Phase-to-Phase Communication Scheme for Downhole Monitoring Tool Design in Electrical Submersible Pump Systems

Abstract

Electrical submersible pumps (ESPs) are commonly used artificial lift method in deep wells in oil industry. To monitor ESP systems operation, downhole monitoring tools are used to transmit data representing the physical condition of the downhole such as temperature, pressure, and vibration to the surface. The most common communication method for downhole monitoring tools in the field is to use a direct current (dc) signal over three phases of the main power cable, and the ground serves as a return path. However, this method cannot operate in the event of a single-line-to-ground (SLG) fault, although the ESP is still in operation due to ungrounded practice in its downhole zone. This method is also prone to failure in the presence of voltage unbalance. To overcome issues in the existing downhole monitoring tool design, a new phase-to-phase communication scheme is proposed in this paper. Intentional disturbances are applied to the ESP system and used as means of binary communication. In this paper, theoretical formulas of the proposed method are derived, and its performance is evaluated using simulation through case and sensitivity studies.