Engineering Survey Vol. XVI, No. 4/2022
Lekhov S.M.
Lekhov S.M., 2022. Slug tests: what are they for? Engineering Survey, Vol. XVI, No. 4, pp. 38–49, https://doi.org/10.25296/1997-8650- 2022-16-4-38-49.
Despite numerous publications and negative assessments, slug tests are still firmly rooted in the arsenal of methods of prospectors who need just to document the work, to show that “pumping tests” have been done. This method is highly doubtful already in its basic theory. The prospector creates the illusion of possibility to estimate “approximate aquifer parameters”, which are suitable for some indicative calculations. Geology is not an exact science. Hydrogeological methods, even the most accurate, for example, multiwell pumping test, give a rough idea about the aquifer parameters. However, they are theoretically justified. In practice, multiwell pumping test allows to avoid a large number of factors complicating interpretation, as well as to check the result using different calculation schemes within the same experiment. Slug test lacks the ability to control themselves. The most common interpretation methods, the so-called linear methods at lgS – t coordinates (S — draw-down, t — time), are based on the same assumptions and the results differ only slightly. On the other hand, more complex methods based on the complete solution of the seepage equation give a whole set of contradictory seepage schemes due to the large number of adjustable parameters when interpreting the experiment. It is also worth noting a small area of experiment impact. So, there is a situation when a large amount of effort and material costs must be spent to conduct a clean experiment. At the same time, the experimental data is supposed to be interpreted by doubtful methods that have significant assumptions in their theoretical basis. This, together with technical difficulties during the test planning leads to the impossibility of using them in hydrogeological calculations.
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STEPAN M. LEKHOV
Lomonosov Moscow State University; Moscow, Russia; trakky@mail.ru
Address: Bld. 1, Leninskie Gory, 119991, Moscow, Russia