Associated gas. Petroleum gas
Any oil field being developed today is a source of not only black gold, but also numerous by-products that require timely disposal. Modern requirements requirements for the level of environmental friendliness of production force operators to invent more and more effective methods by-product processing oil gas. In the last few years, this resource has been processed and is widely used along with.
Associated petroleum gas, or APG for short, is a substance found in oil fields. It is formed above the main reservoir and in its thickness as a result of a decrease in pressure to levels below the oil saturation pressure. Its concentration depends on how deep the oil lies and varies from 5 m 3 to top layer up to several thousand m3 in the lower.
As a rule, when opening a reservoir, oil workers come across a so-called gaseous “cap”. Hydrocarbon gases exist independently and are present in the oil itself in liquid form, being separated from it during refining. The gas itself consists primarily of methane and heavier hydrocarbons. Its chemical composition depends on external factors, such as the geography of the formation.
Main types
The value of associated petroleum gas and the prospects for its further utilization are determined by the proportion of hydrocarbons in its composition. Thus, the substance released from the “cap” is called free gas, since it consists mainly of light methane. As you dive deeper into the formation, its amount noticeably decreases, giving way to other, heavier hydrocarbon gases.
Conventionally, associated petroleum gas is divided into several groups depending on how “hydrocarbon” it is:
- pure, containing 95–100% hydrocarbons;
- hydrocarbon with an admixture of carbon dioxide (from 4 to 20%);
- hydrocarbon with an admixture of nitrogen (from 3 to 15%);
- hydrocarbon-nitrogen, in which nitrogen makes up up to 50% of the volume.
The fundamental difference between associated petroleum gas and natural gas is the presence of vaporous components, high-molecular liquids and substances not included in the hydrocarbon group:
- hydrogen sulfide;
- argon;
- carbon dioxide;
- nitrogen;
- helium, etc.
Methods for processing associated petroleum gas
Back in the middle of the last century, APG, inevitably obtained during the oil production process, was almost completely burned in flares. Processing this by-product was considered so unprofitable that negative consequences Its burning did not receive due attention from the public for a long time. However, the concentration of combustion products in the atmosphere entailed a significant deterioration in public health, which posed a difficult task for the chemical industry: processing APG and its practical use. There are several most popular methods for utilizing associated petroleum gas.
Fractional method
This method of APG processing involves separating gas into components. As a result of the process, dry purified gases and a wide fraction of light hydrocarbons are obtained: these and other products are very popular on the world market. A significant drawback of this scheme is the need for end users via pipeline. Since LPG, PBT and NGL are heavier than air, they tend to accumulate in low areas and form explosive clouds that, if exploded, can cause significant destruction.
Associated petroleum gas is often used to increase oil recovery in fields through its reinjection into the reservoir - this increases the pressure, and 10 thousand tons more oil can be produced from one well. This method of using gas is considered expensive, so it is not widely used in the Russian Federation and is used mainly in Europe. The main advantage of the method is its low cost: the company only needs to purchase necessary equipment. At the same time, such measures do not utilize APG, but only delay the problem for some time.
Installation of power units
Another significant area of exploitation associated gas– is the provision of energy to power plants. Subject to the required composition of raw materials, the method differs high efficiency and is very popular in the market.
The range of installations is wide: companies have launched the production of both gas turbine and piston power units. These devices make it possible to ensure full operation of the station with the ability reuse heat generated in production.
Similar technologies are being actively introduced into the petrochemical industry, as companies strive to become independent from RAO electricity supplies. However, the feasibility and high profitability of the scheme can only be determined by the close location of the power plant to the field, since the costs of APG transportation will exceed the potential cost savings. For the safe operation of the system, the gas needs to be pre-dried and cleaned.
The method is based on a cryogenic compression process using a single-flow refrigeration cycle. Liquefaction of prepared APG occurs through its interaction with nitrogen under artificially created conditions.
The potential of the method under consideration depends on a number of conditions:
- installation performance;
- source gas pressure;
- gas supply;
- content of heavy hydrocarbons, ethane and sulfur compounds, etc.
