Behavior Of Gas Bubbles In Capillary Spaces

Abstract

Natural gas influences the movement of oil throughreservoir rock by affecting the physical properties of the oil and the pressurewithin the reservoir. The presence of gas bubbles changes the laws of flow andthe distribution of forces. The problem of flow of oil and gas through a porousrock is complex, and most authors, in order to analyze their problems, havefound it necessary to make or accept certain generalized assumptions. Some ofthese assumptions, particularly the ones dealing with capillary phenomena andmolecular forces, have not received sufficient attention and by lack ofunderstanding have often been misinterpreted. Herold has called attention to the resistance offeredby gas bubbles in capillary spaces and has drawn some interesting conclusionswith regard to the action of natural gas in a reservoir rock. He has duplicatedan experiment of the French physicist Jamin, has interpreted his findings interms of molar mechanics, and, from experimental observations, has made anumber of assumptions which he later applies in discussing problems of naturalflow and recovery of oil. The Jamin action is an assumption because it lacks aphysical proof and has never been determined quantitatively. Tickell attempts to develop a formula expressing thework performed by a distorted bubble. H. A. Wilson, in the recent publicationof the American Petroleum Institute on the function of natural gas, discussesthe phenomenon in terms of classical physics. Both contributions are incompleteand offer no experimental data. This paper includes a study of the static condition ofequilibrium of gas and liquid bubbles confined to capillary spaces. In order toavoid any possible confusion, it is proposed to restrict the term" Jaminaction"