Abstract: A refrigerant circuit includes a first compression stage for compressing a mixed refrigerant gas, the first compression stage including at least a first compressor body and a second parallel compressor body, each compressor body including a suction inlet and an outlet, a first distribution means for splitting the flow of refrigerant gas to the first stage of compression across the at least two parallel compressor bodies, such that a first stream of refrigerant gas is fed to the suction inlet of the first compressor body and a second stream of refrigerant gas is fed to the suction inlet of the second compressor body, a second compression stage for compressing the mixed refrigerant gas, and a first merging means for recombining the first stream of refrigerant gas with the second stream of refrigerant gas downstream of the first compression stage for delivery to the second compression stage.

Abstract: A refrigerant compressor circuit for use in a liquefaction plant includes a first compression string driven by a first driver; a second compression string driven by a second driver, a pre-cooling refrigerant compression stage arranged in the first compression string to receive a stream of pre-cooling refrigerant at an inlet pressure and discharge the pre-cooling refrigerant at an outlet pressure, a first compression stage arranged in the first compression string to compress a mixed refrigerant gas from a first pressure to a second pressure, and, a second compression stage arranged in the second compression string to compress the mixed refrigerant gas from the second pressure to a third pressure. The pre-cooling refrigerant compression stage and the first compression stage of the circuit are co-axially mounted on a first shaft drivingly coupled to a first driver in the first compression string.

Abstract: A method of acquiring marine seismic data using an acoustic source to generate an acoustic signal, a portion of which is reflected at one or more subsurface formation interfaces as a seismic signal is described. The method includes sailing a surface vessel along a sail line which lies over a survey area while towing a seismic streamer, the sail line having a sinusoidal configuration defined by an amplitude and a wavelength. The streamer includes a plurality of hydrophones for receiving the reflected portion of the acoustic signal. The method is characterised in that the streamer follows the sinusoidal configuration of the sail line while seismic data is acquired, the streamer having a length at least equal to the distance travelled by the surface vessel as it sails along one full wavelength of the configuration as measured along the sinusoidal sail line.

Abstract: A process for removing water from a natural gas in an underwater environment is described. The process comprises dehydrating a natural gas feed stream in an apparatus arranged to exchange heat with the underwater environment, preferably including the step of forming hydrates in a hydrate forming zone of a hydrate vessel. The step of forming hydrates in the hydrate zone may comprise the step of introducing the natural gas feed stream into the hydrate vessel through an expansion device with the expansion device is located at and defines a gas inlet to the hydrate vessel. Heat exchange with the hydrate vessel itself need not occur as in one embodiment, heat exchange with the underwater environment takes place through an arrangement of pipes upstream of the hydrate vessel.

Abstract: A process and corresponding apparatus for regasifying a cryogenic liquid to gaseous form includes a process step and suitable structure to transfer heat from ambient air to the cryogenic liquid across a heat transfer surface by circulating the cryogenic liquid or an intermediate fluid through an atmospheric vaporizer, where the ambient air and the cryogenic fluid or intermediate fluid are not in direct contact; and a process step and suitable structure to mechanically scrape an external portion of the heat transfer surface exposed to the atmosphere to remove frost from the external portion of the heat transfer surface, where defrosting is achieved without the need to discontinue circulating the cryogenic fluid or the intermediate fluid through the atmospheric vaporizer.

Abstract: A process is described for removing contaminants from a natural gas feed stream including water. The process includes the steps of cooling the natural gas feed stream in a first vessel to a first operating temperature at which hydrates are formed, heating the hydrates to a temperature that is above the first operating temperature by introducing a warm liquid to the first vessel so as to melt the hydrates and liberate a dehydrated gas and a water-containing liquid, and removing from the first vessel a stream of dehydrated gas.

Abstract: A method of acquiring marine seismic data using an acoustic source to generate an acoustic signal, a portion of which is reflected at one or more subsurface formation interfaces as a seismic signal, includes: a) sailing a surface vessel along a sinusoidal sail line which lies over an area to be surveyed while towing one or more seismic streamers, each streamer including a plurality of hydrophones to receive the reflected seismic signals, where the streamer follows the sinusoidal sail line while seismic data is acquired. In one embodiment, the method further comprises b) dividing the area to be surveyed using a grid to form a plurality of bins; c) collating the seismic signals using the plurality of bins; and, d) repeating step a) to populate each bin with seismic data, where a range of offsets associated with each event varies between adjacent cross-line and in-line bins.

Abstract: The present invention relates to a process and system for managing boil-off gas generated during ship-to-ship transfer of LNG at sea. The LNG is transferred from a storage tank onboard a delivery vessel to a storage tank onboard a receiving vessel. The process includes the steps of a) operating the receiving vessel storage tank at a pressure greater than the operating pressure of the delivery vessel storage tank; and, b) transferring a portion of the boil-off gas from the receiving vessel storage tank to the delivery vessel storage tank onboard.

Abstract: The present invention relates to a power generation system for a marine vessel including a gas-fired power generation unit such as a gas turbine arranged to receive unodorized natural gas that has been vaporized from LNG stored onboard the marine vessel as a source of fuel gas. Unodorized natural gas is used a source of fuel to keep air emissions to a minimum.

Abstract: A method is provided for building a subsurface velocity model from a plurality of bins of marine acquired seismic traces of the subsurface.

Abstract: In the various methods of the present invention, reliance is placed on a first and second barrier 26 and 30 respectively positioned in a well 10 to provide well control during well suspension, completion and/or workover operations. Each of the barriers is below the depth of the lowermost end of a completion string when that string is installed in the well 10. By not placing either barrier higher up in the well-bore, both of the barriers can remain in place during suspension and completion and workover operations, thus obviating the need to use a BOP stack to supplement well control. This results in a considerable saving in drill rig time and thus significantly reduces the cost of constructing a well.