An oil and gas metering skid automates the measurement process by integrating flow and metering systems into a single structure.

Oil and Gas used in manufacturing have significant financial value. The power, petrochemical, and mining industries distribute large quantities of oil and gas that convert into billions in transactions.

Accurate measurement and tracking of every unit are critical for operational control and financial accountability.

Read further to understand how oil and gas metering skids save time and costs through efficient data collection, ensuring accurate and safe custody transfer.

If you’re looking to optimise oil and gas metering systems in your facility, check out our modular skid design services.

What is an Oil & Gas Metering Skid?

It contains a metering system that records precise oil and gas measurements. In a single steel structural frame, it accommodates all the components of a metering and piping system, making it easy to transport and install in an industrial plant.

An oil and gas metering skid:

  • Measures flow of fuels and liquefied gases
  • Monitors pressure and temperature
  • Filters dirt and chemical impurities
  • Analyses the quality of the filtered liquid and gas

The following components in the skid help achieve these functions:

Components of an Oil & Gas Metering Skid

Flow Meters

It’s a sensor for measuring the flow volume of liquid, gas and vapour through pipes. There are various flow meters (ultrasonic, turbine, Coriolis flow meter), each used for a particular measurement requirement (sound waves, clean liquid and gas flows, density of liquids and gases).

Strainer

A filtration system attached to the piping systems to remove unwanted debris from liquid and gas streams. It is fitted with a mesh or a perforated basket to hold these particles and prevents them from entering the pipes. It acts as a barrier protecting pumps and valves from obstructions, ensuring continuous flow.

PLC (Programmable Logic Controllers)

It helps automate the operation of the pumps and valves connected to the skid. The controllers are connected to a protocol system, such as Modbus, to monitor temperature, leaks, and flow rates.

MMI (Man-Machine Interface) Workstation

It displays data (tracks production time, trends, and input and output) on a visual screen, enabling an operator to control the skid using the data transmitted. The data enables controllers to ensure regular operations, visualise data and diagnose issues before they become potential risks.

Temperature Transmitter

It converts signals (temperature readings) from a temperature sensor and transmits them to the PLC. They are of two types, head-mounted and field-mounted, and are found in power plants and refineries where temperature control is critical for safety and maintaining product quality.

Motor Operated Valves

These valves can be operated remotely from a control room for flow isolation and switching streams. The valve also helps redirect liquid or gas flow towards prover systems for calibrating flow meter readings. It also contains a manual override system so the operator can take over during power shutdowns.

Pipe Provers

A sphere detector moves along a specific section of a pipe to measure and test the volume of liquid (oil). The measurements are compared against the metering system’s electronic output, also known as meter proving. The total tolerance of flow meter accuracy should not be more than 0.02%.

What is Custody Transfer?

Custody transfer is a technical process of transferring ownership of a product, in the oil and gas industry, it can refer to refined petroleum, natural gas, and biofuels.

It involves measuring these products through a custody transfer metering system.

The system calculates the exact volume of oil and gas during manufacturing and processing before being transferred from one party to another.

Oil and gas metering skids house metering systems with built-in provers and flow meters to verify flow measurement accuracy.

Fiscal Metering

It ensures transparency during a commercial transaction for the exchange of oil and gas.

A fiscal metering system provides accurate measurement to determine the financial value of the volume of hydrocarbons and also:

  • Ensures pricing based on verified measurement
  • Supports traceable tax and revenue documentation for an audit
  • Adheres to applicable industrial standards for accurate meter readings
  • Ensures periodic inspection and verification

How are Oil and Gas metering skids designed for custody transfer?

A skid design incorporates all the elements and components required to capture data without hindering the normal production and operating conditions of an industrial plant.

Here’s how it is designed:

Determine Custody Transfer Requirements

All components present in a metering system for measuring fluids and gases are required for a custody transfer. The measurements include temperature, flow rate, pressure range, operating conditions, and other data according to a contract.

