Point-the-bit BHA with Adjustable Reamer for Drilling
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Solution Overview
Problem
Directional drilling operations face equipment failures and increased wellbore tortuosity due to excessive dogleg capability and lateral forces when using point-the-bit bottom hole assemblies with fixed maximum dogleg capability, especially during transitions between steering and straight drilling.
Innovation Solution
A point-the-bit bottom hole assembly with a reamer that can adjust its diameter by activating and deactivating reamer cutting structures to reduce dogleg capability and alleviate stress on drilling equipment, allowing for flexible dogleg adjustments based on the wellbore section being drilled.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a point-the-bit bottom hole assembly with fixed maximum dogleg capability is used, then the drill string can reach tight radius turns, but large lateral forces are exerted on the drill bit, bearings, stabilizers, and other components resulting in very high stresses
Solution Approach 1:
The bottom hole assembly incorporates a reamer with adjustable diameter that can be dynamically changed during drilling operations. The reamer includes a body with a first diameter in a first configuration and a second diameter in a second configuration, allowing the system to transition between different drilling modes (steering vs. straight drilling) to match the actual wellbore requirements and reduce excessive lateral forces on components
Solution Approach 2:
The invention changes the physical parameter of the reamer diameter to adjust the dogleg capability of the bottom hole assembly. By varying the reamer diameter between a first diameter for steering operations and a second diameter for straight drilling, the system optimizes the balance between achieving required curvature and minimizing stresses on drilling components
2Strength
If the reamer diameter is increased to reduce dogleg capability, then lateral forces and stress on components are reduced, but the ability to create tight radius turns is limited
Solution Approach 1:
The reamer is designed with dynamic configurability, allowing it to switch between different diameters based on the drilling task. The reamer body can be configured with a first diameter when tight radius turns are needed and a second diameter when straight drilling is required, providing adaptability while minimizing component stress during straight sections
3Ease of operation
If transitions from steering to straight drilling are made frequently, then the wellbore can be steered to target destinations, but significant tortuosity is imparted to the wellbore
Solution Approach 1:
The system performs preliminary action by pre-configuring the reamer diameter before entering a straight drilling section. By anticipating the need for straight drilling and configuring the reamer with the appropriate diameter in advance, the system reduces the number of transitions and minimizes tortuosity in the wellbore while maintaining steering capability when needed
Data Source
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AI summary
A method includes extending a wellbore using a drill bit that forms a portion of a bottom hole assembly; enlarging a diameter of the wellbore using a reamer of the assembly; and laterally offsetting either a rotary steerable tool or a mud motor of the assembly in the enlarged diameter wellbore. A bend angle is defined between a central axis of either the rotary steerable tool or the mud motor creates and a central axis of the drill bit. Enlarging the diameter of the wellbore using the reamer while steering the assembly decreases the dogleg. Enlarging the diameter of the wellbore using the reamer while rotational drilling a straight section of the wellbore reduces stresses on the assembly and reduces wellbore tortuosity.