Expandable Reamer Fluid Actuation for Borehole Enlargement
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Solution Overview
Problem
Conventional expandable reamers face challenges in enlarging subterranean boreholes without restricting the diameter, which limits production flow rates of hydrocarbons and requires additional casing installation, narrowing the borehole.
Innovation Solution
An expandable reamer apparatus with a tubular body, sliding cutter blocks, and a unique actuation mechanism using fluid pressure and a movable restriction member to extend and retract blades, allowing for efficient enlargement of boreholes while maintaining fluid flow control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If additional casing is installed to increase borehole depth, then the depth of the borehole is improved, but the diameter of the borehole deteriorates (narrows)
Solution Approach 1:
The reamer assembly is divided into multiple independent cutter blocks that can be individually positioned and activated. Each cutter block contains cutting elements that can be extended independently to engage the formation, allowing the reamer to enlarge the borehole while maintaining structural integrity for subsequent casing installation.
Solution Approach 2:
The cutter blocks are designed with movable cutting elements that can be extended and retracted dynamically. The cutting elements are initially retracted to allow passage through casing, then extended to enlarge the borehole, and finally retracted again to allow installation of additional casing beyond the original casing end.
2Length of stationary object
If the borehole diameter is reduced by installing additional casing, then the depth extension is achieved, but the production flow rate deteriorates
Solution Approach 1:
The reamer creates a larger diameter borehole section beyond the existing casing by extending cutting elements radially outward. This enlarged diameter section allows future casing to be installed at a larger size, thereby maintaining higher production flow rates while still achieving the desired depth extension.
3Area of stationary object
If blades are extended to enlarge borehole, then the borehole diameter is improved, but the device complexity increases
Solution Approach 1:
A fluid pressure actuation system is used to extend and retract the cutting elements on the cutter blocks. Fluid pressure is applied to movable restriction members that control fluid flow to the cutter blocks, enabling simple radial extension and retraction of cutting elements without complex mechanical linkages.
Solution Approach 2:
The movable restriction members are biased by springs to automatically return to their initial position when fluid pressure is removed. This self-returning mechanism eliminates the need for additional actuators to retract the cutting elements, simplifying the overall actuation system.
4Area of stationary object
If conventional expandable reamers are used, then the borehole can be enlarged, but the fluid flow is restricted
Solution Approach 1:
The reamer assembly includes multiple cutter blocks positioned at different locations around the tubular body, with fluid ports distributed throughout the structure. This segmentation allows drilling fluid to flow through multiple pathways simultaneously, maintaining fluid flow while the cutting elements are extended to enlarge the borehole.
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 effective enlargement of boreholes without restricting fluid flow, allowing for increased production rates and easier casing installation by using fluid pressure to actuate blade extension and retraction, maintaining operational efficiency.
Implementation Method 1
when the rate of fluid flow through the sleeve member between the open ends thereof meets or exceeds a selected flow rate
Implementation Method 2
the at least one blade of the earth-boring tool may be moved from a retracted position to an extended position responsive to the increase in the pressure of the fluid within the sleeve member
Data Source
AI summary
Expandable reamers for enlarging wellbores include a tubular body and one or more blades configured to extend and retract. A sleeve member within the tubular body has open ends to allow fluid to flow therethrough. A fluid port extends through a wall of the sleeve member. A restriction member within the sleeve is movable between first and second positions. In the first position, fluid flow through the downhole end of the sleeve is generally unimpeded, and fluid flow through the fluid port is generally impeded. In the second position, fluid flow through the downhole end of the sleeve member is generally impeded, and fluid flow through the fluid port is generally unimpeded. The restriction member may be configured to move responsive to changes in the rate of fluid flow through the sleeve member. Methods of using such reamers are also disclosed.