Perforating Gun Initial Propellant Fluid Displacement
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Solution Overview
Problem
Existing perforating guns face performance issues due to well fluid impedance, which decreases the diameter of perforations in the well casing and cement, and the depth of formation penetration, and can lead to excessive pressurization damaging well devices.
Innovation Solution
A perforating gun design where an initial propellant is fired to displace well fluid from the annular region before the shaped charges are activated, allowing the fluid jet to perforate the well casing and cement without interference, thereby improving perforation diameter and depth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the perforating gun is positioned within the well casing with standoff distance, then the gun can be deployed and operated, but the well fluid in the annular region impedes the fluid jet and reduces perforation effectiveness
Solution Approach 1:
The patent applies preliminary action by firing the initial propellant charge before the shaped charges to displace well fluid from the annular region in advance. This preliminary displacement creates a fluid-free path for the subsequent shaped charge jets, eliminating the impedance effect and improving perforation effectiveness.
2Manufacturing precision
If the fluid jet traverses through well fluid, cement, and formation, then perforations are created, but the entrance hole diameter and formation penetration depth are reduced due to fluid impedance
Solution Approach 1:
The initial propellant charge is fired in advance to clear well fluid from the annular region before the shaped charges are activated. This preliminary action ensures that when the fluid jet is generated, it travels through a fluid-free path, thereby achieving the intended entrance hole diameter and formation penetration depth without reduction.
3Reliability
If the shaped charge produces high pressure fluid jet, then perforation is achieved, but excessive pressurization can damage well devices
Solution Approach 1:
The patent segments the pressurization process into two distinct stages: an initial propellant charge that displaces fluid at moderate pressure, and subsequent shaped charges that create perforations. This segmentation allows the system to achieve perforation capability while controlling the pressure profile to avoid excessive pressurization that could damage well devices.
Solution Approach 2:
The initial propellant charge performs the preliminary action of displacing well fluid before the shaped charges are fired. This preliminary displacement reduces the impedance that would otherwise cause excessive pressure buildup when the shaped charges are activated, thereby enabling perforation while controlling peak pressures to protect well devices.
4Length of stationary object
If more powerful shaped charges are used to overcome fluid impedance, then perforation depth is improved, but the complexity and power requirements of the system increase
Solution Approach 1:
Instead of using more powerful shaped charges to overcome fluid impedance, the patent employs preliminary action by displacing the well fluid before perforation. This approach achieves the desired formation penetration depth with standard shaped charge power levels, avoiding the increased complexity and power requirements that would result from using more powerful charges.
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 design enhances the entrance hole diameter and formation penetration, reducing the risk of well device damage and allowing for potentially fewer or less powerful shaped charges to achieve the same fracturing performance.
Implementation Method 1
The solid propellant releases energy approximately 1,000 times slower than the explosive material... the pressure produced by the firing of propellant sleeve creates a secondary gas pressure (typically at about 25,000 psi)
Implementation Method 2
the explosive material of each shaped charge is fired, thereby producing a radially directed fluid jet at a very high pressure (e.g., ̃1 million psi) that traverses the propellant sleeve, the well fluid radially outside the propellant sleeve, the well casing wall
Implementation Method 3
producing a radially directed fluid jet at a very high pressure (e.g., ̃1 million psi)
Implementation Method 4
The high speed and intense pressure of the fluid jet often crushes the subterranean formation materials to create the perforation in the formation
Implementation Method 5
The secondary pressure produced by the slower acting and lower pressure solid propellant produces a different result within the formation, creating a plurality of fractures within the formation in communication with initially formed perforation
Data Source
AI summary
A perforating gun, system and method is provided. The perforating gun includes a body, a plurality of shaped charges, at least one initial propellant and may include an actuating mechanism. The plurality of shaped charges are mounted within the body, and each shaped charge has an amount of an explosive material. The actuating mechanism is in communication with each shaped charge and the at least one initial propellant. The actuating mechanism is configured to fire the at least one initial propellant before firing any of the plurality of shaped charges.