Downhole Perforating Assembly for Friction-Safe Zone Isolation
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Solution Overview
Problem
Conventional perforation techniques like 'plug-and-perf' are not feasible in highly-deviated wellbores with closely spaced producible zones, leading to inefficiencies and potential damage to sealing elements due to mechanical friction and shock waves, making it difficult to isolate and stimulate individual zones effectively.
Innovation Solution
The use of tailored downhole assemblies with friction-reducing subs and lubricants to centralize tools within the wellbore, allowing precise perforation and isolation of individual zones without damaging sealing elements, even in highly-deviated wells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional plug-and-perf perforation technique is used in highly-deviated wellbores, then perforation of multiple zones can be achieved, but sealing elements are damaged due to mechanical friction and shock waves, making zone isolation unreliable
Solution Approach 1:
The tool assembly is segmented into modular components including separate friction reduction subs positioned at different locations (above and below the plug). This segmentation allows each component to perform its specific function independently, with the friction reduction subs protecting the plug from damage while enabling perforation operations in multiple zones
Solution Approach 2:
Friction reduction subs are introduced as intermediary components between the perforating gun and the plug. These subs act as mediators that reduce mechanical friction and absorb shock waves, preventing direct transmission of damaging forces to the sealing elements while still allowing the perforation operation to proceed
2Device complexity
If tools are conveyed through highly-deviated wellbores without friction reduction, then deployment is simpler, but mechanical friction damages sealing elements and prevents reliable zone isolation
Solution Approach 1:
Friction reduction subs serve as intermediary components that specifically address the harmful mechanical friction effect. These subs are positioned to contact the wellbore wall and reduce friction forces, protecting the plug's sealing elements from damage while maintaining the overall simplicity of the deployment process
Solution Approach 2:
The friction reduction subs provide beforehand cushioning by being positioned in advance to absorb and reduce mechanical friction and shock waves before they can reach and damage the sealing elements of the plug, ensuring reliable zone isolation from the outset
3Productivity
If zones are closely spaced in highly-deviated wellbores, then more production zones are accessed, but conventional techniques cannot effectively isolate and stimulate individual zones
Solution Approach 1:
The tool assembly is segmented with friction reduction subs positioned at specific locations to enable precise control during deployment. This segmentation allows the plug to be conveyed through closely spaced zones without damage, enabling effective isolation and stimulation of individual zones even in highly-deviated wellbores with tight spacing
Solution Approach 2:
The patent replaces reliance on purely mechanical strength to withstand friction with a friction reduction system that actively mitigates mechanical forces. This substitution allows the plug to traverse highly-deviated wellbores with closely spaced zones without damage, enabling effective zone isolation and stimulation
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
Enables efficient isolation and stimulation of discrete reservoir zones in highly-deviated wellbores, reducing mechanical friction and maintaining barrier integrity, thereby optimizing production operations.
Implementation Method 1
one or more friction-reducing subs operatively coupled to the perforating gun
Data Source
AI summary
A wellbore stimulation operation method includes conveying a downhole assembly into a wellbore a first time, the downhole assembly including a perforating gun and one or more friction-reducing subs operatively coupled to the perforating gun, axially aligning the perforating gun with a production zone penetrated by the wellbore, triggering operation of the perforating gun and thereby creating a plurality of perforations in the production zone, removing the downhole assembly from the wellbore and replacing the perforating gun with a plug, conveying the downhole assembly including the plug into the wellbore a second time, axially aligning the plug with a location downhole from the plurality of perforations, centralizing the plug within the wellbore with the one or more friction-reducing subs such that sealing elements included in the plug are not damaged while traversing the plurality of perforations, and deploying the plug within the wellbore downhole from the plurality of perforations.