Downhole Nitrogen Concentration Detection via Density Difference Analysis
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Solution Overview
Problem
Current downhole fluid analysis techniques cannot detect nitrogen in real-time, leading to delayed decision-making in production and sampling processes, as nitrogen injected into formations may bypass the formation fluid or not achieve equilibrium, reducing its benefits.
Innovation Solution
An apparatus and method that measure the composition, pressure, and temperature of a downhole fluid sample to determine its nitrogen concentration by comparing measured densities to theoretical densities, using sensors and a processing unit to iteratively adjust fluid composition and calculate nitrogen concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If known downhole fluid analysis techniques are used, then measurement precision for hydrocarbon and carbon dioxide is achieved, but nitrogen concentration cannot be detected
Solution Approach 1:
The patent uses an intermediary substance (salt) to induce phase separation in the downhole fluid sample. This phase separation allows nitrogen to concentrate in the gas phase while hydrocarbons remain in the liquid phase, enabling indirect detection of nitrogen concentration through measurement of the separated phases rather than direct detection in the mixed fluid
Solution Approach 2:
The patent changes physical parameters (temperature and pressure) to control the phase behavior of downhole fluid. By adjusting these parameters, the fluid transitions between single-phase and two-phase states, enabling the separation and subsequent measurement of nitrogen concentration based on its preferential partitioning into the gas phase under specific conditions
2Measurement precision
If numerous samples are obtained and brought to surface for analysis, then nitrogen concentration can be determined, but real-time information is delayed
Solution Approach 1:
The patent performs preliminary phase separation and nitrogen concentration measurement downhole before the sample reaches the surface. By conducting the separation process and nitrogen detection in situ at downhole conditions, the system eliminates the time delay associated with transporting multiple samples to the surface for analysis
Solution Approach 2:
The patent extracts the nitrogen-containing gas phase from the downhole fluid sample through phase separation induced by salt addition. This extraction allows for focused measurement of nitrogen concentration in the separated gas phase, providing rapid downhole determination without requiring surface analysis of the entire fluid sample
3Productivity
If nitrogen is injected into formation to increase production, then production efficiency improves, but nitrogen may bypass formation fluid or not achieve equilibrium
Solution Approach 1:
The patent implements a feedback mechanism by measuring nitrogen concentration in downhole fluid samples in real-time and using this information to assess whether injected nitrogen has achieved equilibrium with the formation fluid. This feedback allows operators to determine if additional nitrogen injection is needed or if the current injection strategy is achieving the desired uniform distribution
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 determination of nitrogen concentration in downhole fluids, improving decision-making and optimizing production by accurately assessing nitrogen's presence and distribution within the formation.
Implementation Method 1
a fluid measurement unit to measure a first fluid composition and a density of at least a hydrocarbon and carbon dioxide in a sample of the downhole fluid
Implementation Method 2
one or more sensors to measure at least a pressure and a temperature of the sample
Implementation Method 3
one or more sensors to measure at least a pressure and a temperature of the sample
Implementation Method 4
a processing unit to determine a first theoretical density based on at least the first fluid composition, the temperature, and the pressure of the sample
Implementation Method 5
an analyzer to determine a first difference between the density of at least the hydrocarbon and the carbon dioxide in the sample and the first theoretical density. The first difference is associated with a concentration of nitrogen in the sample
Data Source
AI summary
Methods and apparatus to determine a concentration of nitrogen in a downhole fluid are described. An example apparatus to determine a concentration of nitrogen in a downhole fluid includes a fluid measurement unit to measure a first fluid composition and a density of at least a hydrocarbon and carbon dioxide in a sample of the downhole fluid. Additionally, the example apparatus includes one or more sensors to measure at least a pressure and a temperature of the sample. Further, the example apparatus includes a processing unit to determine a first theoretical density based on at least the first fluid composition, the temperature, and the pressure the sample. Further still, the example apparatus includes an analyzer to determine a first difference between the density of at least the hydrocarbon and the carbon dioxide in the sample and the first theoretical density. The first difference is associated with a concentration of nitrogen in the sample.