Acoustic Well Fluid Level Measurement Without Gas Venting
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Solution Overview
Problem
Current methods for allocating gas production between multiple wells in oil and gas facilities are prone to errors due to the inability to accurately measure and infer gas production rates, leading to discrepancies in royalty payments, cost allocation, and reserve evaluations.
Innovation Solution
A method utilizing a conduit with a controlled valve to measure gas pressure changes and calculate gas production rates, combined with techniques to determine fluid levels and pressure wave speeds using rarefaction and compression waves, allowing for precise inference of gas production through the annulus and tubing in oil and gas wells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional gas allocation methods are used in oil and gas facilities, then operational simplicity is maintained, but measurement precision and reliability of gas production allocation deteriorate due to inability to accurately measure and infer gas production rates
Solution Approach 1:
The patent replaces traditional mechanical flow measurement devices with acoustic wave-based measurement systems. Acoustic waves are transmitted through the produced fluids in the annulus, and the speed of sound is measured to infer gas production rates. This substitution eliminates the need for complex mechanical flow meters while achieving accurate gas production measurement through acoustic properties of the fluid mixture.
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium to measure gas production indirectly. Instead of directly measuring gas flow, the system uses acoustic wave transmission through the fluid mixture in the annulus as a mediator. The speed of sound in the mixture correlates with gas production rates, allowing indirect but accurate measurement without physical contact with the flowing fluids.
2Productivity
If gas is vented through the casing-tubing annulus to maintain pump efficiency, then volumetric efficiency is improved, but loss of substance increases due to gas discharge to atmosphere
Solution Approach 1:
The patent enables the system to self-monitor and self-optimize by measuring acoustic wave speed in the annulus to determine gas production rates. This information allows the system to automatically adjust operations to maintain optimal fluid levels and pump efficiency without external intervention, while simultaneously capturing and utilizing the gas that would otherwise be vented, thereby eliminating both efficiency loss and environmental discharge.
Solution Approach 2:
The patent implements a feedback mechanism where acoustic measurements of gas production rates are continuously monitored and used to adjust well operations. The measured gas production data provides feedback on well performance and fluid level conditions, enabling real-time optimization of pump operations to maintain volumetric efficiency while minimizing gas venting through informed operational adjustments.
3Measurement precision
If foreign substances are injected into the well to measure fluid properties, then measurement capability is improved, but object-generated harmful factors increase due to potential contamination and operational complications
Solution Approach 1:
The patent replaces invasive measurement methods that require injecting foreign substances with non-invasive acoustic wave transmission. Acoustic waves pass through the produced fluids in the annulus without requiring any chemical or physical alteration of the well environment. This substitution eliminates contamination risks while maintaining accurate measurement of fluid properties through the natural acoustic response of the fluids.
Solution Approach 2:
The patent uses acoustic waves as an intermediary that interacts with the produced fluids without requiring injection of foreign substances. The acoustic waves serve as a clean, non-contaminating probe that measures fluid properties through their speed of sound characteristics. This intermediary approach provides measurement capability while completely avoiding the harmful effects of injecting chemicals or tracers into the well.
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 approach enables more accurate allocation of gas production between wells, reduces errors in financial and reserve-related calculations, and provides continuous, non-invasive monitoring of well performance without venting gas or injecting foreign substances.
Implementation Method 1
create a pressure wave and measure a round trip time for the pressure wave to travel to a fluid top and return to the surface
Implementation Method 2
opening the valve for a selected time interval and then re-closing the valve to create a rarefaction wave in the conduit and in the well
Implementation Method 3
sampling the gas pressure within the conduit over the sampling time period, calculating a rate of pressure change from samples taken over the sampling time period
Data Source
AI summary
A method of determining a fluid level in a well space without substantial venting of gas to the atmosphere or injecting a gas at high pressure. Gas being produced by the well is used to create a pressure differential between two spaces. A wave is induced in the well space by causing the two spaces to come into gaseous communication for a selected time internal. Pressure changes are measured as the induced wave travels through the gas in the well space from the measurement system to a fluid surface and back to the measurement system to determine a round trip travel time of the wave. The fluid level is calculated from the round-trip travel time and a speed of the wave as one-half of the product of the wave speed and the round-trip time.