Welltesting

This course will teach you about measurements and metering

Basic Sediment & Water

Base Sediment and Water (BS&W)


Base Sediment (solids) and Water is a measurement we gain from taking a sample of well effluent, or produced fluids, at predetermined points on the surface equipment.  Usual sampling points are at the choke manifold and the separator oil outlet.

Choke Manifold

Sampling at the choke manifold will provide us with information to determine how the well clean-up is progressing.  Initial flow of a reservoir may have a high volume of solids and after time will reduce due to the finer formation solids being produced.  During the clean-up phase of the well we would not normally be directing flow through the separator as a high solids content can be very erosive and we also do not want to fill the separator with solids.  Once the solids content is at an acceptable level the flow can be directed through the separator.

Separator Oil Outlet

Sampling at the separator oil outlet will provide us with any residual water content in the oil at the separator oil outlet, this is important for accurately determining the correct oil production rate.  Oil meters generally measure the bulk fluid rate passing through them so knowing the water content after the meter will allow us to correct for the actual oil rate, this is known as the water cut.  

Calculation

The amount of water determined from the oil line sample will need to be added to the water production from the separator water outlet for total produced water from the well.  To determine the water cut from the oil line use the following formula.

Water Rate = Total Meter Rate x %BSW / 100


Hand Operated Centrifuge


Electric Centrifuge


Where should we sample BS&W to provide a more accurate determination of produced water?

  • Separator Oil Outlet
  • Choke Manifold

Select the correct sample point