An experimental device for measuring the internal temperature and pressure of rock for rock breaking by pulsed discharge in petroleum exploitation

Abstract

In order to measure the variation of temperature and pressure inside rock subjected to pulsed discharge, a device for measuring the temperature and pressure inside rock is designed in this work. The device is composed of an excitation module and a signal module. Based on the analysis of pulsed discharge process, the structure of key components of the device was designed. The experiment of rock breaking by single pulsed discharge was conducted. The peak values of temperature and pressure inside sandstone rock samples of 20 cm*20 cm*20 cm were measured when they were broken at 8 different voltage levels in the range of 2.5 kV–20 kV. It was found that with the increase of voltage level, the temperature and pressure inside the rock were also significantly increased when the rock was broken. At the maximum 20 kV voltage, the temperature peak inside the rock is 398 °C and the pressure peak is 2.4 MPa. The temperature and pressure inside the rock rose dramatically as it broke. This device can monitor temperature and pressure inside rock during the rock breaking process, and its embedded computer can construct time-varying temperature field and pressure field with transmitted temperature and pressure signals. This technically supports theoretical research on rock breaking by pulsed discharge.

Keywords

• Pulse discharge
• Rock breaking
• Plasma
• Sensor
• Fiber bragg grating