WO2020256565A1 - Élimination de dépôts d'un séparateur sous-marin - Google Patents

Élimination de dépôts d'un séparateur sous-marin Download PDF

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Publication number
WO2020256565A1
WO2020256565A1 PCT/NO2020/050166 NO2020050166W WO2020256565A1 WO 2020256565 A1 WO2020256565 A1 WO 2020256565A1 NO 2020050166 W NO2020050166 W NO 2020050166W WO 2020256565 A1 WO2020256565 A1 WO 2020256565A1
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Prior art keywords
separator
fluid
heated
constituent fluid
interior
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PCT/NO2020/050166
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English (en)
Inventor
Cecilie Gotaas Johnsen
Knut Sveberg
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Equinor Energy AS
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Equinor Energy AS
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Publication of WO2020256565A1 publication Critical patent/WO2020256565A1/fr
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    • 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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B08—CLEANING
    • B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
    • B08B9/00—Cleaning hollow articles by methods or apparatus specially adapted thereto
    • B08B9/08—Cleaning containers, e.g. tanks
    • B08B9/093—Cleaning containers, e.g. tanks by the force of jets or sprays
    • B08B9/0933—Removing sludge or the like from tank bottoms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D12/00—Displacing liquid, e.g. from wet solids or from dispersions of liquids or from solids in liquids, by means of another liquid
    • 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

