Installations of preliminary water discharge upsv. Description of the process flow diagram of a booster pumping station (BPS) What is upsv in the oil industry
The term "UPSV"
UPSV is symbol installation of preliminary water discharge. The preliminary water discharge unit is used to separate associated gas and produced water from oil. Also, this unit carries out oil heating and an increase in the specific energy of the produced oil flow up to the next treatment system. The increase in specific energy is also called booster. The preliminary water discharge unit consists of the following elements - a separation unit, a pumping unit, a tank farm. They are usually located at the locations of booster pumping stations. In this case, the already existing units of the station are used, only the technological scheme is being processed. At the field, such an object is called a booster pumping station with a preliminary water discharge unit. On the device, the liquid successively passes through several stages of separation or demulsification. Different reagents can be added to the liquid at different stages. Associated gas from the separation stages goes to the gas drying unit, and then to the consumer or to the plant. The liquid without gas is heated in heating furnaces and then goes to the demulsifier, where the oil-water emulsion is destroyed. Gravitational sedimentation of oil and subsequent separate withdrawal of oil and water is also carried out there. Then the oil goes to the last stage of separation. From there, the liquid enters the tank farm and mechanical impurities are separated from it. After that, the preliminary discharge of water and its supply to the reservoir pressure maintenance system is carried out. This function uses a bush pumping station or modular station... At the pumping station, formation water is prepared, as well as control of the flow rate of water that goes to the reservoir pressure maintenance system. Water from the stations goes to the water distribution batteries and then to the injection stations. After that, the oil goes to the next stages of its preparation and processing. These operations are carried out at oil treatment plants, and only then at a delivery point or a plant.The most common are the following types of preliminary water discharge installations:
- reservoir type with settling;
- with hardware dehydration;
- with combined dehydration.
Basic technological scheme
Basic technological scheme of the installation
The principle of operation of the DNS.
Oil from the group metering units enters the buffer tanks, is separated, then fed to the intake of working pumps and then to the oil pipeline. The separated gas under pressure enters the field gas collecting manifold through the pressure control unit. Through the gas-collecting manifold, gas is supplied to a gas compressor station or to a natural gas compression unit (CGTU). Gas consumption is measured with a chamber diaphragm installed on the common gas line. The oil level in the buffer tanks is maintained using a float level gauge and an electric valve located on the pressure oil pipeline. When the maximum permissible liquid level in the NGS is exceeded, the level gauge sensor transmits a signal to the control device of the electric drive valve, it opens, and the level in the NGS decreases. When the level drops below the minimum permissible, the electric drive valve closes, thereby ensuring an increase in the liquid level in the oil and gas mixture. For uniform distribution of oil and pressure, the buffer tanks are interconnected by a bypass line.
Each CSN must have a process flow diagram and work procedure approved by the technical manager of the enterprise. According to these regulatory documents control over the operation mode of the CSN is carried out.
preliminary water discharge (UPSV)
The preliminary water discharge unit resembles a simplified diagram of an oil treatment unit. The fundamental difference lies in the absence of equipment for the final oil dehydration up to GOST 51858-2002.
Oil separation and preliminary water discharge are carried out at the WWTP. Associated petroleum gas from the field is used for the needs of boiler houses and is supplied to the gas processing plant.
The fluid produced at the field is pre-dehydrated at the PWDU. After the separators, it enters the parallel working sedimentation tanks, where the emulsion is stratified. Then partially dehydrated oil enters the final separation unit (KSU), where gas is taken at a lower pressure, and then goes to the OTU or CPF for final oil treatment. The treated water is sent to a cluster pumping station, where it is pumped into the reservoir to maintain reservoir pressure.
b) separation of gas from liquid with preliminary gas sampling and final degassing;
Preliminary oil dehydration should mainly be carried out in apparatuses for the combined preparation of oil and water.
The discharge of formation water from the devices for preliminary dehydration of oil should be provided under residual pressure, which ensures their supply to the intake of pumping stations of the waterflooding system or, if necessary, to sewage treatment plant without installing additional pumping stations.
In fig. 10 shows one of the options for the basic process flow diagram of the UPSV installation.
