element threadedly engaged with the flexible tube and the flexible tube is contained in a protective sheath such that as the rotation of the flexible tube is initiated, the flexible tube will be threadedly disengaged from the structure to allow the flexible tube to be lowered from the sheath.  
     
     
         7 . The method of  claim 6 , wherein the structure is positioned in the well by engaging a bottom end of the sheath with a kick-off shoe located in the well casing at the desired elevation, thereby positioning the flexible tube for entry into an elbow of the kick-off shoe having an opposite end aligned with the existing hole in the side of the well casing.  
     
     
         8 . Apparatus for forming a hole in the side of a well casing at a desired elevation within a well, comprising: 
 a rotatable cutter on an end of a flexible shaft and structure positioning and supporting the cutter with a tip thereof in position for cutting the hole into the side of the casing at the desired elevation; and    a drill stop positioned directly adjacent to a largest diametrical portion of the cutter for preventing an end of the cutter opposite the tip from passing into the hole in the side of the casing, the drill stop including a consumable shim positioned for contacting the side of the casing around the hole so as to be damaged by the contact for providing evidence that the hole has been formed to a desired extent therein.