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Maintenance management of geological drill pipe after use

发布时间：

2022-04-07

As an important part of the whole drill string, drill pipe is widely used in hydrological surveying, geological drilling, oil and gas exploration and other fields. The quality of drilling tools, the quality of on-site maintenance and utilization, drilling accidents, and construction costs have a significant impact. The following editors of Huanye Machinery only discuss the use of friction welding bits and the maintenance management of construction sites, and discuss their surface knowledge.

At present, there are four kinds of drill pipes in my country's oil and gas industry: E75, X95, G105 and S135 steel grades, the main drill pipe joints are SAE4137H, the drill pipe diameter is 23/8-65/8, and there are many specifications. The higher the steel grade, the higher the strength and the stronger the bearing capacity. But it must be noted that when choosing drill pipe, the higher the strength, the better. In drilling fluid medium, with the increase of steel level, the corrosion fatigue strength of drill pipe will decrease. In order to meet the strength requirements, according to the principle of selecting the lowest horizontal drilling pipe as much as possible, it is recommended that the user select the most suitable drilling pipe according to the site, thereby reducing the procurement cost and the possibility of accidents.

1. Overall structure of friction welded drill pipe

Friction welded drill pipe consists of inner and outer screw joints and drill pipe body. The drill pipe is rotated by a rotary table or power head, which transfers the power to the bottom of the drill bit and transfers the drilling fluid to the cutting surface of the drill bit.

At present, there are two types of friction welding drilling standards produced by most drilling companies in my country: SY/114-24 Oil and Gas Industry Standard of the People's Republic of China and P5P Drilling Pipe Standard introduced by the American Petroleum Institute. These two standards clearly define the parameters and performance of the drilled pipe body, joints, friction weld zone and other components.

2. Use and management of drilling tools on construction sites

Pre-drilling can stop downhole water

Before the drill pipe is used in the well, the female threaded joint should be placed in an effective drill pipe frame, with sufficient piers above and 0.3 meters above to prevent the corrosion of the drill pipe. The drill pipe frame should be kept parallel to the plane to prevent the drill pipe from bending and deforming.

Before drilling in front of the rig, thoroughly clean and inspect the drill pipe joint threads and shoulder sealing surfaces to confirm their serviceability. During the drilling process, the drill pipe joint must be installed with steel wire to prevent the joint thread and abutment from being collided and damaged.

The winch should be held as quickly as possible as the boom goes up the slide. When the drill pipe is removed from the slide rod, the soft rope should be stopped manually to prevent collision.

Use 60% refined metal lead powder or 4060% refined metal zinc powder oil-locking oil drilling tool, clean the joint thread and shoulder sealing surface before the single rod is connected to the wellhead.

Drill pipe usage considerations:

When using a new drill pipe for the first time, it is recommended to make two rotations at the wellhead with a torque slightly lower than the specified value. After confirming that the joint thread and sealing surface are in good condition, press the joint thread and use it in the well. Using this grinding button is beneficial to strengthen the surface hardness of the thread, improve the adhesion of the thread, and prolong the service life of the drill bit.

When the drill pipe is located at the wellhead joint, it must be corrected manually to prevent the normal joint from hitting the end face or thread of the female joint and causing damage, and then manually identify the bolt with chain tongs and tighten the screw with hydraulic pressure.

The drill string should be replaced and unloaded before each derrick, so that the drill string runs up and down during the three drilling processes, so that each drill bit can be checked in time to reduce problems such as rings, buckles, perforation and leakage. At the same time, the position of the upper and lower drilling tools should be changed regularly to change the stress state of the drilling tools, so that the stress of each part of the drilling tools tends to be consistent, thereby improving the service life of the drilling tools and reducing the occurrence of early failure.

During the drilling process, reasonable drilling speed and pressure should be selected according to the formation, diameter and structure of the drilling tool to ensure that the drilling tool works in an ideal working condition and achieves satisfactory drilling efficiency. When the drill pipe speed reaches the critical speed, the vibration frequencies of the three types of drill pipe rotation are consistent with the natural frequency of the drill pipe, which will cause resonance, make the whole drill pipe in a serious unstable state, and bear additional fatigue stress, thereby accelerating the drilling tool. The higher the pressure of the drill bit, the greater the resistance of the drill bit and the fracture of the drill bit.

When the drill pipe is used in a corrosive environment, deoxidizers and corrosion inhibitors can be added to the drilling fluid, and the pH value of the drilling fluid can be increased to more than 10. Choose sulfur-resistant drill pipes, use inner-coated drill pipes, and choose appropriate measures. Such as low-grade drill pipe to reduce the impact of corrosion factors.

When unloading the drill pipe at the wellhead, the low-speed gear should be used first, and the hook spring should maintain a certain tension to maintain the pressure between the two joint threads. When the joint thread is completely disassembled, the upper hook will rise to prevent the upper tube from being pulled, which also prevents the upper tube from colliding with the wellhead joint.

Maintenance management of drill pipe after use

After drilling, the drilling tools are arranged on the drill frame according to different specifications, wall thicknesses, hole sizes, steel grades and grades. Wash the inner and outer surfaces, joint threads and bridge shoulder covers in time with water, and thoroughly clean and dry. Check the drill pipe surface for cracks, scratches, thread integrity, partial wear of joints, flat shoulders, wear, bending bite marks on the pipe body, corrosion, pits and other defects inside and outside the drill pipe. In order to reduce the occurrence of failure accidents such as joint thread breakage and drilling leakage, the drill pipe body should be subjected to ultrasonic test, magnetic particle test and magnetic particle test. Threads and shoulder drills on the rust oil cover are no problem.

The drill pipe should be marked with paint on site and stored separately to prevent misuse. And drill pipe repair, replacement problems, so as not to affect the later construction. For long-term use of outdoor drill pipes, use rain-proof and waterproof covers, regularly check the corrosion of the inner and outer surfaces of the drill pipes, and do a good job of moisture-proof and anti-corrosion.