Multi-Deflector Assembly for Bullnose Orientation in Wellbores
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Solution Overview
Problem
Accurately directing a bullnose assembly into either a main wellbore or a lateral wellbore is challenging due to the need for precise orientation and diameter compatibility with existing deflector systems, which often require diameter reduction and struggle with varying bullnose assembly lengths.
Innovation Solution
A multi-deflector assembly with upper and lower deflectors separated by a predetermined distance, featuring channels and conduits of specific sizes, directs the bullnose assembly into either the lateral bore or the main bore based on the length of the bullnose tip, preventing lateral movement when the tip exceeds a certain length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a typical deflector is used to direct the bullnose assembly, then the deflector can be positioned in the main wellbore at a junction, but the bullnose assembly requires diameter reduction to pass through and accurate selection becomes difficult
Solution Approach 1:
The deflector is divided into multiple segments (first deflector segment, second deflector segment, third deflector segment) arranged axially. Each segment has progressively smaller outer diameters, allowing the bullnose assembly to pass through without requiring diameter reduction while maintaining deflection capability at each junction level.
Solution Approach 2:
The invention transitions from a single-plane deflection mechanism to a multi-level axial segmentation. The deflectors are arranged at different axial positions with varying diameters, creating a three-dimensional deflection path that guides the bullnose assembly through the junction without requiring diameter reduction.
2Measurement precision
If the deflector and bullnose assembly are correctly orientated, then accurate selection between wellbores is possible, but causing the bullnose assembly to be deflected toward the proper bore remains challenging
Solution Approach 1:
The deflector segments are designed with inclined surfaces that dynamically guide the bullnose assembly based on its position and orientation. The inclined surfaces create a self-correcting mechanism where the bullnose assembly is naturally directed toward the intended lateral wellbore as it passes through each deflector segment, reducing the challenge of precise deflection control.
3Device complexity
If a single deflector is used at a junction, then the structure is simple, but the bullnose assembly cannot be accurately directed based on its length variations
Solution Approach 1:
The deflector is segmented into multiple axial sections with progressively smaller diameters. Each segment can interact with bullnose assemblies of different lengths, allowing the system to adapt to various bullnose dimensions without requiring a completely different deflector design.
Solution Approach 2:
Each deflector segment has a specific local geometry (outer diameter, inclination angle) optimized for particular bullnose assembly characteristics. This local differentiation allows the single deflector structure to handle multiple bullnose length scenarios effectively.
Data Source
Figure 1~2
Figure 3A~4B
Figure 5A~6B
AI summary
Disclosed is a multi-deflector assembly for guiding a bullnose assembly into a selected borehole within a wellbore. One deflector assembly includes an upper deflector arranged within a main bore of a wellbore and defining first and second channels that extend longitudinally through the upper deflector, wherein the second channel exhibits a width greater than that of the first channel, and a lower deflector arranged within the main bore and spaced from the upper deflector by a predetermined distance, the lower deflector defining a first conduit that communicates with a lower portion of the main bore and a second conduit that communicates with a lateral bore, wherein the upper and lower deflectors are configured to direct a bullnose assembly into one of the lateral bore and the lower portion of the main bore based on a length of a bullnose tip of the bullnose assembly as compared to the predetermined distance.