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Service
Oil treatment units (OTU) are purposed for preliminary separation into oil, gas and formation water of products extracted from oil wells for further treatment, metering, product transfer via pipeline, as well as for final oil treatment to achieve saleable quality.
OTU can be operated in areas characterized by the average temperature of the coldest 5 days period up to minus 60 °С.
Equipment is manufactured in moderate-cold and cold climatic execution (UHL, HL respectively), location category 1 according to GOST 15150 – 69.
Enclosed equipment
Process flow diagram design, equipment selection and OTU manufacturing are performed in accordance with physical and chemical characteristics of fluid and gas mixture fed to OTU and requirements towards treatment quality, necessary unit capacity, operation conditions and individual customer’s requirements.
OTU process cycle may include the following stages: oil degasification, oil stabilization, heating, dehydration and demineralization.
Depending on physical and chemical properties and final product quality, oil treatment units are completed with the following equipment: valve manifold; test separator unit; oil and gas separator; oil and gas separator with water discharge; oil heater; formation water treatment unit; gas separator; oil external-internal transfer pumping unit; water pumping station; modular group pumping station; metering and regulating unit; oil commercial (operational) metering unit; gas metering unit; water metering unit; flare unit; buffer and drain vessels; tanks; MCC unit; control room; mechanical workshop; chemical laboratory; system of modern automation devices (transducers of flowrate, temperature, excessive and differential pressure, level meters and level indicators and etc.); shutoff and regulating valves, including gate valves, ball valves, Flowrate and pressure regulators, check valves and PSV and etc.; software design and etc.
Main operational characteristics
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OTU production rate
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As per fluid, m3/day
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up to 30 000
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As per gas, mil. m3/day
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0,1…3,0
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Pressure
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at the OTU inlet, MPa
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up to 4,0
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Design, MPa
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4,0
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At the OTU outlet, MPa
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at the customer’s requirement
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Operating medium
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oil, associated gas, formation water
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Gas ratio, m3/m3
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up to 1500
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Oil density at 20 °С, kg/m3
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800-920
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Formation water density, kg/m3
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1000-1050
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Water cut at the inlet, % vol.
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unlimited
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Water cut at the outlet, % vol.
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0,5
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Electrical part
OTU power supply is performed from external source.
OTU electrical equipment includes local manual operating station for ventilation systems, electrical heating and lighting. PWDU is equipped with the full set of cable structure and cable products.
Automation of technological process
OTU process equipment is completed with local instruments, primary and secondary transducers for automatic control and control of all process parameters: pressure, temperature, level in separators, water flowrate.
Automatic control system is installed in the control unit based on Direct Logic, Siemens controllers and etc. with software for OTU control and operation.
Oil treatment units are also completed with the following equipment:
- automatics cabinets (PLC and secondary devices), located in the control room;
- low voltage package module panels 0.4 kV, Switchgear -6 kV, Reserve switching devices, transformers, placed in MCC, Switchgear -6 kV;
- mounted instruments, cabling (for modular equipment);
- full package of documentation.
All process modular buildings are equipped with lighting, heating (with automatic support of the determined temperature for the module), drain, exhaust ventilation systems, gas-content control sensors (for explosion-hazardous areas), and fire alarm sensors.
The modular shelters’ structure represents a frame, welded from a steel closed profile, encased by three-layer sandwich panels with non-flammable heating material. Shelter unit base is a welded metal framing made of steel hot-rolled profile covered with sheet metal and basalt heat-insulating material.
Heating inside shelter modules is of electrical or hot water type (infrared electrical heaters supply is possible) which maintains the following indoor temperature values inside, not less than:
· process package - plus 5°С;
· low voltage package module panel - plus 5°С;
· control room module – plus 18°С;
· frequency transducers module – plus 5°С.
Terminal boxes connecting outdoor cables are arranged on the inside wall of the module near cable inputs (for modular equipment)
Modular shelters structure provides a possibility to transport them by railway, water and motor transport.
Process of OTU design, manufacture, and delivery of the packaged equipment with a minimum required work at site is 6-8 months.
Technological equipment for oil treatment
Inlet manifold unit
Inlet manifold unit serves to connect production and investigational wells with technological equipment of oilfield collecting and treatment units.
Enclosed equipment
Equipment composition of the inlet manifold unit is defined by individual customer’s requirements.
Standard unit includes the following technological equipment:
- production collecting tank with shut off valves;
- investigational collector with shut off valves;
- drain collector with shut off valves.
Operation description
Production collector, investigational collector, drain collector, shut off valves, instrumentation can be installed in modular shelter with heating systems, lighting, ventilation on an open frame are possible to be performed with different structural design and equipment composition at the customer’s requirement.
Inlet manifold chamber is made of modules with the following dimensions: 3000х6000х2950 mm, 3000х9000х2950 mm, 3000х12000х2950 mm, which can be assembled in different variations at the customer’s and design engineer requirement.
