RI 2236 Prevention Of Evaporation Losses In Lease Tanks

"The tests described below were conducted by the Bureau of Mines at a lease in Oklahoma on installations designed to decrease evaporation losses of crude oil Pram storage tanks. Use of the lease was granted by the Oklahoma Producing and Refining Corporation of America. Tankage was obtained through the courtesy of the Parkensburg Pig and Reel Co. The purpose of the installations and tests was to demonstrate the value of making crude-oil storage tanks gas-tight, rather than to determine the amount of evaporation in any one type of tank. None of the tanks used were absolutely gas-tight, but one of them was very nearly so. They comprised a tank of the ordinary open type with an 18-inch manhole, a tank with a ""4-inch vent"", a tank with a ""smaller vent"", and a tank which had only ""pin holes"" through which air and vapor could pass freely. On the last two tanks any excess pressure was taken care of by an automatic differential pressure regulator.The results obtained in these tests indicate that tight tankage will soon pay for itself. They will not, however, serve as a basis on which a producer can compute the actual number of days necessary for tight tankage to pay out, because the oil used was exceptionally volatile. It is probable that the average evaporation loss in the Mid-Continent field is at least one-half as great as that shown by these tests, and if this is true, the saving that would be effected by providing tight tankage on the lease will undoubtedly justify the expense. The installation of evaporation-proof tanks on the lease has been delayed by the failure of production managers to realize, first, that their evaporation losses are enormous, and, second, that they can practically eliminate these losses by a simple and inexpensive installation."