Push-the-Bit BHA Reamer for Dogleg and Weight Transfer
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Solution Overview
Problem
Directional drilling operations face challenges in achieving sufficient dogleg capability, leading to reduced weight transfer to the drill bit due to friction forces and increased wellbore tortuosity, especially when encountering formations with unexpected geology or sudden changes.
Innovation Solution
A push-the-bit bottom hole assembly with a reamer that includes a rotary steerable tool and a flexible collar, allowing for adjustable dogleg capability by activating or deactivating reamer cutting structures to enlarge the wellbore diameter and reduce frictional drag, thereby improving weight transfer and reducing wellbore tortuosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the BHA operates at its maximum dogleg capability to achieve sufficient directional change, then the dogleg capability is improved, but friction forces increase reducing weight transfer to the drill bit
Solution Approach 1:
The patent changes the physical parameter of wellbore diameter by deploying the reamer to enlarge the wellbore from its original diameter to an enlarged diameter. This parameter change reduces friction forces between the BHA and wellbore wall, thereby improving weight transfer to the drill bit while maintaining dogleg capability.
Solution Approach 2:
The patent segments the drilling system into two functional zones: a reamed section with enlarged diameter for reduced friction and improved weight transfer, and an unreamed section with original diameter for maintaining dogleg capability. This segmentation allows the system to optimize both contradictory requirements in different spatial zones.
2Adaptability or versatility
If the BHA operates at its maximum dogleg capability to reach target destination, then the directional control is improved, but wellbore tortuosity increases
Solution Approach 1:
The patent changes the geometric parameter of wellbore diameter to reduce tortuosity. By enlarging the wellbore diameter in specific sections, the BHA can achieve the necessary directional changes with smoother transitions, reducing overall wellbore tortuosity while maintaining effective directional control to reach the target destination.
3Force
If the wellbore diameter is enlarged using a reamer to reduce friction forces, then weight transfer to the drill bit is improved, but the device complexity increases
Solution Approach 1:
The patent merges the reamer function with the existing BHA by integrating the reamer as an expandable component within the bottom hole assembly. This allows the reaming function to be combined with the directional drilling and weight transfer functions in a single integrated system, reducing overall device complexity compared to using separate tools.
Solution Approach 2:
The patent employs a dynamically deployable reamer that can transition between a retracted state (when not in use) and an extended state (when reaming is required). This dynamic configuration allows the system to maintain low complexity during normal drilling operations while providing the reaming capability when needed, optimizing the balance between functionality and simplicity.
Data Source
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AI summary
A method for constructing a wellbore includes drilling a wellbore along a trajectory using a bit; reaming the diameter of a portion of the drilled wellbore to enlarge a portion of the wellbore; and altering the trajectory of the bit by applying a lateral force to the enlarged diameter wellbore. Reaming the diameter of the portion of the drilled wellbore increases the dogleg of the wellbore.