Rice. 10. Schematic flow diagram of the installation
preliminary water discharge (PRWS):
Streams: I - reservoir oil; II - demulsifier; III - associated petroleum gas; IV - oil after the first stage of separation; V - formation water; VI - oil captured from the water settler; VII - mechanical impurities, sludge; VIII - formation water purified from mechanical impurities and oil; IX - oil at the CPF; X - gas to the torch; XI - water to the cluster pumping station;
Equipment: 1 - separator of the first separation stage; 2 - depulsator compensator; 3 - drop catcher (gas separator); 4 - tubular furnace; 5 - separator; 6 - sump for oil dehydration; 7 - buffer tank; 8 - formation water settler; 9 - degasser; 10, 11 - pumps; 12 - associated petroleum gas metering unit; 13 - oil metering unit; 14 - formation water metering unit
Oil at the UPSV comes from an automated group metering unit (AGZU), mixes with a demulsifier and enters separator 1, where the first stage of oil separation is performed. As a rule, a separator with preliminary gas sampling is installed at the first stage; it has a depulsator-compensator 2 and an external drop catcher (gas separator) 3.
Further, the oil goes directly to the settling tank 6 for dehydration. For heavy and viscous paraffinic oils, before the settler 6, heating in the furnace 4 with additional separation (or without it) in the separator 5 can be provided. If necessary, a pump can be installed in front of the furnace 4 (not shown in the diagram). In the settler 6, oil is dehydrated. Oil from the settler 6 enters the buffer tank 7 of the pump 10, which, through the oil metering unit 13, feeds it to the CPF.
If the formation water separated in the sedimentation tank 6 does not meet the requirements for its injection into the reservoir, the water is purified. To do this, first in the sump 8, formation water is freed from mechanical impurities, sludge and carried away oil droplets. The captured oil from the settling tank 8 is mixed with the main oil flow before the tank 7.
Further, the produced water enters the degasser 9 to remove hydrogen sulfide and residual hydrocarbon gases, which are discharged into the flare. Prepared formation water is then pumped 11 through the water metering unit 14 to the cluster pumping station (SPS) for injection into the reservoir.
With a high productivity of the UPSV unit, water purification in tanks of the RVS type can be provided. In some cases, the degasser is placed as part of the SPS.
In the UPSV scheme, devices such as NGVRP, Heater-Treater from Sivalls (USA), etc. can be used.
a booster pumping station with a preliminary water discharge unit (BPS with PWDU)
The technological complex of the booster pump station with a water recovery unit includes:
1) the first stage of oil separation;
2) preliminary water discharge;
3) heating of well production;
4) transportation of gas-saturated oil to the CPF;
5) compressorless transport of petroleum gas to the GPP;
6) transportation of treated formation water to the reservoir pressure maintenance system;
7) injection of chemicals (inhibitors, reagents - demulsifiers) according to the recommendations of research organizations.
Objects of preliminary separation of well production should be considered as an integral part of a single technological complex of facilities for the collection, transport, treatment of oil, gas and water.
Oil separation and preliminary water discharge are carried out at the booster pump station with a water treatment plant (see Fig. 11). Associated petroleum gas from the field is used for the needs of boiler houses and is supplied to the gas processing plant.
As already mentioned, the liquid produced at the field undergoes preliminary dehydration at a water recovery unit with a booster pump station. After the separators, it enters the parallel working sedimentation tanks, where the emulsion is stratified. Then partially dehydrated oil goes to the OTF and CPF for final oil treatment. The treated water is sent to a cluster pumping station, where it is pumped into the reservoir to maintain reservoir pressure.
The technological scheme of the process should provide:
a) preparation of oil emulsion for stratification before entering the "settling" apparatus;
b) separation of gas from liquid with preliminary gas sampling;
c) preliminary dehydration of oil to a water content of no more than 5 - 10% (wt.).
To prepare the oil emulsion for stratification, it is necessary to supply a reagent - a demulsifier at the end sections of the oil and gas gathering (before the first stage of oil separation), and if there are appropriate recommendations of research organizations - the supply of water returned from oil treatment units.
Rice. 11. Schematic diagram of a booster pumping station with a preliminary water discharge unit (BPS with PWDU).
Equipment: C-1; S-2 - oil and gas separators (NGS), GS - gas separators; OG - horizontal sump; H-1, H-2 - centrifugal pumps.
