Improvement and test of radar imaging logging tool for oil and gas wells

The detection depth of traditional logging tools is basically less than 3 m, and without azimuth resolution, the formation structure in larger area around wells cannot be imaged. Therefore the problems arising in the detection of subtle structure and oil and gas reservoirs can not be solved. In response to such problems, radar imaging logging tool is developed by applying ground penetrating radar imaging technology to logging. In order to improve the detection depth, azimuth resolution and downhole depth of the tool, a nanosecond pulse source and directional receiving antennae are used to detect and image the formation around the well, increasing the detection distance while improving the resolution. Magnetic rings and optocouplers are used to isolate the pulse plate, which effectively suppresses the noise. The high temperature resistance of the tool is improved by adding thermos and selecting high temperature resistant components outside the circuit. Finally, the tool is tested and calibrated by using model wells, and has been applied in three oil wells. The downhole depth of the improved radar imaging logging tool can reach 6 000 m, and its maximum transverse detection depth can reach 12 m. It can locate and image holes and fractures 5 m away from the wellbore, significantly improving the lateral prediction ability of logging technology. The testing results show that as the tool can withstand high temperature and high pressure environment of oil wells with a large detection depth and high resolution, and it has a good imaging effect on the formation interface, fractures and pore structure around the borehole.