Perforating Gun External Orientation Internal Pivot
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Solution Overview
Problem
Existing perforating gun systems in oil and gas extraction face challenges with accuracy, as they either lack precision in orientation (+/- 15 degrees) or rely on costly and unreliable internal mechanisms, leading to random perforation directions, reduced charge size, and decreased shot density, while also failing to adjust for wellbore deviations and maintain reliable select fire systems.
Innovation Solution
An externally-oriented internally-corrected perforating gun system that combines an external protuberance member (EPM) for coarse orientation and an internal pivot support (IPS) for fine correction, allowing for precise alignment of perforating charges within +/- 5 degrees of the desired orientation, eliminating the need for costly bearings and weights, and enabling maximum charge size and shot density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If external orientation method with fins or protuberances is used, then cost is reduced, but orientation accuracy deteriorates to +/- 15 degrees
Solution Approach 1:
The orientation system is divided into two independent segments: an external orientation member (EOM) for coarse orientation and an internal pivot support (IPS) for fine correction. The EOM provides initial positioning at lower cost, while the IPS mechanism refines the orientation accuracy without requiring the entire system to be expensive and complex.
Solution Approach 2:
The internal pivot support acts as an intermediary between the external orientation member and the perforating charges. It receives the coarse orientation from the EOM and translates it into precise charge alignment, mediating between the low-cost external system and the high-precision requirement.
2Manufacturing precision
If internal orientation mechanism with bearings and weights is used, then orientation accuracy improves, but device complexity and cost increase
Solution Approach 1:
The complex bearing and weight mechanisms are extracted from the internal orientation system and replaced with a simpler pivot support structure. The EOM handles the heavy orientation task externally, allowing the internal IPS to use a lighter, simpler mechanism that achieves the same precision goal without the complexity of traditional bearings and weights.
Solution Approach 2:
The pivot support uses a simple, inexpensive mechanical design that can be manufactured at low cost. Rather than using expensive, complex bearing assemblies, the system employs a straightforward pivot mechanism that achieves the required precision through the cooperative action with the EOM.
3Manufacturing precision
If internal orientation mechanism is used, then orientation accuracy improves, but reliability deteriorates due to binding and thermal expansion
Solution Approach 1:
The external orientation member serves as a mediator that performs the heavy lifting of orientation outside the confined internal space. This prevents internal components from experiencing binding and thermal expansion issues, as the EOM operates in the more stable external environment where it can accommodate dimensional changes without affecting charge alignment.
Solution Approach 2:
By separating orientation functions into external (EOM) and internal (IPS) segments, the system isolates the reliability-critical charge alignment function from the environmentally-sensitive orientation mechanism. The IPS remains simple and robust, while the EOM handles environmental variations externally.
4Manufacturing precision
If internal orientation mechanism with bearings is used, then orientation accuracy improves, but charge size is reduced
Solution Approach 1:
The orientation mechanism is extracted from the internal space to the external EOM, freeing up internal volume within the gun assembly. This allows larger charges to be accommodated without the space constraints and weight limitations imposed by internal bearing and weight systems.
Solution Approach 2:
The EOM provides the necessary orientation function without adding weight to the internal charge assembly. By performing orientation externally, the system counteracts the weight penalty that would otherwise reduce the maximum charge size that can be accommodated within the gun.
5Device complexity
If external orientation method is used, then device complexity is reduced, but adaptability to wellbore deviations deteriorates
Solution Approach 1:
The system incorporates dynamic adjustability through the internal pivot support, which allows the charge holder tube to rotate and self-correct for wellbore deviations. This dynamic capability is added to the relatively simple EOM system, providing adaptability without significantly increasing overall complexity.
Solution Approach 2:
The internal pivot support enables the system to self-correct for wellbore deviations automatically. As the gun is deployed, the IPS allows the charges to self-align with the wellbore axis, providing adaptability without requiring complex external adjustment mechanisms or manual 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 system achieves improved accuracy and efficiency by ensuring precise perforation orientation, reducing tortuosity, and maximizing charge size and shot density, while maintaining reliable select fire capabilities and adapting to wellbore deviations, thus enhancing oil and gas extraction performance.
Implementation Method 1
External methods, where a fin or a protuberance (0103) from the perforating gun causes the center of mass of the assembly to be such that the perforating gun tends to be on the low side of the wellbore casing and oriented with the fins to the high side of the wellbore as the guns are pumped down or pulled up the well
Implementation Method 2
an internal pivot support (IPS) that allows the charge holder tube to rotate and self-correct orientation
Data Source
Figure 1~1A
Figure 1B
Figure 2A
AI summary
An externally-oriented internally-corrected perforating gun system and method for accurate perforation in a deviated wellbore is disclosed. The system/method includes a gun string assembly (GSA) deployed in a wellbore with an external protuberance member (EPM) and an internal pivot support (IPS). With the EPM oriented to the high side of the wellbore, the center of mass of the GSA positions the GSA at the lower side of the wellbore surface. The IPS is attached to internal gun components such end plate, charge holder tube, detonating cord or charge case. The charges inside the charge holder tube move with the gravitational vector about the IPS and point more accurately in the desired direction for perforating. The external orientation of the EPM along with limited internal swing about the IPS provide for an accurate orientation of the charges that results in efficient and effective perforating through a hydrocarbon formation.