70 BULLETIN 102, VOL. 1, UNITED STATES NATIONAL MUSEUM. 



The two greatest wastes connected with oil-well drilling are caused 

 by the harmful infiltration of water from water-bearing strata and 

 the uncontrolled escape of natural gas encountered in the course of 

 drilling. Water is a formidable enemy to oil extraction ; as the posi- 

 tion of the oil depends, in part, upon a nice equilibrium between oil 

 and water, the undue influx of water into the drill hole means a 

 reduced recovery of oil, if not a total loss of the well ; and not only 

 may a single well be completely ruined by inadequate protection 

 against water, but what is more grave a whole field of operations 

 may thereby be spoiled. The damage done in the past by water is 

 immeasurable and largely irretrievable, but the danger from water 

 may be controlled by means of a method of cementation already em- 

 ployed with success in California and Texas, whereby a water-tight 

 band of cement is forced into the space between the well casing and 

 the water-bearing stratum. 



Many wells in sinking penetrate gas-bearing formations, and in 

 such instances it has usually been customary to suspend operations 

 while the gas escaped into the air, so that the pressure might be re- 

 lieved against which continued drilling was difficult or impossible. 

 The actual waste of gas due to this circumstance has been first and 

 last enormous, amounting to billions, if not trillions, of cubic feet, 

 with a fuel equivalent of millions of tons of coal; indeed, it would 

 be safe to say that over half of the natural gas developed to date has 

 been made no use of whatever.^ But this physical waste, great as it 

 has been, is of small consequence as compared with the waste of the 

 energy represented by the gas-pressure, the dissipation of which 

 leads to a reduced and more difficult recovery of the oil. The gas, 

 therefore, is not only substance but energy, and represents a force 

 which must be conserved for the sake of later gaining a proper pe- 

 troleum yield. It is rather interesting that the waste of oil and gas 

 involved in the premature production of gas may be prevented by 

 comparatively simple means; namely, by drilling in a medium of 

 mud-laden fluid which serves to encrust the critical parts of the 

 drill-hole, sealing off the formations so that there is no improper 

 escape of gas and preserving the conduit intact down to the produc- 

 tive stratum.^ 



After the oil is struck, there are many methods for controlling the 

 output so as to avoid the waste incidental to much of the current 

 practice. The flow may be controlled by rather elaborate mechanical 



iSee R. S. Blatchley, Waste of Oil and Gas in the Mid-Continent Fields: Technical 

 Paper 45, Bureau of Mines, 1913. 



J. O. Lewis and W. P. McMurray, The Use of Mud-Laden Fluid in Oil and Gas Wells: 

 Bulletin 134, Bureau of Mines, 1916. 



* This process Is described in detail In Bulletin 134, Bureau of Mines, 1916. There 

 are numerous details of drilling practice which are subject to Improvement, but these 

 need not be gone into here. 



