摘要:
There are certain wellhead emergencies that present a danger in that it is extremely hazardous to approach the well close enough to activate the manual emergency shut in valve. An additional way of actuating the shut-in valve is disclosed, employing a remote handheld radio controller. Thus, we describe a well for extraction of hydrocarbons, and an associated control system, comprising a flow conduit for the hydrocarbons leading from a subsurface region to an above-surface region, a normally-closed shut-in valve located in the subsurface region of the flow conduit, a hydraulic system arranged to cause the shut-in valve to open when the hydraulic system is pressurised, and a release valve for releasing pressure in the hydraulic system, a wireless interface having a unique identifier, and being adapted to open the release valve on receipt of a wireless communication from a remote device, and a plurality of remote devices, each comprising a wireless transmitter compatible with the wireless interface and able to transmit control instructions to the wireless interface, at least one control instruction in any sequence of control instructions issued by the remote device induding the unique identifier, wherein the wireless interface is adapted to ignore control instructions containing an identifier differing from the unique identifier. A pressure sensor is ideally provided in the hydraulic system, to detect the pressure of the hydraulic fluid in the hydraulic system. The wireless interface is preferably adapted to transmit data relating to this detected pressure, allowing users to confirm that the shut-in valve has operated. The plurality of remote devices ideally each include a directional antenna for communicating with the wireless interface, which assists in a number of ways.
摘要:
A downhole instrumentation system (1) comprises one or more transducers (11-14) coupled in a DC current circuit between the star point (18) of an electrical submersible pump (2) and the chassis (15). A sensing circuit including a DC power supply (7) and an ammeter (8) is arranged to monitor the current drawn. The system includes active electronic components which provide a sequence of signals that may include reference and measuring signals or multiplexed signals from the transducers (11-14).
摘要:
A measuring apparatus for measuring the internal dimensions of a tube such as a pipe in an oil well includes a central body (1) and number of lateral extending measuring arms comprising pivoted links (31, 32). The links are mounted on the body via slider mechanisms (8, 9, 13, 22) so that the displacement of the inner link end provides a measurement of arm extension. The displacement is measured by a variable inductance device (21, 47), the electrical components of which are shielded from external pressure.
摘要:
An apparatus and method are provided for monitoring and controlling a power system of an electrical submersible pump assembly. A sensor monitors an alternating current component of a downhole electrical imbalance voltage at a neutral point of a motor of the electrical submersible pump assembly. The sensor measurement is transmitted to a controller at the surface. The controller analyzes the alternating current component of the downhole electrical imbalance voltage and then adjusting an operation of the electrical submersible pump assembly, or scheduling maintenance, accordingly. Also, a model of a power system of an electrical submersible pump assembly is created to predict an alternating current component of a downhole electrical imbalance voltage. The model is modified as necessary responsive to measurements from the sensor. A controller adjusts surface currents according to the model of the power system to match downhole motor drive currents to thereby optimize the power system.
摘要:
A communications system comprises a primary wireless network and at least one secondary wireless networks, the primary and secondary wireless networks differing in at least one characteristic, at least one sensor unit comprising a means for sensing a parameter and a node of that secondary network adapted to transmit data relating to the parameter via that secondary network, at least one local data gathering point associated with the at least one secondary wireless network, incorporating a node of that secondary wireless network, a node of the primary network, and a control unit adapted to receive data signals from the at least one sensor unit via the secondary network, construct an outgoing data signal incorporating information from the received data signal, and transmit the outgoing data signal via the primary network, the primary wireless network being a multipoint radio network. The primary wireless network is optimised for relatively long distance communications, of the order of 10 km, and the secondary network or networks are optimised for relatively short distance communications of the order of 100m, the radio power of each network being different and appropriate for each transmission distance required. This means that the secondary wireless network can have a restricted power output suitable for use proximate to wellheads, with the result that the range is unlikely to be greater than 1 km. The at least one sensor can be an oil or gas wellhead pressure sensor, preferably self powered. The nodes of the primary network may contain GPS receivers, to synchronise the sensors with which the nodes communicate, and aid routing performance of the primary wireless meshing network.
摘要:
A compliant seal for a probe can be maintained in compression using a separate spring element mounted inside the probe, which maintains a force on the element with respect to the body such that the seal is always in compression. Thus, a sensor comprises a housing having an aperture, through which at least one element is exposed to an environment, and a seal disposed in the aperture between the housing and the element, the seal being urged into a sealing state by a force exerted on the seal and created by a biasing means located within the housing. The force can be transmitted to the seal via the element, enabling the seal to be compressed by the force between a seat and the element. Also disclosed is a pressure-balancing mechanism, whereby the inside of the probe is filled with a non-corrosive fluid at substantially the same pressure as the corrosive medium on the exterior of the probe. Thus, a sensor comprises a housing with an opening allowing ingress of fluid from the environment external thereto into the interior of the housing, wherein the opening leads to a closed bellows within the housing, a remainder of the interior being filled with a fluid. Finally, such sensors benefit from the inclusion of a corrodible fuse within the body of the probe, such that the occurrence of an open-circuit in this fuse provides an early warning of corrosive fluid ingress into the probe. Typically, these measures will be most useful in a corrosion sensor.
摘要:
Method for a solid phase synthesis of a linear combination of amino acid residues, linked via peptide bonds, starting with an amino acid residue covalently linked to a support and protected by an N-alpha-amino protecting group, comprising the following steps: (a) removing the N-alpha-amino protecting group to obtain an N-alpha-amino group, (b) adding an amino acid residue protected by an N-alpha-amino protecting group, via a peptide bond, to the N-alpha-amino group obtained in step (a) by use of a reactive protected amino acid derivative and, where necessary, a catalyst, (c) repeating steps (a) and (b) until the said liner combination has been obtained. According to the invention the said reactive protected amino acid derivative has the acyl group used to form the peptide bond activated as a pentafluorophenyl ester.
摘要:
A means of investigating the quality and/or nature of perforations in a downhole environment is disclosed. A "pecking1 finger (4) and depth measuring probe (40A) that can be axially and radially displaced enables the perforation to be located and its depth determined, through sequentially pecking around the wall lining in patterns such as radial, axial, and spiral sequences. By swinging a pecking finger that supports a depth measuring probe or cable with a bullet or conically shaped tip and measuring the displacement of the finger, the edge and centre of the hole can be determined with the largest displacement being when the tip is fully in the hole. When this position has been determined, the depth measuring cable is deployed and the depth of the perforation can be established by both an increase in the force required to push the cable and by the displacement of the pecking finger as it is pushed back by the reaction forces on the cable. Thus, a downhole tool comprises a elongate housing for insertion into a downhole environment, from which a probe extends radially by a variable amount, means for driving the probe in a radial direction, and means for sensing resistance to outward radial movement of the probe.