Abstract: The present invention provides a method of recovering a hydrocarbon mixture from a subterranean formation comprising: (i) injecting an oxygen-rich gas into said formation; (ii) combusting said oxygen-rich gas in said formation thereby heating and reducing the viscosity of said hydrocarbon mixture and generating CO2-rich gas; (iii) recovering said heated hydrocarbon; and (iv) capturing at least a portion of CO2 from said CO2-rich gas.

Abstract: The invention relates to a natural gas liquefaction process and particularly to one suited to use offshore. The invention provides a natural gas liquefaction apparatus wherein a carbon dioxide based pre-cooling circuit is provided in a cascade arrangement with a main cooling circuit. The invention also extends to a natural gas liquefaction apparatus wherein a main cooling circuit uses as a refrigerant a gas stream, at least a portion of which is derived from a raw natural gas source.

Abstract: A method of liquefying a hydrocarbon-rich gas, wherein the gas flows through a cascade of three refrigeration stages, each stage comprising a refrigerant circuit and a compressor, wherein at least part of the flow of refrigerant from the second circuit is used for the pre-cooling of the hydrocarbon rich gas in the first refrigeration stage. This balances the load on each of the compressors. By standardizing the drive units and compressors of the three coolant circuits, it is possible to maximize the attainable liquefaction capacity of the liquefaction process using tried-and-trusted drive units and compressors respectively. This method can be applied to mixed refrigerant cascades and circuits with a carbon dioxide pre-cooling circuit. This latter option has benefits for offshore use where large amounts of hydrocarbons are undesirable.

Abstract: A process for liquefying a flow of natural gas with simultaneous recovery of a C3/C4-rich fraction is described, whereby the liquefaction of the flow of natural gas is carried out in heat exchange for at least one refrigerant and/or mixed refrigerant flow, and the flow of natural gas that is to be liquefied, after precooling, is subjected to a rectifying column, in which higher hydrocarbons are separated from the flow of natural gas, and then is subjected to further cooling and liquefaction, whereby a C2+-rich fraction that is recovered in the subsequent cooling of the flow of natural gas is fed to the rectifying column as a reflux liquid. According to the invention, a C4/C5-rich fraction (20, 35) is fed directly and/or indirectly to rectifying column (T1) as an additional reflux liquid, whereby the feed point of the C4/C5-rich [fraction (20, 35) is located at the top of rectifying column (T1) or is identical to the feed point of the C2+-rich fraction (5).

Abstract: A process is described for liquefaction of a hydrocarbon-rich stream, especially a natural gas stream, at least indirect heat exchange taking place between the hydrocarbon-rich stream to be liquefied and the refrigerant mixture of at least one refrigerant mixture circuit, and the refrigerant mixture being separated after completed supercooling into a gaseous fraction and a liquid fraction and these fractions being recombined before and/or during the reheating of the refrigerant mixture. According to the invention, a gas fraction (9) that is identical or similar in composition is added at least from time to time to the gas fraction (4) that has been obtained in the separation (D). In doing so, the addition of the gas fraction (9) that is identical or similar in composition takes place when a minimum amount of the gas fraction (4) obtained in the separation (D) of the refrigerant mixture is not reached.

Abstract: A system for supplying cooling water to a process on board a floating vessel for the production of hydrocarbons, wherein the vessel (1) is anchored by means of a bottom-anchored turning unit (20) mounted in a receiving space (7) in the hull (34) of the vessel and allowing turning of the vessel (1) about the turning unit, and wherein the turning unit (20) supports a swivel unit (24) for the transfer of hydrocarbons from production risers (28) extending between the seabed and the turning unit (20), the system comprising a conduit means (30) depending from the vessel (1) to a depth for taking in cooled sea water, and a pump means (44) for pumping of the sea water from the conduit to a place of use for the process.

Abstract: A system for supplying cooling water to a process on board a floating vessel for the production of hydrocarbons, wherein the vessel (1) is anchored by means of a bottom-anchored turning unit (20) mounted in a receiving space (7) in the hull (34) of the vessel and allowing turning of the vessel (1) about the turning unit, and wherein the turning unit (20) supports a swivel unit (24) for the transfer of hydrocarbons from production risers (28) extending between the seabed and the turning unit (20), the system comprising a conduit means (30) depending from the vessel (1) to a depth for taking in cooled sea water, and a pump means (44) for pumping of the sea water from the conduit to a place of use for the process.

