The paper is dealing with the technical proposal of selfregulating oil storage in rock with mobile water bed. The reservoir can be operated without water pumps and without pumps for pouring oil out of the storage. The storage operation relies upon the principle of gravity. This type of underground storage is applicable on the sites offering comparatively concentrated head of groundwater level ranging from 6 to 10 m. This natural head should allow for gravity pouring of drainage water and raw water surplus out of a cavern on occasion of filling the cavern with oil. This type of oil storage is suitable for remote areas and developing countries where the problems of running and operation of "classical" oil storage in rock might be appreciable.
It is considered that the effects of the difficulties expected to be encountered are uncommonly well pronounced in the following cases:
If the small-capacity storages are in question where the specific, operation and maintenance costs of the storage and installations thereof appear to be notably high.
If the storage is located in remote areas in which the permanent presence of operating personnel of the required qualifications and experience is difficult to provide and if the local supplies and services in respect of maintenance and repairs of the equipment and installations are not available.
If the storage is located in the developing country in which general technical advance and engagement of qualified technical personnel might be extremely unfavourable for application of the underground oil storage of that type.
If the underground oil storage is situated in the rock complex the hydro-geological features of which allow for penetration and inflow of huge amounts of groundwater after intensive storms and floods which are difficult to estimate and if, in such events, the capacities of water pump units are over, or, to be much worse off, under-estimated.
In the present paper is given the technical proposal of the underground oil reservoir with mobile water bed the structure of which, if applicable, is quite suitable to overcome all the above cited drawbacks, because it is capable of being operated automatically, self-independently and without water pumps and energy supply.
The technical proposal dealt with in the present report is based on the assumption that the available head of natural groundwater flow on the site selected is suitable enough to be used, i.e. that it is capable of allowing for formation of the depression in the groundwater table to be used as an oil recipient and gravity disposal and drainage of excessive raw water from the storage. The natural head required for that purpose should be about 6 to 10 m, depending on the height of cavern, bulk density of liquid fuel and design criteria involved. Considering the preconceptions which should be satisfied in case of application of such a type of storage, the most favourable sites thereof seem to be the ones located close to water flows in which the natural concentrated gradient of the required magnitude (waterfalls, rapids) does already exist or can be secured by the help of constructed objects.