Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G33/00—Dewatering or demulsification of hydrocarbon oils
  • C10G33/04—Dewatering or demulsification of hydrocarbon oils with chemical means
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/02—Separation of non-miscible liquids
  • B01D17/0208—Separation of non-miscible liquids by sedimentation
  • B01D17/0214—Separation of non-miscible liquids by sedimentation with removal of one of the phases
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/02—Separation of non-miscible liquids
  • B01D17/04—Breaking emulsions
  • B01D17/047—Breaking emulsions with separation aids
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/08—Thickening liquid suspensions by filtration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D17/00—Separation of liquids, not provided for elsewhere, e.g. by thermal diffusion
  • B01D17/08—Thickening liquid suspensions by filtration
  • B01D17/085—Thickening liquid suspensions by filtration with membranes
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G31/00—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for
  • C10G31/08—Refining of hydrocarbon oils, in the absence of hydrogen, by methods not otherwise provided for by treating with water
• • 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
  • E21B43/40—Separation associated with re-injection of separated materials
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G2300/00—Aspects relating to hydrocarbon processing covered by groups C10G1/00 - C10G99/00
  • C10G2300/40—Characteristics of the process deviating from typical ways of processing
  • C10G2300/4081—Recycling aspects

Definitions

• This invention relates to the recovery of
• the invention relates to improved processes and apparatus for separating mixtures comprising an emulsion of
• Hydrocarbons are a large class of organic compounds composed of hydrogen and carbon.
• asphaltenes are all mixtures of various hydrocarbons. Though hydrocarbons are generally defined as molecules formed primarily of carbon and hydrogen atoms, they may also include other elements, such as, but not limited to, halogens, metallic elements, nitrogen, oxygen and/or sulfur .
• Hydrocarbons are typically recovered or produced from subterannean formations by a variety of methods.
• Primary recovery techniques refer to those techniques that utilise energy from the formation itself to recover the hydrocarbons in the subterranean formation.
• primary recovery techniques are only capable of producing a small fraction of the oil in place in the reservoir. Consequently secondary techniques, such as waterflooding, and numerous tertiary techniques (commonly referred to as “enhanced oil recovery” (EOR) techniques), have been developed, which have as their primary purpose the recovery of additional quantities of hydrocarbons known to be present in the reservoir.
• EOR enhanced oil recovery
• hydrocarbons in place. It is well known that much of the retained hydrocarbons in the reservoir after a typical waterflood are in the form of globules or droplets that are trapped in the pore spaces of the reservoir. The high normal interfacial tension between the reservoir water and hydrocarbons prevents these discrete droplets from deforming to pass through narrow constrictions in pore channels.
• Microemulsions which may be injected or formed within a hydrocarbons formation, are miscellar mixtures of oil, water and a surfactant, frequently in combination with a co-surfactant, co- solvent or other chemicals.
• a surfactant frequently in combination with a co-surfactant, co- solvent or other chemicals.
• microemulsion refers broadly to emulsions which are thermodynamically stable.
• Optimal salinity is usually thought of as the specific salt concentration that produces the lowest interfacial tension between oil and water in a given mixture and thus results in a middle phase microemulsion.
• the recovered liquid from a producing well is usually in the form of a mixture (emulsion) comprising hydrocarbons, water and a surfactant.
• a mixture emulsion
• hydrocarbons hydrocarbons
• surfactant typically comprise, as one component, a microemulsion of water and hydrocarbons.
• microemulsion component for recovering valuable chemicals contained in such mixtures for reuse in cEOR.
• GB 2 146 040 describes a method for breaking oil-water-surfactant emulsions that have as one component a microemulsion. This method separates oil, brine, and surfactant, to produce pipeline quality oil and an injectable brine/surfactant phase by carefully controlling temperature and salinity within certain operable ranges.
• US2009/0281003 relates to a method in which
• chemicals in a cEOR stream are forced into either an aqueous or an organic phase and are then concentrated and re-injected into an oil-bearing formation.