Definitions

  • the present invention relates to the removal of deposits from a fluid separator. It is particularly, but not exclusively, applicable for removing deposits of wax from subsea separators used to separate hydrocarbon-continuing fluid produced subsea.
  • Subsea hydrocarbon wells produce fluid that may contain various combinations of oil, water and gas, along with contaminants, sand etc. These constituents may be separated, typically using a gravity separator. These comprise a vessel into which the produced fluid is supplied by a pipe of substantially smaller diameter than the vessel. As a result, the flow velocity of the fluid reduces to a point that allows the different fluids to separate into“layers” as a result of their differing densities. In a two-phase separator, the liquid phase is then removed from an outlet arranged towards the bottom of the vessel and the gas is removed from one at or near the top. In a“three-phase” separator, the (liquid) oil and water components are regarded as separate“phases”, with separate outlets being provided for each. This relies upon the water being denser than the oil, though in both cases the respective outlets are provided towards the bottom of the vessel. There may be provided a boundary in the form of a weir over which the oil may flow in order to separate it from the water.
  • Subsea separators can operate at different pressures, which can be both below, similar to, or above the surrounding pressure at the seafloor.
  • the subsea separator operating pressure is normally optimised in order to maximise production from the reservoir.
  • the operating temperature is normally determined by that of the wellstream fluids, but will be cooled down by the surrounding seawater. Whilst the operating pressures and temperatures of a subsea reservoir can therefore fall within a wide range, a typical subsea separator may operate in a temperature range of between 10 and 25°C and a pressure range of 10 to 70 bar.
  • a single separator can be connected to a number of producing wellheads.
  • Each wellhead may produce a hydrocarbon-containing fluid with different pressure, temperature and ratios of oil, gas and water (amongst other constituents). When the fluid from each reservoir is combined, these parameters determine the wax appearance temperature (WAT) of the combined fluid.
  • WAT wax appearance temperature
  • the WAT is the temperature below which wax precipitates begin to form in the fluid. Such wax precipitates can cling to the walls of pipelines and other components and can lead to many issues, including a reduced flow, performance, or even a blocked pipeline or separator.
  • sediments e.g. sand particulates
  • sand particulates other substances contained within the fluid produced by the subsea reservoir, such as sediments (e.g. sand particulates), have a tendency to collect in the subsea separator (typically at its base). This collection of particulates further reduces the performance of the separator, and it is therefore important to also reduce the build-up of particulates and occasionally remove them from the separator altogether.
  • One known method of reducing the build-up of sediments over time is to cycle part of the separated fluid back through the separator in order to flush it.
  • a separator may separate produced fluid from the subsea reservoirs into oil, water and gas. Some of the oil and/or water may then be diverted from a point downstream of the separator, back to the interior of the separator, typically via nozzles directed at the base where sediments collect. This“flushes” the separator, and the fluid that is cycled back through the separator can carry sediments and wax precipitates out of the separator. They can then be removed from the fluid by further processing down the line.
  • a drawback with this method is that it is ineffective at removing wax precipitates that cling to the interior walls of the separator, where they are likely to form.
  • a method for removing deposits from the interior of a separator comprising:
  • separating a constituent fluid from a combined fluid in the separator removing the separated constituent fluid from the separator; heating at least part of the separated constituent fluid to a temperature higher than the temperature of the combined fluid in the separator; conveying the heated constituent fluid back into the interior of the separator; and using the heated constituent fluid to remove deposits from the interior or the separator.
  • fluid separated by the separator may be heated and then used to remove deposits from within the separator.
  • the fluid is used to assist in the removal of deposits, such as wax, which may be softened and/or melted and/or rendered more soluble by heat.
  • the invention is particularly useful where the combined fluid is produced hydrocarbon- containing fluid received from a wellhead (in which wax may form) and thus the constituent fluid may be water or oil.
  • the heated constituent fluid is preferably directed towards at least one interior surface of the separator because this is where deposits tend to occur. In particular, this is an effective means of treating deposits of wax which tend to cling to the walls.
  • the heated constituent fluid may be directed at the walls of the separator. In particular, the heated constituent fluid may be directed at interior walls where wax precipitates are most likely to form, and is preferably directed at the side walls of the separator which are normally oil-wetted.
  • These oil-wetted regions are located between the oil and water boundary and the oil and gas boundary in the separator, and so are exposed to oil during the separation process.
  • the heated fluid is preferably directed at the separator’s walls between these boundaries.
  • These regions of the sidewall are typically where a large amount of wax precipitates from the oil forms and clings to the sidewalls as they are cooled by the surrounding seawater. By directing heated constituent fluid directly at these regions that are most affected by wax appearance, wax removal can be improved.
  • the heated constituent fluid when heated constituent fluid is directed at a region of the sidewall in the oil-wetted region, the heated constituent fluid will flow down the side walls as it cools. Provided it initially is at a sufficiently high temperature, as is preferred, it will remain at a higher temperature than the other fluids in the separator as it does so. If the constituent fluid is water, it will then enter the water-wetted region before exiting out of the separator. In this way, residual heat in the constituent fluid can be used to clear wax precipitates from other areas of the sidewall, in particular those below the oil-wetted region at which the constituent fluid is initially directed.
