Abstract: There is provided a process for the prevention or reduction of surge wave instabilities during the transport in a flowline of a three phase gas condensate comprising a gas phase, an aqueous phase and a condensate phase, characterized in that a dispersing agent is added to the three phase gas condensate which is able to disperse the aqueous phase in the condensate phase or the condensate phase in the aqueous phase, and a means for the prevention or reduction of surge wave instabilities during the transportation of a three phase gas condensate.

Abstract: A method for start-up of a liquefied natural gas (LNG) plant, the plant including a liquefaction unit arranged in a flow path of the plant, including removing LNG from a first location in the flow path downstream of the liquefaction unit; vaporizing the removed LNG, or heating the removed LNG so that the removed LNG is transformed to gas phase; and re-admitting the vaporized or transformed LNG to the flow path at a second location upstream of the liquefaction unit. A corresponding LNG plant is also provided.

Abstract: A method and apparatus are provided for laying pipelines. The apparatus is attached to a portion of a pipeline and includes a tensioning member and a buoyancy element attached to a mid-portion of the tensioning member. When the buoyancy element is submerged, the buoyancy force tensions the tensioning member, and the pipeline will take the intended deflected shape to follow seabed depressions.

Abstract: A downhole installation comprises: a first pipe layer 8, a second pipe layer 10 about the first pipe layer 8, an annulus 12 between the first pipe layer 8 and the second pipe layer, and a geological formation outside of the second pipe layer 10.

Abstract: A method of sealing a well comprises creating one or more openings in a tubing installed in a wellbore, in a location for a well seal; using a wireline to locate a stinger in that location; setting the stinger in that location; and forming a seal in the well in that location, by injecting sealant through said stinger.

Abstract: A method is provided of processing data representing a physical system, the method comprising: providing (P2) input data representing differences in the physical system between a first state and a second state of the physical system; and inverting (P5) the input data, or data derived therefrom, in accordance with a parameterized model (PI) of the physical system to obtain differences in the parameters of the model between the first state and the second state, with parameters of the model representing properties of the physical system; wherein the inverting step is performed (P3 to P6) for a plurality of different perturbations (P4) of the parameterized model and/or of the data to obtain a plurality of sets of differences in the parameters of the model; and wherein a statistical analysis (P7) of the plurality of sets of differences is performed to obtain statistical characteristics of the differences in the parameters of the model.

Abstract: The present invention provides, a method of controlling scale formation in a hydrocarbon producing system, comprising; (i) injecting nanoparticles into said system to function as nuclei for scale growth; (if) allowing scale growth to occur on said nanoparticles to produce nanoparticles comprising scale; and. (in) optionally recovering said nanoparticles comprising scale.

Abstract: There is provided a method for removing iron-containing casing from a well bore comprising providing a cathode in said well bore, wherein said cathode is connected to the negative pole of a power source; connecting said iron-containing casing to the positive pole of said power source; injecting an electrolyte into said well bore, wherein said electrolyte contacts said iron-containing casing and said cathode; applying a current so that the iron in said iron-containing casing is oxidised to iron cations; allowing said iron cations to dissolve in said electrolyte; and removing said electrolyte from said well bore. Also provided are a system for removing iron-containing casing from a well bore, a method for monitoring the removal of an iron-containing casing from a well bore and a method for plugging and abandoning a well.

Abstract: A method of sealing an annulus around a drill-pipe when drilling down-hole includes providing a deflated packer on a drill-pipe when drilling down-hole; opening one or more ports to the packer using a ball-activated valve; and circulating drilling fluid to inflate said packer through said one or more ports, to thereby form a seal in the annulus around the drill-pipe. An apparatus to carry out this method is also provided.

Abstract: A method and apparatus for direct tie-in of pipelines are disclosed. An apparatus is attached to a portion of a pipeline, the apparatus including a tensioning member and a buoyancy element attached to the tensioning member such that, when submerged, the pipeline is deflected as a result of a buoyancy force tensioning the tensioning member, and on releasing the buoyancy element, direct tie-in of the pipeline is performed.

