We analyze the skin effect for three single-borehole tests, the flowmeter test, the packer-pumping test, and the dipole-flow test. The estimated aquifer hydraulic conductivity and its anisotropy ratio when obtained from tests conducted on wells surrounded by a highly permeable disturbed zone may be in error by orders of magnitude. Two approaches are presented to eliminate or minimize the skin effect, the meticulous construction of the well envelope and the freezing technique. The first one improves the performance of all the three tests, while the second one improves the performance of only the dipole-flow test and the packer-pumping test.