Although much work was done in two-phase flow in an oil well, the inclination angle of oil well has not been considered yet. The effect of inclination angle in two-phase flow, however, seems to be becoming important. Because there are many directional wells in oil fields. Especially, the number of directional well is more than that of vertical well in the most offshore oil fields. The analytical work for developing the calculation method has not been done in this study. The equipment used in this experiment is shown in Fig. 1. This set-up was simulated a gas lift well in oil field by attaching a sand packed pipe to the bottom of the lift pipe. Air and water were used as gas and liquid, respectively. The pictures of flow patters taken in this study are shown in Fig. 2 through Fig. 7. The flow patterns are the intermediate types between vertical flow and horizontal flow. The flow rates of air and water corresponding to each flow pattern shown in the figures, are listed in Table 1, Table 2 and Table 3. The relationships between the gas injection volume and the water production are shown in Fig. 9, Fig. 10 and Fig. 11. The inside diameters of the pipes used in this study were 2.46cm, 1.60cm and 1.00cm. The results for the inside diameter of 2.46cm are shown in Fig. 9. The water production decreases with increasing the inclination angle, as shown in Fig. 9. The production behaviors in the gas-lift tests were also affected by the diameter of the lift pipe, as shown in Fig. 9, Fig. 10 and Fig. 11. The combination effect of the inclinnation angle and the pipe diameter should be considered in determining optimum pipe diameter in gas lift design.
This paper presents an actual FORTRAN program of probabilistic model for uncertainty analysis in estimating oil reserves. Factors in this calculation are expressed by triangular probability distribution and uniform random numbers are generated by multiplicative congruence method. The authors consider the shape effect of triangular distribution on estimation of oil reserves. Acknowledgment is given to Dr. Paul J. Root, Associate Professor of Petroleum and Geological Engineering, University of Oklahoma for his valuable informations concerning with "Decisions under Uncertainty" in carrying out this study.
Four carbonate strata of Miocene are exposed in Akita area of northern Honshu, Japan. Investigations with the electron-microscope revealed that these carbonate rocks are composed mainly of skeletal debris such as diatoms, forminifera, radiolaria and nannoplankton. The paleo-environments were bathyal to innerneritic. During syn-diagenesis, calcium and magnesium derived from the sea water as well as from volcanic detritus within the basin altered the originally siliceous sediments to dolostone (in deep, cold waters) and limestone (in shallow, warm waters). After the consolidation, the primary texture of carbonate rocks was destroyed gradually by dehydration and recrystallization during ana-diagenesis.