Future Development of Water Control Methods in Air Drilling Operations

In certain cases, the advantages of air drilling are very great. The economic incentives can be high, for we hear of operators who have saved more than $100,000 on one well through the use of air drilling. However, in the great majority of drilling situations, air cannot be used because of the water influx problem. A number of techniques are available to fight water influx. Some have been successful under certain conditions. However, nearly all need considerable further testing and development before they can be considered as routine operations. In short, we are a long way from being over the hump with respect to water control. Now it often costs us considerable money before we even can determine the extent of our problem. Water Control Methods Now Available The best water control method now available is, of course, to drill our wells where we know water will not be encountered. Although this sounds facetious, we should certainly make a thorough study of a prospective air drilling location to determine the possibilities that water will be encountered and to make an estimate of the probable locations and number of water-bearing zones which must be penetrated. An idea of the quantity of water influx would be very helpful. Unfortunately, unless previous air drilling has been done in the immediate area, we normally cannot predict with any high degree of certainty where water will be located. Logs from previous wells in the area are of some value, but apparently do not provide the entire answer. A study by a joint API-AAODC committee indicated that logs are effective in approximately 50 per cent of the cases in locating water-bearing zones. In any case, it behooves us to obtain the best information available in order to intelligently make the decision as to whether or not air drilling should be contemplated. In some cases, planning the casing program with water zones in mind may make the difference between an economic air drilling operation or a series of expensive water shut-off operations.