Oil and gas separator of “НГС” type
Oil and gas separator (НГС) serves non-foaming oil degasification and associated gas treatment in oil treatment units.
Depending on unit’s production rate and physical-chemical parameters of the operating medium, the following separators of different structures are applied: completed with surge vessel – type I; surge vessel and defoaming nozzle – type I-П; without surge vessel or defoaming nozzle – type II; without surge vessel but with defoaming nozzle – type II-П.
Surge vessel (slug catcher) is purposed for preliminary gas extraction before treatment in first stage separators, located in an open area. Gas extraction is performed by diameter increasing and reducing of oil and gas mixture flow velocity.
Under normal process conditions or in case of short-term malfunctions, slug catcher should not pollute environment with emissions release (into air, water, ground) over allowable values determined by standards and sanitary norms.
Technical specification
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Volume, m3
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6,3
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12,5
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25
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50
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100
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200
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Volumetric capacity as per oil, m3/h
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20 ...100
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45…225
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86…430
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160…800
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300…1500
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450…2250
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Volumetric capacity as per gas, m3/h
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20 700
23 300
31 400
39 000
55 000
74 900
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41 400
46 700
62 900
78 000
110 000
149 500
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62 200
70 000
94 400
117 200
165 000
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82 900
93 500
125 500
156 300
220 000
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124 000
140 000
188 000
234 000
33 000
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165 000
187 000
251 000
312 000
440 000
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Design pressure, MPa
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0,6
1,0
1,6
2,5
4,0
6,3
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0,6
1,0
1,6
2,5
4,0
6,3
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0,6
1,0
1,6
2,5
4,0
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0,6
1,0
1,6
2,5
4,0
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0,6
1,0
1,6
2,5
4,0
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0,6
1,0
1,6
2,5
4,0
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Weight (type НГС-II), kg
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2 640
2 640
3 030
3 590
4 980
6 725
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4 178
4 400
5 536
6 970
9 570
13 200
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6 185
7 477
8 472
11 513
16 210
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9 190
10 880
13 776
19 240
28 320
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16 290
18 600
24 790
35 670
52 740
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24 041
30 560
40 100
55 260
95 750
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Oil and gas separator with water discharge of “НГСВ” type
“НГСВ” separator serves to separate oil, gas and water out of well products. Separator represents a horizontal apparatus, completed with technological nozzles, gates made with expanded steel sheets, defoaming nozzle made with L-shaped plates sections, weir gate, fluid jet knockout drum for gas treatment.
Depending on unit’s production rate and physical-chemical parameters of the operating medium, the following separators of different structures are applied: completed with surge vessel – type I; surge vessel and defoaming nozzle – type I-П; without surge vessel or defoaming nozzle – type II; without surge vessel but with defoaming nozzle – type II-П.
Technical specification
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Volume, m3
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25
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50
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100
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200
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Internal diameter, mm
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2 000
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2 400
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3 000
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3 400
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Capacity as per oily mixture, kg/h(m3/h)
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от 6 600 до 22 900 (26 до 70)
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от 45 800 до
132 000
(52,5 до 140)
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от 91 600 до
264 000 (105 до 280)
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от 189 800 до
528 100 (210 до 560)
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Capacity as per gas, m3/h
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6 190
8 500
12 500
18 500
27 400
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12 380 17 100 25 000 37 000 37 000
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54 900 24 700 34 100 49 800 73 900 109 200
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37 050 51 300 75 000
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Design pressure, MPa
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0,6 1,0 1,6 2,5 4,0
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0,6 1,0 1,6 2,5 4,0
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0,6 1,0 1,6 2,5 4,0
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0,6 1,0 1,6
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Net-shaped gas separator of “ГС” type
Net-shaped gas separator of “ГС” type performs final treatment of natural and associated gas from dropping liquid (condensate, oil, water, hydrate growth inhibitor).
There exist two types of Net-shaped separators according to the standard:
Type 1 – cylindrical and vertical, with housing flange, connector diameter - 600, 800 mm at design pressure from 1,6 to 6,4 MPa (from 16 to 64 kgf/sm2).
Type 2 – cylindrical and vertical, with diameters 1200, 1600, 2000 mm at design pressure from 0,6 to 8,8 MPa (from 6 to 88 kgf/sm2).
Type 1 – Q=0,05-0,95 mil m3/day.
Type 2 – Q=0,2-5,6 mil m3/day.
