Axial Sinusoidal Pulser for Mud Pulse Phase Modulation
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Solution Overview
Problem
Existing mud pulse telemetry systems in down-hole drilling operations face challenges in efficiently generating and modulating pressure waves for effective data transmission from downhole conditions to the surface, limiting the safety and efficiency of drilling operations.
Innovation Solution
A mud pulse telemetry system with a drill string, a restriction, a piston, and a pulser that generates a pressure differential and axial movement to create sinusoidal pressure waves through a non-linear pulser body profile, using a valve mechanism to control fluid communication and phase modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional pulser design is used, then the device complexity is reduced, but the productivity of data transmission is insufficient
Solution Approach 1:
The pulser body employs a non-linear profile (logarithmic curve) instead of a straight cylindrical shape. This curved geometry creates variable gap widths as the pulser moves axially within the drill string, generating sinusoidal pressure waves that improve data transmission efficiency through the mud pulse telemetry system.
Solution Approach 2:
The pulser is designed to move axially between an uppermost position and a lowermost position, dynamically changing the gap width between its outer surface and the inner edge of the drill string. This dynamic movement creates the sinusoidal pressure wave pattern needed for efficient data transmission, transforming a static component into a dynamically functional element.
2Ease of operation
If the pulser body moves with constant velocity, then the ease of operation is improved, but the pressure wave quality deteriorates
Solution Approach 1:
The non-linear (logarithmic) profile of the pulser body ensures that even when the pulser moves at substantially constant velocity, the variable gap width creates a sinusoidal pressure wave. The curved geometry transforms uniform motion into the desired sinusoidal pressure pattern, maintaining wave quality without complicating the movement control.
3Measurement precision
If the valve is manually controlled, then the device complexity is reduced, but the measurement precision of pressure wave phase deteriorates
Solution Approach 1:
The valve is automatically actuated by the pulser's own axial movement. As the pulser reaches its uppermost and lowermost positions during its reciprocating motion, it triggers the valve to open and close accordingly. This self-actuating mechanism eliminates manual control while achieving precise phase modulation of the pressure wave, as the valve timing is directly coupled to the pulser position.
4Productivity
If a linear pulser profile is used, then the ease of manufacture is improved, but the productivity of pressure wave generation deteriorates
Solution Approach 1:
The non-linear profile (logarithmic curve) of the pulser body is designed to generate sinusoidal pressure waves, improving the quality and efficiency of pressure wave generation for data transmission. While more complex than a linear profile to manufacture, modern machining capabilities can produce this curved geometry, and the significant improvement in telemetry performance justifies the additional manufacturing complexity.
Data Source
AI summary
A mud pulse telemetry system is disclosed including a drill string positioned within a wellbore, a restriction positioned within the drill string and configured to create a pressure differential between a high pressure region and a low pressure region of the drill string, a piston including a piston opening positioned within a piston chamber and movable along an axis between a first position and a second position, a valve movable to selectively open the piston opening, and a pulser coupled to the piston and positioned for movement within the drill string along the axis. The pulser includes a pulser body having at least a portion thereof with a non-linear profile and a conduit extending through the pulser body and facilitating fluid communication between the drill string and the piston chamber. Movement of the pulser body generates a pressure wave through mud within the drill string.