Excerpt from Compressed Air Magazine, Vol. 26: September, 1921 Pressure may be applied from agencies at the surface through the medium of air or natural gas, or the subterranean pressure may, in effect. Be augmented by a reversal of the compressor, i. E., inducing a partial vacuum. In some districts this latter procedure has answered quite successfully, but there are oil bearing areas where the subterranean condi tions do not lend themselves to a satisfactory operation of this system. To meet the latter circumstances a subsurface pressure must be built up by mechanical means to replace the pressure originally exerted by the pent-up gas. In certain fields gas is tapped from the sand a few feet above the oil-producing formation, and this gas is compressed and forced below to again promote the desired movement of the petroleum. This practice has its drawbacks because it not only tends to waste gas but it subsequently lessens the chance of recover ing much of the oil which finds its way into the gas sand and not toward the shot holes of the wells. The yield of a well may be increased considerably by recourse to gas pumping. As just described. The benefits are as a rule but temporary; and this method of stimulation would not be at all profitable if it were not for the greater measure of gasoline that can be obtained from the gas that is thus enriched by contact with the oil. This gas returns to the surface and is drawn off at the casing head for treatment. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.