Buoyant Guide Sub for Multilateral Wellbore Navigation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional tubing strings tend to veer into low-side exits when traversing multilateral junctions due to their weight, making it challenging to maintain access to the downstream portion of the primary bore.
Innovation Solution
A buoyant guide sub is used to guide the tubing string across the low-side exit by utilizing buoyancy to bias the guide sub towards the high-side of the primary bore, ensuring the downstream portion remains accessible.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional tubing strings are used to traverse multilateral junctions, then the tubing string can be easily installed, but the tubing string veers into the low-side exit due to its weight, losing access to the downstream primary bore
Solution Approach 1:
The patent applies the anti-weight principle by introducing a buoyant guide sub that generates upward buoyant force to counteract the downward gravitational force on the tubing string. The guide sub's buoyancy creates a counterbalancing effect that prevents the tubing from veering into the low-side exit, allowing it to maintain proper orientation and access the downstream primary bore while being traversed through the multilateral junction
2Reliability
If the tubing string weight is reduced to prevent veering, then access to downstream primary bore is maintained, but the tubing string lacks sufficient structural strength and stability
Solution Approach 1:
The patent applies segmentation by dividing the tubing system into two functional components: a conventional tubing string that provides structural strength and a separate buoyant guide sub that provides orientation control. This segmentation allows each component to specialize in its primary function - the tubing maintains structural integrity while the guide sub prevents veering through buoyancy, solving the contradiction between strength and reliability
Solution Approach 2:
The buoyant guide sub acts as an intermediary device between the tubing string and the multilateral junction environment. It mediates the interaction by providing buoyant support that prevents the tubing from veering into the low-side exit, allowing the tubing to maintain its structural properties while achieving proper navigation through the junction
3Reliability
If a buoyant guide sub is introduced to prevent veering, then access to downstream primary bore is maintained, but the device complexity increases
Solution Approach 1:
The buoyant guide sub operates on self-service principle by utilizing the natural buoyancy force of the well fluid environment to automatically counteract the tubing's weight. The device requires no active control systems, power sources, or complex mechanical mechanisms - it simply floats and provides upward force to prevent veering, maintaining reliability while minimizing added complexity
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
The buoyant guide sub effectively navigates the tubing string across the multilateral junction, maintaining access to both the lateral wellbore and the downstream primary bore, thereby facilitating efficient well completion and service operations.
Implementation Method 1
using the buoyancy of the guide sub to bias the guide sub toward a high-side of the primary bore while moving the guide sub across the low-side exit
Data Source
AI summary
In one or more examples, a method comprises advancing a tubing string along a primary wellbore toward a junction having a low-side exit to a secondary wellbore, with a guide sub positioned at a leading end of the tubing string. The guide sub has a buoyancy within a well fluid external to the guide sub. The buoyancy of the guide sub is used to bias the guide sub toward a high-side of the primary wellbore while moving the guide sub across the low-side exit to a downstream portion of the primary wellbore. Subsequently, the guide sub is used to guide a fluid or tubular component between the tubing string and the downstream portion of the primary wellbore across the low-side exit.