Research On Multi-parameter Monitoring Technology For 150℃ ESP Wells

With the depletion of shallow oil pool and the deterioration of well condition, electrical submersible pumps(ESP) facilitate the oil extraction during the middle and later stages based on the advantages of high efficiency, large capacity and high lift. Well depth and temperature tent to increase along with the development of oil extraction technology. Therefore, research on multi-parameter monitoring technology for high temperature down-hole environment is significant for the operation monitoring, failure prediction, efficiency increase and scheme optimization of deep wells as well as high-temperature wells.A multi-parameter monitoring technology for 150℃ ESP wells is lucubrated in this paper. Seven parameters, intake temperature, intake pressure, discharge pressure, motor temperature, pump vibration on X axis, pump vibration on Y axis and leakage current, can be real-time monitored based on key technologies such as down-hole high temperature power supply, MCU time-sharing control, current loop, remote power supply and data processing. The monitoring system can be divided into two parts according to function and structure: the down-hole unit for parameter measurement and the ground instrumentation.The down-hole unit is responsible for multi-parameter measurement and transmission under the high temperature environment. The unit is powered by a fly-back structure power supply based on high temperature core material. Down-hole parameters are measured by the cooperation of high-temperature sensors and low-powered conditioning circuit. Measured signals are sampled and transmitted sequentially under the control of MCU time-sharing control circuit. After that, voltage signals will be transferred to current signals through the V-I conversion circuit, and then transmitted to the ground instrumentation.The ground instrumentation can be divided into three parts: the remote power supply, the main control board based on ARM7 and the MCGS touch screen. A switch power supply was designed based on a TOP264 EG in the structure of fly-back to realize remote power supply. The current signals are acquired by an I-V conversion circuit on the main control board. Besides, many practical functions can be realized though the main control board, such as data transmission to screen, periodic power supply, relaying protection and saving of history data, etc. The interface of the MCGS screen is designed to realize functions such as operation monitoring, data curves, alarming and protective value settings, etc.System performance was tested though a series of experiments after the hardware and software were designed. The experiments illustrate that the down-hole unit is able to work regularly under the temperature of 150℃, and the ground instrumentation is capable for signal acquiring and processing. As a consequence, the whole system has good stability and meets the accuracy requirements.