Abstract: A method to test or monitor the integrity of a cement barrier, comprising providing an assembly therebelow including: a perforating device; a control mechanism to control the perforating device, a pressure sensor, a wireless communication device and a pressure sensor. The perforating device is activated to perforate casing below the barrier and a pressure test may be conducted. The creation of the perforation(s) below the barrier allows an assessment of the integrity of the barrier across its entire width, and especially its bond to the formation, rather than only a central portion of the barrier. Electromagnetic or acoustic wireless signals are used to retrieve data from below the barrier.

Abstract: A rupture apparatus (50) often deployed within a wall of a casing string (53) of an oil and gas well, comprising a housing (51) defining a housing bore (54) with a bore inlet and a bore outlet; a carriage carrying a rupturable component (12) the carriage being moveable in the housing bore between a rupturable position, an open and a closed position. Thus the bore can be opened or closed or closed subject to rupture of the rupturable component (12). Moreover, after rupture the bore can still be closed. Wireless signals are normally used to for control, especially electromagnetic or acoustic signals. A pressure balancing port (6) may be defined in a wall of the housing allowing fluid communication between at least a portion of the housing bore, and an outside of the housing which can pressure-balance the carriage such that it remains stationary unless actuated.

Abstract: Downhole electrical energy harvesting and communication in systems for well installations having metallic structure carrying electric current, for example CP current. In some instances there is a harvesting module (4) electrically connected to the metallic structure (2) at a first location and to a second location spaced from the first location, the first and second locations being chosen such that, in use, there is a potential difference therebetween due to the electric current flowing in the structure (2); and the harvesting module (4) being arranged to harvest electrical energy from the electric current. In addition or alternatively, there may be communication apparatus (4, 5, 6) for communication by modulation of the current, for example CP current, in the metallic structure (2).

Abstract: A subsurface safety valve control system including a downhole station 5 for provision in downhole metallic structure (2) of a well installation which comprises a subsurface safety valve V having an open state allowing flow through the valve and a closed state obstructing flow through the valve. The downhole station (5) is arranged for picking up electrical signals from the downhole metallic structure (2) to obtain valve control signals and for outputting control signals for controlling the subsurface safety valve V in dependence on the signals picked up from the downhole metallic structure. The downhole station (5) comprises a hardware electronics channel (5a) for handling electrical signals picked up from the downhole metallic structure and the hardware electronics channel (5a) is arranged for detecting the presence and/or absence of hold valve open signals.

Abstract: Apparatus for use in sensing temperature in a wellbore, comprising: tubing comprising a plurality of temperature sensor modules provided at locations along the inside of the tubing, said temperature sensor modules comprising temperature sensors provided at least in part by at least one semiconductor element having electrical properties that vary with temperature; an electrical network configured to electrically connect to the semiconductor elements to in use allow measuring of the respective electrical properties of the semiconductor elements to infer a thermal characteristic of the semiconductor element; and at least one control module electrically connected to multiple temperature sensor modules, via the electrical network, and configured to receive and process an electrical signal associated with the temperature sensor modules to enable inference of the temperature of the semiconductor elements and the environment to which the tubing is exposed at the location of that semiconductor element.

Abstract: A method of monitoring a reservoir comprising setting at least one barrier in a well separating it into upper and lower isolated sections. A perforating gun or other perforating device is provided in the lower isolated section, along with a control mechanism, wireless communication device and a pressure sensor. After the barrier is set, the perforating gun is activated in order to create at least one perforation between the well and a surrounding reservoir. The well, or part of it, is suspended or abandoned but the pressure is still monitored and a wireless, preferably acoustic or electromagnetic, data signal is transmitted from the lower isolated section to above the barrier. Data from the suspended/abandoned part of the well may be used to infer characteristics of the reservoir so that it may be exploited more appropriately especially through another well.

Abstract: Downhole electrical energy harvesting and communication in systems for well installations having metallic structure carrying electric current, for example CP current. In some instances there is a harvesting module (4) electrically connected to the metallic structure (2) at a first location and to a second location spaced from the first location, the first and second locations being chosen such that, in use, there is a potential difference therebetween due to the electric current flowing in the structure (2); and the harvesting module (4) being arranged to harvest electrical energy from the electric current. In addition or alternatively, there may be communication apparatus (4, 5, 6) for communication by modulation of the current, for example CP current, in the metallic structure (2).

