Fighting Internal Corrosion -A Big Challenge to Maintain Sustainable Oil Production in Romania

摘要

Romanian oil production is characterized by mature fields with a big variety of different fluid parameters. The total number of wells exceeds 10,000, most of them equipped with sucker rod pumps. Corrosion has been a big challenge in the past decades. Metal consumption was a permanent problem causing high failure rates in pumping units, flowlines, pipelines and production facilities and thus leading to high well intervention and maintenance expenditures as well as to production losses. To maintain the oil production in this environment, the first steps concentrated on identifying corrosion mitigation measures leading to a distinct decrease of internal corrosion covering all operational units.Downhole inhibitor treatment was identified to be most effective to achieve this goal. A key issue was to find inhibitors in laboratory tests showing a maximum protection rate in many different production fluids thus minimizing the number of total inhibitors used. Subsequently the inhibitor treatment had to be established in the fields in a large scale and a corrosion monitoring system had to be established to verify the efficiency of the selected inhibitors in the field. This was done mainly by coupon measurement.The first results showed that inhibitor injection can achieve a high protection rate, but many measures have to be set to achieve an optimum inhibitor concentration at each location.This paper gives an overview of the first results of an inhibitor treatment and corrosion monitoring program recently established and of future corrosion monitoring activities in Romania's mature oil fields.