Section Mill Blades Actuate via Fluid Pressure for Extended Casing Removal
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Solution Overview
Problem
Current section mills are limited in their ability to remove extended axial segments of casing in a wellbore, as their blades become worn down quickly, requiring frequent tool replacements and increasing operational time and costs.
Innovation Solution
A downhole tool with a dual-section mill design, where each section mill has blades that can actuate from an inactive to an active position in response to fluid pressure, allowing for extended cutting capabilities without the need for frequent tool replacement, by using a hinge pin mechanism and a seat to secure the blades in an inactive position until activated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a single section mill with blades is used to mill casing, then the device complexity is low, but the duration of action is limited because blades wear down quickly
Solution Approach 1:
The section mill is divided into multiple independently operable blades (first blade, second blade, third blade, fourth blade) arranged around the body. Each blade can be independently actuated from an inactive to an active position, allowing sequential or simultaneous operation to extend the overall cutting duration while maintaining a relatively simple individual blade structure.
Solution Approach 2:
The blades are designed with movable hinges allowing transition between inactive (retracted) and active (extended) positions. Fluid pressure applied through the bore actuates the blades dynamically, enabling them to engage the casing only when needed and retract when worn, thereby extending the operational duration without requiring complete tool replacement.
2Duration of action of moving object
If blades are made more durable to extend cutting duration, then the duration of action increases, but the weight of the moving object increases
Solution Approach 1:
Instead of making the entire section mill structure heavier with more durable materials, the patent applies enhanced cutting surfaces locally only to the blade edges that contact the casing. The body and hinge mechanisms use standard materials, while only the critical cutting zones are reinforced, extending blade life without proportionally increasing overall weight.
3Duration of action of moving object
If multiple section mills are coupled together to remove extended casing segments, then the duration of action increases, but the device complexity and weight increase
Solution Approach 1:
The section mill uses multiple blades (first, second, third, fourth blades) distributed around a single body, each capable of independent actuation. This segmentation allows the mill to tackle extended casing segments sequentially with one lightweight unit rather than requiring multiple heavy mills coupled together, reducing overall tool string weight while maintaining extended cutting capability.
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
Enables the removal of longer casing segments in a single trip, reducing operational time and costs by extending the cutting duration of the blades, allowing for more efficient wellbore abandonment procedures.
Implementation Method 1
fluid pressure is applied to the section mill via the through-bore of the tool string. The fluid pressure causes one or more blades to extend radially outward from the section mill
Implementation Method 2
The section mill is rotated about its longitudinal axis (by rotating the tool string) causing the blades to cut through the casing
Data Source
AI summary
A section mill for removing a portion of a casing in a wellbore. The section mill may include a body having a first end portion, a second end portion, and a bore formed axially therethrough. A plurality of blades may be coupled to the body. Each of the blades may have a first end portion and a second end portion. The first end portion of each blade may be coupled to the body via a hinge pin, and the second end portion of each blade may have a cutting surface formed thereon. A seat may be formed within the bore. The blades may be adapted to actuate from an inactive position to an active position in response to an impediment forming a seal against the seat.