Wellbore Flow Diversion Tool Using Tortuous Path Apertures
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for re-stimulating shale wells face challenges in effectively isolating sections of the wellbore for re-fracturing, as existing technologies like elastomeric seals are unreliable and create pressure drops, limiting the ability to maintain high pumping rates and control frac fluid volume.
Innovation Solution
A wellbore flow diversion tool with a hollow mandrel pipe and a cylindrical cage featuring tortuous path apertures, which allows fluid flow at low pressures and blocks flow at higher pressures, providing adequate pressure isolation without the need for elastomeric seals, thus enabling efficient re-stimulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If elastomeric seals are used to isolate wellbore sections, then pressure isolation is achieved, but the inner diameter is restricted and pressure drop increases
Solution Approach 1:
The patent removes elastomeric seals from the system entirely, replacing them with a mechanical isolation mechanism using a bridge structure and packing material that achieves pressure isolation without restricting inner diameter or creating pressure drop
Solution Approach 2:
The patent introduces a bridge structure as an intermediary element that spans the annulus between tubing and casing, combined with packing material, to achieve pressure isolation without the need for elastomeric seals that would restrict flow
2Reliability
If elastomeric seals are used to seal the annulus, then isolation is provided, but the structure becomes unreliable and gets stuck with frac sand
Solution Approach 1:
The patent extracts elastomeric seals from the system, replacing them with a mechanical isolation structure using a bridge and rigid packing material that does not interact with frac sand and cannot become stuck
Solution Approach 2:
The patent uses a sacrificial bridge structure that can be left in place or retrieved, combined with packing material that provides reliable isolation without the reliability issues of elastomeric seals that degrade and get stuck with sand
3Reliability
If tubing is inserted barely smaller than parent pipe to isolate sections, then isolation is achieved, but inner diameter is restricted limiting frac fluid injection rate
Solution Approach 1:
The patent introduces a bridge structure as an intermediary that provides isolation across the annulus without requiring reduction of tubing inner diameter, allowing full frac fluid injection rates to be maintained
Solution Approach 2:
The patent moves the isolation mechanism from the internal flow path (which would restrict diameter) to the external annular space using a bridge structure, thereby maintaining full inner diameter for fluid injection
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 tool allows for higher pumping rates and pressure isolation, facilitating successful re-fracturing operations by maintaining a large inner diameter and resisting flow erosion, while being robust and resistant to corrosive environments.
Implementation Method 1
a cylindrical cage having a plurality of generally lengthwise tortuous path apertures generally parallel with one another between the two open ends of the mandrel pipe
Implementation Method 2
the plurality of generally lengthwise tortuous path apertures defining a plurality of bow springs therebetween, the plurality of bow springs bowed outward from the mandrel pipe
Data Source
AI summary
An apparatus for at least partially sealing an annulus of a wellbore comprises a hollow mandrel pipe adapted to attach to a tubing string, and a cylindrical cage surrounding and attached to an exterior length of the mandrel pipe, the cylindrical cage having a plurality of generally lengthwise tortuous path apertures generally parallel with one another between the two open ends of the mandrel pipe, the plurality of generally lengthwise tortuous path apertures defining a plurality of bow springs therebetween, the plurality of bow springs bowed outward from the mandrel pipe.