Streams: GVD at the GPP - gas high pressure for a complex gas treatment unit; LPG - low pressure gas
The process of preliminary oil dehydration should be provided with a water cut of the incoming well production of at least 15-20% and should be carried out, as a rule, without additional heating of the well production using demulsifiers, which are highly effective at moderate and low temperatures of the preliminary oil dehydration process.
Preliminary oil dehydration should mainly be carried out in apparatuses for the combined preparation of oil and water. At the same time, the discharged formation water must have a quality that, as a rule, ensures their injection into the productive horizons without additional purification (only water degassing is provided).
The discharge of formation water from the devices for preliminary dehydration of oil should be provided under residual pressure, which ensures their supply to the intake of pumping stations of the waterflooding system or, if necessary, to treatment facilities without installing additional pumps.
The oil treatment unit is designed for dehydration and degassing of oil to parameters that meet the requirements of GOST R 51858-2002.
The oil treatment unit is located at the CPF. Depending on the physical and chemical properties oil, water cut of oil, remoteness of the CPF from the fields, the presence or absence of preliminary treatment at the booster pump station, the schemes of the OTP may differ significantly from each other. So, if the oil has not undergone preliminary dehydration at the booster pump station and its water cut is at least 20 ... 30%, then in the OTP scheme it is necessary to provide for a preliminary dehydration block.
In fig. 12 shows a schematic diagram of the OTP installation, which includes different possible options preparation.
Consider a variant of the OTP circuit with a preliminary dehydration unit (top row of devices).
Pre-dehydration unit. Oil is mixed with a demulsifier, a corrosion inhibitor and enters the separator 1 of the first separation stage with preliminary gas sampling, which has a depulsator-compensator 2 and an external droplet separator (gas separator) 3. In case of high salinity, water can be supplied to the oil in front of the separator 1 from apparatuses 12, 13 or 14 for flushing oil and dissolving salt crystals. Further, the oil enters the settler 6 for preliminary dehydration. For heavy and viscous paraffinic oils in front of the settler 6, heating in the furnace 4 with additional separation (or without it) in the separator 5 can be provided.
Fig. 12. Schematic diagram of an oil treatment unit (OTP):
Streams: I - oil from booster pump station or from AGZU; II - demulsifier; III - associated petroleum gas; IV - oil after the first stage of separation; V - formation water; VI - oil from the preliminary dehydration unit; VII - water from the second stage of electric dehydration; VIII - commercial oil;
Equipment: 1 - separator; 2 - depulsator compensator; 3 - remote drop catcher (gas separator); 4.10 - tube furnaces; 5,11,15 - separators; 6,7,12 - sedimentation tanks; 8 - buffer tank; 9.17 - pumps; 13.14 - electric dehydrators; 16 - reservoir; 18 - node for recording the quantity and quality of oil
Highly watered (with a water content of 70% and more) heavy and high-viscosity oils must undergo preliminary dehydration in two stages - in sedimentation tanks 6 and 7. In this case, the first stage of dehydration in sedimentation tank 6 is best done at natural temperature without heating in order to discharge the bulk of the water. At the second stage of dehydration in the sump 7, it is possible to use heating in a furnace (not shown in the diagram) or to use devices of the NGVRP or Heater-Treater type instead of the sump. Instead of settling tanks 6 and 7 for heavy oils, tanks of the RVS type can also be used.
The quality of discharged water from sedimentation tanks 6 and 7 must meet the requirements for injection into the reservoir.
The process of preliminary oil dehydration is designed to significantly reduce energy consumption when heating formation water in the oil treatment unit (in furnace 10).
Oil preparation block. Into this block (bottom row of devices) oil can be supplied either from the block of preliminary oil dehydration, or from the IWUU, or directly from the AGSU (at low water cut).
Oil treatment can be carried out in two versions: with and without a feed pump. If the oil pressure at the block inlet is at least 0.6 MPa, then pump 9 can be omitted (and buffer tank 8 too). Without pump 9, the saturated vapor pressure (VVP) of commercial oil is always lower than in the scheme with a pump, but in this case, the associated petroleum gas will contain more heavy hydrocarbons (from propane and above).
