WO2013124338A2 - Method and system for providing fuel gas to a topside facility - Google Patents
Method and system for providing fuel gas to a topside facility Download PDFInfo
- Publication number
- WO2013124338A2 WO2013124338A2 PCT/EP2013/053415 EP2013053415W WO2013124338A2 WO 2013124338 A2 WO2013124338 A2 WO 2013124338A2 EP 2013053415 W EP2013053415 W EP 2013053415W WO 2013124338 A2 WO2013124338 A2 WO 2013124338A2
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- WO
- WIPO (PCT)
- Prior art keywords
- gas
- stream
- crude oil
- subsea
- outlet
- Prior art date
Links
- 239000002737 fuel gas Substances 0.000 title claims abstract description 29
- 238000000034 method Methods 0.000 title claims abstract description 28
- 239000007789 gas Substances 0.000 claims abstract description 74
- 239000010779 crude oil Substances 0.000 claims abstract description 45
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims abstract description 36
- 239000003921 oil Substances 0.000 claims abstract description 26
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 25
- 239000003345 natural gas Substances 0.000 claims abstract description 18
- 230000006641 stabilisation Effects 0.000 claims abstract description 16
- 238000011105 stabilization Methods 0.000 claims abstract description 14
- 239000002253 acid Substances 0.000 claims abstract description 6
- 238000004891 communication Methods 0.000 claims description 20
- 239000012530 fluid Substances 0.000 claims description 20
- 238000010438 heat treatment Methods 0.000 claims description 3
- 239000000243 solution Substances 0.000 description 19
- 150000001875 compounds Chemical class 0.000 description 12
- 238000009434 installation Methods 0.000 description 10
- 239000000446 fuel Substances 0.000 description 7
- 239000007788 liquid Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000008929 regeneration Effects 0.000 description 3
- 238000011069 regeneration method Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000009833 condensation Methods 0.000 description 2
- 230000005494 condensation Effects 0.000 description 2
- 230000003750 conditioning effect Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 229930195733 hydrocarbon Natural products 0.000 description 2
- 150000002430 hydrocarbons Chemical class 0.000 description 2
- 238000003672 processing method Methods 0.000 description 2
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000001143 conditioned effect Effects 0.000 description 1
- 230000018044 dehydration Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 239000003085 diluting agent Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B43/00—Methods or apparatus for obtaining oil, gas, water, soluble or meltable materials or a slurry of minerals from wells
- E21B43/34—Arrangements for separating materials produced by the well
- E21B43/36—Underwater separating arrangements
Definitions
- the present invention relates to an offshore processing method, especially the present invention relates to an offshore processing method for providing fuel for an offshore processing system which can be combined with a method for stabilization of oil for tanker transport.
- the offshore top side processing equipment requires power for driving mechanical equipment and for providing heat.
- the power can be provided through electrical cables connected to onshore power plants or be generated offshore through combustion of fuel or a combination thereof.
- WO 03/033872 relates to an installation arranged on the sea bed for the separation of fluids, comprising at least one separator that is connected to one or more wells, each via an associated well head or similar, and a pipeline.
- the components separated, oil, gas, water or combinations of these substances, are fed fully or partially from the installation to a platform, vessel etc. on the surface via collecting pipelines onto shore, or are re-injected into the formation beneath the sea bed.
- Each separator consist of a long pipe (pipe separator) that may form a major or minor part of the transport pipeline from the well and has a diameter that is mainly equal to or slightly larger that the diameter of the transport pipeline.
- An aim of the present invention is to provide a method for providing fuel to a topside platform from a subsea well which utilizes equipment mainly provided for other purposes.
- Another aim is to provide a method for stabilisation of oil for tanker transport.
- the present invention provides a method for providing fuel gas to a top-side processing system of a sub-sea well stream, where the method comprises separating the sub-sea well stream in a sub-sea arranged three phase separator obtaining a crude oil stream, and a crude natural gas stream, separating acid gasses and/or water from the crude natural gas, pressurizing the gas stream sub-sea, adding at least part of the pressurized gas to the crude oil stream subsea, transporting the added gas together with the oil to the topside, separating the gas from the oil in a first stabilization stage and providing the separated gas as fuel gas to a fuel gas system.
