Equipment for gas-lift operation of wells

2024 Author: Howard Calhoun | [email protected]. Last modified: 2023-12-17 10:16

Gas-lift production of oil and gas resources can be considered as a more progressive alternative to the traditional method of flowing well development. It is distinguished by elements of passive extraction of target materials, which is facilitated by the energy of the gas. This feature of gas-lift operation of wells determines the specifics of the technical organization of the production process, which is directly reflected in the characteristics of the equipment used.

Principles of production in gas lift wells

The technology involves the lifting of formation water or oil from the channel due to excess pressure in the well, which is created by gases. At the same time, it is also necessary to connect active mixtures - in particular, associated gas compressed by a compressor. In some deposits, air under natural pressure also acts as an active agent. Compressor is optional. His introduction to technologythe process largely depends on the requirements for production volumes and the capacity of the equipment used. In any case, the main functional principle of the gas-lift method of well operation is to ensure the process of gassing the liquid resource. The pressure in the well will decrease as gasification increases, so artificial (compressor) compression of the mixture may be required to increase the pressure. The volume of inflow on the surface directly depends on the current parameters of the gas lift, which can be adjusted by the working equipment.

Differences from the operation of flowing wells

By and large, gas lift is the same flowing production method, but with an additional flow stimulator. Active gas is directed from the surface along the wellbore to the shoe, where the enrichment effect occurs, reducing the effort required to lift the resource. Obviously, such a solution needs to connect additional capacities - including the function of pumping equipment. Moreover, in some configurations, the arrangement of a separate gas supply channel is also required. But there are also fundamental factors under which it becomes impossible to operate a well in a flowing way. The gas-lift method of production is a non- alternative replacement for the flowing method in the following cases:

• When liquid temperature is high.
• When the gas content of the extracted resource is high.
• If there is sand in the face.
• In the presence of s alt deposits and paraffin.

In other words, everything thatcomplicates the operation of pumping equipment during well maintenance, to varying degrees determines the need for additional stimulation of the rise of the liquid resource.

Technology for the use of gas-air mixtures

Introducing air into the well with liquid contributes to the formation of a stable emulsion, but this is not enough for subsequent operations with the resource. Typically, surfactants are added in combination to heat and maintain the sludge. During the separation process, already on the surface after removing the solution, conditions are created to prevent a fire, since gas-air emulsions are highly flammable. As for the gas component, hydrocarbon mixtures are most often used. This decision is justified from the economic and technological points of view. The fact is that gas-lift operation of wells with hydrocarbon inclusions requires fewer resources to ensure the processes of stratification and separation. At the surface, the enriched liquid itself separates into conditioned clean oil and gas, which is explained by the insignificant content of oxygen in the composition. The spent hydrocarbon is subsequently collected in a special reserve and disposed of. Depending on the quality of this gas, it can be used to produce unstable gasoline.

Design of equipment used

The infrastructural basis of well operation is formed by annulus equipment, directly pipes and pumps. This system providesthe possibility of fluid flow inside the barrel and its further rise. The column of liquid being lifted is regulated by shut-off valves with valves at several levels. By controlling this equipment, the operator can reduce or increase the power of the flow, depending on the current parameters of the gasification of the resource, which naturally affect the lifting intensity. During the operation of flowing and gas-lift wells, equipment for measuring performance indicators can also be used. In particular, pressure gauges are used to determine pressure and multifunctional devices to record hydrostatic and temperature indicators. To a greater extent, the presence of these devices is dictated by security considerations, but knowledge of the pressure value is necessary as a factor in the regulatory process. In systems with automatic control, pressure gauges can influence the change in the parameters of the flow movement without the participation of the operator. Such a scheme is used in the conditions of high-tech industrial development of deposits, where production records are also mandatory.

Preparing equipment for work

Pipes and valves with associated equipment are allowed to work process, which, in principle, are capable of operating under design pressure conditions. For example, according to the results of the preliminary calculation, valves undergo special tests on stands, where the accuracy of their operation and resistance to mechanical loads are evaluated. All technological equipment is subjected to hydraulic tests with loads in which a gas-lift well will be operated with specificcharacteristics. At this stage of preparation, the main parameter of the test is the tightness of the equipment.

Organization of the operational process

After successful testing, the equipment is sent to the well. On the flange of the column head, the crosspiece of the mounting fittings is fixed. Further, the following components of the technical infrastructure are immersed in the trunk:

• Packer with nipple.
• Nipple directly.
• Downhole camera (complete with valves).
• Isolating valves.

At the final stage, ground fittings with pressure testing equipment and equipment for gas separation and removal are being installed. After connecting the pump, the gas-lift well is put into operation, followed by the supply of a working agent. From this moment, constant monitoring of the state of the valves and pressure in the well chambers begins. When the liquid rises to the first working valve, the equipment is automatically transferred to the steady production mode.

Downhole camera and its varieties

This functional device is a welded structure containing a nipple, a shirt, guide elements and a pocket. It is based on an oval pipe with a window to which a pocket is welded. In the same part, there are also guides for overflow. The nipple, which is located inside the upper end of the jacket, is designed to fix the direction of the gas lift pocket with a valve. ATin the gas-lift well operation system, the chamber takes place under the tubing - it is pointwise positioned under the current liquid level. In practice, cameras of different types are used, which differ in their design, installation method and the presence of additional regulatory equipment.

Downhole camera operation

Before entering into the working process, the camera is inspected and checked for tightness of the inlets. In some configurations, this device is pre-docked with well pipes through threaded connections. To supply gas through the chamber, special branch pipes with valves are connected to the side openings on the body. During the operation of equipment for gas-lift wells, by means of installed nozzles and bellows, the oil resource is aerated already at the bottomhole level to the required coefficient. As the liquid rises, the rate of gas supply can be changed by adjusting the position of the valves. In the event of an accident or after a complete cessation of oil gasification, a blind plug is mounted in the pockets of the chamber.

Gas lift valve arrangement

In this case, the valve acts as a central control link that provides the function of regulating the process of liquid enrichment with gas. The design of this element is quite simple - its basis is formed by a combination of a stem-seat and a fastener. In the gas-lift method of operating oil wells, a check valve can also be used. Thisthe modification contains in the design a housing and a shut-off tip designed to completely stop the flow. Unlike a plug, a check valve does not change its position and, depending on current needs, can be opened to reverse the flow of fluid.

The principle of operation of gas lift valves

In the normal state, the valve keeps the outlet openings of the chamber, constantly being under pressure of a gas-liquid mixture of a certain value. As the bellows load rises to the set value, the valve automatically opens. It releases the mass of the working agent into the liquid, maintaining this mode until the load again drops to the intended level. Also, the function of the valves during the operation of gas-lift oil wells can be regulated by the pressure of the injection gas from the back side. In such a system, an unbalanced scheme of controlled shut-off valves is used.

Conclusion

Using the traditional method of producing flowing wells is considered the best solution in most field development cases. Its technical organization does not require the connection of complex equipment, but in the conditions of systematic production at large deposits, this system is irrational. In turn, production in gas-lift wells with periodic operation demonstrates technical and economic efficiency in fields where there is a decrease in production rate at a level of less than 50 tons per day. The justification for using this method is due toa more advanced system for regulating production by controlling the intensity of resource recovery. The ability to control flows requires large technical and energy investments, but even with increased organizational costs, gas lift wells turn out to be more efficient.