  • the constituent fluid is oil, then it will remain in the oil section of the separator, whereas water would have to be subsequently separated from the oil by settling into the water region.
  • the fluid is preferably directed by means of openings which may be in the form of nozzles. These may be designed to provide jets of fluid, whereby the heated constituent fluid is impinged onto the interior surfaces of the separator. This may provide a mechanical scouring effect in addition to the softening/melting/dissolving effect provided by the elevated temperature. Particularly in combination, the effects of heat and mechanical scouring are effective on deposits such as wax and/or sand.
  • Such nozzles are preferably arranged to direct the heated fluid in such a way that at least the worst- affected areas of the interior side and bottom walls are impinged with the fluid flow.
  • the number and arrangement may be varied as required for a particular application. Pressure drop across the nozzles will vary with spread angle and flow rate. A high volume of flow and high pressure drop is preferred as this will result in the most effective wax removal.
  • the invention may further comprise its own heat source for this purpose, for example, an electrical heater or a heat-exchanger using a separate source of heated fluid as a heat source
  • the constituent fluid is preferably heated as part of a treatment process downstream of the separator.
  • Such processing may involve further separation and/or purification stages.
  • the inventors have realised that it is possible to use residual heat that is a result of such further fluid processing, to more effectively remove deposits such as wax precipitates from the interior of a separator.
  • conventional treatment systems can be used to heat the constituent fluid and existing subsea separator arrangements can be modified for use in the invention.
  • water separated from produced fluid from a hydrocarbon reservoir is usually treated for any number of uses including releasing it into the sea or re-injection into the reservoir in order to support the reservoir pressure.
  • the processing apparatus may treat the separated water to standard that it can be released into the sea, or to such a standard that it can be re-injected into the subsea reservoir in order to support reservoir pressure.
  • This treatment of the separated water typically occurs at temperatures of between 30 and 60 degrees Celsius.
  • the separated water from the subsea separator at temperatures of around 13 degrees Celsius, for example) must be heated and will retain much of this heat after the treatment process is completed.
  • the treatment temperatures of around 30 to 50 degrees Celsius are normally higher than the WAT of fluid produced by subsea reservoirs, and the operating temperatures of separators.
  • the inventors have realised that this warmer treated water can be diverted back into the separator in order to remove wax precipitates from the separator more effectively.
  • the higher temperatures can at least partially melt the wax precipitates, causing them to detach from interior surfaces of the separator and subsequently be removed from the separator.
  • Oil separated from the produced fluid must typically also undergo further processing comprising heating downstream.
  • the source of heat also to be located sub-sea.
  • remote heat sources it is within the scope of the invention for remote heat sources to be used, for example, when treatment occurs topside. If such treated water is then to be re-injected into the subsea reservoir, it must be passed down to the sea bed via a riser. Such re-injection is typically carried out via injection points on the sea bed and the heated separated water will be conveyed through flow lines on the sea bed from the base of the riser prior to reaching these injection points. If processed oil from the topside is to be stored or transported via pipelines subsea, this must also be passed down to the sea bed via a riser
  • the separator is a subsea separator
  • part of the heated water and/or oil can be diverted relatively easily from the flow lines on the sea bed leading to the subsea injection points to instead be directed back to the subsea separator.
  • existing subsea separator arrangements can be modified for use in the invention.
  • heating is provided by means of such downstream processing, in some cases it may be necessary or expedient to provide additional heating after such treatment in order to achieve the desired temperature.
  • This may be provided by an electric heater or heat exchanger, for example, as mentioned above.
  • a dedicated heater or heat exchanger could be used to raise the temperature of part of the constituent fluid before treatment, and this constituent fluid could be diverted back to the separator before any treatment occurs.
  • the particular temperature of the returned constituent fluid may be selected as required for a particular application. However, in a case where wax formation is a particular concern, it may be heated to above the wax appearance temperature of the combined fluid in the separator. Accordingly, the method may further comprise determining the wax appearance temperature of the combined fluid in the separator.
  • the method may further comprise monitoring the performance of the separator, and the step of conveying the heated constituent fluid back into the separator may then be carried out only when the performance of the separator is below a predetermined level.
  • Monitoring of performance may comprise measuring the output (e.g. the flow rate and/or composition) from the separator or measuring the build-up of deposits, e.g. the thickness of wax precipitates on the walls of the separator.
  • Monitoring and control may be carried out by means of a controller, such as a microprocessor-based controller. It may receive inputs from sensors such as temperature and flow sensors and control the flow of heated fluid by means of pumps and/or valves, as will be discussed further below.
  • the deposit-removal process may be controlled in a binary fashion (i.e.“on” or“off”).
  • the amount of water redirected back to separator may be varied, depending on performance - i.e. the flow may be increased in cases of high deposit build-up. If necessary, the flow may be continuous, but more typically the process will be activated as required.
