Fracturing Valve Subassembly Shear Pin Mechanism
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Solution Overview
Problem
Existing down-hole ball valve seat mechanisms for well fracturing face challenges such as inability to be cemented into place, costly open hole packer systems, and restricted fluid flow due to progressively decreasing diameters, limiting the number of stages and flow rate.
Innovation Solution
A fracturing valve subassembly with a tubular valve body and piston, utilizing shear pins and a dart system with grooves and keys to open ports for fracturing fluid flow, allowing for multiple apparatuses with consistent internal diameters and finer graduations in key and sleeve widths to enable higher flow rates and cement breaking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ball valve seat mechanisms with progressively decreasing diameters are used in multiple valve subs, then the number of stages can be increased, but the fluid flow rate becomes increasingly restricted
Solution Approach 1:
The valve sub is divided into multiple independent ports, each port being a separate flow pathway. This segmentation allows each port to maintain full diameter flow capacity while multiple ports collectively increase the number of fracturing stages, resolving the contradiction between stage count and flow rate restriction
Solution Approach 2:
Each valve sub assembly serves multiple functions: it can close off individual production zones using balls of varying sizes, maintain full diameter flow paths when open, and allow multiple such subs to be串联 in a single casing string. This multi-functionality enables high stage count without compromising flow rate
2Adaptability or versatility
If ball valve seat mechanisms are used, then valve subs can control flow through production zones, but they cannot be cemented into place with casing string requiring costly open hole packer systems
Solution Approach 1:
The valve sub assembly uses simple, replaceable components including balls, ball seats, and shearable retention pins. These components are designed to be inexpensive and easily replaceable, enabling the valve sub to be cemented into the casing string permanently without requiring expensive open hole packer systems. The simplicity of components reduces overall system cost
Solution Approach 2:
The patent replaces the complex mechanical open hole packer system with a simpler cemented valve sub assembly. The valve sub uses basic mechanical principles (ball seating, shear pins) rather than complex packer mechanisms, reducing installation complexity and cost while maintaining valve control capability
3Ease of operation
If multiple valve subs are placed in series with progressively smaller diameters, then each valve sub can be selectively closed, but the overall flow rate through the system is constricted
Solution Approach 1:
The valve sub incorporates multiple independently controllable ports within a single assembly. Each port can be closed by a ball of appropriate size, allowing selective zone closure. When open, all ports provide full diameter flow paths, eliminating the progressive constriction effect of series-connected valve subs with decreasing diameters
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 fracturing of multiple production zones with higher fluid flow rates and reduced costs by allowing multiple apparatuses in a single casing string, facilitating cement breaking and consistent fluid flow without diameter restrictions, thus enhancing well production efficiency.
Implementation Method 1
one or more shear pins disposed between the piston and the valve body to hold the piston in the closed position. When sufficient force is placed on the piston, the shear pins can shear away to allow the piston to move from the closed position to the open position
Data Source
AI summary
An apparatus and method is provided for fracturing a well in a hydrocarbon bearing formation. The apparatus can include a valve subassembly that is assembled with sections of casing pipe to form a well casing for the well. The valve subassembly includes a sliding piston that is pinned in place to seal off ports that provide communication between the interior of the well casing and a production zone of the formation. A dart can be inserted into the well casing and propelled by pressurized fracturing fluid until the dart reaches the valve subassembly to plug off the well casing below the valve subassembly. The force of the fracturing fluid against the dart forces the piston downwards to shear off the pins and open the ports. The fracturing fluid can then exit the ports to fracture the production zone of the formation.