- the method further comprises removing water from the crude oil stream subsea to obtain dry crude oil, transporting the dry crude oil to the topside processing system.
- Removing water from the crude oil stream subsea may in another aspect comprise passing the crude oil trough a subsea arranged electrostatic coalescer.
- the crude oil stream is stabilized for tanker transport in the top-side processing system through removal of dissolved gas.
- the first stabilization stage operates at a gas pressure equal to a pressure required for the topside fuel gas system.
- the crude oil is stabilized in the first stage and in a second stage with interstage heating.
- the step of separating acid gasses and/or water from the crude natural gas is performed subsea.
- the present invention provides a subside well, topside fuel gas providing system comprising a sub-sea arranged three phase separator with a well stream inlet and at least a crude natural gas outlet and a crude oil outlet, a riser with a subsea riser inlet in fluid communication with the crude oil outlet and in fluid
- a topside riser outlet in fluid communication with a topside arranged stabilization unit comprising a stabilized crude oil outlet and a fuel gas outlet.
- system further comprises a subsea gas treatment system down stream the three phase separator with an inlet in fluid communication with the crude natural gas outlet and with a treated gas outlet in fluid communication with the riser.
- system comprises a sub-sea arranged water removal unit arranged downstream the three phase separator with a crude oil inlet in fluid communication with the crude oil outlet, a dry crude oil outlet in fluid
- the water removal unit comprises an electrostatic coalescer.
- the fuel gas outlet is in fluid communication with a fuel gas inlet to a topside arranged power generating unit.
- the system further comprises a subsea natural gas compressor with an inlet in fluid communication with the natural gas outlet and a pressurized gas outlet in communication with the riser.
- topside refers to a position in proximity of the sea level.
- part of the equipment may be installed above or below the sea level but with in or on the floating vessel or platform.
- topside should be interpreted to refer to any position on the platform above sea level.
- Figure 1 schematically illustrates a first embodiment of the present invention.
- Figure 2 schematically illustrates a second embodiment of the present invention.
- Figure 3 schematically illustrates a third embodiment of the present invention.
- Figure 4 illustrates the process scheme of a fourth embodiment of the present invention.
- Figure 1 illustrates a first embodiment of the present invention.
- a well stream 1 is fed to a subsea three-phase separator 2, to obtain a water stream 19, a crude oil stream 13 and a gas stream 3.
- the water stream 19 is transferred to a produced water treatment system 4.
- the gas stream 3 is past through a heat exchanger 8 to obtain a cooled gas 5.
- the cooling results in condensation of higher hydrocarbons which are separated in separator 10.
- the liquid stream 7 is via pump 12 and pipe 9 mixed with the main oil stream from the separator 2.
- the gas 1 1 leaving over the top of the separator 10 is subject to a treatment system 22 conditioning the gas for pipeline transport.
- the conditioned gas 51 is pressurized in subsea compressor 52 to obtain pressurised gas 53.
- the oil stream 81 comprising the main crude oil stream 13 and the condensed oil 9 is transported via a pump 80 and a pipeline 83.
- a part 57 of the pressurized gas is added to the oil before the oil is transferred to top side via line 85.
- the rest of the gas is transferred via heat exchanger 54 and pipeline 55 to shore.
- the mixture of gas and oil is transported to a topside installation 90 in riser 85.
- the oil is dehydrated and gas initially present as well as the added gas is removed in a first stabilization step 84.
- Stream 87 is stabilized oil, depending on the restrictions for tanker transport additional oil treatment may if necessary be performed on the topside installation.
- Stream 89 comprises the added gas stream 57 as well as any additional gas released from the crude oil. This stream 89 is fed as fuel gas to a topside gas fuel power providing system 86.
- Figure 2 illustrates an alternative embodiment of the present invention, wherein the at least partly stabilized crude oil 87 is returned from the topside installation to subside, and transported to shore together with the compressed gas 55 as stream 65 via a subsea pipeline. In this embodiment the crude oil is transferred to the topside installation to be dried. For pipeline transport together with the crude gas both the gas and the oil need to be dried to avoid hydrate formation.
