Abstract: A process for generating power using a gas turbine, comprising the steps of: (i) vaporising and pre-heating liquid ammonia to produce pre-heated ammonia gas; (ii) introducing the pre-heated ammonia gas into an ammonia-cracking device suitable for converting ammonia gas into a mixture of hydrogen and nitrogen; (iii) converting the pre-heated ammonia gas into a mixture of hydrogen and nitrogen in the device; (iv) cooling the mixture of hydrogen and nitrogen to give a cooled hydrogen and nitrogen mixture; (v) introducing the cooled hydrogen and nitrogen mixture into a gas turbine; and (vi) combusting the cooled hydrogen and nitrogen mixture in the gas turbine to generate power.

Abstract: A method of reducing the pressure of a liquid includes the steps of providing a conduit containing a packing material, such that a large number of small passages are formed in the packing material, and passing the liquid through the conduit and the packing material. The amount of packing material through which the liquid flows can be varied to vary the pressure drop experienced by the liquid passing through the packing material. The reduction in pressure achieved may be stepwise (discrete) or continuous. The method may be used to reduce the pressure of an aqueous polymer solution for use in a polymer flood technique for oil extraction, and allows the pressure to be reduced without damage to the polymer.

Abstract: A system for surge protection of a riser adapted to transport gas from a hydrocarbon production well or for surge protection in a well, the system comprising: a flexible tubing, wherein a portion of the flexible tubing extends into the riser or into the well and wherein the tubing terminates inside the riser or inside the well; a pressure control system arranged to create a pressure differential within the flexible tubing such that liquid is drawn from the riser or the well into the flexible tubing if liquid is present in the riser or the well; wherein the length of said portion of the flexible tubing is variable depending on the amount of liquid drawn into the flexible tubing

Abstract: A method of controlling a borehole drilling process including a first set of operations and a second set of operations includes generating and outputting at least one control signal by a drilling control system for controlling at least one control parameter associated with the first set of operations; and, subsequent to an indication that the first set of operations is complete, outputting at least one control signal received from an external system at the drilling control system for controlling at least one control parameter associated with the second set of operations.

Abstract: A method of installing a header pipe joint at a subsea structure is provided, comprising providing a header pipe joint having at least one valve installed therein and connecting the header pipe joint inline of a spool or pipeline prior to lowering the header pipe joint to the subsea structure. The header pipe joint is then lowered to the subsea structure, and the valve is connected to the subsea structure (e.g. a subsea production system of the subsea structure such as a xmas tree) with a connection bridge e.g. a choke bridge. This provides a fluidic connection between the subsea structure and the header pipe joint. The subsea structure comprises a foundation, e.g. suction anchors, which provide support for both a wellhead and the header pipe joint. A subsea assembly comprising a subsea structure, header pipe joint and connection bridge is also provided.

Abstract: A subsea well assembly includes a high pressure wellhead housing; and a port for monitoring and/or controlling fluid within an annulus within the high pressure wellhead housing. The port extends through the high pressure wellhead housing. The subsea well assembly further includes a wellhead support for laterally supporting the high pressure wellhead housing, wherein, at an axial height of the port, the wellhead support surrounds the high pressure wellhead housing at circumferentially discrete locations and the port is located at a circumferential location where the high pressure wellhead housing is not covered by the wellhead support. A method of monitoring and/or controlling fluid within the annulus within the subsea well assembly is also provided.

Abstract: An assembly for installing an object under water at a desired location, including a vessel arranged to carry the object; a submersible frame; and a connection between the object and the submersible frame. In use the vessel is spatially separated from the submersible frame along the direction of the water surface. The object, the connection and the submersible frame are arranged such that, when releasing the object from the vessel, the object becomes submerged and carries out a pendulum motion until the object is suspended from the submersible frame.

Abstract: A marine installation system for installing an item on a riser includes a cable extending between two supporting points, the cable being inclined relative to the horizontal; a first ROV arranged to mount the item on the cable at a first position; and a second ROV arranged to remove the item from the cable at a second position, and to install the item on the riser.

Abstract: There is provided a wellhead assembly that includes a production well, a first valve, process equipment, a transport pipe for transporting fluid away from the wellhead assembly, and piping fluidly connecting the production well to the first valve, process equipment, and the transport pipe. The first valve is located between the production well and the process equipment, and there is a fall in the piping between the first valve and the transport pipe such that when the first valve is closed liquid will drain from the first valve into the transport pipe under the action of gravity. There is also provided a method of draining the wellhead assembly, an arrangement for depressurising the wellhead assembly using a service line and a method of depressurising the wellhead assembly.

Abstract: A method of installing an object under water at a desired location includes providing the object on a vessel, connecting the object to a submersible frame located below the water surface, wherein the vessel is spatially separated from the submersible frame along the direction of the water surface, releasing the object from the vessel such that the object becomes submerged and carries out a pendulum motion until the object is suspended from the submersible frame, and moving the object to the desired location.

