Discussion and Optimization on Drainage Radius Measuring Method of Borehole

In order to solve the measured results not accurate occurred due to the method selection and operation as well as other causes during the drainage radi us measuring process, which cause the blank zone problem occurred, with several experiments, the flow method and the drilling cuttings method combined method was applied to for the measurement.With the comprehensive analysis and correction conducted on the two measured results, then based on the sensitive degree of the pred icted index, the measurements were applied to comprehensively determine the result intervals.The practices showed that the measured results of 1.5 msRS1.8 m for th e drainage radius R were accurate and reliable.During the implementation process, the drainage borehole measures could be effective to eliminate the blank zone occu rred.