Abstract: A sensor system for deployment on or close to the seabed in marine seismic surveys includes a central hub, and a plurality of arms coupled to the central hub. Each arm has a degree of freedom of movement with respect to the central hub. The system further includes at least one seismic sensor mounted to each of said arms.

Abstract: A method of plugging a well extending into a formation to facilitate temporary or permanent abandonment of the well. The method comprises conveying in one trip, a plug assembly and one or more explosive charges through the well together with a structure for providing wet sealant. The plug assembly comprises a foundation plug for supporting the wet sealant. The plug assembly is set beneath a plug formation location, prior to providing the wet sealant. The method also comprises providing the wet sealant to the plug formation location via the structure, so as to submerge the one or more explosive charges in the wet sealant, and then detonating the one or more explosive charges in the wet sealant at the plug formation location to cut through a tubular or tubulars of the well and into the formation.

Abstract: There is described a method and associated apparatus for connecting a structure to equipment underwater, in particular for connecting a flange to a pipe under water. The pipe is provided under water, and a welding machine is provided in a welding space provided through a section of the pipe, and used to weld the flange to the end of the pipe, for example by internal metal inert gas welding.

Abstract: A method of lowering an apparatus (1) through a body of water comprising lowering a guiding element (25) and a weight (27) through the body of water, the lower end of the guiding (element 25) being attached to the weight (27) such that the guiding element (25) is under tension and is maintained in a generally vertical orientation when in its lowered position, and lowering the apparatus (1) through the body of water while being guided by the guiding element.

Abstract: A sensor system for deployment on or close to the seabed in marine seismic surveys includes a central hub, and a plurality of arms coupled to the central hub. Each arm has a degree of freedom of movement with respect to the central hub. The system further includes at least one seismic sensor mounted to each of said arms.

Abstract: A method for use in surveying a subsurface region beneath a body of water by detecting compressional, P, waves propagating through the body of water includes locating one or more sensor systems in the water at or close to the subsurface region, using the or each sensor system to detect P waves in the water, and translating all or a portion of the data representing the detected P waves to a higher level above the subsurface region. In the method, the effects of S waves, propagating in the subsurface and converted at the water/subsurface interface into P waves propagating in the water or along the seabed interface, in the translated data is reduced.

Abstract: A method of estimating a velocity of a geological layer includes a. providing a first, initial model including an interval velocity associated with a subsurface location and an uncertainty associated with the interval velocity; b. providing data including an actual or approximated root-mean-square (RMS) velocity associated with a subsurface location and an uncertainty associated with the RMS velocity; and c. estimating a second model including an interval velocity associated with a subsurface location and an uncertainty associated with the interval velocity, based on the interval velocity and the uncertainty of the first model, and the RMS velocity and the uncertainty of the data.

Abstract: A method of dynamically controlling a wind turbine having a rotor supporting a plurality of blades and a main bearing supporting the rotor, the method comprising detecting a load profile around the circumference of the main bearing, generating a control signal based on the detected load profile and dynamically adjusting the load profile of the main bearing using the control signal.

Abstract: A method for use in surveying a subsurface region beneath a body of water by detecting S waves propagating through the subsurface region. The method comprises using a first sensor configuration to detect mixed S and P waves on or in the subsurface region, using a second sensor configuration located on or in relatively close proximity to the subsurface region to detect P waves in the water, and using the P waves detected in the water to compensate the detected mixed S and P waves, and thereby attenuate the effects of P waves in the mixed S and P waves.

Abstract: A method of installing a subsea pipeline having a direct tie-in to a subsea structure includes, during introduction of the pipeline into the sea from a pipe laying vessel, applying a plastic deformation to a region of the pipeline at or close to an end of the pipeline to be tied-in and, either during or following tie-in, elastically deforming the region to increase its radius of curvature.