Abstract: A method of conducting a pressure integrity test for an underground formation includes: whilst fluid is supplied to and/or released and returned from the underground formation under pressure, using an automated monitoring and supervisory system to: monitor the pressure of the fluid being supplied to and/or returned from the underground formation in real-time, monitor a volume of the fluid that is supplied to and/or returned from the underground formation in real-time, determine one or more relationship(s) for the monitored pressure and the monitored volume as the pressure and the volume vary relative to each other and/or with time during the real-time monitoring thereof, and analyze the monitored pressure and volume data using the one or more relationship(s) either in real-time or after completion of the pressure integrity test in order to provide information and/or warnings concerning at least one parameter relating to the underground formation.

Abstract: A sensor apparatus for a downhole tool 12 comprises a sensor 24 for taking downhole measurements; and a sensor support 26, 28 for mounting the sensor 24 to the downhole tool 12. The sensor support 26, 28 includes an actuator 26 for moving at least a part of the sensor 24 in a direction extending along a longitudinal axis of the downhole tool 12, such that in use the moveable part(s) of the sensor 24 can move relative to the tool 12 in a direction extending along a longitudinal axis of a borehole. The sensor apparatus is arranged to log measurements from the sensor using a point on the tool 12 as a reference to determine relative depth between measurements without using an external reference point to obtain an indication of the absolute depth of the measurements.

Abstract: A method of obtaining a model of a sub-surface region, the model comprising a three dimensional matrix of sub-surface material property values. The method comprises providing a first approximation of said model, and performing simulations using the model to generate (i) a reference upgoing energy wave data set d0, where the acquisition parameters used in the simulation are a set of known acquisition parameters, and (ii) a plurality of perturbed upgoing energy wave data sets d0 where the acquisition parameters are obtained by randomly perturbing said set of known acquisition parameters. The method further comprises forming a matrix D, the columns of which are the differences di?d0 between the ith perturbed data set and the reference data set, applying an analysis to the matrix D to describe the matrix using a set of vectors, and selecting the most important vectors from said set of vectors to obtain a subset of vectors that describe said matrix D to an approximation.

Abstract: A method for turndown of a liquefied natural gas (LNG) plant, the plant including a liquefaction unit arranged in a flow path of the plant, includes 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 of monitoring the state of a choke valve in a managed pressure drilling system using a valve state parameter to represent the state of the choke valve includes measuring the flow rate of a material across the choke valve, measuring the pressure differential of the material across the choke valve, obtaining a valve characteristic of the choke valve, and calculating the valve state parameter using the flow rate, the pressure differential and the valve characteristic.

Abstract: An offshore oil and gas platform has equipment and piping associated with an oil and gas installation. A method for optimising fire protection for the platform includes arranging the platform to have an evacuation time of at most 15 minutes or less using one or more evacuation route(s) via a gangway or bridge allowing personnel to escape to a vessel or to another platform, determining a maximum evacuation time for the platform, assessing the risk to personnel using the evacuation route(s) in accordance with the determined maximum evacuation time in the event of a fire, and providing passive fire protection to equipment and/or piping on the platform in order to prevent escalation of the fire that would create a risk to personnel on the evacuation route(s) during the determined evacuation time.

Abstract: Methods of monitoring for influx and/or loss events in a wellbore are disclosed. One method comprises: receiving a measurement relating to fluid entering or leaving the wellbore, wherein the measurement is selected from flow out rate and active volume; and comparing the measurement with an expected value for the measurement to provide a deviated measurement value. The method further comprises receiving a pump pressure value of a pump associated with the wellbore; and comparing the pump pressure value with an expected pump pressure value to provide a deviated pump pressure value. It is then established whether an influx event and/or it is established whether a loss event may have occurred based on at least the deviated measurement value and deviated pump pressure value. Systems configured to monitor for influx and/or loss events in a wellbore are also disclosed.

Abstract: A method of starting up flow of viscous oil in a pipeline, wherein the pipeline has an inlet and an outlet and wherein the viscous oil is initially stationary within the pipeline, includes supplying water to a first section of the pipeline through an inflow control device; initiating a flow of viscous oil within the first section towards the outlet by pressurising the water; supplying water to a second section of the pipeline through a further inflow wherein the first section is closer to the outlet of the pipeline than the second section; and initiating a flow of viscous oil within the second section towards the outlet by pressurising the water.

Abstract: A method and system for dehydration of a gas phase and hydrate inhibition of a liquid hydrocarbon phase in a multiphase hydrocarbon fluid stream containing water. The method may include (i) separating the hydrocarbon fluid stream into a liquid phase and a first gas phase, (ii) adding hydrate inhibitor to the first gas phase, and (iii) separating off condensed liquids and a second gas phase. The first gas phase has a water dew point that is lower than the initial multiphase hydrocarbon fluid stream and the second gas phase has a lower water dew point than the first gas phase. The hydrate inhibitor has a water content that is low enough to enable it to dry the first gas phase, the hydrate inhibitor being separated off with the condensed liquids and mixed with a part or all of the liquid phase from the separation to inhibit the liquid phase.

Abstract: The present invention relates to a method of processing seismic data. The method may include calculating a number of calculated structure tensors for each of a number of seismic data lines, the seismic data lines being spatially distributed about an area of the surface of the Earth. The method also may include interpolating the calculated structure tensors to find interpolated structure tensors in a region of the area between the lines of the seismic data lines, and calculating calculated seismic data from the interpolated structure tensors.