  • the passing of the heated constituent fluid back into the separator is performed periodically at predetermined time intervals.
  • This may be on a simple a“need it or not” basis, with the time intervals estimated conservatively to ensure that there is only an acceptable level of deposit build-up between cycles.
  • the time intervals may be determined based on any one or a combination of: wax appearance temperature of fluid in separator; operating temperature of separator; performance of separator; and wax build up in separator, in order to optimise operation.
  • the invention also extends to a corresponding system for performing it and therefore, viewed from another aspect, there is provided a system for removing deposits from the interior of a separator, the system comprising: a separator for separating a constituent fluid from a combined fluid; a heat source arranged to receive and heat the separated constituent fluid; and a conduit arranged to convey the heated constituent fluid back into the interior of the separator for use in removing deposits from the interior of the separator.
  • a plurality of openings such as nozzles, may be provided by the conduit for the directing the heated constituent fluid towards at least one interior surface of the separator.
  • the heated constituent fluid is preferably directed at the side walls of the separator in oil-wetted zones, as discussed previously.
  • the method and system of the present invention may be employed in any type of separator known in the art, for example gravity separators or centrifugal separators, and the nozzle arrangement may be configured for use with any such separator.
  • it may further comprise a sensor for measuring the operating temperature of the separator; and a controller for controlling the heating of the separate constituent fluid such that it is heated to a temperature greater than the operating temperature of the separator measured by the sensor.
  • a sensor for measuring the temperature of heated constituent fluid may be used to determine the amount of heat that must be supplied to the constituent fluid by the heat source and hence to control, for example, the flow of constituent fluid or the temperature of the source in order to ensure that the desired degree of heating is obtained.
  • the controller may be arranged to control the heating of the separated constituent fluid such that it is heated to a temperature greater than the wax appearance temperature of the combined fluid in the separator. Accordingly, it may also comprise a means for determining the wax appearance temperature of the combined fluid in the separator, based on the parameters discussed above.
  • the system may also comprise one or more sensors for monitoring the performance of the separator, wherein the heated constituent fluid is conveyed back into the interior of the separator only when the performance of the separator is below a predetermined level.
  • sensors may measure the flow and composition of fluid from the separator (on the basis that a build-up of deposits will tend to block parts of the separator and hence reduce the quality of the products out of the separator).
  • a sensor may directly measure the depth of deposit build-up on walls of the separator (e.g. optically or mechanically).
  • the system may provide suitable valves to control the flow of heated fluid.
  • a valve may be provided to control the flow of heated fluid from a location downstream of the separator.
  • the valve which may be a metered valve may be under the control of the controller and may provide feedback thereto.
  • the controller may close the valve so that no heated constituent fluid is diverted back to the separator unnecessarily.
  • the controller can then open this metered valve if the performance drops below the predetermined level in order to remove wax precipitates from the separator.
  • the valve may be variable such that the controller can alter the amount of constituent fluid diverted back to the separator depending on its performance level.
  • the controller can also control the metered valve such that it is opened at predetermined time intervals, so that heated constituent fluid is diverted back to the separator periodically. These periods can be a predetermined cycle or may be based on any of the measurements discussed herein.
  • the controller can also determine the wax appearance temperature of the produced fluid in the separator. This may done by testing the produced fluid, or by measuring relevant parameters such as pressure, temperature, and the ratio of constituents of the produced fluid using additional sensors. The controller can then ensure that the constituent fluid is heated to a temperature greater than the wax appearance temperature of produced fluid in the separator.
  • the system preferably operates in accordance with the method previously described, and in particular, the preferred features thereof.
  • the controller may be microprocessor-based and have inputs from the various sensor discussed above and provide output signals to the valve(s), heat source and optionally other components such as pumps. It may operate under the instructions of suitable software. Accordingly, viewed from a still further aspect, there is provided a computer program product for providing instructions to cause such a processor to perform the method(s) described above.
  • Figure 1 shows a schematic elevation of a prior art three phase separator that is flushed in a manner known in the art
  • Figure 2 shows a schematic elevation of a prior art two phase separator that is flushed in a manner known in the art
  • Figure 3 shows a cross-section along the line A-A of the three phase separator of Figure 1 ;
  • Figure 4 shows a schematic elevation of a three phase separator according to an embodiment of the present invention
  • Figure 5 shows a cross-section along the line A-A of the three phase separator of Figure 4;
  • Figure 6 is a schematic diagram of the control system of the embodiments.
  • Figure 1 shows an example of a three phase subsea separator 1 known in the art, with an inlet 2 for receiving produced fluid 3 from a subsea reservoir (not shown).
  • the produced fluid comprises oil, gas, water and sediments.
  • the separator has walls 4, an internal divide 5, an outlet 6 for gas, an outlet 7 for water and an outlet 8 for oil.
  • the separator 1 is located at the seabed.
  • the separator shown in Figure 1 operates on the known principle of gravity separation.
