Tubing for mining

Tubing is used to extract minerals using drilling rigs. They can also be used to create compact small artesian wells. They may differ in length, wall thickness, material, and so on. Preservation, storage and transportation of these parts must be carried out in accordance with the GOST standard. This will increase the shelf life of the products, making them more durable and reliable. But why do we need tubing? How much does a standard tubing pipe weigh according to GOST? And how to properly store these parts in a warehouse? These issues will be discussed in the article.

Operating principle of drilling rigs

To understand the purpose of tubing, you need to know the principle of operation of drilling rigs. Drilling rigs are used to extract water, gas and oil, which are located deep underground. They differ from each other in many parameters - operating principle, design, performance characteristics and others. Typically, a drilling rig consists of three elements - an aboveground platform, a drill string and a power system. The installation may also include additional elements - a controlling pneumatic drive, a drill cooling system, warning sensors, and so on.

Drilling technology

1. At the preparatory stage, geologists conduct exploration and outline the proposed drilling location. Then the drilling platform is mounted and a test run of the installation is performed. During the test, the following parameters are checked: the quality of the joints of parts with each other, the level of vibration, and the level of load on the electric motor.
2. If everything is fine with the platform, a well is drilled. For drilling, a drill string is used, which is connected to an electric motor. At the end of the column there is a sharp tip-chisel, which destroys hard rocks.
3. During operation, the drill string rotates along its axis, which leads to the formation of a well. At the same time, the waste soil is supplied to the surface. Modern rigs are equipped with a system for supplying protective chemicals, which minimizes the risk of damage to the drill string.
4. After creating a well, it is necessary to fix it. To solve this problem, two technologies can be used. In the first case, an additional pipe is installed in the well, which creates a gap between the column and the pipe itself. Soft mixtures are poured into this gap and quickly harden. In practice, this method is rarely used. In the second case, a casing pipeline is installed in the well, which has thick walls and can withstand any load.
5. After strengthening the well, pipes are inserted into the casing to pump out minerals or water. Tubing can be used as such a pipe. Before they are introduced into the well, they are secured using well couplings, which turn the individual tubing pipes into a single compression string. To extract minerals, an electric motor is started, which pumps oil or gas from the well to the surface. On the drilling platform, minerals are packed into containers (barrels, tanks, vats).

Please note that tubing can be used in other scenarios. A simple example: a pipeline can be configured not to suck in liquids, but to spray them. This technology allows for the injection of liquids, which can be useful in some areas of human activity. Examples - well repair, geological exploration, local increase in pressure, creation of additional inflows to the main well.

Installation

The algorithm for using tubing is as follows. They are inserted into the drilled well, after the casing (fixed) pipes are inserted and also fixed with cement. For this, as well as for securing, packers are used. Products are divided into types depending on what kind of fluid needs to be pumped out. They can be used for completing: oil, bitumen, or gas wells; they are used for injection wells. If it is necessary to produce in one well from different horizons, pipe strings are installed. When designing them, it is important to consider that they must be quickly and safely installed, and also reinstalled if necessary. Today, developers are striving to equip wells with products that can perform various functions without complete removal/replacement.

Manufacturing and heat treatment process

Functions

All tubing is considered according to certain parameters: • supply of optimal flow and its highest surface pressure; • does the product withstand the entire period of well operation for corrosion resistance; • susceptibility to erosion on this term; • indicators of how well the tubing can withstand the loads that stimulation work leads to; • how great is the strength under an action such as tension.

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GOST requirements

The tubing pipe is used to transport liquid and gaseous substances from wells to the surface. In technical terms, they are ordinary seamless pipes. According to GOST, they must have the following properties:

• High strength. During operation of the production platform, liquids and gases will flow through the pipeline under pressure. It is necessary that the pipeline installation retains its strength and does not crack. Even small leaks or cracks will lead to complete depressurization of the installation, which can lead to failure of the entire platform.
• Tensile resistance. Most modern wells are not completely straight. This is caused by various reasons: shortcomings in drilling, changes in the shape of the well due to the movement of the earth, and so on. It is important that the pipes retain their shape and do not crack when bent. In case of low tensile strength, the column may leak, which will lead to the destruction of the system.
• Density, tightness. The material from which the pipeline is made must be dense and airtight. This factor is especially critical for the ends of the installation that will be threaded. If the material is plastic, the thread will be of poor quality. Because of this, the tightness of the seams will be compromised, which can lead to depressurization of the system.
• Corrosion resistance. A large amount of liquid or steam will flow through the pipeline while the drilling rig is operating. This can cause rust to form, causing the pipe string to fail. For the manufacture of tubing, high-carbon steel is used, which contains chromium-based alloying additives. This component prevents the formation of rust and also stimulates the formation of a protective oxide film on the metal surface. Thanks to this, the installation does not crack or rust while the tower is in operation.

