Perforating Gun Charge Load for Larger Entry Holes in Tight Rock
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Solution Overview
Problem
Existing perforating gun assemblies struggle to meet the demanding performance requirements for unconventional oil and gas recovery, particularly in low-permeability rock formations, requiring consistent and large entry-hole diameters, efficient hydraulic fracturing, and increased formation contact.
Innovation Solution
A perforating gun assembly with a steel housing and shaped charges exceeding 26 grams, configured to form consistent perforation tunnels in low-permeability rock formations, featuring a steel material with specific mechanical properties and a design that expands to a swell diameter of 3.78 inches upon discharge, ensuring efficient hydraulic fracturing and increased formation contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional shaped charges are used in perforating gun assemblies, then the device complexity is reduced, but the perforation tunnel volume and formation contact are insufficient for low-permeability rock formations
Solution Approach 1:
The patent applies parameter changes by specifying precise explosive load weights (22.7 grams, 28-35 grams, or 38-45 grams) and corresponding swel diameters (3.38 inches, 3.62 inches, or 3.78 inches) to optimize perforation tunnel volume. This quantitative parameter optimization enables consistent large entry-hole diameters in low-permeability formations without increasing device complexity
Solution Approach 2:
The patent employs dynamics through the swell design of the shaped charge load, which expands to predetermined diameters upon detonation. This dynamic expansion capability allows the charge to create larger perforation tunnels and increase formation contact area, directly addressing the volume requirement while maintaining a relatively simple charge configuration
2Volume of moving object
If larger shaped charges are used to increase perforation tunnel volume, then the formation contact increases, but the housing material requirements become more stringent
Solution Approach 1:
The patent resolves this contradiction through parameter changes by specifying exact material properties: minimum yield strength of 650 MPa, minimum tensile strength of 900 MPa, minimum hardness of 250 HBW or 25 HRC, and minimum impact strength of 70 Joule. These controlled parameter specifications enable the housing to contain larger shaped charges (up to 45 grams) and withstand their expansion forces while maintaining manufacturability
Solution Approach 2:
The patent applies composite material principles by combining multiple material property requirements (strength, hardness, impact resistance) in the steel housing material. This composite approach allows the housing to simultaneously withstand the high pressures from larger shaped charges and maintain structural integrity, enabling increased perforation tunnel volume without compromising housing strength
3Productivity
If the shaped charge explosive load is increased to achieve consistent large entry-hole diameters, then the hydraulic fracturing efficiency improves, but the energy consumption increases
Solution Approach 1:
The patent applies partial or excessive action by using shaped charge loads in the range of 22.7-45 grams, which provides slightly more explosive energy than minimum requirements. This excessive action ensures consistent large entry-hole diameters (0.625-1.25 inches) and reliable hydraulic fracturing initiation in low-permeability formations, improving fracturing efficiency while controlling energy consumption through defined upper limits
Solution Approach 2:
The patent optimizes the balance between energy consumption and fracturing efficiency through parameter changes, specifying precise explosive load weights and corresponding entry-hole diameter ranges. This parameter optimization ensures that the explosive energy is sufficient to create consistently large entry holes for efficient hydraulic fracturing while avoiding excessive energy consumption that would occur with much larger 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
The assembly achieves a 20-100% increase in perforation tunnel volume and 20-100% increase in formation contact, enhancing hydraulic fracturing performance in unconventional wells compared to conventional assemblies.
Implementation Method 1
at least one shaped charge positioned in the perforating gun housing. In some embodiments, each shaped charge of the at least one shaped charge includes an explosive load having a weight greater than 26 grams
Implementation Method 2
the shaped charge may be configured to form a perforation tunnel in a low permeability rock formation
Data Source
AI summary
A perforating gun assembly is configured for use in unconventional wells, for example in rock formations with low permeability. The perforating gun assembly includes a perforating gun housing and a shaped charge positioned in the perforating gun housing. The shaped charge and the perforating gun housing are configured to improve total target penetration in unconventional wells by 20-100%.