Borehole Completion With Triangular Notching to Reduce Flow Resistance
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Solution Overview
Problem
Current wellbore completion methods face limitations due to perforation resistance and near wellbore tortuosity, which restrict fluid flow by narrowing the effective wellbore diameter and creating tortuous paths, especially in unconventional oil and gas, geothermal, and geomechanical pumped storage systems.
Innovation Solution
A method involving the removal of a section of casing and cutting a symmetric triangular notch perpendicular to the casing axis into the rock formation, optimizing the wellbore diameter and extending the fracture intersection, using tools like rotary casing cutters to enhance fluid access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If explosive perforations are used to connect the wellbore to the rock formation, then fluid communication is established, but flow resistance increases and effective wellbore diameter is reduced
Solution Approach 1:
The invention removes a section of the steel casing entirely rather than using perforations through it. This extraction of the obstructive element (casing) eliminates the flow resistance that would otherwise be generated by fluid passing through small perforation holes, directly resolving the contradiction between establishing fluid communication and minimizing flow resistance.
Solution Approach 2:
The invention transitions from two-dimensional perforation holes (small circular openings) to a three-dimensional open wellbore section (cylindrical space). This dimensional change dramatically increases the effective flow area and eliminates the tortuous flow paths associated with perforations, thereby reducing flow resistance while maintaining reliable fluid communication.
2Reliability
If multiple perforations are created to form fluid connection, then fracture connectivity is improved, but near wellbore tortuosity increases
Solution Approach 1:
By removing a section of casing entirely, the invention eliminates the need for multiple perforations and their associated tortuous flow paths. The open wellbore section provides a direct, straight connection between the wellbore and the fracture, removing the complexity of near wellbore tortuosity while maintaining fracture connectivity.
3Stability of the object's composition
If steel casing is used to prevent wellbore collapse, then wellbore stability is improved, but effective wellbore diameter is reduced
Solution Approach 1:
The invention applies segmentation by removing only a specific section of the casing at the fracture location while leaving the rest of the casing intact to provide structural support. This segmented approach maintains wellbore stability in areas where casing is needed while creating an open section that maximizes effective wellbore diameter where fluid flow is critical.
Solution Approach 2:
The invention applies local quality by modifying the casing structure specifically at the fracture zone (removing the section) while maintaining the intact casing structure in other areas. This localized modification ensures that the effective wellbore diameter is maximized only where it is most needed for fluid communication, while preserving wellbore stability elsewhere through the remaining casing.
Data Source
AI summary
A method for improved borehole completion. In one embodiment, the method comprises removing a section of casing entirely and cutting a notch through the cement and into the surrounding rock formation, said notch optimally comprising a symmetric triangle terminating in a sharp point oriented perpendicular to the casing axis. Flow may be further optimized by extending the notch as far as practical into the rock matrix to increase the effective diameter of the wellbore and increase the length of the intersection between the fracture and the wellbore.