The scheme will be most effective if cryogenic complexes are installed at distribution stations.
Membrane cleaning
One of the most promising this moment technologies. The principle of operation of the method is the different speed at which the components of the associated gas pass through special membranes. With the advent of hollow fiber materials, the method acquired many advantages over traditional methods of purification and filtration of APG.
The purified gas is liquefied and then goes through a separation procedure in two industrial segments: to produce fuel or petrochemical feedstock. The process typically produces stripped gas, which is easily transported, and natural gas liquids, which are sent to plants for the production of rubber, plastics and fuel additives.
Scope of application of APG
APG, as mentioned above, is an excellent alternative to traditional energy sources for power plants, which is highly environmentally friendly and allows enterprises to save significant money. Another area is petrochemical production. If you have the finances, it is possible to expose the gas deep processing with the subsequent isolation from it of substances that are in wide demand and play important role both in industry and in everyday life.
In addition to being used as an energy source in power plants and for production in the petrochemical industry, associated petroleum gas is also used as a feedstock for the production of synthetic fuels (GTL). This technology is just beginning to take off and is projected to become quite cost-effective if fuel prices continue to rise.
To date, 2 large projects have been implemented abroad and 15 more are planned. Despite the seemingly enormous prospects, the scheme has not yet been tested in tough conditions. climatic conditions, for example, in Yakutia, and with little probability it can be implemented in similar regions without any significant changes. In other words, even in a good situation in Russia this technology will not be widespread in all regions.
One of the most modern methods effective industrial use of associated gas is called “gas lift”. This technology makes it possible to easily regulate the operating mode of a well, simplify its maintenance and successfully extract oil from fields with a high gas factor. The disadvantage of the technology is that the listed advantages significantly increase capital expenditures on technical equipment wells.
The scope of application of processed APG should be determined by the size of the field from which it was obtained. Thus, it is appropriate to use gas from small wells locally as fuel without spending money on its transportation, while raw materials on a larger scale can be processed and used in industrial enterprises.
Environmental hazard
The relevance of the issue of utilization and applied use of associated gas is associated with the negative effect that it has if it is simply flared. With this method, industry not only loses valuable raw materials, but also pollutes the atmosphere with harmful substances that enhance Greenhouse effect. Toxins and carbon dioxide harm both the environment and to the local population, increasing the risk of developing serious illnesses, including oncological ones.
The main obstacle to the active development of infrastructure that would deal with the purification and processing of associated petroleum gas is the discrepancy between the amount of tax on gas flared and the costs of it effective application. Majority oil companies prefer to pay a fine rather than allocate a significant budget to enterprises protecting environment, which will pay off only after a few years.
Despite the difficulties associated with APG transportation and purification, further improvement of technologies proper disposal this raw material will solve ecological problems many regions and will become the basis for an entire industry on a national scale, the cost of which in the Russian Federation, according to the most conservative estimates of experts, will be about $15 billion.
OIL AND GAS, THEIR COMPOSITION AND PHYSICAL PROPERTIES
OIL
Oil is a flammable, oily liquid, mostly dark in color, with a specific odor. In terms of chemical composition, oil is mainly a mixture of various hydrocarbons contained in it in a wide variety of combinations and determining its physical and chemical properties.
Found in oils the following groups hydrocarbons: 1) methane (paraffin) with general formula S I N 2I + 2; 2) naphthenic with the general formula C„H 2P; 3) aromatic with a general formula
SpN 2l -v- /
Most common in natural conditions hydrocarbons of the methane series. Hydrocarbons of this series - methane CH 4, ethane C 2 H in, propane C 3 H 8 and butane C 4 Nu - at atmospheric pressure and normal temperature are in a gaseous state. They are part of petroleum gases. As pressure and temperature increase, these light hydrocarbons can partially or completely liquefy.
Pentane C 8 H 12, hexane C in H 14 and heptane C 7 H 1 in under the same conditions are in an unstable state: they easily pass from a gaseous state to a liquid state and back.