Technical specification for ГС type 2 separators
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Volume, m3
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4
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8
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8
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16
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Internal diameter, mm
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200
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600
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1 600
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2 000
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Design pressure, MPa (kgf/sm2)
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0,6 (6) 1,0 (10) 1,6 (16) 2,5 (25) 4,0 (40) 6,4 (64) 8,8 (88)
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0,6 (6) 1,0 (10) 1,6(16)
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2,5 (25) 4,0 (40) 6,4 (64) 8,8 (88)
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0,6 (6) 1,0(10) 1,6(16) 2,5 (25) 4,0 (40) 6,4 (64) 8,8 (88)
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Height, mm
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3 400
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3 800
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3 800
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4 500
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Decanters
Horizontal decanter with “ОГН-П” gates and decanter “ОГ 200-П” serve to dehydrate oil (formation water separation from oil due to density difference) separating residual gas out of oil emulsion. Decanter represents a cylindrical apparatus supported by two cradles, equipped with process nozzles and nozzles for instrumentation.
Technical specification for ОГН-П decanter
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Volume, m3
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25
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50
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100
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200
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Capacity as per liquid, m3/day
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2 000
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4 000
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7 500
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15 000
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Design pressure, MPa (kgf/sm2)
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1,0 (10) 1,6 (16) 2,5 (25)
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1,0 (10) 1,6 (16) 2,5 (25)
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1,0 (10) 1,6(16) 2,5 (25)
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1,0 (10) 1,6 (16)
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Internal diameter, mm
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2 400
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2 400
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3 000
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3 400
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Length, mm
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6 285 6 290 6 340
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11 485 11 490 11 540
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14 385 14 395 14 485
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22 090
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Weight, kg
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5 513 7 074 8 901
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8 741
11 572
14 677
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16 044 20 239 27 347
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26 629 35 520
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Operation concept for ОГН-П decanter
Emulsion flow is directed through inlet nozzle and distribution gear. It flows vertical inside the apparatus. Preliminary dehydrated oil is discharged via oil outlet nozzle located in lower part of the apparatus. Extracted water is discharged through water outlet nozzle.
Technical specification for ОГ 200-П decanter
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Volume, m3
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Design pressure, MPa (kgf/sm2)
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Internal diameter, mm
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Length, mm
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200
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1,0 (10)
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3 400
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23 450
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Operation concept for ОГ 200-П decanter
Decanter with horizontal liquid flow operates with a tank completely filled. Water and oil emulsion is supplied through inlet nozzle to decanter. To equally distribute liquid inside the apparatus a distributing knock out drum is installed at the inlet. Dehydrated oil is discharged through upper piping system. Settled water is fed through distributing device to water decanter. Water is discharged upon the signal of interface level sensor “oil-water” through regulating valve. Due to continuous settling and assurance of liquid remixing conditions a complete separation of water and oil is achieved.
Water settling drum
Unit serves to treat wastewater and formation water removing oily residues and mechanical impurities in initial water separation units and oil treatment units purposed for further water application in reservoir-pressure maintenance systems. Settling drums allow water treatment removing fine particles (up to 20 mg/l) and oil residues (up to 15…20 mg/l).
Technical specification
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Volume, m3
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25
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50
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100
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200
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Capacity as per liquid, m3/day
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2 000
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4 000
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7 500
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15 000
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Design pressure, MPa(kgf/sm2)
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1,0 (10) 1,6 (16) 2,5 (25)
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1,0 (10) 1,6 (16) 2,5 (25)
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1,0 (10) 1,6 (16) 2,5 (25)
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1,0 (10) 1,6 (16)
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Internal diameter, mm
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200
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2 400
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3 000
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3 400
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Length, mm
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6 285
6 290
6 340
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11 485 11 490 11 540
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14 385 14 395 14 485
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22 090
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Weight, kg
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5 543 7 103 8 897
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8 921
11 608
14 827
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16 372 20 567 27 654
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27 515 34 407
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Operation concept for decanter with hydrophobic layer
Operation concept of water decanter is based on water drops ability to treat from oil sediments and suspended solid particles by means of passing through hydrophobic filter representing oil layer of required thickness, residing on a water surface inside the decanter. Water drops of required size are formed while impure water inflows into the apparatus through distributing collector installed in oily layer.
Formation water flows from above into the settling drum and then through internal distributing device is fed into hydrophobic layer, where absorption of suspended matters of oil occurs. Then water reaches water layer and mixes with it releasing the rest of oil drops, rough mechanical impurities and after that it is discharged from the unit through collection header.
Gas separated from water due to pressure reduction is collected in piped gas receiver and then supplied to flare line.
Settling drum should be completely filled while operated. In the upper part a hydrophobic oil layer is maintained at thickness of 0,5 m with level control device. Treated oil transfer through drum nozzle is foreseen to produce hydrophobic layer. Upon the signal of limit level sensor entrapped oil discharge is performed through the nozzle into entrapped oil collector, from where it can be pumped for processing.
Decanters of different variations are designed and manufactured for treatment of water with diverse physical and chemical properties. Depending on customer’s water treatment requirements a reservoir-pressure maintenance system of a decanter is equipped with internal devices (gates, distribution device, coaliscer etc.).
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