• the present invention seeks to solve the technical problem of providing a more sustainable and/or cost-effective hydrocarbon separation method and system than the prior art .
• the invention resides broadly in a method of separating a hydrocarbon phase from an input mixture comprising an emulsion of water and
• hydrocarbons in the presence of a surfactant surface- active agent
• the method comprising: adjusting the salinity of the mixture to release hydrocarbons and water from the emulsion into a hydrocarbon phase and a salt- containing aqueous phase respectively; and separating at least a part of the hydrocarbon phase from the salt- containing aqueous phase, wherein at least a part of the salt-containing aqueous phase is recovered (or retained) for further use.
• the input mixture comprises hydrocarbons, water, and a surfactant, it typically comprises, at least as one component, a microemulsion .
• the interfacial tension between hydrocarbons and water in the input mixture may for example be below 1 dyne/cm.
• the input mixture may preferably be a mixture produced by cEOR and may therefore further include a co- surfactant, a co-solvent or other chemicals, as is known in the art. Additionally, cEOR mixtures have a salinity consistent with operational requirements for hydrocarbons recovery. As lowering interfacial tension is a key objective, some cEOR mixtures may be at or close to
• the salinity of the input mixture may vary, e.g. based on operational requirements for hydrocarbons recovery, or as a result of treatment, dilution or concentration carried out before the method of the invention.
• Salinity is known to have an impact on interfacial tension in water-hydrocarbons-surfactant mixtures, and is therefore a state variable that is used in the present invention to control, particularly reduce, the degree of emulsification in such mixtures, with the aim of
• the method of the invention enables reuse of salt and/or water to adjust the salinity of the input mixture.
• salt and/or water need not be sacrificed during the
• the method may comprise reusing at least a part of the salt-containing aqueous phase, for example salt and/or water contained therein, to adjust the salinity of the mixture as described above.
• the method of the invention may be operated continuously, in the sense that more than one batch of input mixture may be subjected (successively) to the method of the invention. Most advantageously, the method may be carried out in a continuous flow.
• the method may be carried out in a
• Batch operation of the method is typically less effective than continuous flow operation but may be of particular benefit where the method is to be used intermittently, or where individual steps of the method are to be carried out in geographically distinct locations, as is optionally contemplated within the scope of the invention.
• the release of hydrocarbons and water from an emulsion into a hydrocarbon phase and a salt-containing aqueous phase may be accomplished by either an increase or a decrease in salinity.
• adjusting the salinity of the input mixture may comprise either increasing or decreasing the salinity of the mixture.
• An increase in salinity may be achieved by adding salt to the input mixture and/or by removing water from the input mixture, whereas a decrease in salinity may be achieved by
• an increase in salinity may be more
• the method may further comprise desalinating the salt-containing aqueous phase to provide a first stream having a relatively high salinity and a second stream having a relatively low salinity.
• Desalination may be carried out in any suitable desalination station or unit, for example by
• the first, high salinity stream may advantageously be used (or recycled) to increase the salinity of the mixture, i.e. to aid emulsion breaking as described above.
• the high salinity stream must have a salinity which is higher than the salinity of the input mixture.
• the high salinity stream may advantageously have a salinity above the salinity of the input mixture.
• the surfactant in the input mixture is generally distributed in both the water and the hydrocarbons.
• the method of the invention may advantageously further comprise washing the hydrocarbon phase to recover surfactant and optionally salt
• the low salinity stream produced by desalination of the salt-containing aqueous phase may be reused to wash the hydrocarbon phase to recover
• the low salinity stream may preferably be desalinated such that its salinity is lower than the salinity of the input mixture.
• the low salinity stream may have a salinity below "optimal salinity" .
• the hydrocarbon phase may preferably be separated to form a purified crude oil stream, leaving behind an aqueous surfactant recovery stream.
• surfactant recovery stream may advantageously be re ⁇ injected into a hydrocarbons bearing formation in a cEOR process, optionally in combination with salt from the first, high salinity stream.