Hydrocarbons from C 8 H 18 to C 17 H sound are liquid substances.
Hydrocarbons with molecules containing more than 17 carbon atoms are classified as solids. These are paraffins and ceresins, contained in varying quantities in all oils.
The physical properties of oils and petroleum gases, as well as their qualitative characteristics, depend on the predominance of individual hydrocarbons or their various groups. Oils with a predominance of complex hydrocarbons (heavy oils) contain smaller amounts of gasoline and oil fractions. Content in oil
V, M-ANT V
large quantity resinous and paraffin compounds makes it viscous and inactive, which requires special measures to extract it to the surface and subsequent transportation.
In addition, oils are divided according to the main quality indicators - the content of light gasoline, kerosene and oil fractions.
The fractional composition of oils is determined by laboratory distillation, which is based on the fact that each hydrocarbon included in its composition has its own specific boiling point.
Light hydrocarbons have low points boiling. For example, pentane (C B H1a) has a boiling point of 36 ° C, and hexane (C 6 H1 4) has a boiling point of 69 ° C. Heavy hydrocarbons have higher boiling points and reach 300 ° C and higher. Therefore, when oil is heated, its lighter fractions boil and evaporate first; as the temperature rises, heavier hydrocarbons begin to boil and evaporate.
If the vapors of oil heated to a certain temperature are collected and cooled, then these vapors will again turn into a liquid, which is a group of hydrocarbons that boil away from oil in a given temperature range. Thus, depending on the heating temperature of the oil, the lightest fractions - gasoline fractions - evaporate from it first, then the heavier ones - kerosene, then diesel fuel, etc.
The percentage of individual fractions in oil that boil away in certain temperature ranges characterizes the fractional composition of the oil.
Typically, in laboratory conditions, oil distillation is carried out in temperature ranges up to 100, 150, 200, 250, 300 and 350 ° C.
The simplest processing oil is based on the same principle as the described laboratory distillation. This is the direct distillation of oil with the separation of gasoline, kerosene and diesel fractions from it under atmospheric pressure and heating to 300-350 ° C.
In the USSR there are various oils chemical composition and properties. Even oils from the same field can differ greatly from each other. However, the oils of each region of the USSR also have their own specific features. For example, oils from the Ural-Volga region usually contain significant amounts of resins, paraffin and sulfur compounds. Oils from the Embensky region are distinguished by relatively low sulfur content.
The greatest variety of composition and physical properties possess oil from the Baku region. Here, along with colorless oils in the upper horizons of the Surakhani field, consisting almost exclusively of gasoline and kerosene fractions, there are oils that do not contain gasoline fractions. In this area there are oils that do not contain tarry substances, as well as highly tarry ones. Many oils in Azerbaijan contain naphthenic acids. Most oils do not contain paraffins. In terms of sulfur content, all Baku oils are classified as low-sulfur.
One of the main indicators of the commercial quality of oil is its density. The density of oil at a standard temperature of 20° C and atmospheric pressure ranges from 700 (gas condensate) to 980 and even 1000 kg/m 3 .
In field practice, the density of crude oil is used to roughly judge its quality. Light oils with a density of up to 880 kg/m 3 are the most valuable; they tend to contain more gasoline and oil fractions.
The density of oils is usually measured with special hydrometers. A hydrometer is a glass tube with a widened lower part in which a mercury thermometer is placed. Due to the significant weight of mercury, the hydrometer takes a vertical position when immersed in oil. In the upper narrow part of the hydrometer there is a scale for measuring density, and in the lower part there is a temperature scale.
To determine the density of oil, a hydrometer is lowered into a vessel with this oil and the value of its density is measured along the upper edge of the formed meniscus.
