Application of various temperature measurement methods in Well-GR1in Qinghai Gonghe hot dry rock

Abstract:

Temperature is an important indicator for evaluation of hot dry rock geothermal resources. At present, most temperature measuring instruments for geological survey work only can work below 180℃. However, with the increase of the depth and temperature in hot dry rock drilling, downhole temperature may exceed the tool measurement range, or error may occur in temperature measurement due to high temperature and high pressure. During drilling of hot dry rock Well-GR1 in Qinghai Gonghe hot dry rock, single-point temperature measurement was performed with BZM electronic multi-point thermometer, MTCHT-H thermometer and multiple groups of thermometers in conjunction with multi-point continuous temperature measurement with the SKD-3000B logging truck and GRY-1 borehole inclinometer. Comparison of the measurement results show that single-point temperature measurement is closer to the real temperature, but it has low efficiency and poor accuracy; the GRY-1 tool gives lower temperature due to slow temperature transmission caused by heat insulation. It is necessary to develop accurate, effective and economical high-temperature measuring instruments or methods.

Key words:hot dry rock; drilling temperature measurement; high temperature measurement; single-point temperature measurement; multi-point continuous temperature measurement