Downhole Casing Expansion Tool for Constant Borehole Diameter
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Solution Overview
Problem
In deep, ultra-deep, and complex wells, the progressive reduction in casing size and borehole size due to increased casing layers hinders the ability to reach target depths and affects subsequent drilling operations, necessitating a solution to maintain a constant borehole size.
Innovation Solution
A downhole casing expansion tool comprising an expansion module and a drive module that uses hydraulic pressure to expand casings, featuring a central tube, core tube, and outer tube arrangement with expansion cone sheets, which are driven to expand the casing by shearing shear pins under liquid pressure, maintaining a consistent borehole size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple casing layers are installed to ensure stratum blocking and safety, then well security is improved, but borehole size progressively reduces and target depth cannot be reached
Solution Approach 1:
The patent applies the dynamics principle by designing an expandable casing system that transitions from a compressed state during installation to an expanded state during operation. The casing includes expansion cones that can be activated to increase the borehole diameter, allowing the system to adapt its dimensions dynamically based on operational requirements rather than being fixed during installation.
Solution Approach 2:
The casing is divided into multiple segments with expansion cones positioned at specific locations. Each segment can be independently expanded using expansion members, allowing selective expansion at different zones along the casing length. This segmentation enables targeted borehole enlargement without affecting the entire casing structure.
2Length of stationary object
If casing size is reduced to fit deeper wells, then well depth is improved, but subsequent drilling operations are affected by too small borehole sizes
Solution Approach 1:
The patent applies preliminary action by expanding the casing borehole before subsequent drilling operations commence. The expansion cones are activated in advance to create a sufficiently large borehole diameter, ensuring that all subsequent drilling, completion, and production operations can be performed with adequate space and equipment size requirements are met.
Solution Approach 2:
The system transitions the casing from a compact installed state to an expanded operational state, dynamically adjusting the borehole diameter to accommodate different operational phases. This allows deep well installation with small casings followed by expansion to enable standard-sized drilling operations.
3Shape
If expansion cone sheets are continuously driven downstream, then casing expansion is achieved, but hydraulic pressure must be maintained to shear shear pins
Solution Approach 1:
The patent extracts the hydraulic pressure requirement from continuous operation by designing a one-time expansion mechanism. The shear pins are sheared during the initial expansion phase to release the expansion members from their constrained position, after which the expansion cones can be driven downstream without requiring continuous high hydraulic pressure to maintain the sheared state.
Solution Approach 2:
The expansion process occurs in distinct periodic phases: first the shear pins are sheared under high hydraulic pressure to enable expansion member movement, then the expansion cones are driven downstream to achieve the expanded shape, and finally the hydraulic pressure is reduced. This periodic action separates the high-pressure expansion initiation from the lower-pressure expansion execution.
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
Facilitates the expansion of casings under hydraulic pressure, allowing for consistent borehole diameters, reducing operational challenges in deep wells, and enabling monohole well drilling with reduced costs and improved efficiency.
Implementation Method 1
introducing the liquid into the hydraulic chamber to shear the fourth shear pin so as to drive the outer tube to move downstream
Implementation Method 2
the expansion cone sheets expand axially, so that the expansion of the casing is realized
Implementation Method 3
supported by the cone seat, the expansion cone sheets expand axially
Implementation Method 4
the first connecting member, the second connecting member, the downstream core tube segment and the upstream outer tube segment together define a hydraulic chamber
Data Source
AI summary
A downhole casing expansion tool and a method of expanding casings using the same. The expansion tool includes an expansion module for expanding casings and a drive module for driving the expansion module. The diameter of the openhole can be kept consistent by the expansion tool, so that monohole well drilling and completion operations can be carried out. The expansion tool is particularly suitable for constructions in deep, ultra-deep and complex wells.