The development of gas fields is associated with features and a number of requirements for the organization of the process. The reservoir pressure available at the time of development of the field is enough to transport gas from the well to the main preparation unit and gas pipeline without the use of compressor equipment. However, reservoir pressure gradually decreases during the production process, as a result of which there may be a lack of pressure to supply gas to the gas pipeline. For this reason, field development, from a technological point of view, is divided into two stages - uncompressed and compressor. They differ in the use of a compressor unit, which allows to increase the pressure of the produced gas. Such equipment is called booster compressor stations. I use them to solve the following problems:
- Low pressure gas production.
- Compression of associated and petroleum gas for the purpose of further transportation.
- Maintaining a specific gas outlet pressure.
- Blowing, cleaning and crimping pipelines.
Compressor Applications
An important component of field development is the compressor phase. The selection of 50-60% of the total gas supply is carried out during the uncompressed stage, while the compressor mode allows the extraction of additional 20-30% of the total reserves. The equipment used to prepare the gas is designed to work under a certain pressure, under which gas will be subsequently supplied to the main gas pipeline. When the pressure of natural gas drops, the booster compressor ensures its stability by increasing the pressure by the required amount. Due to this, booster stations are considered the most important equipment for gas production.
Booster compressors, or boosters, are installed not only in wells, but also in underground gas storages, where they are used to take gas from the store and then supply it to the gas pipeline under the necessary pressure. The reverse procedure - the selection of gas and its injection into the storage - is carried out by the same compressor station. The equipment must develop a high outlet pressure, otherwise the volume intended for storage will be used irrationally. In underground storages created in solid rocks, gas can be stored at a pressure of from 0.8 to 1 MPa.
Design and principle of operation
Booster compressors may vary in configuration and design, however, they distinguish several basic elements:
- Drive unit.
- Compressor unit
- Optional equipment.
For the increase in gas pressure, the main component of the booster compressor is responsible - the compressor or a group of compressors. It is driven by a drive connected to it. Ancillary equipment means any devices that ensure the correct operation of the station - cooling systems, oil circulation, instrumentation kit and others. The station, represented by a separate module, can be equipped with lighting, heating, ventilation systems and others.
Classification
The key element of the booster compressor stations is the compressor unit, which provides the movement and injection of gas. The classification of stations is carried out depending on the type of compressor used:
Piston compressors
Booster piston compressors are classified as volumetric. The principle of their work is based on reducing the volume of the working chamber created by the cylinder and the movable piston, and in which the gas is compressed. The advantages of such models are a simple design, which facilitates repair and maintenance, reliability and simplicity. In comparison with analogues, reciprocating compressors develop a high gas pressure. The flip side of such advantages is the unevenness of the gas flow caused by a cyclical change in the volume of the working chamber, which is associated with reciprocating piston operation. In addition, such compressors are subjected to vibrational loads and are noisier. Booster stations equipped with reciprocating compressors have similar features. They are easy to operate, affordable, and can compress gas to high pressures. Compact models can be placed on the receiver, while large ones require dimensional and stable platforms.
Screw compressors
A screw booster compressor is also ranked as a volumetric model, however, its working chambers are formed by cutting off the necessary space with screws and a compressor casing interlocked with each other. Unlike reciprocating compressors, they develop high pressure and do not require the creation of a multi-stage gas compression system. Screw DCSs are more complex and expensive in comparison with similar compressors, but at the same time simple and reliable in operation with strict observance of all standards of service and work. The compact size and minimum noise level allow the use of screw gas booster compressors in mobile stations, but at the same time they are also installed in large compressor stations at high-tech enterprises, since they create an even gas flow without pulsations characteristic of reciprocating compressor stations.
Centrifugal compressor
The gas pressure in a centrifugal oxygen booster compressor is increased by giving kinetic energy to its flow, which subsequently transforms into potential pressure energy. Kinetic energy is transmitted from the rotating impeller blades, while its conversion occurs in the diffuser, at the outlet of the compressor. This method of gas compression is called dynamic. Unlike screw and reciprocating compressors, centrifugal compressors do not create such a high pressure, as a result of which they are made multi-stage in order to achieve the necessary compression value. But at the same time, such booster nitrogen and gas compressors and similar stations provide a large gas flow rate, which makes them most in demand in gas producing fields, enterprises and in other places where large volumes of gas are required. Gas injection by a centrifugal compressor occurs evenly, which greatly facilitates its pumping.
Drive Type Classification
The type of fuel used to operate booster compressors depends on the type of drive used in compressor stations. The possibility of fuel supply is crucial, since such equipment is often installed in hard-to-reach places and at a distance from transport routes. The following types of drives are most commonly used:
- Gas engine.
- Gas turbine.
- Electric.
Gas engine drive
The gas-engine drive is based on an internal combustion engine using gaseous fuel - one of the cheapest and most affordable energy sources. Such models are unpretentious in operation and reliable. The drive is started using compressed air, and the change in gas supplied to the cylinders allows you to adjust the speed.
Gas turbine drive
The generation of mechanical energy in a gas turbine drive takes place using a turbine in which the hot gas generated in the combustion chamber expands. The compressor sucks in air, which is why the gas turbine drive requires the installation of a separate source of energy - the starter. The combustion chamber, compressor and turbine are the main structural components of a gas turbine device. This type of drive is in demand, because it does not need third-party fuel and runs on gas pumped by the booster station. Excesses of generated energy can be used for power supply and heating of both the station itself and nearby facilities.
Electric drive
Booster compressor stations equipped with electric drives have certain advantages over gas-turbine and gas-engine counterparts, despite the need for power supply. The use of electricity allows you to save pumped fuel and improves the environmental friendliness of the stations by reducing emissions of harmful substances into the atmosphere. Adjustment and automation of the electric motor is much easier, which greatly simplifies the maintenance and control of the entire station and reduces the number of working personnel. Elimination of vibration, noise and dustiness of the air increases working conditions at similar booster compressor stations.