- FIG. 3 illustrates a further embodiment of the present invention.
- the initial oil treatment system 6 is arranged subsea.
- the crude oil is dehydration for instance by use of electrostatic coalescers. Separated water is past as stream 15 to the produced water treatment system 4.
- the dehydrated oil 81 is via pump 80 transferred to the topside installation 90 together with treated gas 57.
- the stabilization system 84 comprises one or more stabilization steps where gas is flashed of from the crude oil.
- the first step is preferably performed at a pressure equal to the pressure required by the fuel gas system 86 so that it is not required to compressed the fuel gas 89 before feeding it to the fuel gas system 86.
- the fuel gas is a combination of the added gas 57 and the gas present in the crude oil prior to stabilization.
- Additional stabilization steps may be included within unit 84 to allow for removal of additional gas to secure quality applicable for tanker transport. These additional steps will be performed at a lower pressure than the pressure of the fuel gas. If significant amounts of gas are released at a lower pressure, then the treatment system may also comprise a compressor to increase the pressure of the removed gas to the pressure required by the fuel system. Alternatively, if there are two fuel gas systems topside; 1) for feeding the generator turbine (high pressure) and 2) one for feeding a direct fired heater to provide heating medium, then the gas released at lower pressure is fed to the fuel system for the direct fired heater.
- FIG. 4 illustrated an embodiment of the present invention in further detail.
- the well fluid 1 enters a phase separator 2, where the gas stream 3 is separated from the liquid.
- a water stream 19 is passed to a produced water treatment system 4, and the oil stream 13 is past to an oil treatment system 6.
- the gas 3 is initially cooled by cooler 8 to obtain cooled gas 5.
- the cooling results in condensation of higher hydrocarbons which are separated in separator 10.
- the liquid stream 7 is via pump 12 and pipe 9 mixed with the main oil stream from the separator 2.
- the gas 1 1 leaving over the top of the separator 10 is subject to a gas treatment system.
- a gas treatment system In figures 1-3 this was referred to as system 22 whereas here one embodiment of this system is disclosed in detail. However it should be noted that other subsea systems for gas conditioning are equally applicable.
- the crude gas stream 1 1 comprising a compound to be removed such as C0 2 and/or other acid gasses is fed to a contactor system 14, 16 arranged subsea.
- the contactor system is a 2 stage process with an initial direct contactor 14 and a traditional contactor column 16.
- the present invention is not limited to this embodiment but any contactor system applicable for subsea arrangement may be employed.
- the gas stream In the direct contactor the gas stream is brought in contact with a treatment solution stream fed trough pipe 23.
- the obtained gas treatment solution mixture proceeds as stream 17 into the contactor column 16.
- Lean treatment solution is provided to the column from pipe 21.
- the treatment solution for the direct contactor is obtained from the column 16 at a level above the gas inlet, however the present invention is not limited to this solution as lean treatment solution could also be fed to the direct contactor as well as the column.
- the treatment solution comprises one or more species that at least with some selectivity absorb the compound to be removed from the crude gas stream.
- a species and solvent/diluent applicable for forming an effective treatment solution can be selected by the user depending on the compound to be removed and the prevailing conditions within the system.
- the compound to be removed is absorbed in the solution.
- the crude gas accordingly at least partly depleted from the compound to be removed leaves over the top of the column trough pipeline 31.
- the main crude gas stream accordingly stays subsea during the treatment process.
- the rich treatment solution leaves the contactor 16 trough the bottom outlet pipeline 25.
- a pump 18 is provided to force the rich treatment solution 25 to proceed up through the riser or pipeline 27.
- a regeneration system 20 is installed on a topside facility 90 . The system receives the rich solution from pipeline 27, desorbes and separates the absorbed compound there from and obtains a depleted treatment solution which is send back to the subsea contactor system trough pipeline/riser 21. The desorbed compound leaves the regeneration unit 20 as stream 29. If the compound is C0 2 the stream 29 may be treated and compressed in unit 60 and from there transported via pipeline 61 to a subsea injection well (not shown).
