Downhole Salinity Measurement Sonde
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Solution Overview
Problem
Existing downhole salinity measurement methods in well bores are inaccurate due to the complex, non-homogeneous fluid environment with multiple phases and variable velocities, as a single-point measurement does not represent the actual borehole fluid salinity effectively.
Innovation Solution
A sonde equipped with fluid conductivity sensors and a data processor is deployed in the well bore to collect fluid samples and determine salinity based on conductivity measurements, using multiple conductivity cells and sensors to account for fluid non-homogeneity and multiphase flow, with temperature and pressure measurements for accurate data analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If acoustic wave propagation methods are used for downhole salinity measurement, then measurement capability is provided, but measurement precision deteriorates due to complex non-homogeneous fluid environment with multiple phases
Solution Approach 1:
The patent extracts a fluid sample from the complex downhole environment into a controlled sample chamber, isolating the measurement from the problematic multiphase flow conditions. The conductivity sensor measures the extracted sample rather than the in-situ fluid, eliminating interference from gas bubbles, sand, and variable flow velocities while maintaining measurement representativeness through proper sampling methodology.
2Measurement precision
If single-point measurement is performed in the wellbore, then measurement simplicity is maintained, but measurement precision deteriorates as it does not represent actual borehole fluid salinity
Solution Approach 1:
The patent segments the continuous wellbore fluid into discrete samples at multiple depth locations using the moving sonde. By collecting and measuring samples at various depths, the system creates a segmented representation of the overall fluid composition, providing statistically representative data without requiring complex continuous monitoring of the entire wellbore volume.
3Measurement precision
If multiple conductivity cells and sensors are used to account for fluid non-homogeneity, then measurement precision improves, but device complexity increases
Solution Approach 1:
The patent combines multiple conductivity cells and sensors within a single integrated sonde assembly, merging their functions into one unified measurement device. This consolidation provides comprehensive sampling and measurement capabilities at multiple points while maintaining a compact, manageable device structure that can be deployed as a single unit in the wellbore.
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 provides accurate and representative salinity measurements at various depths, improving the accuracy of fluid characterization and differentiation between fresh and saline water, and identifying salt water intrusion, thereby enhancing the evaluation of formation fluids and moveable oil in reservoirs.
Implementation Method 1
at least one fluid conductivity sensor measuring conductivity parameters of the fluid sample volume in the sample chamber
Data Source
AI summary
A downhole salinity measurement and logging sensor system has multiple cells, each to measure conductivity, temperature and pressure of fluids at depths of interest in a wellbore. The multiple cells protect against effects of non-homogeneous wellbore fluids. The system also determines salinity of the liquid in the wellbore from conductance measurements, and stores the salinity data along with the temperature and pressure readings from the well. The sensors of conductivity, temperature and pressure are made using micro-fabrication technologies, and the system is packaged to comply with harsh downhole environments. The system may be deployed in the well with coiled tubing (CT), wireline or vehicles with a robotic system. The system can be deployed with an onboard memory, or with wireline surface access for real time access to measurement data or programming the device.