1. The planning of the development of oil and gas fields as well as the method to be used in such planning are derived from the results of operations research. On the basis of the estimations of reserves and average initial daily production per well, we carry out research for the most appropriate period of recovery and numbers of development wells, and further, we make plans on the arrangement of well, equipment and facilities for production. 2. If we can predict the modes for the occurrence of oil and gas, or the distributions of productive and non-productive areas of the fields that are investigated, it contributes to the estimations of reserves and initial daily production per well. The writer considered some volcanic rock reservoirs in Niigata Prefecture for the basic data of the investigations above mentioned.
To drill an oil well at a minimum cost, it will be essential to use the most suitable bit type for the ground and to control both the bit load and the rotary speed at the optimum values respectively every moment. The authors have first discussed on the equations for the rate of drilling and the rate of wear of the bit teeth and bearings. Secondly they have investigated the values of several constants involved in the equations by referring to the drilling bit records taken by the Japan Petroleum Exploration Co., Ltd. It results in that four of the seven constants are found, while for the remaining three a method of determining them from a drill test which is to be carried out at the begining of each drilling operation is proposed. Lastly they have shown how to determine the optimum bit load and the rotary speed every moment, and have proved theoretically the profit which may be obtained by the minimum cost drilling by comparing its total cost with those of conventional drilling under various conditions.