Natural gas measurement technicians play a critical role supporting the integrity of their company’s contracts. The contract governs the purchase, sale, and and transport of natural gas throughout the cycle from producer through processor to transporter and eventually to the customer.
In each exchange, measurement must be performed in adherence to the contract. Natural gas measurement technicians must be able to repeatedly and reliably perform accurate measurement of natural gas into and out of their systems.
Measurement processes and field practice that do not conform to contract terms could result in disputes with other parties in the contract, financial reporting discrepancies, and inaccurate data for decision-making and planning.
That’s why a natural gas measurement technician’s most important job is to understand how to perform measurement to support the contract.
1. Understand the Baseline for Natural Gas Measurement
Many technicians learned the basics of natural gas measurement by following around an experienced technician or a supervisor who “showed them the ropes” in the field.
While that experience is valuable, it needs to be accompanied by a fundamental understanding of the basics of measurement.
– First, natural gas is exchanged on the basis of energy (the amount of heat), which is a combination of volume and heating value. Energy is exchanged using the British thermal unit (BTU) as the baseline measurement unit to determine the energy content of gas exchanged. BTU is equal to the amount of heat used to raise the temperature of one pound of water one degree Fahrenheit.
– Second, you need to factor in the contract atmospheric pressure depending on what is specified in the contract. Gas is highly compressible and therefore volumes are adjusted from flowing pressure to a reported pressure. The goal is to find the constant pressure to generate a consistent and reliable measurement.
– Third, you need to take into account the temperature specified in the contract. A typical contract says the natural gas should be delivered between 40 and 120 degrees Fahrenheit. Understand the temperature specified in the contract.
2. Understand the Tools to Perform the Measurement
There are many types of meters used such as an orifice meters, turbine meters, ultrasonic meters, and positive displacement meters. Each meter type has unique installation, operation, and calculation requirements.
Understanding the meter types and how they are used is critical to measure the volume of natural gas being transported. In addition to meters, pressure and temperature instruments are critical for accurate volume measurement.
To determine the energy of the gas, various tools will also help you determine the gas composition (quality) of natural gas and its heating value. These can include gas samplers, lab analysis, and field chromatographs.
Each of the tools used will have requirements for accuracy. This accuracy is achieved through proper operation and maintenance of calibration devices, and the use of those devices to ensure accurate calibration of the tools.
If there is a repeated error with the recording of the values, then you should consider your role of calibrating tools. In particular, field chromatographs are critical to determining heating value. Therefore, a contract will typically require that the chromatograph is recalibrated once per month.
The contract will specify measurement and gas quality factors that must meet the terms of the agreement. The inability to meet the standards outlined in the contract could lead to a dispute or the receiver not accepting delivery of the product.
Finally, following any recalibration test, if the recording equipment is determined to be inaccurate, then measurements should be adjusted accordingly. Otherwise, this could lead to additional costs to correct the measurements in the back office.
3. Understand How to Identify Discrepancies
Once you have a baseline understanding of the measurement basics and how to use the equipment in the field for measurement and recording, you need to be able to identify discrepancies.
A discrepancy could include:
- Input of natural gas measurement not matching output.
- Failure of the various meters in the field.
- Actual measurements not matching the predicted measurements.
The key is knowing how to address each discrepancy and understanding what steps to take in the event of an unanticipated discrepancy.
Rely on Gas Certification Institute for Natural Gas Measurement Training
Gas Certification Institute (GCI) helps measurement technicians gain confidence in their job performing accurate measurement to support the contract.
We offer a Gas Measurement Fundamentals certification course that provides direct instruction on the fundamentals of measurement, gas measurement standards, measurement tools, and how to interpret measurements.
View our schedule to find the next fundamentals course offered at our training facility in Houston. We look forward to serving natural gas measurement technicians with fundamental training.