Abstract: Apparatus for use in monitoring particles in a fluid flow comprises: a duct (1) for receiving the fluid flow; light generating means (6) adjacent the duct for transmitting light into the fluid flow via a first at least partially light-transmissive part (4) of the duct; light-responsive detection means (7) adjacent a second at least partially light-transmissive part (5) of the duct for receiving light from the light generating means which has passed through the fluid flow; processing means (8) for location remotely from said duct; and means (9) for coupling the processing means with the detection means, the processing means being adapted for processing signals therefrom to provide data relating to particles in the fluid flow.

Abstract: A method of monitoring a microseismic event includes detecting the event to produce a first signal dependent on the event. The first signal includes noise at a frequency of, for example 50 Hz. A first sample of the first signal is taken. Then a second sample of the first signal is taken, the second sample occurring n/f seconds after the first sample, where n is an integer (e.g. 1). Subtracting the first and second samples from each other produces a farther signal dependent on the event in which the noise has been at least partly compensated for.

Abstract: A first passageway (17) provides a first fluid flow path, in a well between a first zone (9) and a, common region (26). A second passageway (23), outside the first passageway (17), provides a second fluid flow path; between the second zone (10) and the common region (26). The first passageway (17) is provided with a first flow controller (25), for controlling the flow of fluid between the first zone (9) and the common region (26). The second passageway (23) is provided with a second flow controller (28), for controlling the flow of fluid between the second zone (10) and the common region (26).

Abstract: A flow control device comprises an outer sleeve having an outer sleeve wall and at least one aperture through the outer sleeve wall; a inner sleeve having an inner sleeve wall and at least one aperture through the inner sleeve wall; and means for providing relative sliding movement of the sleeves between “open” positions allowing variable flow of fluid through the apertures of the sleeves and a “closed” position, so that relative movement of the sleeves produces available amount of opening through which fluid can flows. The apertures are arranged so that the change in the coefficient of velocity (CV) of fluid flowing through the apertures caused by a change in the relative displacement of the sleeves is substantially proportional to said change in relative displacement.

Abstract: Packers are expandable sealing devices used to seal off zones in a well. Packers are expanded to seal the bore of the well by means of expansion fluid supplied via individual pipelines. However, packers near the top of the well have to accommodate all of the pipelines for packers below. The invention provides a packer system comprising a plurality of packers (22-28) and fluid delivery means arranged to supply fluid to the packers, to expand them in use. The fluid delivery means includes a common fluid pipeline (36) for the packers. Thus, only one expansion fluid pipeline has to pass through the upper packers (22, 23), irrespective of the overall number of packers in the system.

Abstract: Actuators for subsea downhole chokes have tended to include hydraulic pistons which are prone to failure and crude in accuracy. The invention provides an actuator (1) having first and second rotary motors (2, 16) and an output region (3) arranged to engage a load, such as a choke sleeve. In a first mode of operation, the first rotary motor (2) imparts linear motion to the output in a first screw connection (4, 5). In a second mode of operation, the second rotary motor (16) imparts linear motion to the output via a second screw connection (12, 14). The provision of screw connections permits gradual linear motion of the output to be achieved. The provision of two motors permits continuing performance in the event of failure of one of the motors.

Abstract: Signals from microseismic events are used to obtain a parameter of reservoir such as porosity, permeability or saturation.

Abstract: An oil pipeline, which connects a Christmas tree at its lower end to an oil rig at its upper end, is fitted with a stainless steel tube sheathed telecommunications grade optical fiber, forming part of a distributed temperature measurement device, such as to be in thermal contact with the oil flowing along the pipeline. Also fitted to respective ones of three discrete positions on the pipeline are ultrasonic deposit thickness measurement devices, the one nearest of which to the Christmas tree is a few hundred meters downstream from a position where preliminary studies of the pipeline system have indicated that deposits are likely to form during oil production. A computer, located on the oil rig, is connected to be able to provide control over and to receive measurement signals from the temperature measurement devices and the deposit thickness measurement devices. A model of at least deposit deposition stored in the computer is revised in response to these signals.

Abstract: Modern subsea wells utilise an electrohydraulic control system which switches hydraulic power to various control components in dependence on received control signals. The mounting and interconnection of the control components tends to be complicated. The invention provides a manifold comprising a first manifold body 6 having a number of openings and flow passageways therethrough. The manifold body is selectively configurable by selecting predetermined openings in order to achieve a desired configuration of flow passageways between control devices 1, 2, 13, 4. The manifold simplifies the interconnection of the hydraulic components and provides greater flexibility in the location of the components. The manifold body also provides a platform for mounting the control devices.

Abstract: A flow meter for use in an oil well has a central bore region in which an annular tube is fixed co-axially with the central bore region by a ring, which also seals the gap between the inner bore of the central bore region and the tube at its downstream end, thus forming a pocket open to the direction of fluid flow through the central bore region. The pocket brings the fluid to rest, thereby converting all of the dynamic pressure of the fluid into static pressure. This has the effect of maximizing the pressure differential obtainable between the central bore region and a position upstream of the tube, which allows an electronic calculation to be made to provide a more accurate flow rate measurement than would have been possible without the pocket.

Abstract: An apparatus for sensing strain applied to a region of a hydrocarbon well comprises an optical fiber in communication with the region. The optical fiber is responsive to strain applied to the region and to a light signal transmitted through it, in order to produce a sensing light signal incorporating scattered light. A characteristic of the scattered light is indicative of the strain being applied to the region.

Abstract: A flow control device comprises an outer sleeve having at least one aperture through its wall, and an inner sleeve having at least one aperture through its wall. Relative sliding movement of the sleeves is provided between “open” positions allowing for variable flow of fluid through the apertures of the sleeves and “closed” positions. A pressure-reducing region is arranged to reduce the pressure of fluid flowing through at least one aperture of one of the sleeves.

Abstract: It is desirable to be able to monitor the condition of a filter in a fluid flow system, for example a sandscreen 3,4 in a fluid well. The invention provides monitoring apparatus including an optical fibre 6 having a pressure sensor 7. Pressure is exerted on the sensor, by fluid flowing through the sandscreen, via ports 10 and 11. The pressure sensor is responsive to a light signal, and to the exerted pressure, to produce a sensing light signal indicative of a characteristic of the fluid flow, such as pressure differential or fluid velocity. This, in turn, is indicative of the condition of the sandscreen or filter.