Hole bottom combined drilling tool used for fishing broken falling objects in drilled hole and fishing method of hole bottom combined drilling tool

Abstract

The invention provides a hole bottom combined drilling tool used for fishing broken falling objects in a drilled hole and a fishing method of the hole bottom combined drilling tool. The drilling tool at least comprises a double-wall drilling tool body, a gas-water mixing device, a single-wall drilling tool body and a fishing cylinder. The lower end of the outer wall of the double-wall drilling tool body is connected with the gas-water mixing device. The lower end of the inner wall of the double-wall drilling tool body is connected with the single-wall drilling tool body. The fishing cylinder is arranged at the lower end of the single-wall drilling tool body and comprises a connector, a cylinder body, steel wire ropes and cutting teeth. The upper end of the cylinder is connected with the drilling tool through the connector. The cutting teeth are arranged on the edge of the lower end of the cylinder body. At least one layer of fishing net composed of the steel wire ropes is arranged in the cylinder body. By means of the hole bottom combined drilling tool and the fishing method, according to the gas lift reverse circulation principle, the broken falling objects in the hole are fished with the help of the strong suction effect generated at the bottom of the hole. The fishing cylinder is simpler in structure, low cost, and wide in application range, continuous fishing can be achieved, the number of drilling times is decreased, and the fishing efficiency is effectively improved.

Description

technical field [0001] The invention relates to the technical field of drilling, in particular to a combined drilling tool at the bottom of a hole for fishing fine debris in a drilling hole and a fishing method thereof. Background technique [0002] Large-diameter drilling (≥Ф450mm) hard rock section construction generally adopts the method of "small drilling, large drilling expansion", that is, one or more times of hole expansion, mainly using roller cone bits, mud positive circulation process (or gas lift reverse circulation process) )To be done. In order to reduce construction costs, most of the large-diameter reaming roller cone bits used are second-hand roller cone bits recovered from the oil drilling industry (only 1 / 3 of their lifespan is used in oil drilling). Assembled and combined, during the reaming drilling construction process, a common accident in the hole is that the tooth palm of the reaming roller cone bit falls off. There are also irregular fine objects s...

AI Technical Summary

Problems solved by technology

[0003] Comparing and analyzing the above-mentioned fishing methods and tools, many methods use the principle of reverse circulation to salvage. Among them, the detonation-type powerful air lift fishing method can establish an instantaneous full-hole reverse circulation channel. Practice has proved that this method can be salvaged under a huge pressure difference The efficiency is very high, but it is only suitable for use in the casing or in a relatively clean open hole; other reverse circulation fishing methods use a special overshot structure to establish a local reverse circulation at the bottom of the hole to implement the salvage operation

The above-mentioned reverse circulation fishing methods cannot realize continuous fishing, that is, when there are sediments such as thick silt and cuttings in the hole, it is necessary to drill down to wash the bottom of the hole first, and then go down to carry out the salvage operation

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