Chifeng City, Inner Mongolia is the birthplace of full hydraulic tunnel drill, which has been widely used in non-coal mine tunnels and surface in recent years. The following talks about the core taking method and the applicable working conditions of the tunnel drill.

Common double tube coring

This is also the original coring method since the tunnel drill, which is suitable for drilling coring of various Angle holes on the surface and in the pit, mostly for 37mm and 47mm bore holes. The effective length of the drill pipe is usually 1.5 meters, the application of 1.5 meters of double pipe drilling tool or 3 meters of butt double pipe drilling tool, play a drill pipe or two drill pipes, the core filled with the core tube, the drill pipe is put forward, the core of the core tube is placed in the core box, and the rod is continued to be sent, drilling, and so on. At present, the double tube coring is also widely used in the condition that the high core extraction rate is required by the large Angle upper inclined hole.

The double-pipe drilling tool comprises a drill bit, a reamer and a double-layer core pipe, and the double-layer core pipe includes a core outer pipe, a core inner pipe, a reducing receiver, a circlip, a circlip seat and an inner pipe short joint. There are several terms that we often hear, double double action, double single action, reverse circulation reducing receiver and special reducing receiver for crushing belt, negative pressure coring, straight through receiver and single pipe and so on.

Double tube and double action coring refers to the synchronous rotation of the inner tube and the outer tube of the core, that is, the angular speed is equal, which is suitable for soft, easy to collapse, afraid of erosion rock layer. Double-tube single-action coring refers to the non-synchronous rotation of the outer tube and the inner tube of the core, which is also a double-tube coring method commonly used in various formations. Double-tube single-action and double-tube double-action drilling tools are only different in reducing diameter, and there is no other difference. The parts connecting the outer tube and the parts connecting the inner tube can be relatively rotated, which is called double-tube single-action, and those that cannot be relatively rotated are called double-tube double-action.

The reverse circulation reducing receiver and the special reducing receiver of the crushing belt are only called different, referring to the same reducing receiver, the usual reducing receiver, whether double pipe single action or double pipe double action, can make water flow from the drill pipe inside the hole to the core between the inner tube and the core outside the pipe, so as to cool the drill bit, and then flow to the rock hole wall and the gap between the drill tool. In addition, the reverse circulation reducer also adds a fluid channel, which can make the inner pipe communicate with the rock wall but not the original water channel. In the process of drilling a diamond bit, the core continues to fill the inner tube of the core, the remaining space of the inner tube of the core is getting smaller and smaller, and the compressed air inside is faster than the discharge speed. Negative pressure is generated in the inner tube of the core, thus affecting the speed of the core being loaded into the inner tube of the core, and the role of reverse circulation reducing is to discharge the negative pressure inside the inner tube of the core. The core can be smoothly loaded into the inner tube of the core and the drilling efficiency can be improved. The application of reverse circulation reducing hand double pipe drill core is usually called "negative pressure core", "reverse circulation core", in order to distinguish from the true sense of reverse circulation core, this kind of core can also be called "small reverse circulation core". The straight-through receiver is different from other reducing receivers and is used for single tube, also called single tube coring. When playing a single pipe, there is usually no requirement for the core rate, see the ore to the core. When playing a single pipe, we should always pay attention to the water pressure gauge of the mud pump to prevent the occurrence of water plugging and drilling.

Second, rope coring

Since 2015, 60mm and 75mm diameter rope coring has been popularized in the tunnel, especially the application of rope coring in horizontal holes and small Angle upper inclined holes, which has brought great convenience to drilling operations. As we all know, rope coring was first applied in surface drilling, and there are many series and standards of rope double-pipe drilling tools. However, Q series and TW series of straight drill pipe and double core drill tools are commonly used in tunnel drilling RIGS.

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The wireline core drilling tool is composed of two parts, the outer pipe system and the inner pipe system, the inner pipe system and the outer pipe system can be separated. When the horizontal hole is drilled, the inner pipe system is sent to the front end of the hole with high pressure water of the mud pump. When the downward hole is drilled, the inner pipe system slides into place by its own weight. When the ejector plate of the ejector card assembly reaches the ejector chamber, the ejector plate will open and the inner pipe system will remain in the front end. When the fishing device is sent to the front end through high pressure water, the vertical fishing device is also sliding into place by its own weight when it goes down the hole, and the spearhead of the fishing device will jam the clip assembly, and the inner pipe system will be pulled out with the wire rope of the winch, and so on. It is not necessary to pull a drill pipe, only when the drill bit needs to be changed.

Third, reverse circulation coring

Reverse circulation coring, also known as "large reverse circulation coring", means that water is sent to the drill bit through the gap between the rock wall and the outer wall of the drill pipe to cool the drill bit, and the core is continuously flushed out through the center of the drill pipe, and the operator does a good job of core collection and placement. This coring method is only suitable for horizontal holes and oblique upward holes, and is not suitable for downward azimuth holes. At the same time, if the rock layer has large cracks or fractures, it can not be cored. In addition, reverse circulation drilling is mainly used in water exploration engineering. Only under suitable working conditions will reverse circulation drilling be used for ore exploration and core-taking.

Iv. Summary

No matter what kind of coring method is adopted, the equipment conditions can be met, but there are differences in the selection of supporting drilling tools according to the actual working conditions. The domestic portable drilling rig, that is, the top drive drilling rig, is mainly used in the drilling of downward azimuth holes between 0 degrees and 90 degrees on the surface, extracting the core with the rope core method, which is not suitable for other azimuth hole drilling operations, nor for other core taking methods, so the portable drilling rig takes over some of the vertical shaft drilling rig in the surface can not meet the azimuth hole drilling market. Because of its electric power, tunnel drilling machine is widely used in 360 degree azimuths in any Angle drilling core and electricity convenient or generator conditions of surface drilling operations. Because of the difference in the coring method, the tunnel prospecting drill has also been nicknamed "reverse circulation drill" and so on.

Chifeng Jiexing drilling equipment manufacturing Co., LTD

Phone: 18204870825