  • the density difference between the oil, water and gas causes them to settle into“layers” and separate due to their differing densities and the effect of gravity.
  • Figure 1 shows an example boundary 9 between gas G and oil O and a boundary 10 between oil O and water W.
  • the configuration of internal divides and the outlets makes it possible to remove the layers of oil, water and gas from the separator individually. It will be noted that water collects behind divide 5 and that oil may flow over the divide, which acts as a weir, into the region where outlet 8 is provided. Any sediment will typically collect at the bottom of the separator.
  • a pump 11 is provided for pumping separated oil out of the separator from the outlet 8 to a conduit 13.
  • Conduit 13 leads to further processing apparatus for processing the oil in the conventional manner.
  • second pump 12 is provided for pumping water out of the separator through outlet 7 to conduit 14.
  • Conduit 14 leads via further conduit 18 to further processing apparatus for treating the separated water.
  • conduit 16 There is a metered valve 16 provided downstream of the outlet 7 and pump 12 so that the separated water (or a portion of it) may be diverted through it from conduit 14. The remainder of the separated water continues along conduit 18 to further processing apparatus, re-injection apparatus or to be released into the sea.
  • Metered valve 16 leads to conduit 17, which in turn leads back to the separator at inlet 19.
  • Conduit 19 leads, via inlet 19, to the interior of the separator where it divides into many branches, two of which 21 , 22 are shown. These each have a plurality of openings 23.
  • the separated water in conduit 17 is directed through branches 21 , 22 and out of openings 23.
  • the openings 23 are in the form of nozzles directed at bottom 31 of the separator such that sediment and wax that has collected here is flushed out by the water through outlet 7 and removed further downstream.
  • Figure 2 shows a two phase separator 20 known in the art for separating gas G from liquid L, i.e. there is no separate oil-water separation. However, it is otherwise generally similar to the first separator described above. Thus, a boundary 28 can be seen between gas G and liquid L phases. Also similar to separator 1 , this two phase separator has an inlet 2 for produced fluid 3 and an outlet 6 for gas. However, this two-phase separator has only one outlet for liquid, outlet 29. This separator does not feature the internal divide of the three-phase separator (as this is unnecessary in a two-phase separator).
  • the flushing system is similar to that described above in relation to Figure 1 in that separated water is supplied via a conduit 17 and inlet 19 to nozzles 23 arranged within the separator 20 to remove collected sediment and wax.
  • Figure 4 shows a three-phase separator 1 generally similar to the separator described in relation to Figure 1 , except the separator 1 is additionally provided with a system for controlling and removing the build-up of wax and particulates using heated water and/or oil that has been output from the separator.
  • separator 1 is provided with an inlet 2 for receiving produced fluid 3 from a subsea reservoir (not shown).
  • the produced fluid comprises oil, gas, water and sediments.
  • the separator has walls 4, an internal divide 5, an outlet 6 for gas, an outlet 7 for water and an outlet 8 for oil. It is also located at the seabed.
  • a pump 11 is provided at the base of the separator 1 for pumping separated oil out of the separator from the outlet 8 to a conduit 13.
  • Conduit 13 leads to further processing apparatus for processing the oil in the conventional manner.
  • second pump 12 is provided for pumping water out of the separator through outlet 7 to conduit 14.
  • Conduit 14 leads via further conduit 18 to further processing apparatus for treating the separated water.
  • a metered valve 16a is provided downstream of pump 12 so that the separated water (or a portion of it) may be diverted through it from conduit 14 to conduit 17a.
  • Conduit 17a branches so that a portion of this water flows to inlet 19 from which it flows via conduits 21 and 22 to openings 23 at the base of the separator (see Figure 5) as previously described. However, the remainder flows via a heat source (shown indicatively at 15a), which heats the water before it enters the separator at heated water inlet 19a for use in removing built up wax as will be described below.
  • the heat source 15a is advantageous for the heat source 15a to be located downstream of valve 16a and the branch in conduit 17a (as shown), so that only the portion of the separated water necessary for removing the build-up of wax is heated.
  • the heat source could be located upstream of valve 16a, for example in conduit 14 or downstream of valve 16a but upstream of the branch in conduit 17a.
  • Heat source 15a may be part of the conventional water processing apparatus or a separate heat source, as will be described further below.
  • a metered valve 16b is provided downstream of pump 11 so that the separated oil (or a portion of it) may be diverted through it from conduit 13 to conduit 17b.
  • a heat source (shown indicatively at 15b) is provided for heating some or all of the oil flowing through conduit 17b. This may be part of the conventional oil processing apparatus or a separate heat source. Again, this could be alternatively located upstream of valve 16b.
  • Conduit 17b is insulated and may have additional heat exchangers incorporated into it for heating of the separated oil.
  • the heated oil is then returned to the separator at inlet 19b.
  • the pressure in both the oil and water conduits 13, 14 downstream of the separator is higher than the separator pressure, and consequently pumps are required to maintain the flow of oil and water out of the separator.
  • pumps 11 , 12 are not necessarily required and may be exchanged for metered valves, and metered valves 16a, 16b may be exchanged for pumps.
  • Conduit 17a leads, via inlet 19a, to the interior of the separator where it divides into many branches, two of which 21a, 22a are shown; these each have a plurality of openings 23a.
  • opening 23a along with a corresponding arrangement for the heated oil terminating in a plurality of openings 23b, can be seen.
  • inlets 19, 19a and 19b are shown for each of the conduits 17, 17a and 17b in Figure 4, it will be appreciated that conduits 17, 17a and 17b could be configured to all enter the interior of the separator through the same inlet point (e.g. by means of a concentric arrangement at the location of inlet 19).