• the invention broadly resides in a hydrocarbons separation system suitable for
• the system comprising: an inlet for introducing a mixture comprising an emulsion of water and hydrocarbons in the presence of a surfactant; a salinity adjustment station for adjusting the salinity of the mixture; separating means for separating from the mixture a hydrocarbon phase and a salt-containing aqueous phase; and recovery means for recovering at least a part of the salt-containing aqueous phase for further use.
• the recovery means may advantageously comprise a conduit for recycling at least a part of the salt- containing aqueous phase to the salinity adjustment station to adjust the salinity of the mixture.
• the separation system may comprise a membrane, for example of the ceramic type. The membrane may act as the sole separating means or may be combined with a phase separation vessel.
• the system may further comprise
• the desalination means for desalinating the salt-containing aqueous phase to provide a first stream with a relatively high salinity and a second stream with a relatively low salinity.
• the desalination means may comprise a reverse osmosis unit, or a nanofiltration unit, or a
• nanofiltration, ultrafiltration or microfiltration unit upstream of a reverse osmosis unit.
• the system may comprise a conduit for channelling the first stream to the salinity adjustment station to increase the salinity of the mixture.
• the system may advantageously further comprise washing means for washing the hydrocarbon phase and recovering a surfactant recycle stream, and a conduit for channelling the second, low salinity stream to the washing means.
• the invention contemplates the further use and reuse of various components separated from a mixture comprising water, hydrocarbons and a surfactant.
• the invention resides in a chemical enhanced oil recovery process comprising injecting surfactant
• the surfactant may be combined with salt recovered as described anywhere herein, for example prior to inj ection .
• emulsion refers simply to a mixture of two or more immiscible liquids.
• an emulsion of water and hydrocarbons in the presence of a surfactant can lead to the formation of at least an amount of a "microemulsion", i.e. a thermodynamically stable emulsion.
• interfacial tension refers to the strength of the film separating two immiscible fluids (hydrocarbons and water) measured in dynes per centimetre, according to ASTM D971.
• salt refers to all salts soluble in water. Sodium chloride is a preferred salt.
• Salinity refers to the amount of dissolved salt in water. Salinity referred to herein may be determined according to the Practical Salinity Scale 1978 (PSS78), originally developed for seawater, which involves a conductivity comparison to a solution of 32.4356 g/kg KC1 at 15°C.
• PSS78 Practical Salinity Scale 1978
• optimal salinity refers to the salt concentration that produces the lowest
• interfacial tension between oil and hydrocarbons in a given mixture of hydrocarbons, water and a surfactant may be measured by standard interfacial tension
• surfactant or "surface active agent” as used herein refers to any chemical agent capable of reducing the interfacial tension between hydrocarbons and water .
• Figure 1 is a schematic diagram of a hydrocarbons separation system for separating hydrocarbons from a hydrocarbons recovery mixture according to a first embodiment of the invention
• Figure 2 is a schematic diagram of a hydrocarbons separation system for separating hydrocarbons from a hydrocarbons recovery mixture according to a second embodiment of the invention.
• Figure 3 is a schematic diagram of a hydrocarbons separation system for separating hydrocarbons from a hydrocarbons recovery mixture according to a third embodiment of the invention.
• the hydrocarbons separation systems and methods (or processes) each serve to extract or separate a hydrocarbon phase from an input mixture.
• the input mixture comprises an emulsion of water and hydrocarbons in the presence of a surfactant (surface-active agent) .
• a surfactant surface-active agent
• the input mixture could stem from any suitable source, in practice, such mixtures are most commonly obtained from chemical enhanced oil recovery (cEOR) streams.
• the hydrocarbons separation systems and methods according to the three exemplary embodiments of the invention comprise adjusting, specifically increasing, the salinity of the input mixture to release hydrocarbons and water from the emulsion into a hydrocarbon phase and a salt-containing aqueous phase respectively. Thereafter, at least a part of the hydrocarbon phase is separated for further use, and at least a part of the salt-containing aqueous phase is recovered for reuse.
