Multi-Stage Hydraulic Fracturing Tool Actuation
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Solution Overview
Problem
Current multi-stage hydraulic fracturing methods, such as the plug and perforate and ball activated sliding sleeve systems, are limited by the number of stages due to frictional constraints and equipment complexity, leading to inefficiencies and increased costs.
Innovation Solution
A multi-stage hydraulic fracturing tool system that uses an elongated casing with ports and an actuation member with a wedged portion and groove to selectively expose ports along the wellbore, allowing for controlled exposure of multiple fracture stages without the limitations of prior systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ball activated sliding sleeve systems are used, then the number of frack stages can be increased, but the system complexity and equipment requirements increase significantly
Solution Approach 1:
The system divides the frack tool into multiple modular stages, each with its own sliding sleeve and port. Each stage can be independently activated by dropping a ball to the corresponding depth, allowing sequential fracking without complex centralized control mechanisms.
Solution Approach 2:
The system uses the weight and position of dropped balls to automatically activate the corresponding stage. The ball's gravity-driven descent and engagement with the sliding sleeve at the predetermined depth creates a self-actuating mechanism that eliminates the need for external actuators or complex control systems for each stage.
2Productivity
If graduated ball sizes are used to activate sliding sleeves, then stage isolation is achieved, but the number of stages is limited by casing diameter
Solution Approach 1:
The sliding sleeve design incorporates a universal engagement mechanism where a single ball size can activate any stage's sliding sleeve through the same engagement principle. The sliding sleeve has a groove and protrusion geometry that works with standard balls regardless of the specific stage depth, allowing the same ball to potentially activate multiple stages if dropped to different depths.
Solution Approach 2:
Instead of using ball size (one dimension) to differentiate stages, the system uses ball position/depth (another dimension) as the differentiating factor. Multiple stages can be activated using the same ball size by controlling how deep the ball travels, effectively adding a depth dimension to stage selection.
3Ease of repair
If coiled tubing units are used for plug and perforate method, then frack plugs can be milled out, but frictional reach constraints limit wellbore length
Solution Approach 1:
The system extracts the frack plugs from the wellbore through a dedicated retrieval mechanism that pulls the plugs out through the casing at the surface. This separates the plug removal function from the fracking operation, allowing long wellbores to be fracked without the frictional constraints that would limit coiled tubing retrieval operations.
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 and controlled exposure of multiple fracture stages, reducing equipment complexity and cost, while mitigating issues like sand filling and frictional constraints, thereby enhancing the hydraulic fracturing process.
Implementation Method 1
the biasing force is generated by one or both of: resilient radial outward deformation of a deformation region of the sliding sleeve member, the deformation region including the protrusions; and resilient radial inward deformation of the actuation member
Implementation Method 2
the biasing force is generated by one or both of: resilient radial outward deformation of a deformation region of the sliding sleeve member; and resilient radial inward deformation of the actuation member, said resilient radial outward and inward deformation occurring in response to action of the wedged portion on the protrusions during downhole motion
Data Source
AI summary
The invention relates to a multi-stage hydraulic fracturing tool and system for controllably exposing selected locations along a wellbore to a pressurized fluid. The system comprises an elongated casing (for disposal within the wellbore) defining an internal borehole extending longitudinally, and having one or more ports; an actuation member configured for travelling down the borehole and includes a wedged portion and a groove having a first length in the longitudinal direction, formed at least partially circumferentially around an outer surface of the actuation member, a sliding sleeve member having an aperture for receiving the actuation member, and one or more inward-facing protrusions having a length less than or equal to the first length, connected to the sliding sleeve member and at least initially protruding radially into the aperture.