Oil pump 9 (or under its own pressure) enters the furnace 10 for heating, then into the separator 11, the sump 12, the electric dehydrator 13 (or two electric dehydrators 13 and 14) and the final separator 15 (KSU). Then the commercial oil enters the reservoir 16, from where it is pumped 17 to the metering unit for the quantity and quality of oil 18.
If the electrical dehydration is performed in one stage in the electrical dehydrator 13, then before it it is necessary to supply deaerated water for oil washing in an amount of 3 ... 5% for oil and, if necessary, a demulsifier (not shown in the diagram). If two stages of electrical dehydration are used, then water from the second stage (from apparatus 14) must be supplied to flush oil before the first stage (in front of apparatus 13). If the oil is slightly mineralized, then fresh water can be skipped.
For low-mineralized formation waters and low-emulsion oils in the oil treatment block one of four options for the minimum set of apparatus of the scheme can be implemented:
1) furnace 10 - sump 12 - separator 15 - reservoir 16 - pump 17;
2) furnace 10 - separator 11 - sump 12 - separator 15 - reservoir 16 - pump 17;
3) furnace 10 - separator 11 - electric dehydrator 13 - separator 15 - reservoir 16 - pump 17;
4) furnace 10 - electric dehydrator 13 - separator 15 - reservoir 16 - pump 17.
For highly emulsion oils of medium and high density the following sequence of devices is required: furnace 10 - sump 12 - electric dehydrator 13 - separator 15 - reservoir 16 - pump 17. The first stage of dehydration in this case must be thermochemical, the second - electric.
For heavy and very heavy oils preparation should take place in two electrical stages: furnace 10 - electric dehydrator 13 - electric dehydrator 14 - separator 15 - reservoir 16 - pump 17.
This kind installations of the collection and treatment system is the final stage in the path of the produced product from the well to the treated and refined oil intended for further processing.
Federal Agency for Education
State educational institution of higher professional education
"Tyumen State Oil and Gas University"
CALCULATION OF TECHNOLOGICAL
COLLECTION SYSTEM INSTALLATION
AND WELL PREPARATION
PRODUCTS
AllowedEducational and methodological association of universities
Russian Federation for oil and gas education
educational institutions studying in the specialty 130503
"Development and operation of oil and gas fields"
areas of training of specialists 130500 "Oil and Gas Business",
on the proposal of the Academic Council of GOU VPO "Tyumen
State Oil and Gas University "
BBK 33.131ya73
Doctor of Technical Sciences, Professor
candidate of physical and mathematical sciences, associate professor
Leontiev, S. A. |
|
Calculation of technological units for the collection and preparation of well products [Text]: tutorial /,. - Tyumen: TyumGNGU, 2010 .-- 116 p. |
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The textbook provides methods for calculating technological processes for collecting and preparing well products, provides general information about gathering systems for oil wells, provides designs, principles for the rational operation of equipment and installations that take place in a sealed system for collecting and preparing well products at fields in Western Siberia. The manual can be useful for scientific, technical, engineering workers, full-time and part-time students studying the processes of field gathering and preparation of well products in the fields. |
BBK 33.131ya73
Introduction ……………………………………… .. …………………. ………. 5
1. Description of process flow diagrams for collection and preparation of well products ... ... ... .... …… 6
1.1. General information about the collection and preparation system of well products ..................... 6
1.2. Description of the process flow diagram of the booster pumping station (BPS) …………………………………. ……… .. ………. eight
1.3. Description of the process flow diagram of a booster pumping station with a preliminary water discharge unit (BPS with UPSV) ... 10
1.4. Description of the basic technological scheme of the installation
preliminary water discharge (PWDU) …………………………. ……… 12
1.5. Description of the process flow diagram of the oil treatment unit (OTP) ………………………………………. ……… .... 13
2. Description of the equipment used in the collection and preparation of well products 17
2.1. Capacitive equipment 17
2.1.1. Vertical and horizontal containers. 17
2.1.2. Equipment for separation of well products 25
2.1.3. Sediments 30
2.1.4. Electric dehydrators .. 32
2.2. Heating equipment used in the installation
new developments in the field preparation of well products 34
2.2.1. Tubular furnaces. 34
2.2.2. Travel heater PP-1.6 / 1.6-1 ................... 37