Select the required Metering system

A metering system is determined based on the product and specific requirements agreed upon for a transaction. Factors such as flow rate, pressure, fluid properties influence the choice of meters. Common options include ultrasonic (for high-flow oil and gas), Coriolis (direct mass-flow measurement), and turbine (liquid hydrocarbons).

Design Piping and Flow Arrangement

Accurate piping arrangement and design ensure oil and gas flow remains continuous and undisturbed. Placing valves, strainers, flow conditioners at appropriate locations according to the measurement and design standards requirements ensures accuracy in meter readings.

Measurement through Instrumentation

Instrumentation automates and regulates pipe flow and helps convert raw meter readings into volumes that can be used to calculate financial value. A flow computer is equipped to receive measurement signals, converting them into data with the exact mass rate of liquid or gas flowing through the skid.

Hazard Classification for Safe Operation

Skids installed in industrial facilities are exposed to hazardous chemicals. Hazardous areas are classified, and other conditions such as emergency shutdowns, pressure containment, drainage/venting are considered during skid design.

Applicable Standards for Metering Skid Design

The following internationally recognised standards are referred to for designing oil and metering skids and measuring hydrocarbons accurately with reliable metering systems.

Metering

API MPMS (Manual of Petroleum Measurement Standards) –

Chapter 5 Liquid Metering Guidelines for installation, specification, and operation of ultrasonic, Coriolis, turbine, and displacement metering systems for measuring liquid hydrocarbons.

Chapter 6 Metering Assemblies It specifies the design, installation, operation, and material selection of metering systems for measuring liquid hydrocarbons, custody transfer, aviation fueling, loading racks, pipeline, and viscous-hydrocarbon applications.

Chapter 12 Calculation of Petroleum Quantity This standard is referred to for calculating petroleum volume quantities using a specific calculation procedure with the appropriate sequence and parameters.

AGA (American Gas Association) Reports –

AGA-3 Design and practical implementation of metering systems using orifice plates and meter tubes for natural gas streams.

AGA-7 Design, calculation, operation, and installation of axial-flow turbine meters for measuring fuel gas.

AGA-9 Design, construction, installation, and maintenance of multipath ultrasonic transit-time flow meters for measuring natural gas.

ISO Standards –

ISO 5167 Measuring fluid flow through orifice plates, venturi tubes, measuring cones, and wedge flowmeters in pipes under load.

Design

ASME Standards –

ASME B31.3 Pipe Design and Fabrication – Process Piping It helps ensure that process piping systems are designed, fabricated, inspected, and tested according to the code requirements in facilities such as petroleum refineries and chemical plants.

ASME B31.4 Liquid Petroleum Piping Transportation System It specifies the design, assembly, and operation of liquid pipeline systems for safe transportation between petroleum production and storage facilities, and gas processing plants, refineries and pump stations.

AWS Standards –

AWS D1.1 Structural Steel Code (Skid Fabrication) – Welding Standards It specifies requirements for the design, fabrication, qualification, and inspection of structural welds in carbon and low-alloy steel structures. Clause 8 focuses on maintenance, strengthening, and repair of existing structures.

Reliable Oil and Gas Metering Skid Solutions for Custody Transfer

Custody Transfer acts as a financial cash register, ensuring accurate measurement and accounting when hydrocarbon properties are transferred between tanks, pipelines, or refineries.

Metering systems are essential for custody transfer, and skids fit these systems into compact and transportable frames.

At Sedin Engineering, we support manufacturers, EPCs, and OEMS by providing oil and gas metering skid design solutions that:

  • Minimise operational hindrances during critical production and transfer activities
  • Ensure compliance with metering, skid design and fabrication standards
  • Provide real-time fluid flow monitoring and diagnosis for faster identification of metering issues
  • Support skid integration with your facility’s existing process and instrumentation systems
  • Reduce downtime and lifecycle costs by simplifying maintenance

Planning for a commercial custody transfer? Contact our plant and piping design services team for a reliable, compliant, and fit-for-purpose oil and metering skid design.