Electro-Mechanical Linear Actuator Tractor for Extended Reach Wellbores
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Solution Overview
Problem
Extended-reach horizontal wellbores pose challenges in transporting coiled tubing strings to the toe of the well and back due to increased frictional forces, mechanical buckling, and the limitations of existing tractor technologies, which require hydraulic pressure or vibratory devices that can damage equipment and compromise well integrity.
Innovation Solution
An electric motor-actuated tractor system, known as the e-Tractor, is developed to provide higher pulling and pushing capacities without hydraulic pressure or vibratory devices, using bi-directional electric motors and gripper assemblies to move coiled tubing strings efficiently and reliably, with the option to switch between intermittent and continuous motion modes based on operational needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If hydraulic pressure or vibratory devices are used to move coiled tubing strings in extended-reach wellbores, then the tubing can be transported to the toe of the well, but equipment damage and compromised well integrity occur
Solution Approach 1:
The patent replaces hydraulic and vibratory mechanical systems with an electro-mechanical linear actuator system. The actuator uses a screw mechanism with a nut to convert rotational motion into linear motion, providing controlled pushing and pulling forces on the coiled tubing string without the harmful effects of hydraulic pressure or vibration. This substitution eliminates the harmful factors while maintaining the ability to transport tubing through extended-reach wellbores.
2Length of moving object
If coiled tubing strings are run longer to reach extended-reach laterals, then wellbore exposure to pay zone is multiplied, but frictional forces and mechanical buckling increase making it difficult to reach the toe
Solution Approach 1:
The patent segments the force application mechanism into multiple sections along the coiled tubing string. Multiple linear actuators are distributed at different locations (e.g., proximal, intermediate, and distal sections) along the tubing string. Each actuator independently applies force to its local section, allowing the long tubing string to be pushed or pulled in segments. This segmentation overcomes the cumulative effect of frictional forces and prevents mechanical buckling that would occur with a single continuous force application on a long, flexible tubing string.
Solution Approach 2:
The patent introduces linear actuators as intermediary devices between the coiled tubing string and the wellbore environment. These actuators serve as mediators that apply controlled forces to the tubing string at specific locations, enabling the tubing to overcome frictional forces and reach extended laterals without direct surface intervention. The actuators translate rotational motion from electric motors into linear pushing or pulling forces, facilitating the transportation of long tubing strings through complex wellbore geometries.
3Ease of operation
If surface pipe injection systems are used to push and pull coiled tubing, then tubing can be moved in and out of the well, but the force capacity is limited and cannot handle extended-reach laterals
Solution Approach 1:
The patent replaces the surface-based pipe injection system with downhole linear actuators that are integrated directly onto the coiled tubing string. This substitution enables force application at the point of need within the wellbore, dramatically increasing the effective force capacity. The electro-mechanical actuators can generate sufficient pushing and pulling forces to handle extended-reach laterals, eliminating the force limitations of surface injection systems while maintaining ease of operation through automated control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The e-Tractor system enables the efficient and reliable transportation of heavier coiled tubing strings in extended-reach wellbores by generating higher tractoring forces while minimizing wear and avoiding the use of harmful vibratory devices, thus enhancing the operational efficiency and longevity of well completion operations.
Implementation Method 1
at least one bi-directional electric motor which is directly or indirectly coupled to an end of the screw
Implementation Method 2
a linear actuator subassembly, in the inner body assembly, comprising a longitudinally extending screw, at least one bi-directional electric motor which is directly or indirectly coupled to an end of the screw, and a nut which is positioned on the screw
Data Source
AI summary
An electric motor-actuated tractor (e-Tractor) apparatus and method for use in downhole operations. The apparatus includes a power subassembly, a tractor subassembly and one or more gripper subassemblies and can be: run in a single or multiple e-Tractor configuration; run in either intermittent-motion tractoring mode or continuous-motion tractoring mode with the ability to switch between the two modes; used to generate both distal and proximal longitudinal forces to move the run-in string into or out of the wellbore; repeatedly activated and deactivated without run-in string manipulation or hydraulic pressure; and combined with tensiometer and other sensor package options to provide real-time data to the surface to optimize tractoring operations. The apparatus and method are well-suited for application in an c-coil conveyed workover or completion system, and for use in extended reach laterals in horizontal wells.