Abstract: A method to manipulate a well, comprising running an apparatus (60a) having a container (68a) with a volume of gas at a higher pressure than a surrounding portion of the well. The well is isolated, and a wireless control signal, such as an electromagnetic or acoustic signal, is sent to operate a valve assembly (62a) to selectively allow or resist fluid exit from a portion of the container (68a), via a port (61a). Some of the pressurised gas may itself be expelled in to the surrounding portion of the well, or it may be used to drive a fluid out of the container, such as an acid.

Abstract: A method to manipulate a well comprising providing an apparatus (60) in a well (14) below a packer (22) or other annular sealing device, the apparatus comprising a container (68) having a volume of gas which is sealed at the surface and nm into the well, such that the pressure in the container (68) is at a lower pressure than the surrounding well. When the apparatus is below the packer, a wireless control signal, is sent to operate a valve assembly (62) to selectively allow fluid to enter the container whereby at least 50 litres of fluid is drawn into the container. In this way, the apparatus can be used independent of perforating guns, to clear perforations or other areas in the well or may be used for a variety of tests such as an interval test, drawdown test or a connectivity test such as a pulse or interference test.

Abstract: Downhole electrical energy harvesting and communication in systems for well installations having metallic structure carrying electric current, for example CP current. In some instances there is a harvesting module (4) electrically connected to the metallic structure (2) at a first location and to a second location spaced from the first location, the first and second locations being chosen such that, in use, there is a potential difference therebetween due to the electric current flowing in the structure (2); and the harvesting module (4) being arranged to harvest electrical energy from the electric current. In addition or alternatively, there may be communication apparatus (4, 5, 6) for communication by modulation of the current, for example CP current, in the metallic structure (2).

Abstract: A well (10) in a geological structure (11), the well (10) comprising: a first casing string (12a) and a second casing string (12b) inside the first casing string (12a) and defining a first inter-casing annulus (14a) therebetween. A wirelessly controllable valve (16a), in the second casing string (12b) provides fluid communication between the first inter-casing annulus (14a) and a second casing bore (14b). The first or second casing string are less than 250 meters longer in length than the second or first casing string respectively and may be the same length. The distal ends of the first and second casing strings may be in a substantially impermeable formation (11). A number of benefits can be realised from such an arrangement. For example, in the event of a “blow-out”, kill fluid may be introduced into the well bore without the need to drill a relief well.

Abstract: A rupture apparatus (50) often deployed within a wall of a casing string (53) of an oil and gas well, comprising a housing (51) defining a housing bore (54) with a bore inlet and a bore outlet; a carriage carrying a rupturable component (12) the carriage being moveable in the housing bore between a rupturable position, an open and a closed position. Thus the bore can be opened or closed or closed subject to rupture of the rupturable component (12). Moreover, after rupture the bore can still be closed. Wireless signals are normally used to for control, especially electromagnetic or acoustic signals. A pressure balancing port (6) may be defined in a wall of the housing allowing fluid communication between at least a portion of the housing bore, and an outside of the housing which can pressure-balance the carriage such that it remains stationary unless actuated.

Abstract: Downhole electrical energy harvesting and communication in systems for well installations having metallic structure carrying electric current, for example CP current. In some instances there is a harvesting module (4) electrically connected to the metallic structure (2) at a first location and to a second location spaced from the first location, the first and second locations being chosen such that, in use, there is a potential difference therebetween due to the electric current flowing in the structure (2); and the harvesting module (4) being arranged to harvest electrical energy from the electric current. In addition or alternatively, there may be communication apparatus (4, 5, 6) for communication by modulation of the current, for example CP current, in the metallic structure (2).

Abstract: Apparatus for use in sensing temperature in a wellbore, comprising: tubing comprising a plurality of temperature sensor modules provided at locations along the inside of the tubing, said temperature sensor modules comprising temperature sensors provided at least in part by at least one resistive element having electrical properties that vary with temperature; an electrical network configured to electrically connect to the resistive elements to in use allow measuring of the respective electrical properties of the resistive elements to infer a thermal characteristic of the resistive element; and at least one control module electrically connected to multiple temperature sensor modules, via the electrical network, and configured to receive and process an electrical signal associated with the temperature sensor modules to enable inference of the temperature of the resistive elements and the environment to which the tubing is exposed at the location of that resistive element.

