Elliptical Orifice Gas Flow Measurement Without Separation
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Solution Overview
Problem
The challenge in accurately measuring dry gas flow from hydrocarbon wells is exacerbated by the presence of liquids, which requires costly separation equipment and leads to measurement errors, increased operational costs, and safety risks due to high-pressure vessels at well sites, especially in developing unconventional gas resources where production is below expectations and capital expenditures are substantial.
Innovation Solution
A method utilizing a differential flow measurement device with an elliptical throat at the well site, which includes testing the stream for gas composition and physical characteristics, computing liquid-gas ratios, and employing empirical models to derive dry gas flow rates, thereby eliminating the need for on-site separation equipment and reducing capital and operational costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If gas-liquid separator is installed upstream of gas measurement device, then measurement accuracy is maintained within prescribed limits, but capital expenditures and operational costs increase significantly
Solution Approach 1:
The patent extracts the liquid separation function from the measurement system by using computational methods to separate liquid and gas flow rates mathematically rather than physically. The system calculates liquid-gas ratios and derives dry gas flow rates through empirical models, eliminating the need for physical gas-liquid separators while maintaining measurement accuracy within regulatory limits.
Solution Approach 2:
The patent replaces the mechanical separation system (gas-liquid separator) with a computational system consisting of differential pressure measurements, temperature sensing, and empirical modeling. The mechanical separation process is substituted with mathematical calculations that compute liquid-gas ratios and derive dry gas flow rates from wet gas measurements.
2Measurement precision
If gas-liquid separator is installed at well site, then accurate separation of liquids from gas stream is achieved, but operational costs and maintenance requirements increase
Solution Approach 1:
The measurement system performs self-service by using the differential pressure device to simultaneously measure both wet gas flow rate and liquid-gas ratio. The system derives dry gas flow rate through computational processing of its own measurements without requiring external separation equipment, reducing operational complexity and maintenance requirements.
Solution Approach 2:
The patent replaces the mechanical separation system with computational processing. Instead of physically separating liquids and gases through mechanical means, the system uses empirical models and mathematical calculations to determine dry gas flow rates from combined wet gas measurements, eliminating maintenance-intensive mechanical separation equipment.
3Device complexity
If wet measurement method is used without separation equipment, then capital costs are reduced, but measurement accuracy may be compromised
Solution Approach 1:
The patent introduces an intermediary computational layer between the differential pressure measurement and the final dry gas flow rate determination. The system first measures wet gas flow rate, then uses empirical models and liquid-gas ratio calculations as intermediaries to accurately derive the dry gas flow rate, maintaining measurement precision without requiring physical separation equipment.
Solution Approach 2:
The patent changes the measurement parameters by simultaneously measuring differential pressure, temperature, and liquid-gas ratio, then using these multiple parameters in empirical models to calculate dry gas flow rate. This multi-parameter approach compensates for the absence of physical separation and maintains measurement accuracy.
4Measurement precision
If multiple measurement parameters are collected and processed through empirical models, then accurate dry gas flow rate is derived, but computational complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-establishing empirical models that correlate differential pressure, temperature, and liquid-gas ratio with dry gas flow rate. These models are developed beforehand through laboratory testing and field data collection, allowing the field system to simply input measurements and obtain accurate results without performing complex real-time computations.
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 method allows for accurate dry gas flow measurement without separation equipment, reducing capital and operational costs, increasing production, and enhancing safety by eliminating pressure vessels, while enabling fair allocation of production volumes and royalty payments through onsite processing and data transmission.
Implementation Method 1
measuring a pressure differential (dP) in the differential flow measurement device (orifice)
Implementation Method 2
measuring a flowing temperature (T) of the stream
Data Source
AI summary
A method of measuring a dry gas flow from hydrocarbon wells. The hydrocarbon wells produce a stream which contains liquids and natural gas. The method comprises providing an differential flow measurement device (orifice) located at a well site containing the hydrocarbon wells. The method further includes testing the stream for gas composition and physical characteristics. Additionally, the method comprises measuring a static temperature (T) of the stream, measuring a static pressure (Ps), and measuring a pressure differential (dP) in the differential flow measurement device (orifice). The method includes computing the liquid-gas ratio (LGR) of the stream, computing the wet gas flow rate (Qw) of the stream, computing a first dry gas flow rate (Qd1) and a second dry gas flow rate and utilizing a iterative process to correct and obtain the dry gas flow rate. The data may be transmitted to another location.