- the obtained treated gas 31 enters a second system for removal of a second compound, such as water.
- the system comprises a direct contactor 34, where the gas is brought in contact with a treatment solution stream 43.
- the obtained mixture is fed to a contactor column 36.
- the rich treatment solution leaves via the bottom as stream 45, via pump 38 and is transported via pipeline 47 to a top side installation 90 and a regeneration unit 40.
- the compound absorbed in the rich treatment solution is released resulting in a compound stream 49 and a lean treatment solution 41 being returned to the subsea contactor 36.
- the stream 49 is steam that can be released to the atmosphere.
- the treated gas stream 51 leaving over the top of 36 can be compressed in compressor 52 and the temperature of the compressed gas 53 controlled by heat exchanger 54.
- heat exchanger 54 the temperature of the compressed gas 53 controlled by heat exchanger 54.
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
- Separation By Low-Temperature Treatments (AREA)
Abstract
A method for providing fuel gas to a top-side processing system of a sub-sea well stream is provided. The method comprises separating the sub-sea well stream in a sub-sea arranged three phase separator obtaining a crude oil stream, and a crude natural gas stream, separating acid gasses and/or water from the crude natural gas, pressurizing the gas stream sub-sea, adding at least part of the pressurized gas to the crude oil stream subsea, transporting the added gas together with the oil to the topside, separating the gas from the oil in a first stabilization stage and providing the separated gas as fuel gas to a fuel gas system.
Description
Method and system for providing fuel gas to a topside facility
The present invention relates to an offshore processing method, especially the present invention relates to an offshore processing method for providing fuel for an offshore processing system which can be combined with a method for stabilization of oil for tanker transport.
Background
The exploitation of subsea wells has gone through considerable developments since the start of the offshore era. The location of the wells has changed both with respect to sea depth as well as distance to shore. This has resulted in new systems for handling the well streams. One such system includes a subsea installation near the well head combined with a topside platform, which can be a floating processing platform. Transportation of the well products can take place either through subsea pipelines or via tanker transport. Due to the limited space on a floating platform generally the amount of process equipment need to be adjusted to the available space. Transport of crude oil on tankers requires that the crude oil has been stabilized to an extent that gas which can be released from the oil during transport is limited. The release of gas during transport is a result of changes in the conditions for instance due to changes in the temperatures of the surroundings, but also a result of settlement over time during transport. Stabilization of crude oil for tanker transport comprises controlled degasification of the crude oil.
The offshore top side processing equipment requires power for driving mechanical equipment and for providing heat.
The power can be provided through electrical cables connected to onshore power plants or be generated offshore through combustion of fuel or a combination thereof.
Prior art
Stabilisation of crude oil through degasification is well known in the art, and WO 03/033872 is mentioned as an example. WO 03/033872 relates to an installation arranged on the sea bed for the separation of fluids, comprising at least one separator that is connected to one or more wells, each via an associated well head or similar, and a pipeline. The components separated, oil, gas, water or combinations of these substances, are fed fully or partially from the installation to a platform, vessel etc. on the surface via collecting pipelines onto shore, or are re-injected into the formation beneath the sea bed. Each separator consist of a long pipe (pipe separator) that may form a major or minor part of the transport pipeline from the well and
has a diameter that is mainly equal to or slightly larger that the diameter of the transport pipeline.
Objectives of the invention
An aim of the present invention is to provide a method for providing fuel to a topside platform from a subsea well which utilizes equipment mainly provided for other purposes.
Another aim is to provide a method for stabilisation of oil for tanker transport.
The present invention provides a method for providing fuel gas to a top-side processing system of a sub-sea well stream, where the method comprises separating the sub-sea well stream in a sub-sea arranged three phase separator obtaining a crude oil stream, and a crude natural gas stream, separating acid gasses and/or water from the crude natural gas, pressurizing the gas stream sub-sea, adding at least part of the pressurized gas to the crude oil stream subsea, transporting the added gas together with the oil to the topside, separating the gas from the oil in a first stabilization stage and providing the separated gas as fuel gas to a fuel gas system.