  • the heated water in conduit 17a is directed through branches 21a, 22a leading to a plurality of openings 23a.
  • the openings 23a are directed at interior surfaces of the separator, in this embodiment the openings 23a are directed at the side walls 32 of the separator in the oil-containing region.
  • the plurality of openings 23a comprise nozzles arranged to direct the heated water and impinge it on the interior surfaces of the separator.
  • the walls 4 of a subsea separator and in particular the region 32 of the walls in the region where the oil O is found, are typically where wax precipitates collect because the separator is surrounded by cold seawater. This seawater cools the walls to a temperature slightly below the operating temperature of the rest of the separator, thereby inducing the formation of precipitates.
  • the wax removing effect is two-fold.
  • the pressure of the water/oil directed through the nozzles and impinging on the surface can detach wax precipitates from the interior walls of the separator by mechanical action.
  • the heat from the heated water/oil can at least partially melt or soften some of the accumulated wax, thus making it easier to detach it off from the walls.
  • the plurality of openings 23a may direct the heated water at the side walls of the separator and this may be at a different pressure to that from the openings 23 for the unheated separated water located towards the bottom of the separator. For example, a higher pressure may be used if wax precipitates are more likely to be found on the side walls of the particular separator, or a lower pressure may be used order to limit the mixing of water into the separated oil.
  • Heated water from nozzles 23a impinged on the sidewalls will typically remain close to the interior wall of the separator, and gradually flow down it due to the effects of the gravity separation. In this way, the entirety of the side walls of the separator from the plurality of openings 23a downwards can be partly heated by the heated water. This can help to remove wax precipitates from a greater interior surface area of the separator in this variant embodiment.
  • the use of the heated water is also effective for removing sediments from the separator because sediments typically collect in lower regions as the produced fluid in the separator begins to settle, and the heated water will flow down the side walls of the separator into the water region W, before exiting through outlet; in doing so it can remove sediments in this region.
  • the separator is operating normally. As such, the reintroduced water is eventually separated out again via the normal separation process and no shutdown of the separator is required in order to carry out the removal of wax precipitates.
  • heated oil from nozzles 23b impinged on the sidewalls will typically remain close to the interior wall of the separator, and gradually flow down it due to the effects of the gravity separation. However, heated oil will remain in the oil region O, preventing the need for further separation.
  • separator comprises a number sensors for use in controlling the build-up control system described above.
  • the operating temperature of the separator is measured by a sensor S1 in the interior of the separator and/or at the outlets for water and oil 7, 8 (S2).
  • the system also comprises sensors S3 for measuring the temperature of the separated water and oil respectively after heating.
  • sensors S4 are provided for measuring the performance of the separator (i.e. outlet the flow rate), and hence indicating whether there is a significant build-up of wax precipitates.
  • a controller 30 (see Figure 6) is provided which is connected to the sensors S1-S4, heat sources 15a and 15b and metered valves 16a and 16b. Controller 30 is a microprocessor-based control system.
  • the controller determines when the performance of the separator drops below a predetermined level, indicating a build up of wax precipitates. When this occurs it activates the build-up control system, whereby heated water and/or oil is returned to the separator for use in removing the wax.
  • the controller determines the temperature of water and/or oil leaving the separator and provides control signals to the heat sources 15a and/or 15b to raise the temperature to the desired level. Feedback control of the heated water and/or oil temperature is then provided by sensors S3. Once the water and/or oil is sufficiently heated, metered valves 16a and/or 16b, which are also connected to the controller, are opened. The flow rate through the valves may also be adjusted as part of the control of temperature (a lower flow rate resulting in a higher temperature from a given amount of heat applied to a smaller volume of water/oil).
  • the controller is able to control the flow and temperature of heated water/oil via the metered valves as required based on measurements of the operating temperature of the reservoir and the measured temperature of the heated water/oil.
  • the controller can ensure that the separated water/oil is heated to a temperature significantly higher than the operating temperature of the separator.
  • the controller may also vary the amount of water/oil supplied depending upon the degree of wax build-up detected.
  • the wax control system described above may also be employed in a two phase separator like that shown in Figure 2.
  • heated constituent fluid(s) typically oil
  • the heated constituent fluid would be provided via a conduit 17 and inlet 19 to nozzles arranged within the separator 20 and configured to direct the heated fluid at regions of the separator where wax is likely to appear.
  • the heated constituent fluid would be provided and its supply controlled by means of a controller 30 in a manner similar to that previously described.
  • heat is added from a heat source 15a, 15b which is part of the conventional treatment process of the water or oil. This raises the temperature of the separated water/oil to above the operating
  • the heat added to the water or oil can also raise the temperature of the separated water/oil to above the wax appearance temperature of the produced fluid in the separator.
  • Heat may also be added to the separated water/oil via a heat source which is separate from (and/or additional to) the conventional processing means.
  • the separated water/oil could be heated by a heat exchanger prior to or after the treatment of separated water.

