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North Star Drilling Tools | Φ146 + Φ76 Double Pipe Drilling for Sichuan Reservoir Anchoring Project

Project Overview

  • Location: Sichuan, China
  • Constructor: Sinohydro Bureau 5 Co., Ltd.
  • Project Type: Reservoir impoundment slope anchoring reinforcement
  • Drilling Depth: Vertical 28 meters
  • Drilling Tools: North Star Φ146 outer large pipe + Φ76 inner small pipe double pipe drilling tools
  • Drilling Technology: Water flushing double pipe drilling Supporting
  • Drilling Rig: Qiutian 360 Multi-function Hydraulic Drill Rig
North Star Drilling Tools Φ146 + Φ76 Double Pipe Drilling for Sichuan Reservoir Anchoring Project
North Star Drilling Tools Φ146 + Φ76 Double Pipe Drilling for Sichuan Reservoir Anchoring Project

This anchoring project is located in Sichuan and undertaken by Sinohydro Bureau 5. It is a slope stabilization project built to guarantee slope safety under hydraulic pressure after reservoir impoundment. For vertical deep anchoring boreholes in fractured reservoir slope strata, high-performance drill rods and casing tools are essential to prevent borehole collapse and maintain borehole quality. The construction site adopted North Star double pipe drilling tools (Φ146 outer pipe and Φ76 inner pipe), matched with the Qiutian 360 multi-function hydraulic drill rig. The North Star dual drill pipe assembly completed vertical 28m deep anchoring holes with water flushing cuttings removal technology.

Construction Challenges

  1. Broken and complex geology on reservoir slopes. Deep vertical drilling faces high risk of borehole collapse, requiring heavy-duty casing drill tools for continuous hole wall protection.
  2. Vertical 28-meter deep borehole. Traditional single drill rods cannot provide effective wall support, leading to high risk of borehole instability.
  3. Rock cuttings and mud easily accumulate inside the borehole, which may cause drill sticking, poor borehole straightness and hinder subsequent anchor cable installation.
  4. Drill tools endure continuous alternating loads in deep hole drilling, requiring outstanding torsion resistance and wear resistance for long service life.

Advantages of North Star Drilling Tools & Construction Technology

  1. North Star Φ146 + Φ76 double pipe system: The North Star Φ146 outer pipe serves as protective casing to stabilise loose rock formations and stop hole collapse. The inner Φ76 North Star drill rod transfers torque and delivers flushing water. This matched double pipe set preserves borehole integrity throughout the full 28m vertical anchoring hole.
  2. Water flushing cuttings removal process: Circulating water flows through the annulus between North Star’s inner and outer pipes to continuously carry rock debris out of the borehole. This keeps the hole bottom clean, reduces bit abrasion and lowers drill sticking risks.
  3. Premium alloy steel of North Star drill rods: North Star double pipes are manufactured from high-grade alloy steel with precision heat treatment. The drill tools deliver strong anti-torsion and anti-bending capacity to withstand vibration and impact loads in harsh deep-hole anchoring works.
  4. Excellent rig compatibility: North Star double pipe drilling tools fit seamlessly with the Qiutian 360 multi-function hydraulic drill rig. Stable torque transmission and smooth pipe tripping are guaranteed at the construction site.

On-site Application Results

North Star Φ146+Φ76 double pipe drilling tools successfully solved the borehole collapse challenge of 28m vertical deep anchoring holes on reservoir slope.

  • The borehole wall stayed stable during the whole drilling process; no major collapse incidents occurred.
  • Continuous water circulation ensures efficient cuttings discharge and keeps borehole bottom clean.
  • Completed boreholes maintain high straightness and fully meet the design specifications of reservoir anchoring engineering.
  • North Star double pipe drill tools deliver reliable performance and long service life under muddy, tough water conservancy site conditions.

Case Summary

This Sichuan reservoir impoundment anchoring project constructed by Sinohydro Bureau 5 proves that North Star Φ146+Φ76 double pipe drilling tools, paired with Qiutian 360 multi-function hydraulic rig and water flushing double pipe drilling technology, is a trusted solution for vertical deep anchoring holes on reservoir slopes.

North Star custom double pipe drill rods and casing tools are widely applicable to reservoir anchoring, dam reinforcement, high slope stabilization, foundation deep-hole anchoring and other water conservancy deep hole drilling projects.

Application Scope: Water conservancy reservoir anchoring, dam reinforcement, mountain high slope support, foundation deep-hole anchoring.

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