Laser Purging Head With Coaxial-Helical Gas Flow for Wellbore Rock Drilling
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Solution Overview
Problem
Current wellbore stimulation methods face challenges in effectively creating fluid flow paths through hydrocarbon-bearing rock formations with low permeability, as existing techniques often result in inefficient penetration and irregular hole shapes due to debris disruption and melting of rock.
Innovation Solution
A laser tool configured with optical transmission media and a purging head that discharges coaxial and helical purging gas streams to clear the laser beam path, allowing for precise sublimation of rock and creation of fluid flow paths by rotating and manipulating the laser beam to achieve targeted penetration depths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional laser drilling is used without purging gas streams, then the laser beam path is blocked by dust and vapor, but the use of purging gas streams increases device complexity
Solution Approach 1:
The purging head is segmented into multiple independent gas stream channels (coaxial and helical), each capable of being controlled separately. This segmentation allows the system to effectively clear dust and vapor from the laser beam path while maintaining manageable device complexity through modular design.
Solution Approach 2:
Purging gas streams are introduced as an intermediary substance between the laser beam and the dust/vapor particles. The gas streams act as a mediator that carries away the debris generated during laser drilling, preventing blockage of the optical path without requiring direct mechanical intervention.
2Productivity
If high power laser is used to increase drilling speed, then productivity improves, but undesired melting of rock occurs
Solution Approach 1:
Purging gas streams are applied preliminarily and continuously during the laser drilling process to remove dust and vapor before they can cause melting. This preliminary action of debris removal prevents the accumulation of materials that would otherwise melt under high power laser exposure, enabling faster drilling with better geometric control.
Solution Approach 2:
The dust and vapor generated by high power laser drilling, which would normally cause harmful melting effects, are converted into a beneficial situation by using purging gas streams to immediately remove them. The harmful debris is transformed from a problem into a controlled byproduct that is efficiently evacuated from the drilling zone.
3Productivity
If laser drilling is performed in hydrocarbon-bearing formations, then stimulation is achieved, but debris disruption causes irregular hole shapes
Solution Approach 1:
Pneumatic purging gas streams are used to remove debris from the laser drilling zone in hydrocarbon-bearing formations. The pressurized gas flows coaxially and helically around the laser beam path, effectively clearing dust and vapor that would otherwise cause irregular hole shapes, thereby maintaining smooth cylindrical geometry while creating fluid flow paths.
Solution Approach 2:
The introduction of purging gas streams changes the physical parameters of the drilling environment by controlling the removal of debris. This parameter change (debris concentration and flow dynamics) directly affects hole geometry, transforming the drilling process from one producing irregular shapes to one achieving smooth, consistent cylindrical holes.
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 solution enables efficient and precise creation of fluid flow paths with smooth, deep holes in rock formations, reducing drilling time and costs by effectively clearing debris and maintaining hole geometry, allowing for higher power laser usage without undesired melting.
Implementation Method 1
The laser beam has an energy density that is great enough to cause at least some of the rock in the rock formation to sublimate
Implementation Method 2
The two or more purging gas streams may include a coaxial purging gas stream flowing in a direction parallel to the axis
Implementation Method 3
The two or more purging gas streams may include a helical purging gas stream flowing in a helical pattern around and substantially along the axis
Data Source
Figure 1
Figure 2~4
Figure 5A~5B
AI summary
An example laser tool (30) is configured to operate within a wellbore (4) of a hydrocarbon-bearing rock formation (2). The laser tool (30) includes one or more optical transmission media as part of an optical path originating at a laser generator configured to generate a laser beam having an axis. The laser tool (30) includes an optical element for receiving the laser beam (60) from the one or more optical transmission media and for output to the hydrocarbon-bearing rock formation (2). The laser tool (30) includes a purging head (100) for removing dust or vapor from a path of the laser beam (60). The purging head (100) is for discharging two or more purging gas streams. The purging head (100) may include a coaxial flow assembly and a helical flow assembly. A coaxial purging gas stream may flow in a direction parallel to the axis. A helical purging gas stream may flow in a helical pattern around and substantially along the axis.