Natural Gas Measurement and Accounting
Course Overview
Reliable gas accounts depend on sound measurement, accurate gas quality data and clear allocation rules. Meter readings must be corrected to the contractual base conditions, combined with composition data and reconciled before they can support an invoice. Errors at any stage can affect revenue and lead to disputes.
This course takes operations, measurement, production accounting and commercial staff through that process. It covers gas properties and standard conditions, metering systems and validation, gas quality, and thetreatment of line pack, shrinkage and unaccounted-for gas. Participants then apply these principles to allocation among fields, producers and shippers, and to the sales, transportation and billing arrangements that rely on those quantities.
The four-day programme gives participants time to practise the gs accounting methods in detail. A full day isdevoted to gas balance and allocation, including the issues behind operator disputes and royalty calculations. One case study runs throughout the course, from the wellhead and gas plant to the custody transfer point andthe shipper’s statement. Allocation is taught with reference to ISO/TS 26762:2025 and API MPMS Chapter 20.1..
Expected Learning Outcomes
By the end of the course, participants will be able to:
- Calculate standard volume, mass and energy from meter, pressure, temperature and composition data at the contractual base conditions, using AGA 8 or ISO 12213 for compressibility and ISO 6976 for heating value. Explain how a change in base conditions affects billed quantities.
- Explain the operating principles of orifice, ultrasonic, turbine and Coriolis meters, how flow computers process their signals, and the requirements for validation, calibration and proving under ISO 5167, AGA 9, AGA 7, AGA 11 and the Network Code.
- Manage gas quality measurement from sampling to validation: apply ISO 10715, ISO 6974, ASTM D1945, GPA 2286 and ISO 10723; normalise analyses; compare online averages with composite sample results; and check compliance with gas entry conditions.
- Prepare plant and system gas balances that account for receipts, deliveries, own use and fuel, flare, vent and line pack. Calculate shrinkage and unaccounted-for gas, and assess the imbalance against the metering uncertainty.
- Design and operate an allocation system using ISO/TS 26762 and API MPMS Chapter 20.1. Define allocation points and the allocation basis, select pro rata, by-difference or uncertainty-based methods, and address fuel, flare and losses. Document the agreement, validation and audit trail, and explain the royalty implications under the Petroleum Industry Act.
- Interpret metering, quality, nomination, imbalance and mismeasurement clauses in gas sales and transportation agreements. Prepare settlement statements and assemble evidence to support or defend a mismeasurement claim.
Course Modules
Course delivery method
The teaching is practical and centred on one case study facility. Each session introduces a method and its supporting standard, then moves within the hour to an Excel calculation. The facilitator works through an example with the class before participants apply it to their group’s data in their own workbooks. The same facility and workbooks are used across all four days, with each day’s results feeding into the next. By Day Four, participants have a complete, traceable set of calculations and templates they can adapt for their own
operations.
Group exercises reflect the meetings participants encounter at work: data reviews, month-end close meetings, verification opening meetings and dispute discussions. Facilitators take the roles of the other parties. The Day Four written assessment focuses on applying the methods taught, rather than recalling clause numbers from standards.
Target Audience
The course is intended for measurement, instrumentation and metering engineers and technicians; production and hydrocarbon accountants; and gas plant, pipeline and terminal operations staff. It is also relevant to commercial, marketing and contract management teams responsible for nominations, invoicing and settlement; finance, internal audit and joint venture staff who review gas accounts; and regulatory affairs staff who liaise with NUPRC and NMDPRA on measurement matters.
Highlighted Speakers
