The paper presents the general view of the data processing system of the aeromagnetic survey now adopted in Geological Survey of Japan. The important problem in the qualitative and quantitative interpretation is the problem concerning with the accuracy of the compiled and the processed aeromagnetic map. In the off-shore prospecting, the accuracy of the compiled map is largely affected with the positionlocation system used. Applying the Decca, Loran C or Doppler navigation system to determine the flight path and its intersection, some inaccuracy would be produced. The adoption of the least square techinique to adjust the flight path without misclosur is necessary. The accuracy of the processed map depends upon the frequency characteristics of the applied digital sampling filter and the method of the interpolation from grid value. After discussing these problems, the examples of the frequency characteristics of the upward continuation filter and the continuation map are shown. In the last section, the method of the machine contouring by the computer are presented. The interpolation from the grid value are based on the Lagrange formula.
In this paper writers refer to calculation procedures for two technical problems in development of natural gas field. One is the confirmation of Poetmann and Carpenter's method for design of Gas-lift system and studies on the modification of the method to make fit for field data. The other is the pressure predication of natural gas field applying Van Everdingen and Hurst's equation of unsteady-state flow. Because of many steps and frequencies of calculation in each case, it is impossible to calculate by common calculater. Only by electronic speed the results and solution of the problems is given. Writers refer mainly to the algolithm, calculation procedure, block flow chart for digital computer, and comparison of calculation time by digital computer and common calculater. In the first case, one group of calculations which needs 300 hours by common calculater is treated in 2 minutes by digital computer.
Utilization of computer in the fields of reservoir studies has not been popular in our company. It is supposed that the use of computer in reservoir studies plays a very important part in getting more accurate reservoir computations, but there are some problems for us in making the program for reservoir studies because of the lack of experience for computer programing. Some examples of our recent reservoir studies using omputer are as follows.
Here are explained the applications of computer for natural gas fields of JAPEX. Some of the application programs we have developed for natural gas field are the followings: (1) calculation of open flow capacity from the results of the well flow tests (2) calculation of gas effective permeability, skin effect, and productivity ratio from the results of flow tests (3) estimation of bottom hole pressure from well head pressure (4) calculation of multiple flush separation (5) performance calculation of gas condensate reservoir (6) gas reserve calculation by volumetric method (7) gas reservoir simulation. Some of above programs are outlined in this paper.
In this paper, the applications of electronic computer to the log interpretations are described. As regarding the examples, the log interpretations in Yasuda gas field and Sarukawa oil field are conducted by using multiple logging curves. The method used here to estimate water saturations and shale constents of the reservoirs is based on the de Witte Type equations developed by Simandoux. These calculations are perfarmed with electronic computers. The results are summarized as follows; 1) As for the sand-shale series ordinerly encountered in Japan oil fields, the results of this method indicated to be fairly good. 2) As for igneous rock, further investigation should be carried out. Eleetronic computations for dipmeter interpretations are also described in this paper.
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.