Operation

There are a number of rules that must be followed when operating tubing. 1. They should not be dropped to the ground during loading and unloading. You need to use a crane. 2. Pipe trucks are an essential element of their transportation. Dragging or bending in such a way that they sag or bend is prohibited. 3. Before laying the pipes on the site, you need to place wooden blocks under them. Safety rings for pipes must be screwed on if they are placed on threaded parts. 4. Before lifting via bridges, it is necessary to determine the condition of the product. To do this, a template is passed through it, having a diameter several millimeters less (two or three) than the internal diameter of the part. The length of the template is 5-10 cm. Before it comes out, the lower end of the product is held. 5. It is imperative to go over the threads of the coupling and nipple with a metal brush before starting screwing, and treat the threads with lubricant. 6. It is unacceptable to hit the coupling with a sledgehammer.

Dimensions, weights and tolerances of unset tubing couplings

Functions, features of tubing

The main functions of pumping and compression pipelines are the extraction of liquids and gases from wells, maintaining reservoir pressure, and major workover of wells. The starting material is usually steel with a medium or high carbon content. Other materials can also be used - plastic, aluminum, copper + various alloys. Such pipeline systems will have low strength, so tubing made from these materials is used only in the case of small wells (dacha plots, small artesian wells). For mining, pipes are attached to each other to form a single column.

The following technologies are used to connect individual elements to each other:

• Threaded connection. This technology is applicable only if the ends of the pipes have threads (applied at the factory). To connect two separate parts, a tubing coupling is used, which has an internal thread. To connect, the ends of the pipelines are cleaned using polishing tools. Then the tubing coupling is screwed onto one pipe (half the thread). After this, the second tubing pipe is also screwed into the coupling. If necessary, additional adjustments are made to the parts to ensure a tight connection.
• Welding or soldering. This technology is used if the ends of the pipes do not have threads (or their quality is low). To connect, the parts are placed close to each other - then they are connected using a welding machine. Any welding method can be used - automatic, semi-automatic, electric arc method and others. The main difficulty in welding is that the piping parts are usually made of steel. Therefore, the ends will have to be heated to high temperatures, which complicates the technical procedure. In practice, welding technology is rarely used due to its complexity.

Tubing pipe weight

The weight of the tubing pipe depends on three parameters - overall diameter, wall thickness and typical length. Compression tubing tubing73-5.5 and tubing tubing89-7 are popular - the numbers indicate the cross-sectional diameter and wall thickness. Long, thick-walled pipes have a lot of weight, while short, thin parts will have little weight.

How to properly operate tubing

When using tubing pipes, not only the requirements for their characteristics, but also the conditions for their transportation, storage and installation must be strictly observed. There are a number of generally accepted rules here.

• In the event that pipes need to be stored for some time before use, a special area should be prepared for this. Thus, pumping and compression pipes cannot be stored on the ground - they must be laid on wooden blocks and ensure that the products do not sag under their own weight.

Tubing storage

• To transport tubing pipes, you must use only specially designed transport (pipe trucks). Under no circumstances should tubing pipes be transported by dragging.
• In the event that it is necessary to unscrew a stubborn coupling from a tubing pipe, the threaded connection must not be subjected to shock loads. To do this, you can use special liquids or thoroughly clean the threaded connection from dirt.
• When transporting and storing pipes, their threaded ends should be protected using special safety rings.

Even when removing already used pipes from the well, they should be handled very carefully and stored on pre-laid wooden blocks.

Features of operation and storage

Let's consider some features of the operation and storage of tubing:

• Using lubricant. Before installing the tubing string, it is necessary to lubricate the end of the tubing with a protective lubricant. The type of lubricant depends on the nature of the well, the type of casing and the category of metal from which the pipeline is made. The lubricant must be applied carefully in accordance with the dosage rules. A lack of lubrication or its excess negatively affects the strength of the structure and also complicates its installation.
• Welding protective environment. Soldering should be carried out in a protective environment (argon). If shielding gas is not used, there is a risk that the metal edges of the part will be damaged during welding. This seriously increases the likelihood of corrosion, which will lead to deformation and cracking of the pump string.
• Removing a pipe from the system. In case of prolonged downtime of the drilling platform, it is necessary to dismantle the tubing. After all, the edges of the pipe are in constant contact with the liquid medium, which can lead to corrosion. After dismantling, it is necessary to rinse the installation and lubricate it with protective lubricant. Check for damage, cracks, and corroded areas.

