Capillary Phenomena as Related to Oil Production

Abstract

Petroleum engineers are displaying considerable interest in thosefundamental properties of matter and energy that control the phenomena of oiland gas production. The subject is a difficult one to investigate by laboratoryexperiments for two reasons:it is impossible to reproduce in thelaboratory the scale of forces and dimensions that exist in the undergroundreservoir;if we attempt to scale down the dimensions we are unable toreduce all proportionally.It is as if we tried to construct a model blastfurnace for the reduction of iron ore, and reduced all lineal dimensions. Weshould find that the interstices between the miniature chunks of ore would notpermit rapid transfer of gases, that combustion and heat transfer would nottake place as in the full size furnace and that, in short, the contraptionwould not work. Just so, when we attempt to make a reduced scale oilfield wefind we must have, not only miniature reservoir and miniature wells, but"miniature" sand, oil, gas, etc. Much valuable work, however, has been donealong these experimental lines and more will no doubt follow, but investigatorsshould bear this point in mind and strive to attain dimensional homogeneity anddynamical similarity in order that their conclusions may be translated intoterms applying to the oil reservoir. As Gibson says, "These conditions areattained when all terms of the physical equation have the same dimensions…when all corresponding particles of the two systems trace out similar paths andwhen the velocities are such as to make all corresponding forces acting on twosuch particles in the same ratio." It is the purpose of this paper todiscuss the mechanics of fluid movement as it pertains to the oil pool and topoint out the complexity of the laws of fluid delivery under the conditionsoften found.We have to do, fundamentally, with confined fluids, possessing potential energywhose expenditure is restricted by certain properties of the confining mediaand of the fluids themselves. The equation of motion and time is completelystated when we can assign values to the propulsive