2.2.3. Oil and gas water separator with direct heating (NGVRP) 38
2.3. Transfer equipment 50
2.3.1. Centrifugal pump CNS 105 * 294 50
3. An example of the calculation of installations used in the field for the collection and preparation of well products 52
3.1.1. Material balance of the first separation stage 52
3.1.2. Material balance of the second stage 57
3.1.3. General material balance of the installation 62
3.2. An example of calculating the material balance of a booster pumping station with a preliminary water discharge unit (BPS with PWDU) 63
3.2.1. Material balance of the first separation stage 63
3.2.2. Material balance of the second stage with water discharge 68
3.2.3. Calculation of the material balance of water discharge 73
3.2.4. Total material balance of the installation 75
3.3. An example of calculating the material balance of a preliminary water discharge unit (PWDU) 75
3.3.1. Material balance of the first separation stage 76
3.3.2. Material balance of water collection unit 81
3.3.3. Material balance of the second stage of separation 83
3.3.4. Overall material balance of the installation 87
3.4. An example of calculating the material balance of an oil treatment unit (OTP) 88
3.4.1. Material balance of the first separation stage 88
3.4.2. Sludge block 94
3.4.3. Block of electric dehydrators 95
3.4.4. Material balance of the second stage of separation 97
3.4.5. Overall material balance of the installation 102
Application
Application
Application
References 115
Introduction
Technological processes for the collection and preparation of hydrocarbon raw materials consist in a sequential change in the state of the production of an oil well and its individual components (oil and gas), resulting in the receipt of marketable products. The technological process after the separation of the well production consists of oil and gas material flows.
The main technological units that make up the collection and preparation system are:
Booster pumping station (BPS);
Booster pumping station with a preliminary water discharge unit (BPS with UPSV);
Preliminary water discharge unit (UPSV);
Oil treatment unit (OTP), which is part of the CPF.
V last years the number of new technological processes used to collect and prepare well products has increased. Correspondingly, the equipment was created for the implementation of these processes.
Well-known physical and chemical phenomena are widely used in the operating principles of the developed equipment.
One of the most important conditions for the normal operation of sealed transport systems is the high-quality preparation of well products in the fields in accordance with the requirements of GOST R.
The purpose of the tutorial is to help in calculating the material balances of the main technological installations for coursework, diploma and design works, a description of the technological installations and equipment used on them.
1. Description of the basic process flow diagrams for the collection and preparation of the borehole
products
1.1. General information about the collection system
and preparation of well products
The system for collecting and treating oil, gas and water at an oil field must ensure:
1) automatic measurement of oil, gas and water for each well;
2) sealed collection of oil, gas and water along the entire route from wells to the main oil pipeline;
3) bringing oil, gas and formation water at technological units up to the norms of marketable products (Table 1.1), automatic accounting of these products and their transfer to transport organizations;
4) the possibility of putting into operation a part of the field with full utilization of petroleum gas before the completion of the construction of the entire complex of structures;
5) reliability of operation of technological installations and the possibility of their complete automation;
6) manufacturing of the main units of the oil and gas gathering system and equipment of technological units in an industrial way in block and modular design with full automation of the technological process.
Table 1.1
Regulatory data on oil quality
in accordance with the requirements of GOST R
Index | Oil group |
||
Maximum water content,%, no more | |||
Maximum content of chloride salts, mg / l, no more | |||
Maximum content of mechanical impurities,%, no more | |||
Maximum saturated vapor pressure (VVP) at a temperature of 37.8 ° C, kPa, no more | |||
Mass fraction of organic chlorides, ppm (ppm) | |||
Mass fraction of hydrogen sulfide, mln-1 (ppm), no more | |||
Mass fraction of methyl - and ethyl mercaptans in the amount, mln-1 (ppm), no more |
In this case, the discharged formation water must have the qualities determined by the standards of the values presented in table. 1.2.
