Oil & gas production facilities and offshore platforms require the ability to periodically test the individual wells for oil, water, brine, condensate, gas, and other fluids to understand the production trends and if well operating parameter adjustments will be required. Piping and valve work to accomplish this testing has historically been complicated and has required periodic maintenance.
An EE Publishers article, Multiport flow selector optimises oil and gas production testing, by Emerson’s Chaitanya Shah, Prathesh Selvaraj and Paul Schafbuch, describes how multiport flow selectors (MPFS) simplifies this piping and improves production testing and reservoir management.The authors highlight the complexity of traditional piping:
One manifold connects all wells to production. A second manifold connects the well selected for testing to a shared multi-phase flow meter or separator plus single phase flow meter set.
While this conventional approach uses common valves, actuators, and piping components, it is more expensive and electrically complex than a multiport system.
Onshore fields and offshore platforms have different requirements due to distances and space considerations:
Typical onshore oil and gas production has wells scattered over a large area, such that it is not practical to manually open and close the manifold on/off valves. The oil field may be in remote deserts, deep jungles, or in sub-zero environments, such that local 24 x 7 human intervention means additional infrastructure. Any scattered network of wells requires high investment during the green field stage of the project capital expenses (CAPEX) and more maintenance operating expenses (OPEX) during the operation stage…
In offshore fields, it is important for platform equipment to be as light and small as practical so that the platform is less costly to construct, operate, and maintain.
The authors note how multiport flow selectors can simplify the piping arrangement:
An MPFS typically has eight inlet and two outlet connections.
Inlets: out of eight inlets it is recommended to connect seven to the wells, the eighth connection is generally used as a parking location and/or observation port for the selector plug. This allows for an observation port for temporary maintenance, and flushing and allows production of all seven wells if the test system is offline. The internal plug diverts one well’s fluid stream to the test port at a time. The plug is rotated to align with the well inlet to be tested.
Outlets – MPFS: Test outlet connects to the test system and the group outlet carries the flow of all other wells together to the production header.
These MPFS devices are driven by electrical actuators:
…with electronic controls enables easy control and monitoring of a MPFS. Whenever well testing is to be performed, operators can simply issue a remote command to position the diverter plug to the desired well inlet. This reduces the chances of manual error in the field which may lead to production downtime and untoward incidents.
The authors conclude:
A single MPFS commonly replaces 14 valves and actuators and significantly reduces piping and wiring. These benefits are larger in offshore and sour field production.
With MPFS, well flow is inherently not interrupted when switching lines for testing. Automation is simplified with a single MPFS actuator. Operations and maintenance work hours are reduced, along with the risks related to health, safety, and environmental standards.
Give the article a read if you are designing a well test system on for your production field or offshore platform.