Electrically Activated Friction Reduction Sub for Downhole Tubulars
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Solution Overview
Problem
In the drilling and completion industry, coiled tubing often experiences 'lock-up' due to insufficient surface snubbing force to overcome frictional forces between the tubing and the casing or formation wall, especially in highly deviated or horizontal boreholes, leading to difficulties in further transmission of the tubing into the borehole.
Innovation Solution
An electrically activated friction reduction assembly that senses lock-up and reduces friction by creating pressure pulses without blocking the flowbore, allowing continued fluid flow through the tubing, using mechanisms like annulus type flow interruptors, vibration mechanisms, or ballistically actuatable friction reducers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a valve is used to cyclically interrupt flow within the tubing to create pressure pulses, then frictional forces between the coiled tubing and the borehole environment are reduced, but the valve temporarily blocks the flowbore of the tubing thereby disrupting flow that could be used by other downhole tools or bottom hole assemblies
Solution Approach 1:
The invention extracts the flow interruption mechanism from the main flowbore path by placing it in a separate annulus space between the tubing and casing. This allows pressure pulses to be generated in the annulus without blocking the central flowbore, thus reducing friction while maintaining fluid flow to downhole tools.
Solution Approach 2:
The patent introduces an intermediary annulus space as a mediator between the tubing and casing. This annulus serves as a separate channel where flow interruption can occur to generate pressure pulses for friction reduction, while the main flowbore remains unobstructed for continuous fluid flow to downhole equipment.
2Ease of operation
If surface initiated snubbing force is applied to overcome frictional forces, then the tubing can be transmitted into the borehole, but the snubbing force is insufficient when the tubing reaches a point of lock-up in highly deviated, long horizontal, lateral, or vertical boreholes
Solution Approach 1:
The invention uses mechanically generated pressure pulses that create vibratory motion within the tubing and annulus system. These pressure pulses reduce static friction and enable the tubing to overcome lock-up conditions without requiring increased surface snubbing force.
Solution Approach 2:
The patent employs periodic flow interruption in the annulus to generate repeated pressure pulses. This periodic action creates cyclic pressure variations that progressively reduce frictional buildup, allowing continuous tubing advancement through deviated and horizontal sections where constant force application fails.
3Object-affected harmful factors
If flow is interrupted to create pressure pulses for friction reduction, then frictional forces are reduced, but the flowbore is blocked thereby disrupting flow that could be used by other downhole tools
Solution Approach 1:
The invention segments the flow paths into two independent channels: the central flowbore for continuous fluid flow to downhole tools, and the outer annulus for pressure pulse generation. This segmentation allows friction reduction operations in the annulus without affecting the reliability of fluid supply through the flowbore.
Solution Approach 2:
The flow interruption mechanism is extracted from the main flowbore and relocated to the annulus space. This extraction ensures that the valve operations for creating pressure pulses occur in a separate channel, completely independent of the flow path required by downhole tools, thereby maintaining flow continuity and system reliability.
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
Effectively reduces friction between the tubing and the borehole environment, enabling further insertion of the tubing without disrupting downhole tool operations or blocking fluid flow, thus facilitating successful delivery of tools and reducing operational challenges.
Implementation Method 1
incorporating a valve to cyclically interrupt flow within the tubing to create pressure pulses. While such pressure pulses are capable of reducing frictional forces between the coiled tubing and the borehole environment
Implementation Method 2
vibration mechanisms
Implementation Method 3
ballistically actuatable friction reducers
Data Source
AI summary
A friction reduction assembly for a downhole tubular. The friction reduction assembly includes an electrically activated friction reduction sub. The sub includes a flowbore fluidically connected to a flowbore of the tubular and remaining open for fluid flow therethrough during both activated and non-activated states of the friction reduction sub. A friction reducer responsive to an indication of lockup of the tubular, wherein friction between the tubular and surrounding casing or borehole is reduced in an electrically activated state of the friction reduction sub. A method of reducing friction in a downhole tubular is also included.