In one aspect of method according to the present invention the method further comprises removing water from the crude oil stream subsea to obtain dry crude oil, transporting the dry crude oil to the topside processing system. Removing water from the crude oil stream subsea may in another aspect comprise passing the crude oil trough a subsea arranged electrostatic coalescer.
In a further aspect of the method according to the present invention the crude oil stream is stabilized for tanker transport in the top-side processing system through removal of dissolved gas.
In yet another aspect of the method according to the present invention the first stabilization stage operates at a gas pressure equal to a pressure required for the topside fuel gas system.
In an additional aspect of the present invention the crude oil is stabilized in the first stage and in a second stage with interstage heating.
In a further aspect of the method according to present invention the step of separating acid gasses and/or water from the crude natural gas is performed subsea.
Further the present invention provides a subside well, topside fuel gas providing system comprising a sub-sea arranged three phase separator with a well stream inlet and at least a crude natural gas outlet and a crude oil outlet, a riser with a subsea riser inlet in fluid communication with the crude oil outlet and in fluid
communication with the crude natural gas outlet and a topside riser outlet in fluid
communication with a topside arranged stabilization unit comprising a stabilized crude oil outlet and a fuel gas outlet.
In one aspect of the system according to the present invention, the system further comprises a subsea gas treatment system down stream the three phase separator with an inlet in fluid communication with the crude natural gas outlet and with a treated gas outlet in fluid communication with the riser.
In a further aspect the system comprises a sub-sea arranged water removal unit arranged downstream the three phase separator with a crude oil inlet in fluid communication with the crude oil outlet, a dry crude oil outlet in fluid
communication with the riser and a water outlet. In one aspect of the system the water removal unit comprises an electrostatic coalescer.
In yet another aspect the system according to the present invention the fuel gas outlet is in fluid communication with a fuel gas inlet to a topside arranged power generating unit. In an additional aspect of the system according to the present invention the system further comprises a subsea natural gas compressor with an inlet in fluid communication with the natural gas outlet and a pressurized gas outlet in communication with the riser.
The term "topside" as used here refers to a position in proximity of the sea level. For floating topside installations part of the equipment may be installed above or below the sea level but with in or on the floating vessel or platform. For platforms with one or more legs connected to the seabed the term "topside" should be interpreted to refer to any position on the platform above sea level.
Brief description of the drawings The present invention will be discussed in further detail with reference to the enclosed figures where:
Figure 1 schematically illustrates a first embodiment of the present invention.
Figure 2 schematically illustrates a second embodiment of the present invention.
Figure 3 schematically illustrates a third embodiment of the present invention. Figure 4 illustrates the process scheme of a fourth embodiment of the present invention.
Principal description of the invention
The figures illustrated different embodiments of the present invention. The same reference numbers are used to refer to equally elements within the different
embodiments. It should be understood that features of the different embodiments may be combined to provide additional embodiments of the present invention.
Figure 1 illustrates a first embodiment of the present invention. A well stream 1 is fed to a subsea three-phase separator 2, to obtain a water stream 19, a crude oil stream 13 and a gas stream 3. The water stream 19 is transferred to a produced water treatment system 4. The gas stream 3 is past through a heat exchanger 8 to obtain a cooled gas 5. The cooling results in condensation of higher hydrocarbons which are separated in separator 10. The liquid stream 7 is via pump 12 and pipe 9 mixed with the main oil stream from the separator 2. The gas 1 1 leaving over the top of the separator 10 is subject to a treatment system 22 conditioning the gas for pipeline transport. The conditioned gas 51 is pressurized in subsea compressor 52 to obtain pressurised gas 53.
The oil stream 81 comprising the main crude oil stream 13 and the condensed oil 9 is transported via a pump 80 and a pipeline 83. A part 57 of the pressurized gas is added to the oil before the oil is transferred to top side via line 85. The rest of the gas is transferred via heat exchanger 54 and pipeline 55 to shore.