Table 1.2
Requirements for water quality for injection into the OST reservoir
Reservoir permeability, 10-6 m2 | Specific formation fracturing | Permissible content in water, mg / l |
|
mechanical impurities | |||
6.5 to 2 incl. | |||
35 to 3.6 incl. | |||
Rice. 1.1. Diagram of a sealed two-pipe high-pressure oil, gas and water gathering system:
1 - production wells; 2 - flow lines; 3 - AGZU "Sputnik";
6 - oil treatment unit (OTP); 7 - automated measuring unit of commercial oil; 8 - cluster pumping station (SPS); 9 - injection wells; 10 - collector of commercial oil; 11 - a fleet of commodity tanks; 12 - head pumping station; 13 - main oil pipeline; 14 - collecting gas pipeline; 15 - natural gas compression unit (UKPG); 16 - booster pumping station (BPS)
This is important for obtaining high flow rates (1.5-2.5 m / s), preventing the formation of so-called "gas bags" in elevated areas of the terrain, which lead to significant pressure pulsations in the collection system and to disruption of the normal operation of separation plants , oil treatment plants and water treatment and discharge plants.
1.2.
booster pump station (BPS)
Booster pumping stations (BPS) are used in cases where there is not enough reservoir energy in the fields (a group of fields) to transport the oil and gas mixture to the preliminary water discharge units (PWDU) or the oil treatment and pumping shop (CPF). Typically, CSNs are used in remote fields.
Booster pumping stations are designed for separating oil from gas, cleaning gas from droplet liquid, further separate transportation of oil by centrifugal pumps, and gas - under separation pressure. There are several types of BPS depending on the liquid throughput.
The booster pumping station consists of the following blocks:
· Collection and pumping of oil leaks;
· Pumping unit;
· Spark plugs for emergency gas discharge.
All CSN units are unified. Horizontal oil and gas separators (NGS) with a volume of 50 m3 and more are used as a buffer tank. The booster pump station has a reserve buffer tank and a pumping unit. Buffer tanks are designed by the BPS technological scheme:
· For receiving oil in order to ensure a uniform flow of oil to the receiving pumping pumps;
· Separation of oil from gas;
· Maintaining a constant back pressure of the order of 0.3-0.6 MPa at the pump intake.
To create a calm liquid mirror, the inner plane of the buffer tank is equipped with lattice transverse partitions. Gas from the buffer tanks is discharged to the gas-collecting header.
The pumping unit includes several pumps, a ventilation system, a system for collecting liquid leaks, a system for monitoring technological parameters and a heating system. Each pump has an electric motor. The system for monitoring technological parameters is equipped with secondary sensors, with the output of the readings of the instruments to the control panel in the control room of the booster pump station. The pumping unit provides several protection systems in case of deviation of the pump operation parameters from the regime ones.
1. Automatic shutdown of pumps in case of emergency decrease or increase in pressure in the discharge line. The control is carried out using electrocontact manometers.
2. Automatic shutdown of pumps in case of an emergency increase in the temperature of the bearings of pumps or electric motors. Control is carried out using temperature sensors.
3. Automatic shut-off of valves at the discharge of pumps in case of shutdown.
4. Automatic activation of exhaust ventilation when the maximum permissible gas concentration in the pumping room is exceeded, while the pumps should be automatically turned off.
The block for collecting and pumping out leaks consists of a drainage tank with a volume of 4 - 12 m3, equipped with an HB 50/50 pump with an electric motor. This block is used to collect leaks from the pump oil seals and from the safety valves of the buffer tanks. The pumping of liquid from the drainage tank is carried out to receive the main process pumps. The level in the tank is monitored by means of float sensors, depending on the set upper and lower levels.
The principle of operation of the DNS.
Oil from the group metering units enters the buffer tanks, is separated, then fed to the intake of working pumps and then to the oil pipeline. The separated gas under pressure enters the field gas collecting manifold through the pressure control unit. Through the gas-collecting manifold, gas is supplied to a gas compressor station or to a natural gas compression unit (CGTU). Gas consumption is measured with a chamber diaphragm installed on the common gas line. The oil level in the buffer tanks is maintained using a float level gauge and an electric valve located on the pressure oil pipeline. When the maximum permissible liquid level in the NGS is exceeded, the level gauge sensor transmits a signal to the control device of the electric drive valve, it opens, and the level in the NGS decreases. When the level drops below the minimum permissible, the electric drive valve closes, thereby ensuring an increase in the liquid level in the oil and gas mixture. For uniform distribution of oil and pressure, the buffer tanks are interconnected by a bypass line.
Each CSN must have a process flow diagram and work procedure approved by the technical manager of the enterprise. According to these regulatory documents, control over the operation mode of the CSN is carried out.
