Abstract
For the purpose of Predicting drillability in exploratory wells, the writers attempted to express drillability of each well and formation by examining the records of 13 wells drilled in Niigata Prefecture. The attempt was made by means of establishing standardized index which would compensate the differences of the drilling parameters obtained from such data as bit weight, rotary speed, hole size and rate of penetration. The computations of these factors and graphical representations were performed by electronic computer.
Regarding the applications, the writers attempted to determine standard rates of penetration for each formation. However, it was proved that these were affected by area rather than by formations. Furthermore, in order to establish the drilling schedule of Matsuto exploratory well, the prediction on the rate of penetration was applied.
