1. Field of the Disclosure
The present disclosure relates generally to cutting windows in casings and forming lateral wellbores from a main wellbore using a mud motor-driven cutting device.
2. Description of the Related Art
Many operations in wellbores for recovery of hydrocarbons (oil and gas) include milling a portion of a casing in the wellbore or forming a lateral wellbore from a main cased or open wellbore. Windows are milled or the side wells are formed from specified locations in the main wellbore. To perform such a cutting operation during a single trip, a downhole tool is conveyed in the wellbore that includes a whipstock connected to a cutting device. The cutting tool is operated by a fluid-driven motor, such as a progressive cavity motor. The motor is typically mechanically locked to prevent it from rotating the cutting tool as that will cause the whipstock to rotate. Once the whipstock has been oriented, an anchor attached below the whipstock is hydraulically set by flowing fluid through the locked motor and without breaking the lock on the motor. After the anchor and whipstock have been set, the cutting device is mechanically disengaged from the whipstock and the motor lock is hydraulically broken by rotating the motor. The cutting device is then lowered along the whipstock to perform a milling operation.
The disclosure herein provides apparatus and method for performing milling/cutting operations downhole without locking the motor or flowing fluid through the motor to set the anchor.
In one aspect, a method of performing a downhole operation is disclosed that in one embodiment may include: conveying a downhole tool in the wellbore that includes an anchor, a whipstock below the anchor, a cutting device, and an unlocked fluid-operated motor that rotates the cutting device the into a wellbore; wirelessly transmitting signals relating to orientation of the downhole tool from a sensor associated with the downhole tool; orienting the whipstock in response to the transmitted signals, setting the anchor without flowing fluid through the motor; disengaging the cutting device from the downhole tool; and performing the downhole operation by operating the cutting device by the motor.
In another aspect, an apparatus for performing a downhole operation is disclosed that in one embodiment may include a cutting device, a fluid-operated motor that rotates the cutting device, a whipstock connected to motor, wherein the motor is free to rotate, a sensor configured to provide measurements relating to orientation of the tool in a wellbore, a telemetry device configured to wirelessly transmit signals relating to the orientation measurements to a surface location and a hydraulically-operated anchor downhole of the whipstock.
Examples of certain features of the apparatus and method disclosed herein are summarized rather broadly in order that the detailed description thereof that follows may be better understood. There are, of course, additional features of the apparatus and method disclosed hereinafter that will form the subject of the claims.
For detailed understanding of the present disclosure, references should be made to the following detailed description, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals and wherein:
Still referring to
In operation, in one embodiment sensors 152 send measurement signals to the controller 170, which processes the sensor signals and sends the processed signals to the surface controller 190 via the telemetry device 180. The surface controller 190 determines the orientation of the downhole tool 120 from the received signals. One or more repeaters 158 may be provided along the drill string. The number and spacing of the repeaters 158 depend upon the wellbore depth and the attenuation of the transmitted signals. Each repeater 158 may include a receiver 158a that receives the transmitted wireless signals, an amplifier 158b that amplifies such received signals and a transmitter 158c that transmits the amplified signals. A common transceiver may be used both as the transmitter and the receiver in each repeater. The repeater components may be powered by battery pack.
To mill a window or drill a side hole in the wellbore 101 at location 165, the downhole tool 120 is conveyed into the wellbore 101 to the depth 103 so that the lower end 140a of the whipstock 140 is so positioned that the bit 130 will cut the hole at the location 165. The controller 170 processes the signals from the orientation sensors 152 and sends the processed signals to the surface controller 190 via the wireless telemetry device 180 and the repeaters 158, if used. The surface controller 190 determines the orientation of the downhole tool 120 and thus the orientation of the whipstock 140 because the whipstock location relative to a location on the tool 120 is known. The whipstock 140 is oriented along a desired direction based on the determined orientation of the tool 120 determined by the controller 190. In one aspect, the whipstock may be oriented by applying rig hand rotation of the drill pipe. The right hand rotation at the surface is transmitted downhole and the orientation device reads the change in position relative to the wellbore thus determining the orientation of the whipstock face. In a coiled tubing application the orientation of the whipstock through surface manipulations cannot be done due to the inability of coiled tubing to rotate. In such a case, the orientation of the whipstock face can be a fixed orientation relative to the wellbore. The orientation of the whipstock may be monitored and confirmed by continually processing the orientation sensor 152 signals. In aspects, the downhole controller 170 and/or the surface controller 190 may be programmed to determine the whipstock orientation before, during and after setting the anchor 142. The hydraulic sub 144 is then activated to set the anchor 142 in the wellbore 101, without flowing fluid 160 through the motor 132. After setting the anchor 142, the whipstock 140 is disengaged from the bit 130 by pulling or pushing the bit 130 and breaking the mechanical connection between the whipstock and the rest of the downhole tool 120. The drilling assembly 120 is then moved downhole along the whipstock 140 to contact the wellbore at location 165. The bit 130 is then rotated by flowing fluid 160 under pressure through the motor 132 to perform a cutting operation downhole during a single trip of the downhole tool 120 in the wellbore 101.
In the downhole tool 120 embodiment shown in
While the foregoing disclosure is directed to the preferred embodiments of the disclosure, various modifications will be apparent to those skilled in the art. It is intended that all variations within the scope and spirit of the appended claims be embraced by the foregoing disclosure.