The importance of filtration

Aykut Selcuk of Armada Offshore looks at the significance of filters in the production of crude oil, both on and offshore.

“I believe the oil production process is a good market for filtration and sedimentation equipment”
-Aykut Selcuk

The production of petroleum oil is basically a very simple process – a hole is drilled down into the earth’s crust, until an oil-bearing rock formation is reached, whereupon the oil is forced up the drilled hole to the surface. The consequent ‘gusher’ is a familiar sight to moviegoers. But the actual process is a good deal more complex than this. Somewhere along the line comes in the  importance of filtration for more efficient petroleum production. The oil recovery processes involve large flows of liquids and gases, most of which have essential needs for filtration and sedimentation to separate oil from water, and liquid or gas from solids. The most important liquid flow is, of course, the crude oil transported up the well bore for treatment at the surface.

The recovery of crude oil from underground requires separation treatment in two main places: at the well bottom, and at the well head. In the very restricted space at the bottom of the producing well, solid/liquid filtration is necessary to prevent the passage up the well pipe of as much suspended solids as possible. This is done by the well screen, a zone of perforated material that is either built in to the end of the well pipe, or fitted as a sleeve over a very coarsely perforated part of the pipe. The well screen is a specialised form of filter and is, of course, used for water production as well as oil. It can be made from wire mesh, wire wound, perforated plate or porous metal fibre material. The prime objects of this stage of filtration are to prevent blockage in the well pipe, and to protect whatever pump is being used down-hole to carry the oil to the surface. Perforated screens and woven wire meshes provide a more accurate and consistent aperture than does a mat of nonwoven metal fibres.

Once the oil reaches the surface, there is more working space for any required filtration, and the major separation requirement is to recover the crude oil from its mixture with the produced water. Production economies dictate that this separation should be as efficient as possible, since the separated water may be going to waste, carrying any unseparated oil with it. In the liquid/liquid separator a further amount of suspended solids will also be separated, and this may be sufficient solids removal to enable the separated oil to be transported to its ultimate refinery destination without damage to the transporting system. If not, then further filtration will be necessary at the well head, although the flow rates will be high, and the filters will have to be automatically cleaned.

On the other hand, natural gas produced in association with crude oil will not normally present a filtration problem - from solids at least, although it may need separation from oil or water droplets. However there is nowadays an increasing need for the injection of gases into underground strata, to improve oil production rates. This can be into the gas cap over the reservoir - when the need for filtration is low, or directly into the rock formation as an enhanced oil recovery process. The direct injection of gases will require that they be free from suspended solids, possibly down to the same size level as is the case for water injection. This will be done in the same sort of filters as are used for engine intakes, using V-block minipleat filter panels for more efficient results. In conclusion, I believe the oil production process is a good market for filtration and sedimentation equipments. Although some parts of it - the primary production - are relatively mature, others, in particular tertiary processing and recovery from tar sands, still have major growth ahead of them.

Aykut Selcuk is Managing Director at Armada Offshore. Despite his parents being both lawyers, he decided to pursuit a carrier in different path. After finished his Bachelor's Degree in Communications (Journalism), he moved to USA to study Computer Technologies. He was named to be the youngest Managing Director in Armada and has now shifted his focus to filtration technologies.