The mixture of gas and oil is transported to a topside installation 90 in riser 85. Within the oil treatment system 6' the oil is dehydrated and gas initially present as well as the added gas is removed in a first stabilization step 84. Stream 87 is stabilized oil, depending on the restrictions for tanker transport additional oil treatment may if necessary be performed on the topside installation. Stream 89 comprises the added gas stream 57 as well as any additional gas released from the crude oil. This stream 89 is fed as fuel gas to a topside gas fuel power providing system 86. Figure 2 illustrates an alternative embodiment of the present invention, wherein the at least partly stabilized crude oil 87 is returned from the topside installation to subside, and transported to shore together with the compressed gas 55 as stream 65 via a subsea pipeline. In this embodiment the crude oil is transferred to the topside installation to be dried. For pipeline transport together with the crude gas both the gas and the oil need to be dried to avoid hydrate formation.
Figure 3 illustrates a further embodiment of the present invention. Here also the initial oil treatment system 6 is arranged subsea. Here the crude oil is dehydration for instance by use of electrostatic coalescers. Separated water is past as stream 15 to the produced water treatment system 4. The dehydrated oil 81 is via pump 80 transferred to the topside installation 90 together with treated gas 57. The stabilization system 84 comprises one or more stabilization steps where gas is flashed of from the crude oil. The first step is preferably performed at a pressure equal to the pressure required by the fuel gas system 86 so that it is not required to compressed the fuel gas 89 before feeding it to the fuel gas system 86. The fuel gas
is a combination of the added gas 57 and the gas present in the crude oil prior to stabilization. Additional stabilization steps may be included within unit 84 to allow for removal of additional gas to secure quality applicable for tanker transport. These additional steps will be performed at a lower pressure than the pressure of the fuel gas. If significant amounts of gas are released at a lower pressure, then the treatment system may also comprise a compressor to increase the pressure of the removed gas to the pressure required by the fuel system. Alternatively, if there are two fuel gas systems topside; 1) for feeding the generator turbine (high pressure) and 2) one for feeding a direct fired heater to provide heating medium, then the gas released at lower pressure is fed to the fuel system for the direct fired heater.
Alternatively if the pressure of the removed gas obtained in the first step is larger than the pressure needed for the fuel system. The two gas streams, from the first step with to high pressure and from the additional step with to low pressure may be combined before they are fed to the fuel gas system with the correct pressure. Figure 4 illustrated an embodiment of the present invention in further detail. The well fluid 1 enters a phase separator 2, where the gas stream 3 is separated from the liquid. In the illustrated embodiment a water stream 19 is passed to a produced water treatment system 4, and the oil stream 13 is past to an oil treatment system 6. The gas 3 is initially cooled by cooler 8 to obtain cooled gas 5. The cooling results in condensation of higher hydrocarbons which are separated in separator 10. The liquid stream 7 is via pump 12 and pipe 9 mixed with the main oil stream from the separator 2. The gas 1 1 leaving over the top of the separator 10 is subject to a gas treatment system. In figures 1-3 this was referred to as system 22 whereas here one embodiment of this system is disclosed in detail. However it should be noted that other subsea systems for gas conditioning are equally applicable. The crude gas stream 1 1 comprising a compound to be removed such as C02 and/or other acid gasses is fed to a contactor system 14, 16 arranged subsea. In the illustrated embodiment the contactor system is a 2 stage process with an initial direct contactor 14 and a traditional contactor column 16. However the present invention is not limited to this embodiment but any contactor system applicable for subsea arrangement may be employed. In the direct contactor the gas stream is brought in contact with a treatment solution stream fed trough pipe 23. The obtained gas treatment solution mixture proceeds as stream 17 into the contactor column 16. Lean treatment solution is provided to the column from pipe 21. In the illustrated embodiment the treatment solution for the direct contactor is obtained from the column 16 at a level above the gas inlet, however the present invention is not limited to this solution as lean treatment solution could also be fed to the direct contactor as well as the column. The treatment solution comprises one or more species that at least with some selectivity absorb the compound to be removed from the crude gas stream. A species and solvent/diluent applicable for forming an effective treatment solution can be selected by the user depending on the compound
to be removed and the prevailing conditions within the system. During contact with the treatment solution the compound to be removed is absorbed in the solution. The crude gas accordingly at least partly depleted from the compound to be removed leaves over the top of the column trough pipeline 31. The main crude gas stream accordingly stays subsea during the treatment process. The rich treatment solution leaves the contactor 16 trough the bottom outlet pipeline 25.