Abstract: A well (10) in a geological structure, the well (10) comprising a first casing string (12a) with a second casing string (12b) partially inside, and a third casing string (13c) partially inside the second casing string (12b). A first inter-casing annulus (14a) is defined between the first (12a) and second casing strings (12b), and a second inter-casing annulus (14b) is defined between the second (12b) and third casing strings (12c). A primary fluid flow control device (16a), such as a wirelessly controllable valve, on the second casing provides (12b) fluid communication between the first inter-casing annulus (14a) and the second inter-casing annulus (14b); and a secondary fluid flow control device (16b), such as a second wirelessly controllable valve, on the third casing string (12c) provides fluid communication between the second inter-casing annulus (14b) and a bore of the third casing (14c).

Abstract: Downhole electrical energy harvesting and communication in systems for well installations having metallic structure carrying electric current, for example CP current. In some instances there is a harvesting module (4) electrically connected to the metallic structure (2) at a first location and to a second location spaced from the first location, the first and second locations being chosen such that, in use, there is a potential difference therebetween due to the electric current flowing in the structure (2); and the harvesting module (4) being arranged to harvest electrical energy from the electric current. In addition or alternatively, there may be communication apparatus (4, 5, 6) for communication by modulation of the current, for example CP current, in the metallic structure (2).

Abstract: Downhole electrical energy harvesting and communication in systems for well installations having metallic structure carrying electric current, for example CP current. In some instances there is a harvesting module (4) electrically connected to the metallic structure (2) at a first location and to a second location spaced from the first location, the first and second locations being chosen such that, in use, there is a potential difference therebetween due to the electric current flowing in the structure (2); and the harvesting module (4) being arranged to harvest electrical energy from the electric current. In addition or alternatively, there may be communication apparatus (4, 5, 6) for communication by modulation of the current, for example CP current, in the metallic structure (2).

Abstract: Apparatus for use in sensing temperature in a wellbore, comprising: tubing comprising a plurality of temperature sensor modules provided at locations along the inside of the tubing, said temperature sensor modules comprising temperature sensors provided at least in part by at least one semiconductor element having electrical properties that vary with temperature; an electrical network configured to electrically connect to the semiconductor elements to in use allow measuring of the respective electrical properties of the semiconductor elements to infer a thermal characteristic of the semiconductor element; and at least one control module electrically connected to multiple temperature sensor modules, via the electrical network, and configured to receive and process an electrical signal associated with the temperature sensor modules to enable inference of the temperature of the semiconductor elements and the environment to which the tubing is exposed at the location of that semiconductor element.

Abstract: A method of controlling a well in a geological structure, the well comprising: a first casing string (12a), and a second casing string (12b) at least partially inside the first casing string thus defining a first inter-casing annulus therebetween. A primary fluid flow control device (16a), such as a wirelessly controllable valve, is provided in the second casing string (12b) to provide fluid communication between the first inter-casing annulus (14a) and a bore (14b) of the second casing string (12b). In the event of well “blow-out”, a relief well (40) may be drilled and a fluid communication path formed between the relief well and the first casing string of the well rather than extend to lower and/or narrower sections of casing. A kill fluid can then be introduced via the relief well (40) and the primary fluid flow control device (16a) used to direct fluid to the second casing bore (14b).

Abstract: Apparatus (100) for use in sensing temperature in a wellbore, comprising: tubing (110) comprising a plurality of temperature sensor modules (120, 320, 420, 520, 620, 720) provided at locations along the inside of the tubing, said temperature sensor modules comprising temperature sensors (321, 421) provided at least in part by at least one semiconductor element having electrical properties that vary with temperature; an electrical network (115) configured to electrically connect to the semiconductor elements to in use allow measuring of the respective electrical properties of the semiconductor elements to infer a thermal characteristic of the semiconductor element; and at least one control module (130, 330, 430) electrically connected to multiple temperature sensor modules, via the electrical network, and configured to receive and process an electrical signal associated with the temperature sensor modules to enable inference of the temperature of the semiconductor elements and the environment to which the tubi