At the present time, Rosneft Oil Company is applying various technologies to minimize scaling problem. One of these techniques is, for example, a continuous injection of inhibitors using surface dosing systems to protect downhole equipment from damage caused by scale deposits (more than 1200 wells are equipped with dosimeters). It has been discovered that this method has some disadvantages, in particular an abnormal high rate of downhole equipment corrosion. As a result, wells are destroyed within less than a year. Our estimation shows that for some cases the corrosion rate is higher than 20 mm/year. Corrosion types and mechanisms have been determined. Corrosivity testing of the production from the above wells has been performed using coupons made of the least corrosion resistant material in the injection system, and an industrial adaptation of the material followed the examination. The corrosivity has been studied in a wide temperature and partial pressure CO2 range. Testing and selection of chemicals for corrosion prevention technologies have been carried out.

Keywords:
flowline corrosion, Subsurface Corrosion, annular space, water management, well integrity, mechanism, Pipeline Corrosion, riser corrosion, corrosion inhibitor, materials and corrosion
Subjects:
Production Chemistry, Metallurgy and Biology, Pipelines, Flowlines and Risers, Materials and corrosion, Well Integrity, Subsurface corrosion (tubing, casing, completion equipment, conductor), Corrosion inhibition and management (including H2S and CO2)
Copyright 2006, Society of Petroleum Engineers
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