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  • Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

Abstract

L'invention concerne un système permettant d'éliminer des dépôts de l'intérieur d'un séparateur (1), ledit système comprenant : un séparateur (1) pour séparer un fluide constitutif d'un fluide combiné ; une source de chaleur (15a) ; (15b) agencé pour recevoir et chauffer le fluide constitutif séparé ; et un conduit (17a) ; (17b) agencé pour transporter le fluide constitutif chauffé à l'intérieur du séparateur (1) pour une utilisation dans l'élimination de dépôts de l'intérieur du séparateur.
PCT/NO2020/050166 2019-06-18 2020-06-17 Élimination de dépôts d'un séparateur sous-marin Ceased WO2020256565A1 (fr)

Applications Claiming Priority (2)

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GB1908736.0A GB2584998A (en) 2019-06-18 2019-06-18 Removing deposits from a subsea separator
GB1908736.0 2019-06-18

Publications (1)

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WO2020256565A1 true WO2020256565A1 (fr) 2020-12-24

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PCT/NO2020/050166 Ceased WO2020256565A1 (fr) 2019-06-18 2020-06-17 Élimination de dépôts d'un séparateur sous-marin

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GB (1) GB2584998A (fr)
WO (1) WO2020256565A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11603722B2 (en) * 2019-09-06 2023-03-14 Saipem S.A. System for collecting solid particles accumulating at the bottom of a subsea oil/water separation station

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015036041A1 (fr) * 2013-09-13 2015-03-19 Statoil Petroleum As Appareil de séparation d'hydrocarbures avec boucle de recirculation
WO2017196234A1 (fr) * 2016-05-10 2017-11-16 Recondoil Sweden Ab Procédé et système de purification de produits hors spécification et d'émulsions industrielles comprenant deux processus exécutés en parallèle

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4913819A (en) * 1987-08-28 1990-04-03 Atlantic Richfield Company Liquid jet solids removal system for process vessels
US5776257A (en) * 1996-07-09 1998-07-07 Landry Service Co. Inc. Gas tight tank cleaning method
US20070283981A1 (en) * 2006-06-08 2007-12-13 Stewart Tracy E Method for cleaning storage tanks
CN201581883U (zh) * 2009-12-08 2010-09-15 江苏三星化工有限公司 一种高效泥沙冲洗装置
US8864887B2 (en) * 2010-09-30 2014-10-21 Rodney T. Heath High efficiency slug containing vapor recovery
US9884997B2 (en) * 2011-09-30 2018-02-06 Mcw Energy Group Limited Oil from oil sands extraction process

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015036041A1 (fr) * 2013-09-13 2015-03-19 Statoil Petroleum As Appareil de séparation d'hydrocarbures avec boucle de recirculation
WO2017196234A1 (fr) * 2016-05-10 2017-11-16 Recondoil Sweden Ab Procédé et système de purification de produits hors spécification et d'émulsions industrielles comprenant deux processus exécutés en parallèle

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11603722B2 (en) * 2019-09-06 2023-03-14 Saipem S.A. System for collecting solid particles accumulating at the bottom of a subsea oil/water separation station

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GB2584998A (en) 2020-12-30

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