Metal Tube Variable Area Flow Meters are the preferred mechanical flow measurement devices for EPC contractors in oil & gas projects, particularly in the design and engineering of Wellhead Platforms (WHPs).
Wellhead Platforms
A Wellhead Platform (Figure A) is an offshore structure that supports equipment to extract oil or gas from subsea wells. Typical features include an integrated deck, utility systems, wellhead systems, helideck, and sometimes drilling facilities. WHPs are usually linked to Floating Production, Storage, and Offloading (FPSO) vessels or to central production platforms. Designed to be normally unmanned and operated remotely, with only periodic inspection and maintenance visits, WHPs require highly reliable and maintenance-free instrumentation. This makes metal tube rotameters ideal, as they function efficiently without the need for routine servicing, provided process conditions remain stable.
Figure A) Typical Well Head Platform
These flow meters find applications across various WHP systems, such as:
- Wellhead Control Panels (WHCP)
- Chemical Injection Skids
- Corrosion Inhibitor Systems
- Sampling and Jet Mixing systems
Wellhead Control Panels (WHCP)
Also known as Wellhead Shutdown Systems (WSD) or Emergency Shutdown Systems (ESD), Well Head Control Panels (Figure B) integrate hydraulic and electrical components and interface with PLC (programmable logic controllers), SCADA (supervisor control and data acquisition systems) or RTU (remote terminal units) systems. Their role is to continuously monitor wellhead pressure and flow, trigger alarms, and activate hydraulic lines to close the main well valves in emergencies.
Since WHCPs must keep oil wells and nitrogen accumulator systems constantly pressurized, they often operate in critical environments. Typical measurements include return oil flow to the reservoir, nitrogen charging system flow for accumulators, and pump line flow within the WHCP.
A few factors differentiate the Brooks MT3809G metal tube rotameter for these given applications, such as its ability to operate under extreme pressure conditions (up to 6,000 psi for standard products and 20,000 psi for custom models). Also, it is globally approved for use in explosive and hazardous environments, meeting the highest international safety requirements.
Figure B) Well Head Control Panel (WHCP)
Chemical Injection Skids
The initial phase of refining crude oil or natural gas starts at the wellsite, where chemical injection skid units inject specialized chemicals into the process stream or reservoir. These chemicals support processes like hydrate prevention, corrosion control, and improved oil recovery.
Chemical injection skid packages can be installed on WHPs or FPSOs connected to them. Modern chemical injection skid systems (Figure C) often feature modular double-deck designs for scalability and ease of installation, as well as advanced safety features such as high-point vents, flame arrestors, emergency stop controls, and comprehensive leak detection. Many packages carry certifications like the American Bureau of Shipping (ABS) class approval.
The MT3809G rotameter provides flexibility for installation due to its varying connection types and orientations, allowing for vertical and horizontal connections. This feature is crucial when there is a need to optimize piping space in a chemical injection skid system.
Figure C) Chemical Injection Skid installed in an FPSO with Brooks MT3809G Model
Corrosion Inhibitor Systems
A specific application of a chemical injection skid is a corrosion inhibitor system (Figure D). Corrosion mitigation is essential to protect pipelines, production equipment, and the environment from aggressive corrosion caused by harsh operating conditions and corrosive gases. Corrosion inhibitor systems periodically inject selected chemicals into pipelines and systems, chosen based on material specifications and process requirements.
The MT3809G is an optimal rotameter choice for these types of systems for monitoring chemical injection flow rates, because of its selection of corrosion resistant wetted materials. Utilizing Brooks MT3809G ensures reliable protection of assets within the entire corrosion inhibitor system.
Figure D) Corrosion Inhibitor System with Brooks MT3809G Model
Sampling / Jet Mixing System
Accurate sampling is critical to verify the quality and composition of crude oil or gas extracted at the wellhead. It is vital that samples truly represent the process stream.
To achieve this, EPCs employ mixing technologies that ensure a fully homogeneous flow at the sampling point, in compliance with international standards. The Sampling and Jet Mixing system (Figure E) conditions the flow, eliminating stratification and ensuring any sample or measurement reflects the entire process stream, regardless of blend rate variations.
Figure E) Sampling / Jet Mixing System with Brooks MT3809G Model
Flow measurement within these systems will use the Brooks MT3809G because of its high level of accuracy, and because it can be paired with a flow transmitter using either HART or FOUNDATIONTM Fieldbus capabilities that send data to remote monitoring systems. This setup improves measurement accuracy and reliability, which is critical for process optimization and compliance.
