Improving Offshore Oil & Gas Production Level Measurements

I’ve always held a fascination for offshore oil and gas production. It was my first job out of school as a newly minted Electrical Engineer working as a systems engineer out of New Orleans.

Better-level-measurementTechnologies have advanced quite a bit since that time back in the mid-to-late ’80s. In an Offshore Design & Engineering Equipment magazine article, Better level measurement, the technologies used in measuring levels and their reliability has significantly improved.

Level measurement is required on several pieces of processing equipment including:

…separators, scrubbers and storage tanks, where the traditional approach is to use mechanical float switches or displacers to monitor liquid levels.

The mechanical devices are:

…affected by changes in media density and have moving parts that wear or get stuck and require scheduled maintenance. Regular recalibration is required to maintain accuracy.

As we’ve highlighted in several guided wave radar (GWR)-related posts, this technology has several advantages, including:

…accurate, reliable and maintenance free way to measure level in a wide range of applications. GWR level transmitters are not density dependent and measurement accuracy is unaffected by high turbulence or vibrations. Since there are no moving parts to stick or wear, maintenance costs are reduced and the problems of false readings, which can result in hazardous situations, are avoided.

Diagnostics can also help flag if the liquid being measured is building up over time on the probe on which the low-energy microwave pulse travels. For vessels that have obstructions preventing a probe from being installed, non-contacting radar level measurement technology is available. This technology works:

…by sending a signal through the vapour space that bounces off the surface and returns to the gauge. Like GWR, changes in pressure, temperature, and vapour space conditions have no impact on the accuracy. In addition, radar devices have no moving parts, therefore maintenance is minimal.

Guided wave radar and non-contacting radar provide continuous level measurements in a vessel. Complementing these technologies are vibrating fork level switches for low and high-level alarms. They operate:

…on the principle of a tuning fork, whose frequency varies depending on whether the fork is immersed or dry. The latest generation vibrating fork level switches feature built in diagnostics and fast update rates that make them suitable for a wide range of critical applications. In addition, the design of the fork is such that they require very minimal maintenance, ideally suited to offshore installations.

Offshore platforms can be a difficult place to add wired instrumentation if the infrastructure, such as cable trays and junction boxes, is not already in place. Wireless instrumentation makes it possible to easily add these level measurement devices to replace unreliable, high-maintenance, or non-existing measurements.

Wireless vibrating fork and radar transmitters have all the functionality and features of their wired equivalents but with the additional benefits and convenience provided by wireless technology. On existing installations, replacing older technology with the latest level measurement devices reduces maintenance and enables accurate measurement.

You’ll want to read the article to see examples of these wireless measurements applied to separator applications and flare knock-out tanks. The results are less unplanned downtime, increase production and more safe & reliable operations.

The article concludes:

Replacing traditional level measurement with modern guided wave or non-contacting radar devices improves accuracy and reliability. Being able to continuously monitor a process helps to optimise processes and the increased visibility enables operators to identify problems much earlier that could interrupt production. With the availability of wireless enabled level devices achieving these improvements has become much easier, with many of the cost and installation obstacles removed.

You can connect and interact with other level measurement experts in the Level group in the Emerson Exchange 365 community.

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