2015 Volume 80 Issue 2 Pages 119-124
We have tried to develop crosshole electromagnetics for oil fields utilizing a high-temperature superconducting quantum interference device (HTS-SQUID). Enhanced Oil Recovery (EOR) technology utilizing CO2 is an epoch-making technique for efficient production of oil. Recently, a new technique of changing CO2 to CH4 based on biotechnology has also attracted attention. CO2 - EOR is important not only for oil producing countries but also for the earth from the aspect of environmental conservation. To control the EOR, it is important to improve accuracy of monitoring technique of EOR. Though monitoring techniques utilizing seismography and gravity are useful for this objective, combination with an electromagnetic method using a highly sensitive magnetometer is expected to provide promising improvement of EOR monitoring technology. The HTS-SQUID has potential to monitor CO2 movement in oil reservoir because of its high sensitivity in a wide frequency range from DC to over 1 MHz. As the first step of the developments, a vessel for a SQUID system was prepared by using carbon fiber reinforced plastic (CFRP) with pressure tightness of 28 MPa and heat-resistance of 200 °C. By using the SQUID system placed at a depth of 50 m in a steel-cased borehole filled with water, magnetic signals from a transmitter coil in another borehole were successfully measured. We will improve the pressure- and heat-resistant performance, safety, and reliability of the technique to satisfy the requirements for application to oil fields.
