| 摘要 |
PROBLEM TO BE SOLVED: To provide an in-situ water-sampling method, by which water can be sampled under an in-situ state by conducting fresh-water excavation applying directional drilling technique to an aquifer in a thick muddy sedimentary rock and chemical analysis can be executed with accuracy by the water sampling. SOLUTION: A main-tunnel well 2 is excavated by a rotary type excavation method using swelling inhibition type slurry as an excavation fluid, a whipstock 8 is installed in KOP depth for executing side stacking for sampling stratum water under an in-situ, a window hole 9 is bored, directional drilling is conducted up to a section just above an aimed stratum by a downhaul motor and MWD organization through the window hole 9, and a casing 15 is set to the directional drilling section. The outside of the casing 15 is filled with cement and water-shielded, the excavation fluid is replaced with fresh water, a water- sampling well 16 is directional-drilled by drill strings, tubing strings 18, to which a bare-hole packer 19 is set, is inserted into the water-sampling well 16, the main-tunnel well 2 and the water-sampling well 16 are interrupted by the bare- hole packer, and water sampling and measurement are conducted under the in-situ state of an aquifer 7 through the insides of the tubing strings 18.
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