• the methods according to the exemplary embodiments of the invention are each carried out in a continuous flow manner, in a single system or facility.
• the individual stages of the methods could also be performed in batches, either in a single facility, or in several geographically distinct locations.
• hydrocarbons in the form of crude oil
• water and a surfactant is input into a hydrocarbons recovery system.
• the surfactant in the cEOR mixture 1 may be of any known type suitable for cEOR.
• the cEOR mixture may comprise other additives as known in the art .
• the cEOR mixture 1 has an original salinity that supports effective cEOR, at which the surfactant provides a lowered interfacial tension between the oil and the water, e.g. in the order of less than 1 dyne/cm. Usually, the cEOR mixture 1 is at or close to optimum salinity.
• Salinity has a strong impact on the ability of surfactants to lower surface tension in cEOR mixtures. For example, high salinities, in excess of the "optimum salinity" of a cEOR mixture, cause microemulsions to be broken, leading to the
• the salt content of the mixture tends to dissolve mainly in the aqueous phase, although some salt will also be present in the oil phase, whilst an increased proportion of surfactant is pushed into the hydrocarbons oil with increasing salinity.
• a high-salinity input 11 is mixed with the cEOR mixture 1 to increase the salinity of the mixture to a salinity in excess of the "optimum salinity" of the cEOR mixture.
• the high-salinity input 11 has a greater salinity than the cEOR mixture 1 and comprises recycled salt, as will be described later.
• the ratio at which the cEOR mixture 1 and the high- salinity input 11 are mixed depends on a number of factors, such as the composition (including salinity) of the cEOR mixture 1 and the salinity of the high salinity input 11.
• the skilled person may choose to determine the requisite salinity increase in the mixture 2 simply by carrying out periodic visual inspections to determine whether the degree of emulsion in the cEOR mixture 2 is reduced.
• phase separation or demulsifier
• phase separation vessel A and indeed all phase separation vessels mentioned herein, may take any suitable form and may for example be of the type described in Perry' s Chemical Engineer' s Handbook, 6 th edition, page 21-64 and further.
• the phase separation vessel A separates the
• the aqueous phase 6 is channelled via a membrane M to a desalination station B.
• the membrane M serves to remove any remaining oil from the aqueous phase 6.
• the process of phase separation typically only provides a certain degree of purity, which in the case of the aqueous phase 6 is supplemented by the use of the
• the membrane M may be any membrane suitable for removing hydrocarbons from water, such as for example a ceramic membrane.
• Suitable ceramic membranes comprise T1O2, ZrC>2, AI2O3 or SiC.
• the pore size of a suitable ceramic membrane is suitably smaller than 100 nm, preferably smaller than 50 nm, more preferably smaller than 30 nm and most preferably smaller than 10 nm.
• a hydrophobic membrane may be used, the use of which results in an efficient removal of the oil phase from the water phase.
• Suitable hydrophobic membranes include grafted ceramic membranes, for example a grafted ZrC> 2 - containing membrane, and polymeric membranes, for example poly (dimethylsiloxane) (PDMS) or poly-imide based
• the aqueous phase 6 enters the desalination station B, where it is processed into a low salinity stream 7 and a high salinity stream 8.
• the desalination station B may employ conventional reverse osmosis or nanofiltration
• desalination station B may be used wholly or partly as the high salinity input 11 added to the cEOR mixture in the salinity adjustment station S.
• the high salinity stream 8 may be split at a salinity outlet 10.
• the salinity outlet 10 may remove salt from the system, for example for use in cEOR reinjection 12.
• the aqueous low salinity stream 7 produced by the desalination station B is used to wash the oil phase 3 resulting from phase separation of the cEOR mixture 2.
