Eccentric Dual String Exit Module for Lateral Wellbore Drilling
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Solution Overview
Problem
Current milling operations in wellbore drilling lack accuracy due to instability when directing milling devices through multiple strings and completion configurations.
Innovation Solution
An eccentric deflection device with a guide tube and stabilizers maintains the guide tube in an eccentric position within the wellbore, supporting a whipstock to accurately direct a drill string and milling device to create an exit window in the casing for lateral wellbore drilling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a milling device is directed through multiple strings and completion configurations, then the milling device can reach the desired location, but the operation becomes unstable and inaccurate
Solution Approach 1:
The system is divided into separate functional components: a guide tube that provides a stable reference path, a whipstock that provides directional control, and a milling device that performs the cutting. This segmentation allows each component to optimize its function independently, with the guide tube ensuring stability and the whipstock enabling precise orientation control.
Solution Approach 2:
The guide tube acts as an intermediary element between the wellbore and the milling device. It provides a stable reference structure that mediates the interaction between the completion configuration and the milling operation, eliminating the instability that would otherwise occur when directing the milling device through multiple strings.
2Measurement precision
If the guide tube is positioned centrally in the wellbore, then it is easier to install, but it cannot provide the precise eccentric positioning needed for accurate lateral wellbore drilling
Solution Approach 1:
The guide tube is deliberately positioned eccentrically (off-center) in the wellbore rather than centrally. This asymmetric positioning is achieved through the interaction between the guide tube and the casing, where the guide tube naturally settles against the casing wall. This asymmetry is essential for providing the precise positioning needed for accurate lateral wellbore drilling, as it creates a defined reference point for the whipstock and milling device orientation.
3Ease of operation
If space between the guide tube and casing is increased, then the milling device has more room to maneuver, but the guide tube cannot be maintained in a stable eccentric position
Solution Approach 1:
The system creates different spatial conditions in different locations: where the guide tube contacts the casing, there is minimal space for stable positioning, while at the exit window location, there is sufficient space for the milling device to maneuver. This local variation in space allocation allows both stability and maneuverability to be achieved in their respective required locations.
Data Source
AI summary
A method and device for drilling a lateral wellbore off of a main wellbore. The device includes a guide tube for guiding a drill string to a selected location in a wellbore, the guide tube configured to support a whipstock. One or more stabilizers maintains the guide tube at an eccentric position in the wellbore. The guide tube is disposed in the main wellbore with a contact side of the guide tube against the casing. The whipstock is conveyed through the guide tube to the selected location. The drill string is conveyed through the guide tube to the selected location. The drill string is directed via the whipstock to mill an exit window in the contact side of the guide tube and the casing, thereby drilling the lateral wellbore.