In order to bring the resulting measurement of oil density at a given temperature to standard conditions, i.e., to a temperature of 20 ° C, it is necessary to introduce a temperature correction, which is taken into account by the following formula:
р2о = Р* + в(<-20), (1)
where p 20 is the desired density at 20° C; p/ - density at measurement temperature I; A- coefficient of volumetric expansion of oil, the value of which is taken from special tables; she
Occupies associated petroleum gas. Previously, this resource was not used in any way. But now the attitude towards this valuable natural resource has changed.
What is associated petroleum gas
This is a hydrocarbon gas that is released from wells and from reservoir oil during the process of its separation. It is a mixture of vaporous hydrocarbon and non-hydrocarbon components of natural origin.
Its amount in oil can vary: from one cubic meter to several thousand in one ton.
According to the specifics of production, associated petroleum gas is considered a by-product of oil production. This is where its name comes from. Due to the lack of necessary infrastructure for gas collection, transportation and processing, large quantities of this natural resource are lost. For this reason, most of the associated gas is simply flared.
Gas composition
Associated petroleum gas consists of methane and heavier hydrocarbons - ethane, butane, propane, etc. The composition of gas in different oil fields may vary slightly. In some regions, associated gas may contain non-hydrocarbon components - compounds of nitrogen, sulfur, and oxygen.
Associated gas, which gushes out after opening oil reservoirs, is characterized by a smaller amount of heavy hydrocarbon gases. The “heavier” part of the gas is found in the oil itself. Therefore, at the initial stages of oil field development, as a rule, a lot of associated gas with a high methane content is produced. During the exploitation of deposits, these indicators gradually decrease, and most of the gas consists of heavy components.
Natural and associated petroleum gas: what is the difference
Associated gas contains less methane than natural gas, but has a large number of its homologues, including pentane and hexane. Another important difference is the combination of structural components in different fields in which associated petroleum gas is produced. The composition of APG can even change at different periods in the same field. For comparison: the quantitative combination of components is always constant. Therefore, APG can be used for various purposes, and natural gas is used only as an energy raw material.
Obtaining APG
Associated gas is obtained by separating it from oil. For this purpose, multi-stage separators with different pressures are used. Thus, at the first stage of separation a pressure of 16 to 30 bar is created. At all subsequent stages, the pressure is gradually reduced. At the last stage of production, the parameter is reduced to 1.5-4 bar. The APG temperature and pressure values are determined by the separation technology.
The gas obtained in the first stage is immediately sent to the gas. Great difficulties arise when using gas with a pressure below 5 bar. Previously, such APG was always flared, but recently the gas utilization policy has changed. The government began to develop incentive measures to reduce environmental pollution. Thus, at the state level in 2009, an APG flaring rate was established, which should not exceed 5% of the total associated gas production.
Application of APG in industry
Previously, APG was not used in any way and was burned immediately after extraction. Now scientists have seen the value of this natural resource and are looking for ways to use it effectively.
Associated petroleum gas, the composition of which is a mixture of propanes, butanes and heavier hydrocarbons, is a valuable raw material for the energy and chemical industries. APG has a calorific value. So, during combustion it emits from 9 to 15 thousand kcal/cubic meter. It is not used in its original form. Cleaning is required.
In the chemical industry, plastics and rubber are made from methane and ethane contained in associated gas. Heavier hydrocarbon components are used as raw materials for the production of high-octane fuel additives, aromatic hydrocarbons and liquefied petroleum gases.
In Russia, more than 80% of the volume of associated gas produced comes from five oil and gas producing companies: OJSC NK Rosneft, OJSC Gazprom Neft, OJSC Neftyanaya OJSC TNK-BP Holding, OJSC Surgutneftegaz. According to official According to data, the country annually produces more than 50 billion cubic meters of APG, of which 26% is processed, 47% is used for industrial purposes, and the remaining 27% is flared.
There are situations in which it is not always profitable to use associated petroleum gas. The use of this resource often depends on the size of the deposit. Thus, it is advisable to use gas produced from small fields to provide electricity to local consumers. In medium-sized fields, it is most economical to extract liquefied petroleum gas at a gas processing plant and sell it to the chemical industry. The best option for large fields is to produce electricity at a large power plant and then sell it.
