Bottomhole Acoustic Transducer for Early Gas Kick Detection
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Solution Overview
Problem
Current methods for detecting gas influx in oil and gas well drilling operations are limited by the need for real-time measurements, as existing techniques often rely on surface-based readings or density measurements that are not responsive to dissolved gases, and may involve safety hazards like radioactive sources.
Innovation Solution
A bottomhole assembly equipped with a transducer assembly that generates acoustic pulses and uses reflections to detect gas influx in the borehole fluid, providing real-time indications through measured impedance changes, allowing for early detection of pressure kicks and formation fluid inflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional density measuring devices are used to detect gas influx, then gas must be present in sufficient quantities to affect the density of the mud, but dissolved gas that may be a precursor to a gas kick would not register
Solution Approach 1:
The patent replaces conventional mechanical density measurement devices with acoustic measurement technology. The acoustic transducer emits sound waves through the drilling fluid, and the acoustic properties (velocity, attenuation) change in response to dissolved gas concentrations. This substitution enables detection of dissolved gas at much lower concentrations than conventional density meters, providing early warning before a kick develops.
2Measurement precision
If prior art density measurement methods are used, then measurements are responsive to the density of the formation, but they require the use of a radioactive source - a safety hazard during drilling operations
Solution Approach 1:
The patent substitutes radioactive sources with acoustic transducers for measuring formation and fluid properties. The acoustic transducer emits sound waves that interact with the drilling fluid and formation, providing measurement data without requiring radioactive materials. This eliminates the safety hazards associated with radioactive sources while maintaining measurement capabilities.
3Loss of time
If surface-based readings are used to detect gas influx, then measurements are not available in real-time, but waiting for bottom hole fluid to reach the surface delays detection
Solution Approach 1:
The patent performs measurements at the bottom of the wellbore where the drilling fluid is first exposed to formation pressures, before the fluid returns to the surface. The acoustic transducer detects changes in acoustic properties of the drilling fluid in real-time at the measurement location, providing early warning of gas influx or kicks before the fluid reaches the surface, thus eliminating the detection delay inherent in surface-based monitoring.
4Reliability
If balanced drilling techniques are used to maintain fine margin between effective pressure control and blowout prevention, then pressure control is optimized, but the system becomes highly sensitive to pressure changes requiring immediate detection
Solution Approach 1:
The patent implements real-time acoustic monitoring of the drilling fluid at the bottom of the wellbore, providing continuous feedback on the state of the fluid column and any influx from the formation. This early detection capability allows the drilling operation to maintain balanced pressure control while rapidly responding to pressure changes or kicks, as the system can detect and respond to changes immediately rather than waiting for surface indicators.
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
Enables real-time detection of gas influx and formation fluid inflow, reducing the risk of blowouts and formation damage by providing immediate pressure control and avoiding the use of radioactive sources, thus enhancing drilling safety and efficiency.
Implementation Method 1
a transducer in contact with the borehole fluid and configured to generate an acoustic pulse in the borehole fluid
Implementation Method 2
a stepped reflector on the transducer assembly configured to produce at least two reflections of the acoustic pulse
Implementation Method 3
a processor configured to use a response of the transducer to the at least two reflections to provide an indication of the gas influx
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
A stepped reflector on the outside of a bottomhole assembly produces two reflections in response to excitation of a transducer. The velocity of the fluid in the borehole is estimated using the two reflections. Alternatively, a change in the gas content of the borehole fluid is estimated from changes in the electrical impedance of a transducer in contact with the borehole fluid.