Downhole Permanent Monitoring Tackles Problematic Electrical Submersible Pumping Wells

Abstract

Abstract Permanent monitoring of downhole equipment and production in artificial lift wells is an excellent method of diagnosing conditions and determining the appropriate approach to avoid loss of production or of the well. Belayim Petroleum Company in Egypt (Petrobel) has used permanent monitoring sensors since 1994. The systematic data are used by the reservoir and production engineering staff to tackle problems such as high failure rate, sand fill-up, scale, ESP wear, and electric failures. Petrobel currently has twenty downhole gauges, and 8 other systems are waiting associated accessories before installation. Each permanent gauge sends nine measurements per minute to the surface in real time yielding an incredible volume of information. Downhole gauges supply accurate information about the reservoir, downhole, and the pumping system. This knowledge, in turn, is used to increase the run life of the artificial lift system through optimization of the reservoir pressure and artificial lift system performance. This paper demonstrates the long-term benefits of using subsurface permanent gauges to complement artificial lift equipment and provide real-time data to optimize well and/or field production. Case studies illustrate both offshore and onshore problems. Examples are given of wells that have been converted into successful artificial lift completions through proper interpretation of the gauge measurements and use of the information to optimize production. This paper brings data interpretation to a new level of prediction, which enhances economics and minimizes risk in production operations, especially offshore. Introduction Surface measurements alone cannot easily distinguish reservoir effects from effects of the submersible pumping system. The multistage centrifugal pump is driven by an electric motor. The pump and motor are normally suspended from the production tubing with the motor positioned below the pump, which discharges directly into the production tubing.1 The pressure and temperature gauges below pump provide information at the interface between the reservoir and the pump. Control and monitoring of pump performance are essential to achieving long run life. Using real-time data of downhole and surface parameters, personnel can maintain the equipment within its recommended operating range and have the capability to detect abnormal operating conditions and take appropriate actions that avoid failures. Historical trend analysis can also be used to identify changes in pump and reservoir performance. This analysis, therefore, provides input data to assist reservoir modeling.2 Monitoring of the pumping system and well performance is achieved through the use of downhole multiple gauges (multisensors). A multisensor provides a ‘semi-redundant’ measure of flowrate, intake pressure and temperature, discharge pressure, vibration, leak of current and motor winding temperature. Digital signal processing techniques are used to eliminate noise and measure the frequencies with a high degree of accuracy and resolution. The millivolt-level signals, which were once unidentifiable, can now produce pressure and temperature measurements with resolutions suitable for reservoir analysis. In fact, as the frequency and fidelity of the data increase, the accuracy and precision of the model increase as well.