The major portion of the production of the Gulf Coast area, represented bySouth Texas and South Louisiana, comes from the flanks of well-defined saltdomes. This oil, containing an excellent lubricating stock, ranges from 17? to28? Be. gravity. Some lighter oil is encountered but the life of such fieldsis, in general, an open question. In fact, there are few light-gravity fieldswhich have proved of much value. In all of the fields water encroachment, or, more properly, water producedwith the oil, is a vital factor. After the first head of high-pressure gas isremoved, ever-increasing percentages of water appear, and naturally the life ofthe wells is materially affected thereby. The sands are, as a rule, extremely fine, very soft, and must be carefullyexcluded from the hole by the use of fine screen to prevent sanding up. Allsands are tipped at such extreme angles as to make coring essential for thelocation of water strata, oil-bearing sands and important shale beds. Even withmodern coring, the correlation of logs is a difficult problem. Due to the fact that the bulk of the oil is refined for its lubricatingproperties, little attention has been paid to losses by evaporation in thefield. This is largely influenced by the fact that the major companies have seta price schedule, showing but two grades, "A" and "B." Theaverage oil company, therefore, does not attempt to use the gas-lift but reliesprimarily on the air-lift and then only on wells considered to be particularlyadapted to its use, namely those capable of producing large quantities of fluidand yet not having sufficient "kick" to flow. Furthermore, as the gas contained in the reservoirs is mostly methane, suchgas being very quickly vaporized and produced in large quantity in the earlylife of the fields, there is little gas left after the first flush flowingperiod of the wells. In fact, it is very generally conceded that gas is aprecarious fuel to depend on in any of the coastal fields. This situationlargely accounts for the fact that air, as the lifting medium, is almostuniversally used.