W.S. Keys
1968
<p>In<span> 1966 more than 50 billion gallons of </span>water<span> was pumped daily from an estimated 10 to 15 million </span>water<span> wells </span>in<span> the United States. This was more than one‐sixth of the national withdrawal of </span>water<span>. On the basis of past rates of increase, a much greater future use of </span>ground<span> </span>water<span> is suggested. Our annual investment </span>in<span> </span>water<span> wells is one‐half to three‐quarter billion dollars, not including pumps and plumbing. </span>In<span> 1964 approximately 436,000 new wells were drilled; however, less than 1 percent of these wells were logged by any geophysical means. The application of _ge_o.phy.sical </span>well<span> </span>logging<span> to </span>ground‐water<span> </span>hydrology<span> is comparable to its use </span>in<span> petroleum exploration </span>in<span> the 1930's; however, we can take advantage of equipment and interpretation techniques developed </span>in<span> the oil industry that are available now for use </span>in<span> </span>ground‐water<span> investigations. Although most petroleum </span>well<span> </span>logging<span> techniques may be utilized </span>in<span> </span>hydrology<span>; modifications </span>in<span> equipment and interpretation are necessary because of basic economic and environmental differences between petroleum and </span>ground‐water<span> evaluation. If </span>logging<span> is to be widely applied to </span>ground‐water<span> exploration and evaluation, the expense of equipment and services must be reduced. Fortunately, this can be accomplished, because most </span>water<span> wells are not as deep as oil wells and the temperatures and pressures are lower. The </span>Water<span> Resources Division of the U. S. Geological Survey is conducting research on the application of borehole geophysics to </span>ground‐water<span> </span>hydrology<span>. The following </span>logging<span> devices are utilized </span>in<span> the evaluation of </span>ground‐water<span> environments: spontaneous potential, resistivity, gamma, gamma‐gamma, neutron, radioactive tracer, flowmeter, caliper, fluid resistivity, gradient and differential temperature, and sonic velocity. Lightweight </span>logging<span> sondes and control modules are operated by one man, either on a vehicle‐mounted 6,000‐foot logger or on a suitcase‐mounted 500‐foot logger. An inexpensive magnetic tape system has been developed and is used routinely for log recording and playback. If commercial </span>well<span> </span>logging<span> service is to be widely used </span>in<span> </span>ground‐water<span> exploration and development, </span>water<span> </span>well<span> contractors, and State and municipal agencies must be educated on the advantages of obtaining more information from each hole drilled. It will be necessary also to demonstrate how </span>well<span> </span>logging<span> can provide much of this information. </span>In<span> addition, the </span>well<span> </span>logging<span> industry must adapt their equipment and services to the requirements of </span>ground‐water<span> </span>hydrology<span>. The need for additional </span>logging<span> capability </span>in<span> this field exists at the present time and is expected to increase. Hopefully industry will be able to fill the gap.</span></p>
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10.1111/j.1745-6584.1968.tb01630.x
en
NGWA The Groundwater Association
Well logging in ground‐water hydrology
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