HFI-welded steel pipes for oil gathering systems in water-flooded oilfields
Primary oil production, in which oil is recovered by means of the pressure existing in the reservoir, is a technically mature process. Over time, however, the reservoir pressure declines and production rates are reduced. In secondary oil recovery, the reservoir pressure is maintained by water injection, which significantly increases the production rates and total recoveries from an oilfield. On the technical side, this is achieved by means of injection lines for water flooding and oil gathering systems (flowlines). After decades of oil recovery around the globe, the development of economic solutions for these pipe systems has increasingly gained importance.
The chemical composition of the media recovered by secondary production is different to that of oil (water addition, a high degree of mineralization, as well as solid constituents and dissolved gases), which calls for new concepts regarding the lining of oil gathering or flowlines. In particular, the lining must provide efficient corrosion protection as well as protection from abrasion by the solids contained in the produced medium.
Mannesmann Line Pipe has developed a concept for this requirement profile. Following numerous laboratory tests and several years of successful field testing of a trial pipe system, this concept can now be considered technically mature and particularly economic: the HFI-welded pipes used for the oil gathering systems are provided with a modified cement mortar lining (mCM). The pipe string is made up using slip-welding joints. The joint area is protected with a special sealant, an elastic thermosetting material that is applied to the socket base. This ensures unbroken corrosion protection along the string. External protection of the pipes is provided by coating systems that have proved themselves for many years in pipeline construction.
Further information can be found at www.mannesmann-innovations.com.