• the oil phase 3 typically contains a substantial concentration of surfactant as a result of the salinity increase in the cEOR mixture, together with some salt. Therefore, the low salinity stream 7, is mixed with the oil phase 3 to form a mixture with a salinity below "optimum salinity" in which
• surfactant and salt are washed out of the oil by the low salinity stream. Despite the presence of surfactant, the mixture shows only minimal emulsification because of the low level of salinity. Furthermore, surfactant and salt are washed from the oil phase 3 into the low salinity stream 7, turning the low salinity stream into an aqueous surfactant recycle stream 9 and the oil phase into a washed crude oil stream 5.
• the surfactant recycle stream 9 is separated from the crude oil stream 5 in a second phase separation (demulsifer) vessel C.
• the crude oil stream 5 may be refined and processed further as desired, whilst the surfactant recycle stream 9, containing substantial concentrations of surfactant and salt may be used for cEOR reinjection 12.
• the crude oil stream 5 is particularly suitable for further refining because it has already been desalinated, saving on desalination operations at the refinery .
• the hydrocarbons separation system and method according to the first exemplary embodiment of the invention envisage increasing the salinity of a cEOR mixture to break emulsions (particularly microemulsions ) therein, separating a hydrocarbon phase from the cEOR mixture for further use, reusing or recycling salt from the remaining aqueous phase within the separation system, and reusing water and optionally remaining salt from the aqueous phase for cEOR reinjection.
• a hydrocarbons separation system and method according to a second embodiment of the invention is identical to the system and method according to the first embodiment of the invention, with like reference numerals being used for like parts, save for the working of the desalination step in station B.
• the desalination station of the system according to the second embodiment of the invention comprises a nanofiltration unit Bl arranged in series with a reverse osmosis unit B2.
• nanofiltration unit Bl may be an ultrafiltration unit or microfiltration unit (not shown in Figure 2) .
• the nanofiltration unit Bl removes and discards divalent cations.
• the reverse osmosis unit B2 processes the remaining salt and water in the salt-containing aqueous phase 6 in the manner of the desalination station B of the first embodiment of the invention, to form the high salinity stream 8 and the low salinity stream 7.
• a hydrocarbons separation system and method according to a third embodiment of the invention is identical to the system and method according to the first embodiment of the invention, with like reference numerals being used for like parts, save that the membrane M acts as a phase separator, thereby
• Phase separation in the third embodiment of the invention occurs at the membrane M, which permits only the passage of aqueous phase, but not of the hydrocarbon phase.
• the hydrocarbon phase can then be channelled and separated for further processing using gravimetric principles and techniques known in the art, whilst the aqueous phase continues, via the membrane M, to desalination station B.
• membrane M as a phase separator enables an increase in the salinity of the input mixture by the removal of water rather than the addition of salt. Accordingly, in a variant of the third embodiment of the invention, input of salt at the salinity adjustment station S is not necessary and hence omitted, meaning that salt in the high salinity stream 8 may be reused elsewhere for example in cEOR reinjection 12, via salt outlet 10.
• embodiments of the invention are non-essential and may be omitted, modified or replaced without departing from the scope of the invention.

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• Chemical & Material Sciences (AREA)
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• Engineering & Computer Science (AREA)
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• General Life Sciences & Earth Sciences (AREA)
• Environmental & Geological Engineering (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
• Extraction Or Liquid Replacement (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 2011
  • 2011-09-09 EP EP11752570.9A patent/EP2613863A1/en not_active Withdrawn
  • 2011-09-09 WO PCT/EP2011/065658 patent/WO2012032161A1/en active Application Filing
  • 2011-09-09 BR BR112013004602A patent/BR112013004602A2/pt not_active IP Right Cessation
  • 2011-09-09 CN CN201180043778.5A patent/CN103096989B/zh not_active Expired - Fee Related
  • 2011-09-09 US US13/821,628 patent/US20140008271A1/en not_active Abandoned
  • 2011-09-09 EA EA201390365A patent/EA201390365A1/ru unknown
  • 2011-09-09 MX MX2013002580A patent/MX2013002580A/es not_active Application Discontinuation
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