Abstract: A fracturing method, to cause a crack in bedrock, includes installing a depressurizing device in a well in the bedrock, and depressurizing the inside of the well with the installed depressurizing device. The installing step includes installing, in the well, a connecting pipe, which is connected to the depressurizing device, and a packer, which is attached to the connecting pipe, and the depressurizing step includes shutting off a gap between the well and the connecting pipe, with the packer, and depressurizing a region in the well below the packer, with the depressurizing device.

Abstract: A packer connected to a casing pipe, the packer including a connecting tube made of metal and connected to the casing pipe, and a packer part made of metal and attached around the connecting tube. The packer part has a hollow part inside. A sealed liquid that thermally expands is sealed in the hollow part. An outer peripheral wall of the packer part includes an expansive part that protrudingly deforms outward with the thermal expansion of the sealed liquid.

Abstract: A well drilling bit for drilling bedrocks includes a columnar bit body, and a drilling fluid flow path formed in the bit body to wash away drilled cuttings from a bottomhole and/or a periphery of the bit body. The flow path is provided with a venturi mechanism including a venturi tube having a reduced-diameter portion where a cross sectional area is reduced and capable of generating a decompression region around a tip of the bit body, the decompression region being more decompressed than a surrounding by the Venturi effect.

Abstract: A packer connected to a casing pipe, the packer including a connecting tube made of metal and connected to the casing pipe, and a packer part made of metal and attached around the connecting tube. The packer part has a hollow part inside. A sealed liquid that thermally expands is sealed in the hollow part. An outer peripheral wall of the packer part includes an expansive part that protrudingly deforms outward with the thermal expansion of the sealed liquid.