In the illustrated embodiment a pump 18 is provided to force the rich treatment solution 25 to proceed up through the riser or pipeline 27. The is only an illustration of one possible way of securing transport of the rich treatment solution up trough the pipeline 27 other methods of providing the needed pressure and flow can equally be employed. On a topside facility 90 a regeneration system 20 is installed. The system receives the rich solution from pipeline 27, desorbes and separates the absorbed compound there from and obtains a depleted treatment solution which is send back to the subsea contactor system trough pipeline/riser 21. The desorbed compound leaves the regeneration unit 20 as stream 29. If the compound is C02 the stream 29 may be treated and compressed in unit 60 and from there transported via pipeline 61 to a subsea injection well (not shown).
The obtained treated gas 31 enters a second system for removal of a second compound, such as water. The system comprises a direct contactor 34, where the gas is brought in contact with a treatment solution stream 43. The obtained mixture is fed to a contactor column 36. The rich treatment solution leaves via the bottom as stream 45, via pump 38 and is transported via pipeline 47 to a top side installation 90 and a regeneration unit 40. Here the compound absorbed in the rich treatment solution is released resulting in a compound stream 49 and a lean treatment solution 41 being returned to the subsea contactor 36. If the compound is water the stream 49 is steam that can be released to the atmosphere.
The treated gas stream 51 leaving over the top of 36 can be compressed in compressor 52 and the temperature of the compressed gas 53 controlled by heat exchanger 54. Hereby providing a treated gas stream 55 adjusted for subsea pipeline transport.
Claims
Method for providing fuel gas to a top-side processing system of a sub-sea well stream, where the method comprises separating the sub-sea well stream in a sub-sea arranged three phase separator obtaining a crude oil stream, and a crude natural gas stream, separating acid gasses and/or water from the crude natural gas, pressurizing the gas stream sub-sea, adding at least part of the pressurized gas to the crude oil stream subsea, transporting the added gas together with the oil to the topside, separating the gas from the oil in a first stabilization stage and providing the separated gas as fuel gas to a fuel gas system.
Method according to claim 1 , characterized in that the method further comprises removing water from the crude oil stream subsea to obtain dry crude oil, transporting the dry crude oil to the topside processing system.
Method according to claim 2, characterized in that removing water from the crude oil stream subsea comprises passing the crude oil trough a subsea arranged electrostatic coalescer.
Method according to claim 1 , 2 or 3, characterized in that the crude oil stream is stabilized for tanker transport in the top-side processing system through removal of dissolved gas.
Method according to anyone of the previous claims, characterized in that the first stabilization stage operates at a gas pressure equal to a pressure required for the topside fuel gas system.
Method according to anyone of the previous claims, characterized in that the crude oil is stabilized in the first stage and in a second stage with interstage heating.
Method according to anyone of the previous claims, characterized in that the step of separating acid gasses and/or water from the crude natural gas is performed subsea.
A subsea well topside fuel gas providing system comprising a sub-sea arranged three phase separator with a well stream inlet and at least a crude natural gas outlet and a crude oil outlet, a riser with a subsea riser inlet in fluid
communication with the crude oil outlet and in fluid communication with the crude natural gas outlet and a topside riser outlet in fluid communication with a topside arranged stabilization unit comprising a stabilized crude oil outlet and a fuel gas outlet.
9. System according to claim 8, wherein the system further comprises a subsea gas treatment system down stream the three phase separator with an inlet in fluid communication with the crude natural gas outlet and with a treated gas outlet in fluid communication with the riser.
10. System according to claim 8 or 9, wherein the system further comprises a subsea arranged water removal unit arranged downstream the three phase separator with a crude oil inlet in fluid communication with the crude oil outlet, a dry crude oil outlet in fluid communication with the riser and a water outlet.