Harm from burning APG
Burning associated gas pollutes the environment. There is thermal destruction around the torch, which affects the soil within a radius of 10-25 meters and vegetation within a radius of 50-150 meters. During the combustion process, nitrogen and carbon oxides, sulfur dioxide, and unburned hydrocarbons are released into the atmosphere. Scientists have calculated that as a result of burning APG, about 0.5 million tons of soot are released per year.
Also, gas combustion products are very dangerous to human health. According to statistical data, in the main oil refining region of Russia - the Tyumen region - the incidence of the population for many types of diseases is higher than the average for the entire country. Residents of the region especially often suffer from pathologies of the respiratory organs. There is a tendency to increase the number of neoplasms, diseases of the sensory organs and nervous system.
In addition, PNH cause pathologies that appear only after some time. These include the following:
- infertility;
- miscarriage;
- hereditary diseases;
- weakened immunity;
- oncological diseases.
APG utilization technologies
The main problem of oil gas utilization is the high concentration of heavy hydrocarbons. The modern oil and gas industry uses several effective technologies that make it possible to improve gas quality by removing heavy hydrocarbons:
- Gas fractionation separation.
- Adsorption technology.
- Low temperature separation.
- Membrane technology.
Ways to utilize associated gas
There are many methods, but only a few are used in practice. The main method is to utilize APG by separating it into components. This processing process produces dry stripped gas, which is essentially the same natural gas, and a wide fraction of light hydrocarbons (NGL). This mixture can be used as a feedstock for petrochemicals.
Petroleum gas separation occurs in low-temperature absorption and condensation units. Once the process is complete, the dry gas is transported through gas pipelines, and the NGL is sent to refineries for further processing.
The second effective way to process APG is the recycling process. This method involves injecting gas back into the formation to increase pressure. This solution allows increasing the volume of oil extraction from the reservoir.
In addition, associated petroleum gas can be used to generate electricity. This will allow oil companies to significantly save money, since there will be no need to purchase electricity from outside.
Unlike natural gas, associated petroleum gas contains, in addition to methane and ethane, a large proportion of propanes, butanes and vapors of heavier hydrocarbons. Many associated gases, depending on the field, also contain non-hydrocarbon components: hydrogen sulfide and mercaptans, carbon dioxide, nitrogen, helium and argon.
When oil reservoirs are opened, gas from the oil caps usually begins to gush out first. Subsequently, the main part of the produced associated gas consists of gases dissolved in oil. Gas from gas caps, or free gas, is “lighter” in composition (with a lower content of heavy hydrocarbon gases) in contrast to gas dissolved in oil. Thus, the initial stages of field development are usually characterized by large annual production volumes of associated petroleum gas with a larger proportion of methane in its composition. With long-term exploitation of the field, the production of associated petroleum gas is reduced, and a large share of the gas falls on heavy components.
Injection into the subsoil to increase reservoir pressure and, thereby, the efficiency of oil production. However, in Russia, unlike a number of foreign countries, this method, with rare exceptions, is not used, because it is a highly costly process.
Use locally to generate electricity for the needs of oil fields.
When significant and stable volumes of associated petroleum gas are released - use as fuel at large power plants, or for further processing.
The most effective way to utilize associated petroleum gas is its processing at gas processing plants to produce dry stripped gas (DSG), wide fraction of light hydrocarbons (NGL), liquefied gases (LPG) and stable gas gasoline (SGG).
A large consulting company in the fuel and energy sector, PFC Energy, in its study “Utilization of Associated Petroleum Gas in Russia,” noted that the optimal option for using APG depends on the size of the field. Thus, for small fields, the most attractive option is to generate electricity on a small scale for their own field needs and the needs of other local consumers.
For medium-sized fields, according to researchers, the most economically feasible option for associated petroleum gas utilization is the extraction of liquefied petroleum gas at a gas processing plant and the sale of liquefied petroleum gas (LPG) or petrochemical products and dry gas.
