Общие проблемы и решения сверхдлинного траверса направленного бурения

1. What are the common problems in the construction of ultra-long-distance horizontal directional drilling through pipelines?
(1) Steering construction: The main problem is that the instability of the drill pipe is difficult to control and the drilling trajectory is difficult to measure in real time.
(2) During the reaming construction: there are dangers such as “holding the pole” и “collapsed hole”.
(3) When the pipeline is towed back: there are problems such as easy damage and deformation of the pipeline due to the excessive drag force of the drilling rig; and the foundation of the drilling rig may slip and become unstable when it is towed back.
(4) Mud ratio problem: Mud is blood that traverses horizontally. During long-distance construction, the stratum that the drill pipe passes through will include clay, Ила, high-hard rock, Гравий, Ила, sand and so on. Поэтому, the mud is required to have good rheology to ensure a strong ability to carry drill cuttings; to have a low friction coefficient to ensure good lubrication performance; to have a strong wall protection function, which can form mud with a certain mechanical strength on the hole wall It can maintain the stability of the hole wall and prevent the leakage of mud.
2. Answers to the above questions:
(1) Steering construction: In the face of ultra-long-distance horizontal directional drilling construction, the international advanced pilot hole double drilling rig synchronous docking construction technology is adopted; at the excavation point and the earth entry point, the double drilling rigs work synchronously and coordinated to solve the problem of long distance. Problems such as instability and insufficient strength of the drill pipe in the construction of passing through the pilot hole.
(2) Reaming construction: One drilling rig is installed at the entry and exit points, one provides torque, and the other provides tension, which avoids the problem of out-of-control of the reamer caused by the excessively long drill pipe, and reduces the risk of reaming construction. Increase hole reaming speed.
Hole cleaning: After each round of hole reaming construction, a reeling cage should be used for hole cleaning. If a satisfactory effect cannot be achieved with one hole cleaning, 2 Кому 3 hole cleaning should be performed to thoroughly clean out the gravel and debris in the hole. impurities.
(3) Back-hauling construction: В “два по одному” construction method is adopted to reduce the frictional resistance during the back-hauling process, and solve the construction problems such as excessive drilling rig thrust and easy damage to the pipeline in the back-hauling of long-distance pipelines.
(4) Slurry process:
1. Mud ratio in the guiding stage:
(1) The inclined hole section of the pilot hole: In order to ensure the carrying of drilling cuttings and the cleaning of the hole, control the water loss of the mud, and prevent the hole from collapsing, it is necessary to increase the content of the solidifying agent and the tackifier.
(2) Horizontal hole section of pilot hole: increase the content of chip remover and lubricant, appropriately reduce viscosity and shear force, ensure good rheological properties of the mud, make the drilling cuttings return to the ground smoothly, enhance the lubricity of the mud, and reduce the drilling rig Rotation and propulsion resistance.
2. Mud ratio in the hole expansion stage: In the hole expansion section, in order to enhance the wall-building performance of the mud and prevent the hole wall from collapsing and shrinking in diameter, it is necessary to increase the content of wall solidifying agent and tackifier.
3. Mud ratio in the dragging stage: to improve the lubricity of the mud, reduce the frictional resistance, and enhance the chip carrying effect, it is necessary to increase the content of chip remover and lubricant.
The viscosity control of the mud should be based on the stratum conditions of the crossing section. Во время строительства, the special mud that meets the requirements, high quality and high performance must be prepared according to the actual stratum conditions.