1 1. System according to claim 10, characterized in that water removal unit
comprises an electrostatic coalescer.
12. System according to any one of the claims 8 to 1 1 , characterized in that the fuel gas outlet is in fluid communication with a fuel gas inlet to a topside arranged power generating unit.
13. System according to anyone of the claims 8 to 12, characterized in that the system further comprises a subsea natural gas compressor with an inlet in fluid communication with the natural gas outlet and a pressurized gas outlet in communication with the riser.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US14/380,720 US20150021235A1 (en) | 2012-02-23 | 2013-02-21 | Method and system for providing fuel gas to a topside facility |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
NO20120188 | 2012-02-23 | ||
NO20120188A NO20120188A1 (en) | 2012-02-23 | 2012-02-23 | Method and system for providing fuel gas to a topside facility |
Publications (2)
Publication Number | Publication Date |
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WO2013124338A2 true WO2013124338A2 (en) | 2013-08-29 |
WO2013124338A3 WO2013124338A3 (en) | 2014-04-10 |
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Application Number | Title | Priority Date | Filing Date |
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PCT/EP2013/053415 WO2013124338A2 (en) | 2012-02-23 | 2013-02-21 | Method and system for providing fuel gas to a topside facility |
Country Status (3)
Country | Link |
---|---|
US (1) | US20150021235A1 (en) |
NO (1) | NO20120188A1 (en) |
WO (1) | WO2013124338A2 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20150075660A (en) * | 2013-12-26 | 2015-07-06 | 대우조선해양 주식회사 | Topside Separator System having Bypass |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2013124336A2 (en) * | 2012-02-23 | 2013-08-29 | Fmc Kongsberg Subsea As | Offshore processing method and system |
US9879663B2 (en) * | 2013-03-01 | 2018-01-30 | Advanced Cooling Technologies, Inc. | Multi-phase pump system and method of pumping a two-phase fluid stream |
US10287509B2 (en) | 2016-07-07 | 2019-05-14 | Hellervik Oilfield Technologies LLC | Oil conditioning unit and process |
GB2584079B (en) * | 2019-05-13 | 2022-02-09 | Equinor Energy As | A method and system for preparing a fluid produced at an offshore production facility for transportation |
US20240093108A1 (en) * | 2022-09-21 | 2024-03-21 | Air Liquide Advanced Technologies U.S. Llc | System and method for recovery of fuel gas from crude oil purification |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2003033872A1 (en) | 2001-10-17 | 2003-04-24 | Norsk Hydro Asa | An installation for the separation of fluids |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NO312138B1 (en) * | 2000-05-04 | 2002-03-25 | Kongsberg Offshore As | Process and sea-based installation for handling and processing of multi-fraction hydrocarbons for sea |
NO20010589A (en) * | 2001-02-05 | 2002-08-05 | Navion Asa | Procedure and sea-based plant for treatment and handling of hydrocarbons |
WO2003086976A2 (en) * | 2002-04-08 | 2003-10-23 | Abb Offshore Systems, Inc. | Subsea well production facility |
-
2012
- 2012-02-23 NO NO20120188A patent/NO20120188A1/en not_active Application Discontinuation
-
2013
- 2013-02-21 WO PCT/EP2013/053415 patent/WO2013124338A2/en active Application Filing
- 2013-02-21 US US14/380,720 patent/US20150021235A1/en not_active Abandoned
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2003033872A1 (en) | 2001-10-17 | 2003-04-24 | Norsk Hydro Asa | An installation for the separation of fluids |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR20150075660A (en) * | 2013-12-26 | 2015-07-06 | 대우조선해양 주식회사 | Topside Separator System having Bypass |
KR102203738B1 (en) * | 2013-12-26 | 2021-01-15 | 대우조선해양 주식회사 | Topside Separator System having Bypass |
Also Published As
Publication number | Publication date |
---|---|
NO20120188A1 (en) | 2013-08-26 |
US20150021235A1 (en) | 2015-01-22 |
WO2013124338A3 (en) | 2014-04-10 |
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