Flexible Fiber Sheet Plugging Formation Fractures
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Solution Overview
Problem
Lost circulation during wellbore drilling occurs when drilling fluid flows into formation fractures, leading to mud waste and downhole problems, which necessitates a solution to prevent fluid loss and maintain drilling efficiency.
Innovation Solution
A plugging assembly comprising a flexible fiber sheet releasably coupled to a pumpable dart is deployed to the downhole location, where the sheet forms a bridge at the fracture, allowing lost circulation material to accumulate and form a fluid plug, thereby preventing fluid loss. The flexible fiber sheet is configured to unwrap and separate from the dart using a dissolvable gel, and the lost circulation material is added to the drilling fluid to accumulate on the sheet, effectively plugging the fracture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If drilling fluid is circulated at high rate to maintain drilling efficiency, then productivity is improved, but lost circulation through formation fractures increases
Solution Approach 1:
The flexible fiber sheet is deployed in advance to the fracture location and positioned to bridge the fracture before significant fluid loss occurs. The sheet is releasably coupled to a pumpable dart, allowing it to be delivered ahead of time and held in position until needed, then released to form the bridge structure that prevents further fluid loss while maintaining drilling operations
Solution Approach 2:
The flexible fiber sheet acts as an intermediary element between the drilling fluid and the formation fracture. It provides a transitional structure that allows controlled interaction - the sheet bridges the fracture and provides a surface for lost circulation material to accumulate, creating a progressive plug that stops fluid loss without completely blocking the fracture immediately
2Loss of substance
If lost circulation material is added to plug the fracture, then fluid loss is prevented, but device complexity increases
Solution Approach 1:
The plugging system is divided into separate functional components: a pumpable dart for delivery, a flexible fiber sheet for bridging, and lost circulation material for plugging. This segmentation allows each component to perform its specific function independently and be deployed through the existing drill string without requiring complex integrated equipment
Solution Approach 2:
The flexible fiber sheet is designed to automatically unwrap and deploy when released from the pumpable dart at the fracture location. The sheet self-positions to bridge the fracture without requiring external manipulation or complex deployment mechanisms, and the lost circulation material naturally accumulates on the sheet to form the plug
3Reliability
If a flexible fiber sheet is deployed to bridge the fracture, then plugging effectiveness is improved, but ease of operation decreases
Solution Approach 1:
The mechanical coupling between the flexible fiber sheet and the pumpable dart is replaced with a dissolvable gel attachment mechanism. This allows the sheet to be securely held during transport through the drill string but automatically released when the gel dissolves upon contact with drilling fluid at the fracture location, eliminating the need for complex mechanical release mechanisms
Solution Approach 2:
The attachment mechanism transitions from a mechanical bond to a chemical dissolution process. The dissolvable gel changes its properties when exposed to drilling fluid, transforming from a strong attachment state during transport to a dissolved state at the deployment location, enabling automatic release without mechanical intervention
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
This solution prevents drilling fluid from leaving the wellbore through fractures, saving time and resources, and is compatible with various wellbore fluids, allowing for quick deployment without specialized personnel, enhancing well longevity and cementing operations.
Implementation Method 1
a gel dissolvable in the drilling fluid at the downhole location, and where the flexible fiber sheet is configured to separate from the pumpable dart when the dissolvable gel is dissolved in the drilling fluid
Implementation Method 2
lost circulation material configured to accumulate on a portion of the flexible fiber sheet to at least partially fluidically plug the formation fracture
Data Source
AI summary
A method of plugging a formation fracture includes drilling, with a drill string configured to flow drilling fluid, a wellbore, where, at a downhole location, the drilling fluid is lost through a formation fracture. The method also includes deploying, through the drill string, a plugging assembly to the downhole location of the wellbore. The plugging assembly includes a flexible fiber sheet releasably coupled to a pumpable dart such that when the plugging assembly reaches the downhole location, the flexible fiber sheet is released from the dart to flow, with the drilling fluid, to the formation fracture to at least partially overlay the formation fracture. The method also includes adding, to the drilling fluid, lost circulation material configured to accumulate on a portion of the flexible fiber sheet to at least partially fluidically plug the formation fracture.