For large fields, the most attractive option is to generate electricity at a large power plant for subsequent wholesale sale to the power grid.
According to experts, solving the problem of associated gas utilization is not only an issue of ecology and resource conservation, it is also a potential national project worth 10-15 billion dollars. Only the utilization of APG volumes would make it possible to annually produce up to 5-6 million tons of liquid hydrocarbons, 3-4 billion cubic meters of ethane, 15-20 billion cubic meters of dry gas or 60-70 thousand GWh of electricity.
Russian President Dmitry Medvedev instructed the Russian government to take measures to end the practice of irrational use of associated gas by February 1, 2010.
First of all, let's find out what is meant by the term “associated petroleum gas” or APG. How does it differ from traditional extracted hydrocarbons and what features does it have?
Already from the name itself it is clear that APG is directly related to oil production. This is a mixture of gases, either dissolved in the oil itself, or located in the so-called “caps” of hydrocarbon deposits.
Compound
Associated petroleum gas, unlike traditional natural gas, in addition to methane and ethane, contains a significant amount of heavier hydrocarbons, such as propane, butane, and so on.
An analysis of 13 different fields showed that the percentage composition of APG is as follows:
- methane: 66.85-92.37%,
- ethane: 1.76-14.04%,
- propane: 0.77-12.06%,
- isobutane: 0.02-2.65%,
- n-butane: 0.02-5.37%,
- pentane: 0.00-1.77%,
- hexane and higher: 0.00-0.74%,
- carbon dioxide: 0.10-2.77%,
- nitrogen: 0.50-2.00%.
One ton of oil, depending on the location of a particular oil field, contains from one to several thousand cubic meters of associated gas.
Receipt
APG is a by-product of oil production. When the next formation is opened, the first thing that happens is that the associated gas located in the “cap” begins to flow. It is usually “lighter” than dissolved directly in oil. Thus, at first, the percentage of methane contained in APG is quite high. Over time, with further development of the field, its share decreases, but the percentage of heavy hydrocarbons increases.
Methods for utilization and processing of associated gases
It is known that APG has a high calorific value, the level of which is in the range of 9-15 thousand Kcal/m 3 . Thus, it can be effectively used in the energy sector, and the large percentage of heavy hydrocarbons makes the gas a valuable raw material in the chemical industry. In particular, plastics, rubber, high-octane fuel additives, aromatic hydrocarbons, and so on can be made from APG. However, two factors hinder the successful use of associated petroleum gas in the economy. Firstly, this is the instability of its composition and the presence of a large number of impurities, and secondly, the need for significant costs for its “drying”. The fact is that oil gases have a moisture content level of 100%.
APG combustion
Due to the difficulties of processing, for a long time the main method of utilizing petroleum gas was its banal combustion at the production site. This barbaric method leads not only to the irreversible loss of valuable hydrocarbon raw materials and wasted energy of combustible components, but also to serious consequences for the environment. This includes thermal pollution, the release of huge amounts of dust and soot, and contamination of the atmosphere with toxic substances. If in other countries there are huge fines for this method of utilizing oil gas, making it economically unprofitable, then in Russia things are much worse. In remote fields, the cost of APG production is 200-250 rubles/thousand. m 3 and transportation costs up to 400 rubles/thousand. m 3, it can be sold for a maximum of 500 rubles, which makes any method of processing unprofitable.
Injecting APG into the reservoir
Since associated gas is produced in close proximity to an oil field, it can be used as a tool to increase reservoir recovery. To do this, APG and various working fluids are injected into the reservoir. Based on the results of practical measurements, it turned out that additional production from each site is 5-10 thousand tons per year. This method of gas utilization is still preferable to combustion. In addition, there are modern developments to increase its effectiveness.
Fractional processing of associated petroleum gas (APG)
The introduction of this technology makes it possible to achieve increased profitability and production efficiency. Commercial products obtained as a result of processing hydrocarbon raw materials are: gas gasoline, stable condensate, propane-butane fraction, aromatic hydrocarbons and much more. In order to optimize costs, processing plants are mainly built in large gas and oil fields, and in small fields, thanks to scientific and technological progress, modular compact equipment for processing raw materials is used.