The schematic diagram of the installation is shown in Fig. 1.2.
Rice. 1.2. Schematic diagram of a booster pumping station (BPS)
Equipment: S-1; S-2 - oil and gas separators (NGS), GS - gas separators;
Н-1 - centrifugal pump. Flows: GVD at the GPP - high pressure gas for the integrated gas treatment unit, LPG - low pressure gas
1.3. Description of the process flow diagram
a booster pumping station with a preliminary water discharge unit (BPS with PWDU)
The technological complex of the booster pump station with a water recovery unit includes:
1) the first stage of oil separation;
2) preliminary water discharge;
3) heating of well production;
4) transportation of gas-saturated oil to the CPF;
5) compressorless transport of petroleum gas to the GPP;
6) transportation of treated formation water to the reservoir pressure maintenance system;
7) injection of chemicals (inhibitors, reagents - demulsifiers) according to the recommendations of research organizations.
Objects of preliminary separation of well production should be considered as an integral part of a single technological complex of facilities for the collection, transport, treatment of oil, gas and water.
Oil separation and preliminary water discharge are carried out at the booster pump station with a water recovery unit. Associated petroleum gas from the field is used for the needs of boiler houses and is supplied to the gas processing plant.
As already mentioned, the liquid produced at the field undergoes preliminary dehydration at a water recovery unit with a booster pump station. After the separators, it enters the parallel working sedimentation tanks, where the emulsion is stratified. Then partially dehydrated oil goes to the OTF and CPF for final oil treatment. The treated water is sent to a cluster pumping station, where it is pumped into the reservoir to maintain reservoir pressure.
b) separation of gas from liquid with preliminary gas sampling;
c) preliminary dehydration of oil to a water content of no more than 5-10% (wt).
Rice. 1.3. Schematic diagram of a booster pumping station with a preliminary water discharge unit (BPS with PWDU)
Equipment: S-1; S-2 - oil and gas separators (NGS), GS - gas separators; OG - horizontal sump; Н-1, Н-2 - centrifugal pumps. Streams: GVD at the GPP - high-pressure gas for the complex gas treatment unit; LPG - low pressure gas
Preliminary oil dehydration should mainly be carried out in apparatuses for the combined preparation of oil and water. At the same time, the discharged formation water must have a quality that, as a rule, ensures their injection into the productive horizons without additional purification (only water degassing is provided).
The discharge of formation water from the devices for preliminary dehydration of oil should be provided under residual pressure, which ensures their supply to the intake of pumping stations of the waterflooding system or, if necessary, to treatment facilities without installing additional pumps.
The schematic diagram of the installation is shown in Fig. 1.3.
1.4. Description of the process flow diagram
water pre-discharge units (PWDU)
The preliminary water discharge unit resembles a simplified diagram of an oil treatment unit. The fundamental difference lies in the absence of equipment for the final dehydration of oil until it meets GOST.
Oil separation and preliminary water discharge are carried out at the WWTP. Associated petroleum gas from the field is used for the needs of boiler houses and is supplied to the gas processing plant.
The fluid produced at the field is pre-dehydrated at the PWDU. After the separators, it enters the parallel working sedimentation tanks, where the emulsion is stratified. Then partially dehydrated oil enters the final separation unit (KSU), where gas is taken at a lower pressure, and then goes to the OTU or CPF for final oil treatment. The treated water is sent to a cluster pumping station, where it is pumped into the reservoir to maintain reservoir pressure.
The technological scheme of the process should provide:
a) preparation of oil emulsion for stratification before entering the "settling" apparatus;
b) separation of gas from liquid with preliminary gas sampling and final degassing;
c) preliminary dehydration of oil to a water content of no more than 5 - 10% (wt.).
To prepare the oil emulsion for stratification, it is necessary to supply a reagent - a demulsifier at the end sections of the oil and gas gathering (before the first stage of oil separation), and if there are appropriate recommendations of research organizations - the supply of water returned from oil treatment units.
The process of preliminary oil dehydration should be provided with a water cut of the incoming well production of at least 15-20% and should be carried out, as a rule, without additional heating of the well production using demulsifiers, which are highly effective at moderate and low temperatures of the preliminary oil dehydration process.
Preliminary oil dehydration should mainly be carried out in apparatuses for the combined preparation of oil and water.