Abstract: The invention relates to a natural gas liquefaction process and particularly to one suited to use offshore. The invention provides a natural gas liquefaction apparatus wherein a carbon dioxide based pre-cooling circuit is provided in a cascade arrangement with a main cooling circuit. The invention also extends to a natural gas liquefaction apparatus wherein a main cooling circuit uses as a refrigerant a gas stream, at least a portion of which is derived from a raw natural gas source.

Abstract: In the liquefaction of a hydrocarbon by indirect heat exchange with the refrigerant mixture of a refrigerant mixture cycle, the refrigerant mixture being compressed in multiple stages, the compressed refrigerant mixture (23) is at least partially condensed (E4) downstream of the penultimate compressor stage and is fractionated (D4) into a higher-boiling liquid fraction (26) and a lower-boiling gas fraction (24). The lower-boiling gas fraction (24) is compressed to the final pressure, partially condensed (E5) and fractionated (D5) into a lower-boiling gas fraction (10) and a higher-boiling liquid fraction (27). The higher-boiling liquid fraction (27) is added to the partially condensed refrigerant mixture stream (23), and the gas fraction (10) forms the lower-boiling refrigerant mixture fraction and the liquid fraction (26) forms the higher boiling refrigerant mixture fraction of the refrigerant mixture cycle.

Abstract: The invention relates to a method for liquefying a stream rich in hydrocarbons, especially a stream of natural gas, by the indirect exchange of heat with the refrigerants in a closed-circuit cascade of mixed refrigerants. According to the invention, said closed-circuit cascade of mixed refrigerants consists of at least 3 circuits of mixed refrigerants, with each circuit comprising different refrigerants. The first of the three mixed refrigerant circuits is used for pre-cooling (E1), the second for liquefying E2), and the third for super-cooling (E3) the hydrocarbon-rich stream (1) to be liquefied. The method provided for in the invention reduces specific energy consumption and investment costs since the three circuits of mixed refrigerants are or can be optimally adjusted to the enthalpy temperature curves of the hydrocarbon-rich stream to be liquefied and the refrigerant mixtures.

Abstract: A method of liquefaction/conditioning of a compressed gas/condensate flow extracted from a petroleum deposit, for transport in liquefied form with a transport vessel, especially for such processing of a compressed gas/condensate flow which has been separated from a crude oil extracted from an offshore oil field. The gas/condensate flow is depressurized and cooled in several steps for producing a stabilized liquefied natural gas (LNG) and a stabilized liquefied petroleum gas (LPG), for transport thereof in separate tanks.

Abstract: A method and a system for offshore production of liquefied natural gas, wherein natural gas is supplied from an underground source to a field installation for gas treatment. The gas is transferred in compressed form from the field installation to an LNG tanker. The transfer takes place via a pipeline surrounded by sea water. The compressed gas is supplied to a conversion plant which is provided on the LNG tanker and is arranged to convert at least a part of the gas to liquefied form, and the liquified gas is transferred to storage tanks on board the tanker. When the storage tanks on the LNG tanker are filled up, the pipeline is disconnected from the LNG tanker and connected to another, similar tanker. The pipeline is permanently connected to a submerged buoy which is arranged for introduction and releasable securement in a submerged downwardly open receiving space in the tanker, and which is provided with a swivel unit for transfer of gas under a high pressure.

Abstract: A method and a system for offshore production of liquefied natural gas, wherein natural gas is supplied from an underground source (4) to a subsea production plant (1). The gas is transferred under a high pressure directly from the production plant (1) to an LNG tanker (6), the transfer taking place through a pipeline (5) surrounded by sea water and causing the temperature of the high pressure gas to be lowered to a desired low temperature. This gas is supplied to a conversion plant (12) provided on the LNG tanker (16) and arranged for converting at least a part of the gas to liquid form, and the liquefied gas is transferred to storage tanks (17) on board the vessel (6).