Slug Catchers

The slug catcher you can’t refuse

A SlugOTSO™ slug catcher’s most distinctive feature is that an “inverted harp” arrangement of storage fingers is utilized for slug storage. The liquid header is located near to the slug receiver and feeds liquids to the rows of storage fingers (the inverted harp). The storage fingers also empty through this header. Current slug catchers typically have the liquid header at the far end of the storage fingers and it isn’t used to fill the fingers. A single slug receiver performs the bulk vapor/liquid separation. A mist scrubber is included on the combined vapor flow from the slug receiver and vapor header. 

Quicker and Less Expensive: SlugOTSO™ slug catchers are typically less expensive and require less lead time than current technology slug catchers with similar storage capacity. 

Proven technology: The first SlugOTSO™ slug catcher is already in service and the second one has been ordered. CFD analyses have been performed to assure performance. 

Flexibility concerning plot space

Slug catchers take up substantial plot space at plants. This can pose problems. In common with current technology SlugOTSO™ slug catchers also take up substantial plot space. But there is greater flexibility:

  • The storage fingers can be located hundreds of feet from the slug receiver
  • The storage fingers can be located hundreds of feet from the mist separator
  • Multiple sets of harps: If plot space is fragmented, the slug storage can be divided into multiple sets of harps.
  • Stacked sets of harps: Where plot space is very limited, the harps can be stacked vertically
  • Harp burial: The harps can be substantially buried freeing up surface space for other purposes

Isolation and expandability without downtime

  • Inspections: With the addition of valves on the connectors from the liquid and vapor headers to the storage fingers each storage finger can be isolated and depressured for inspections while in-service. Manways would be needed.
  • Expandability without downtime: Future fingers could be added where extended headers have valves installed. This is especially useful for situations where the production will ramp up over a number of years. Fingers can be added as needed minimizing initial investment. This also mitigates risk concerning future production uncertainty.
OTSO Slug Catchers are designed to handle slugging issues that arise while transporting mixed-phase flow in pipelines over long distances; or across fluctuating elevations in the line, where liquids have a tendency to collect in low spots and then suddenly burp over. At velocities commonly experienced by process, production, and transportation systems, periodic slug flow occurs often in a varying but somewhat consistent pattern.


The OTSO Slug Catcher provides the following main benefits to customers:

  • Mitigates slug formation in pipelines
  • Contains slug storage volume between the normal liquid level (NLL) and the high level switch (LSH)
  • Prevents the oil layer from rising above the oil bucket spillover lip
  • Ensures large amounts of oil don’t underflow the bucket into the water section
  • Maintains oil-water segregation with a fixed weir design

Contact an OTSO representative for more information on this product.