Casing Buoyancy via Degradable Material for Deviated Well Running
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Solution Overview
Problem
In the resource recovery industry, running casing strings in highly deviated or horizontal boreholes is challenging due to friction issues caused by gravitational forces, and existing solutions that use air plugs to leverage buoyancy create complications with plug removal.
Innovation Solution
A casing/liner string buoyancy arrangement that includes a material with a lower specific gravity than downhole fluids, which is selectively removable through degradation, allowing for adjustable buoyancy and elimination of the need for air plugs, using a disappear-on-demand material that can be triggered to reduce buoyancy as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If air plugs are used in the casing string to leverage buoyancy, then the casing can float in the borehole reducing friction, but the plugs create complications with removal
Solution Approach 1:
The invention extracts the buoyancy function from removable air plugs and integrates it directly into the casing string structure. Buoyancy elements are built into the casing itself, eliminating the need for separate plug components that would require removal procedures.
Solution Approach 2:
The invention employs degradable material that provides buoyancy temporarily during casing installation, then degrades automatically to dissolve or disappear, eliminating the need for complex removal operations. The buoyancy material is consumed after serving its purpose.
2Device complexity
If degradable material is used for buoyancy, then plug removal is eliminated, but the material must be selectively removable through degradation
Solution Approach 1:
The invention makes the buoyancy property dynamic and controllable through degradation triggers. The material can transition from providing buoyancy to degrading based on specific conditions or signals, allowing adaptive control during different operational phases.
Solution Approach 2:
The invention changes the physical or chemical parameters of the buoyancy material through degradation. By altering properties such as solubility, biodegradability, or thermal stability, the material transitions from a buoyant state to a degraded state that no longer provides buoyancy.
3Ease of operation
If buoyancy is maintained throughout the operation, then friction is reduced during running, but the casing cannot be properly positioned or set
Solution Approach 1:
The invention applies buoyancy periodically or sequentially during the operation. Buoyancy is active during the running phase to reduce friction, then deactivated through degradation when positioning is required, creating distinct operational phases with different buoyancy states.
Solution Approach 2:
The invention prepares the casing with buoyancy elements before installation. The degradable material is pre-positioned within the casing string, ready to provide buoyancy during running, and will automatically degrade when needed for positioning operations.
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
This solution enables efficient running of casing strings in challenging borehole geometries by maintaining buoyancy while allowing for controlled reduction of buoyancy as needed, eliminating the need for complex plug removal methods and reducing frictional resistance.
Implementation Method 1
the volume being of a lower specific gravity than the same downhole fluids
Data Source
AI summary
A casing/liner string buoyancy arrangement including a casing/liner string, and a material defining a volume disposed within the string, the material excluding downhole fluids from the volume, the volume being of a lower specific gravity than the same downhole fluids. A method for managing buoyancy of a casing/liner string including configuring a casing/liner string, running the string, and selectively maintaining or degrading the material to adjust buoyancy of the string. A borehole system including a borehole in a subsurface formation, and an arrangement disposed in the borehole.