Techniques to improve MV cascaded H bridge inverter (CHBI) VFDs availability applied to drive high power esp oil wells

摘要

Artificial Lift systems are routinely employed in the petroleum industry in order to provide the energy needed for the fluid to be transferred from the reservoir to the surface. The ESP system is a method of artificial lift widely used in recovery, often applied in mature fields or fields with heavy oil (low API gravity), as well as high flow rate wells. The energy for ESP systems is supplied by a submerged motor pump set, often driven by a medium voltage adjustable speed drive on the surface. Electrical systems present in oil production units generally depend on redundancy of electrical equipment, primarily related to operational and production safety, in order to increase system reliability. However, in the case of offshore ESP systems, the power to each well is dependent on the operation of a dedicated frequency converter, and redundancy is practically impossible due to the dimensions of the equipment located on the production platforms. Due to the high cost of interventions for replacement of the ESP equipment, the system requires the maximum availability possible. The reliability of applied frequency converters for ESP drives becomes essentially important to the operation of this system. A failure in the converter translates directly into lost production from that well, as well as high intervention costs. The objective of this paper is to analyze the availability and reliability of frequency converters used in medium voltage multilevel CHDI drive topology for ESPs. A method to improve availability of MV frequency drives using the implementation of technical resources, focusing on increased system availability over the entire useful life of the ESP, is proposed. This will enable achievement of lower production losses and a better economic return on investment.