The discharge of formation water from the devices for preliminary oil dehydration should be provided under residual pressure, which ensures their supply to the intake of pumping stations of the waterflooding system or, if necessary, to treatment facilities without installing additional pumping stations.
The schematic diagram of the installation is shown in Fig. 1.4.
1.5. Description of the process flow diagram
oil treatment units (OTP)
The oil treatment unit is designed for dehydration and degassing of oil to parameters that meet the requirements of GOST R.
In the S-1 oil and gas separator, oil degassing occurs at a pressure of 0.6 MPa, which is maintained by a pressure regulator. To facilitate the destruction of the water-oil emulsion, a demulsifier from the chemical dosing unit is introduced in front of the S-1 separator.
From separator C-1, partially degassed oil and produced water enters the inlet of the sludge block, the pressure in which is maintained at 0.3 MPa by a pressure regulator. Produced water from the sludge block is sent to sanitary facilities for subsequent disposal. Partially dehydrated and degassed oil from exhaust gas is sent to an electric dehydrator (EDG) for final oil dehydration, then the dehydrated oil enters the terminal separation unit - KSU, in which the pressure is maintained at 0.102 MPa. Prepared oil from the KSU is fed by gravity to the tank farm for storage and subsequent auto-removal or supply of oil to the transport pipeline.
Raised from the well to the surface, it enters the collection and preparation system. This entire system is a rather complex complex of oilfield equipment, consisting of pipelines, shut-off and control equipment, metering units, separators, tanks. A system for gathering and treating oil is being formed in accordance with the Field Development Project, which is being developed by a specialized design organization (design institute).
The production of oil wells almost never consists of pure oil. As a rule, it is a mixture of oil, water and gas with small admixtures of other substances. Therefore, the most important task of the oil collection and treatment system is separation, that is, the separation of oil, gas and water from each other.
Figure 1. Schematic diagram of the collection and treatment of oil
Separation usually takes place in several stages. At each stage can be used Various types separators. By the principle of operation, the separators are divided into centrifugal and gravitational, by design - into horizontal, vertical, spherical. For a more efficient separation of water from oil and prevention of the formation of a hard-to-break emulsion, various demulsifying reagents are added to the well production. Also, at certain stages, oil is heated to accelerate the separation of water from oil.
Oilfield pipelines are generally classified into:
- Oil pipelines;
- Gas pipelines;
- Oil and gas pipelines;
- Water pipelines (water pipelines).
Pipelines leading from the wellhead to group metering units are called flow lines... And from group installations to collection points - collectors.
At the first stage of collection and preparation, the well fluid flows through the flow line to group metering unit (GZU), where the amount of liquid produced from the wells is determined and the partial separation of associated gas and water from oil is performed. Further oil through booster pump station (BPS) through prefabricated collectors goes to central collection point (CPS).
“Collection point” is a rather rough concept. This can be anything from a very simple gathering station to a sophisticated integrated treatment center where produced fluids are treated and separated into gas, condensate liquids, water and stabilized oil.
Usually, one CPF is arranged at one oil field. But sometimes it is advisable to use one CPF for several fields and place it on a larger one. In this case, complex collection points (CSP) can be built at individual fields, where the liquid extracted from the wells undergoes partial separation and treatment.
The main purpose of the booster pumping station is to provide additional head for pumping oil to the central heating station from remote fields. CSN is often combined with installation of preliminary water discharge (UPSV), where partial separation of oil, gas, water is carried out and their further pumping by separate pipelines.
The final oil treatment is carried out at an integrated oil treatment unit (ICPU), which is an integral part of the CPF concept. The final oil treatment process includes:
- Degassing(final separation of gas from oil)
- Dehydration(destruction of the water-oil emulsion formed when lifting the product from the well and transporting it to the UKPN)
- Demineralization(removal of salts by adding fresh water and re-dehydration)
- Stabilization(removal of light fractions in order to reduce oil losses during its further transportation)
Prepared (marketable) oil is sent to the commodity park, which includes tanks of various capacities: from 1000 m³ to 50,000 m³. Then the oil is fed through the head pumping station to the main oil pipeline. The volume of oil delivered for transportation is measured at the Metering Unit, equipped in accordance with the technical specifications (TU) of AK Transneft.