Tubing pipes can be stored in any cool, dry place. It is better to pack them in special blocks made of wood, plastic and metal. It is best to store such units in a warehouse with good ventilation. In accordance with GOST rules, each spare part must be marked. It should contain all the important data about the part - markings, type, brief information about the manufacturer, information about the workers responsible for its production in the workshop. Blocks with pipes can be transported in any convenient way (using trucks or trains, planes, water transport, and so on). In the event of a sale at the request of the buyer, control procedures must be performed to prove that the parts are in proper condition.

Kinds

There are two types of pump and compressor products according to GOST 633-80, which are produced with significant differences in the structure of the ends: they can be made smooth, or with external threads. If the ends are set outward, this allows a device such as a coupling to be screwed onto the part. The lubricant that is applied to the thread acts as a sealant and anti-corrosion coating.

Characteristics of strength groups of tubing pipes

Decryption

The marking, located approximately half a meter from the edge of the product, contains information about its diameter, what strength group the steel belongs to, its thickness, the product mark, and the date of manufacture. Smooth products and couplings provided for them are made from steel belonging to strength groups K, E, L, M. Threaded parts are made from steel of the following groups: D, K, E, L, M. The length of the products produced ranges from 6 to 10.5 m. Sometimes pipes are made whose length reaches 11.5 m. The diameter of the tubing is in the ratio with the parameters of their walls: • thickness 0.3 cm d -27 mm; • thickness 0.35 cm - d - 33 and 42 mm; • thickness 0.4 cm - d - 48 mm; • thickness 0.5 cm d - 60 mm; • thickness 0.67 and 0.7 cm - d -73 mm; • thickness 0.8 cm - d - 89 mm; • thickness 0.65 cm - d - 102 mm; • thickness 0.7 cm - d - 114 mm.

steel grade

Coupled tubing has a number of varieties, depending on what cross-section they have, the presence of threads, the properties of what they are made of, etc. For both types of pipes, according to the criterion of the structure of the ends, smooth and coupling, the tightness of the connection is guaranteed at a pressure of up to 50 MPa. This is achieved thanks to the seal (for smooth ones). By means of a trapezoidal thread, both types are connected. It is necessary to note certain advantages of products made from alloys containing aluminum. They are less susceptible to corrosion, and their low weight contributes to higher specific strength values ​​than steel ones. Often, pump and compressor parts are coated with a special protective layer. This helps prevent corrosion and deposits. The choice of this product prolongs the maintenance-free operation of the column. To cover the inner surface, enamel, varnish, resin are used, glass coating is the most popular option.

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Production technology

Tubing pipes are made in several stages:

1. Manufacturing of standard type pipes. After smelting the metal, a hollow semi-finished product is formed, which ends up in the pipe-rolling shop. Here, a full-fledged part is formed from a blank using the cold or hot rolling method. At the end, the part is hardened and cooled (if necessary). If the spare part will be stored in the workshop for some time, then intermediate marking will be applied to it in accordance with GOST rules.
2. Preparatory work. Now the finished pipeline part enters the production workshop. Here the spare part is degreased and then cleaned. Grinding equipment is used for cleaning; manual processing is rarely used due to its low efficiency.
3. Threading on one end. After treatment, control ultrasonic flaw detection is performed. If everything is fine with the spare part, a thread is applied to one of its edges using special tools. Immediately after applying the thread, repeated flaw detection is carried out, which makes it possible to determine the quality of the thread. If all is well, a tubing coupling is mounted on the end of the part. Then the installation is cleaned with water.
4. Threading the second end. Now the worker uses tools to apply threads to the other end of the part. Then he performs control flaw detection, and the check is performed twice, since a protective coupling will not be mounted on this end. If everything is fine with the spare part, a protective casing-protector is screwed onto the thread.

At the end, final processing, packaging, and transportation are performed. Upon completion of all work, the finished spare part is washed and checked for defects, damage, and scratches. Control weighing is also carried out and GOST markings are applied. If all is well, the spare part undergoes a preservation procedure. Finally, it is packed into metal, plastic or wooden blocks for storage in a warehouse.