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Symmetix Overburden Drilling SOD Robit & Atlas design analysis
What difference of ROBIT and Atlas's Symmetric casing system for water well drilling
This is the three-dimensional assembly drawing of the Robit structure and the ring drill bit drawing. The slot adopts a spiral loading method: that is, the center drill bit is rotated downwards, and the ring bit set ( ring bit + casing shoe ) drawing can be easily installed.
This is the Atlas structure. The annular drill bit has a bulge in the hole and must be aligned with the polit bit powder discharge groove and then rotated. Only the center drill bit can be installed into the ring drill bit. When the workpiece is at the bottom of the hole, secondary alignment and installation is more problem!
Symmetrix casing system of Atlas Copco design
In addition, due to structural reasons, the Robit series can be matched to form steps and tubes. Like the Atlas SOD 168 series, when the wall thickness of the tube is 7 mm, the inner hole of the annular drill bit also has 140mm, but the outer diameter of the annular drill bit is 198mm.
For the Atlas SOD 219 series, when the casing wall thickness is 6.5 mm, the inner diameter of the annular drill bit is 190mm. 198 is larger than 190, which means that the 168 concentric drilling tool reaming component cannot pass through the inner hole of the 219mm annular drill bit.
How to identify Robit SOD is actually very simple. The inner hole of the annular drill bit has a positioning block. The annular drill bit of Robit has a spiral groove. The annular drill bit and the pipe shoe are combined to form a reaming assembly. The two can rotate freely with each other, but cannot be separated. Expanding the hole Components are welded to the tube.
The application scenario shows that depending on the outer diameter of the pipe, the wall thickness of the pipe and secondary drilling, the drill bit size Robit has advantages, refer to the picture
Looking at the picture No. 3 , you can follow up with either a full face drill bit or a matching concentric drill.
The larger one is the 219R reaming component, and the smaller one that sits on the ground is the 168R reaming component. The video shows that the 168R reamed component can pass through the 219R reamed component!
Therefore, you can first follow up with the 219R pipe drilling tool, and then continue to follow up with the 168R pipe drilling tool, so that the depth of the step and pipe will be deeper.
There was a water well construction. After the SOD219 concentric pipe drilling tool drilled to 133 meters, the 168 concentric pipe drilling tool was used to follow it to 245 meters.
In this construction, the concentric(symmetrix) drill pipe Robit structure is used. The advantages are summarized as follows:
First, it shows that the level of welders is very high. The wall thickness of the following pipe is only 6mm, and the connection between the following pipes can only be achieved by electric welding. At the drilling site, welding conditions are very poor, and the skill of the welder determines everything.
The second is to explain that the material of welded steel pipes may not be very demanding.At that time, this kind of product was made entirely for the international market, because we were worried that domestic steel pipes and welding could not meet the requirements. Facts have proved that what foreigners can do, we Chinese can also do.
Third, the advantages of SOD symmetric (concentric) casing drilling tools over ODEX eccentric pipe drilling tools are not only reflected in the three aspects of penetration speed, reliability and adaptability to geological conditions, but also their penetration depth is much better than that of eccentric pipe drilling tools.
