Panel Discussion: Underground Storage of Crude Oil, Products and Gases

Panel Discussion: Underground Storage of Crude Oil, Products and Gases

In his introduction the CHAIRMAN pointed out the increasing importance of the underground storage of fluids and gases, especially in oil and gas importing countries. In the United States there are about 600 caverns with 30 million m3 storage capacity. In Europe more than 200 caverns have been or will be built in the near future with more than about 70 million m3.Nearly 20 % of these European caverns will be used for high-pressure natural gas and air storage. In countries without salt deposits, crude oil and products can be stored in mined caverns in low permeable rocks, like granite and limestone. Underground storage of gases in aquifers is of increasing importance in countries where gas fields are missing or not yet depleted.The CHAIRMAN (opening the discussion after paper 1): What is the effect of micro-cracks in the salt crystals generated during strength-testing on the porosity and the permeability? Dr DREYER: The difference between micro-cracks and pores lies in the fact that micro-cracks are twodimensional

pores, however, are three-dimensional in extent. The porosity of rock salt is very small, amounting to below 0.5%. Under rock pressure, microcracked rock salt has a porosity tending to the value zero approximately.M. PENART: J'ai compris que vous avez utilisé un mécanique modèle pour faire vos travaux. Avez-vous pu vérifier les résultats de ce modèle sur des cavernes réelles ? Mr FÜRER: In the F.R.G. we have been leaching caverns since 1960. We have made rock mechanical investigations in salt mines as well as in laboratories.Our theoretical calculations based on the laboratory experiments are in full agreement with the results obtained in practice.Mr CLAESSON (Sweden) (giving a supplementary comment on the experiences regarding unlined caverns in rock after the presentation of papers 2, 3 and 4): In the Nordic countries during the last 20 years about 100 storage plants have been constructed as unlined caverns with a total storage volume of about 15 million m3. During this period we developed a great deal of experience in judging rock stability, choice of equipment and the required safety arrangements. The Swedish authorities today try to locate all new types of storage facilities in unlined caverns. The construction of this type of storage plant has developed rapidly. As to the geological conditions, Sweden has extensive deposits of hard rock. But you will find good rock conditions for constructing caverns practically all over the world. There is also some research going on in storing LNG in rock caverns in Sweden.The main principles of storage in unlined caverns are as follows: The stored product floats on a waterbed, surrounded by ground water, which prevents the product from penetrating the surrou

1975-05-11

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