APG purification
APG processing begins with its purification. Cleaning from mechanical impurities, carbon dioxide and hydrogen sulfide is carried out to improve the quality of the product. First, the APG is cooled, while all impurities are condensed in towers, cyclones, electric precipitators, foam and other devices. Then there is a drying process in which the moisture is absorbed by solid or liquid substances. This process is considered mandatory, since excess moisture significantly increases transportation costs and makes it difficult to use the final product.
Let's look at the most common APG purification methods used today.
- Separation methods. These are the simplest technologies used exclusively for the release of condensate after gas compression and cooling. The methods can be used in any environment and have low waste levels
- However, the quality of the resulting APG, especially at low pressures, is low. Carbon dioxide and sulfur compounds are not removed.
- Gas-dynamic methods. Based on the processes of converting the potential energy of a high-pressure gas mixture into sonic and supersonic flows. The equipment used is low cost and easy to operate. At low pressures, the effectiveness of the methods is low; sulfur compounds and CO 2 are also not removed.
- Sorption methods. They allow drying of gas using both water and hydrocarbons. In addition, it is possible to remove small concentrations of hydrogen sulfide. On the other hand, sorption purification methods are poorly adapted to field conditions, and gas losses amount to up to 30%.
- Glycol drying. Used as the most effective way to remove moisture from gas. This method is in demand as a complement to other cleaning methods, since it does not remove anything other than water. Gas losses are less than 3%.
- Desulfurization. Another highly specialized set of methods aimed at removing sulfur compounds from APG
- For this purpose, amine washing, alkaline cleaning technologies, the Serox process, and so on are used. The disadvantage is 100% humidity of the APG at the outlet.
- Membrane technology. This is the most effective method for purifying APG. Its principle is based on different rates of passage of individual elements of the gas mixture through the membrane. The output is two streams, one of which is enriched with easily penetrating components, and the other with difficult-to-penetrate components. Previously, the selective and strength characteristics of traditional membranes were not enough to purify APG. However, today new hollow fiber membranes have appeared on the market that are capable of working with gases that have a high concentration of heavy hydrocarbons and sulfur compounds. Specialists from NPK Grasys conducted tests at various sites for several years and came to the conclusion that this technology based on a new membrane can significantly reduce the costs of APG purification. Accordingly, it has serious prospects in the market.
APG analysis
Whether fractional utilization of associated petroleum gas is cost-effective can be determined after a thorough analysis at the enterprise is carried out. Modern equipment and innovative technologies open up new vistas and limitless possibilities for this method. Processing of APG makes it possible to obtain “dry” gas, which is close in composition to natural gas and can be used in industrial or municipal enterprises.
The studies have confirmed that stopping the flaring of associated petroleum gas will lead to the fact that with the help of modern processing equipment it will be possible to obtain an additional about 20 million cubic meters of dry gas per year.
Use of APG in the operation of small energy facilities
Another obvious way to utilize such gas is to use it as fuel for power plants. The efficiency of APG in this case can reach 80% or higher. Of course, for this, power units must be located as close as possible to the field. Today there is a huge number of turbine and piston units on the market that can operate on APG. An additional bonus is the ability to use exhaust gas to organize a heat supply system for field facilities. In addition, it can be injected into the reservoir to enhance oil recovery. It should be noted that this method of APG utilization is already widely used in Russia today. In particular, oil and gas companies are building gas turbine power plants at their remote fields, which can generate more than a billion kilowatt-hours of electricity per year.
“Gas-to-liquids” technology (chemical processing of APG into fuel)
All over the world, this technology is developing at a rapid pace. Unfortunately, its implementation in Russia is significantly complicated. The fact is that such a method is profitable only in hot or temperate latitudes, and in our country gas and oil production is carried out mainly in the northern regions, in particular in Yakutia. Adapting the technology to our climatic conditions requires serious research work.