Downhole Acoustic Fluid Characterization via Pressure Variation
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Solution Overview
Problem
Current downhole acoustic methods fail to make measurements at varying pressures and do not determine the equation of state (EOS) or its parameters, such as virial coefficients, for fluid properties, which are essential for reservoir management in oil exploration, and they do not preserve the integrity of subsurface fluid samples during retrieval.
Innovation Solution
A tool and method that insert a fluid sample into a wellbore, change its pressure and temperature, and use acoustic transducers to evaluate the sample's properties by analyzing acoustic signals at multiple pressure and temperature states, allowing for in-situ EOS determination and fluid property estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acoustic measurements are made at a single pressure point, then the measurement process is simple, but the equation of state and fluid properties cannot be determined
Solution Approach 1:
The system dynamically adjusts the pressure of the fluid sample through a pressure control mechanism, enabling acoustic measurements to be taken at multiple pressure points. This dynamic pressure variation allows the determination of the equation of state and fluid properties that cannot be obtained from single-point measurements, resolving the contradiction between measurement simplicity and property determination capability.
Solution Approach 2:
The invention changes the pressure parameter of the fluid sample systematically to obtain acoustic measurements at different states. By varying pressure and measuring corresponding acoustic velocity changes, the system can calculate EOS parameters and fluid properties, transforming a simple single-point measurement into a multi-parameter characterization process.
2Measurement precision
If fluid samples are retrieved to the surface for analysis, then comprehensive analysis can be performed in PVT laboratories, but sample integrity is compromised due to pressure and temperature changes
Solution Approach 1:
The invention replaces the mechanical retrieval and laboratory analysis system with an in-situ acoustic measurement system. Instead of physically transporting samples to surface laboratories where pressure and temperature changes compromise integrity, the system uses acoustic transducers to measure fluid properties directly downhole, substituting complex mechanical handling with non-intrusive acoustic characterization.
Solution Approach 2:
The downhole tool performs self-characterization of the fluid sample by measuring acoustic velocity at multiple pressure points directly in the wellbore environment. The system serves itself by obtaining all necessary fluid property data in-situ without requiring sample retrieval, eliminating the integrity issues associated with transporting samples to surface laboratories.
3Productivity
If multiple sample tanks are deployed to test fluids from more zones, then more zones can be analyzed, but the number of tanks is limited and requires return trips into the well
Solution Approach 1:
The acoustic measurement system is designed to be universally applicable to multiple zones and fluid types. A single tool can characterize fluids from different zones by measuring acoustic velocity at multiple pressure points, eliminating the need for multiple specialized sample tanks. This multi-functional capability allows continuous analysis as the tool moves through different zones, increasing productivity without requiring return trips.
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 accurate in-situ evaluation of fluid properties, maintaining sample integrity and reducing the need for surface analysis, thereby improving the efficiency and accuracy of reservoir management by providing EOS and other fluid property data directly from the wellbore.
Implementation Method 1
making acoustic velocity measurements on the fluid sample at a plurality of pressures
Data Source
AI summary
Techniques for evaluating physical aspects of a formation fluid from within a wellbore include changing at least one of a pressure on and a temperature of a sample of the formation fluid and transmitting at least one acoustic pulse through the fluid sample and analyzing acoustic information collected. Apparatus and methods for the evaluating involve using at least one acoustic transducer. Analyzing typically involves use of formulae that relate equation (s) of state and other properties for the fluid to a change in the sound speed in the fluid.