First : PILOT HOLE DRILLING
The pilot hole is drilled from the entry point to the exit point following a previously designed profile and alignment. The Drilling Tools and rig equipment selected for each job is largely determined based on the results of the geotechnical investigation and the size of the crossing (length and diameter). During the pilot hole drilling, a directional guidance system is used to navigate the pilot hole along its pre-designed profile. Marine Support including vessel and dive crew management is essential on Shore Crossing Projects.
Second : HOLE ENLARGEMENT
In small diameter crossings the pipeline may be directly installed in the pilot hole. However in most cases pilot hole enlarging, known as [pre-reaming," will be necessary. Pre-reaming is required to provide a bore diameter large enough so that the pipeline can be installed in the drilled crossing. Based on the final desired diameter and soil conditions this process may include one or more stages.
Third : PULL BACK
Once the drilled hole has been enlarged to the required diameter and cleaned adequately, the pipeline is installed. When applicable, the pipeline is pre-assembled in a single string and placed on rollers prior to pullback. For pullback, a reamer is connected to the Drill Pipe. Behind the reamer a swivel is connected allowing the drill pipe to rotate the reamer without allowing the transfer of torque to the product pipe. The drill pipe is then pulled back towards the entry point until the pipeline is fully installed.
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51 steel pipe net latest offer: Q195, Q215, Q235, Q255 and Q275, etc. represent the steel grades, steel grades represented by the yield point of the letter (Q), yield point value, quality, quality and other symbols (A, B, C , D) The deoxidation method symbols are composed of four parts in order. From the chemical composition points, the low-carbon steel grades Q195, Q215, Q235, Q255 and Q275 are large. The higher the carbon content and manganese content, the more stable the plasticity. Divided from the mechanical properties, the above grades indicate the yield point of steel with thickness ≤ 16mm. The tensile strengths were 315-430, 335-450, 375-500, 410-550, and 490-630 (obN/mm2), respectively; the elongations of qi were 33, 31, 26, 24, and 20 ( 0.5?). Therefore, when introducing steel products to customers, customers should be reminded to purchase steel materials of different materials according to the required product materials so as not to affect product quality.