Views: 61 Author: Site Editor Publish Time: 2021-01-17 Origin: Site
1. Project Profile
Project Name：Project of Single Point Mooring in Bangladesh
Builder: China Petroleum Pipeline Engineering Co. Ltd
Project location: Mattbari, southern port of Chittagong, Bangladesh Crossing length：1220m
Characteristic of project: The last landing directional drilling project in the south of Bangladesh single point mooring project, with a diameter of 914 mm, a wall thickness of 31.75 mm and a length of 1580 meters, has created the largest diameter and long distance construction for Chinese enterprises in the field of directional drilling of land and sea crossing.
Geological conditions: complex geological conditions, sand geology.
Engineering difficulties: land-to-sea crossing, very innovative and challenging; sand geology, large-grade reaming easy to collapse holes; local high temperature and rainy and Fani strong platform attack and other extreme weather.
Construction Equipment：Goodeng GT5000 pipe thruster
Picture 1: Topographic map of Bali, Matt
2. Technical Proposal Selection
There are some practical problems, such as limited pre-positioning operation space, poor performance stability of seawater mud system, stress rebound of offshore drill pipe pullback and easy hole collapse in sand layer geology. On the basis of fully drawing lessons from the successful experience of crossing in the early stage, the construction unit finally chooses the "safety and security weapon" of large directional drilling construction —— Goodeng "GT5000 pipe thruster" to carry on the pullback assistant.
Picture 2: GT5000 Pipe Thruster
3. Technical Programme Implementation
3.1 Determination of the Position of GT5000 Pipe Thruster
Through the two hydraulic arms of the pipe thruster (the working angle of the pipe thruster can be adjusted between -15°-5 degrees), the GPS tool was used to locate the pipe thruster in the axial position of the unearthed point pipeline.
Picture 3: Determination of the Position of GT5000 Pipe Thruster
3.2 Setting of Ground Anchor of GT5000 Pipe Thruster
Since the max thrust & pullback force produced by the pipe pushing machine is 5080 kN, the pipe thruster should be fixed on a solid foundation to resolve the force from the machine to the seat when thrust the pipe. Goodeng’s after-sales service engineer customized steel anchor box with length 6 000mm、 width 4 000mm、 height 2 000mm for the pipe thruster. Because the geology of unearthed side site is silt, the steel pipe is used to pile around to 6-8 meters deep to increase anchoring force.
Picture 4: Setting of Ground Anchor of GT5000 Pipe Thruster
3.3 Installation of GT5000 Pipe Thruster
Goodeng’s after-sales service engineer set up the pipe thruster on the anchor box and adjusted the position of the pipe thruster according to the diameter of the back towing pipe.
Picture 5: Installation of GT5000 Pipe Thruster Completed
（5）Prepare for Pullback
Considering the influence of the pipe entry point on the hole and the height of the pipe thruster, the angle of entering the hole and the sag angle of the steel pipe under the action of self-weight, the prefabricated pipe is hoisted with the hanging basket of the crane (pipe crane), and the required angle is raised with the pipe pushing machine to ensure the smooth entry of the pipe into the hole with the designed unearthed angle.
Picture 6: Prepare for Pullback
4. Application Process and Effect
At 02:00 p.m. on May 11,2019, the last landing directional drilling project in the south of Bangladesh single point mooring project began. When pullback to 100 meters, the starting tension of the rig reached 1500 KN, the pipe was not moved, so it was decided to use the GT5000 pipe thruster to help. As the thruster & pullback force of the pipe thrust reaches 1000 KN, the pipe begins to move. Since then, each drill pipe has been towed using a thrust force, the pullback force is between 1000-3500 KN, the distance between 1-3 m at each time At 03:00 p.m. on May 17, 2019, after 145 hours, the total length of 1580 meters was completed to pullback. At this moment, the last landing directional drilling project in the south of Bangladesh single point mooring project was successfully completed.
Picture 7: Pullback Starting
Picture 8: Pullback processing
Picture 9: Pullback Processing
Picture 10: Jobsite - Joyful for pullback successfully
The successful completion of the last landing directional drilling project in the south of Bangladesh single point mooring project has accumulated valuable experience for the complex environment directional crossing project and set up an industry example. It also marks the technological progress of Chinese enterprises in the field of directional drilling of land and sea crossing. Goodeng GT5000 pipe thruster" is an escort , which will be high efficiency, easy to operate and other humanized characteristics for the large directional drilling construction.