Abstract: 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.

Abstract: A means of investigating the quality and/or nature of perforations in a downhole environment is disclosed. A ‘pecking’ finger and depth measuring probe 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.

Abstract: A system for monitoring an Electrical Submersible Pump is disclosed comprising a rotation rate sensor located in an ESP gauge (6). When the Electrical Submersible Pump is started the rotating elements rotate in a first direction whilst the static elements will experience an opposing torque in a second opposite direction. The small rotational movement of the ESP gauge housing is sensed by the sensor and is used to determine the initial direction of rotation of the motor (5) and pump (6).

Abstract: A system for monitoring a condition of a downhole electrical submersible pump (ESP) assembly is disclosed. The system includes: a downhole assembly configured to be disposed in a wellbore in an earth formation; the ESP assembly connected to the downhole assembly and including a motor and a pump, the ESP assembly in electrical communication with a surface electrical source via a conductor; a power gauge unit configured to measure the electrical power supplied to the ESP assembly; and a processor configured to receive data from the power gauge unit and calculate a flowrate of the ESP assembly based on at least the electrical power supplied to the ESP assembly.

Abstract: A process is provided for the solid-phase synthesis of a peptide amide which comprises attaching an ?-nitrogen protected C?-carboxamide amino acid to a solid support by its side chain, removing the ?-nitrogen protecting group, assembling a peptide chain on said ?-nitrogen and then cleaving the assembled peptide amide from the solid support. Novel amino acid analogues, peptide amides and solid-phase supports are also provided.

Abstract: 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.

Abstract: An electrical signalling system comprises a modulator arranged to accept information and encode that information in an alternating signal containing repeated rising and falling edges, the encoding being by way of the time between consecutive rising and falling edges a transmission path for the signal from the modulator to a demodulator, wherein the modulator is arranged to precede a data signal with a reference signal of a known time, and the demodulator is arranged to detect that reference signal and calculate a calibration error therefrom. The demodulator can record the calibration error and subtract this from subsequent data signals. The demodulator can alternatively (or in addition) adjust the threshold for future signals, on the basis of the calibration error. This is particularly suited to inductive transmission paths such as a three-phase electrical supply cable leading to downhole sensors in the oil and gas extraction industries.

Abstract: A measurement head particularly for borehole use can measure multiple parameters with no electronics in the head and only a single conductor cable. Double-ended tuning forks (26, 28 and 38, 40) in the head are arranged to respond to different parameters such as temperature and pressure by adjusting their resonant frequencies. A drive signal on the conductor (50) is applied to transducers (30, 32, 42, 44) on all the tuning forks and those whose instantaneous resonant frequency is close will resonate. The signal is removed and the transducers return a decaying signal at the resonant frequency along the conductor. Other drive frequencies are tried, to locate the other sensors whose frequency ranges are separate.

Abstract: A downhole corrosion monitor comprises a sensor head suspended on a cable, the cable being extensible so as to raise and/or lower the sensor head downhole and having a signal conductor to return data from the sensor head to the surface, the sensor head comprising a plurality of mutually insulated electrical sensors and means for detecting the voltages and/or currents existing therebetween. The electrical sensors can detect corrosion rate by one or both of linear polarisation rate and electrochemical noise and thus there will usually be at least three. The sensor head can further comprise sensors for at least one of temperature, pressure, vibrations, acceleration, flow sand rate and water cut. A corresponding method of obtaining data is also disclosed, together with a method of designing an item of downhole equipment and the item of downhole equipment thus designed.

Abstract: A process is provided for the solid-phase synthesis of a peptide amide which comprises attaching a ?-nitrogen protect C?-carboxamide amino acid to a solid support by its side chain, removing the ?-nitrogen protecting group, assembling a peptide chain on said ?-nitrogen and then cleaving the assembled peptide amide from the solid support. Novel amino acid analogues, peptide amides and solid-phase supports are also provided.

Abstract: A corrosion monitor comprising electronic circuitry arranged such that DC current flowing between two electrodes is reduced to essentially zero, while allowing any naturally occurring AC current noise to flow unhindered and be monitored by the instrumentation. The two electrodes consist of one inert reference electrode, and one electrode constructed of the material to be monitored (the working electrode). Even though the two electrodes will have different galvanic potentials, by reducing the DC current to zero the electronic circuitry is able to avoid galvanic effects. Furthermore, the voltage potential can be monitored between the inert current reference electrode, and a third electrode also constructed of an inert material. As corrosion activity occurs on the working electrode, both current noise and voltage noise may then be monitored simultaneously.

Abstract: A measurement head particularly for borehole use can measure multiple parameters with no electronics in the head and only a single conductor cable. Double-ended tuning forks (26, 28 and 38, 40) in the head are arranged to respond to different parameters such as temperature and pressure by adjusting their resonant frequencies. A drive signal on the conductor (50) is applied to transducers (30, 32, 42, 44) on all the tuning forks and those whose instantaneous resonant frequency is close will resonate. The signal is removed and the transducers return a decaying signal at the resonant frequency along the conductor. Other drive frequencies are tried, to locate the other sensors whose frequency ranges are separate.

Abstract: A transducer assembly for measurement of downhole temperature and (if required) pressure includes a crystal resonator responsive to temperature and a pair of temperature sensors such as thermocouples or RTDs. One sensor is located with the crystal resonator and the other is exposed to external conditions such as those adjacent the pressure resonator. Thus, the sensors provide a correction signal for the resonator and allow improvement in the transient response of the transducer. A feedback circuit for correcting the resonator output is also disclosed.

Abstract: A corrosion monitor comprising electronic circuitry arranged such that DC current flowing between two electrodes is reduced to essentially zero, while allowing any naturally occurring AC current noise to flow unhindered and be monitored by the instrumentation. The two electrodes consist of one inert reference electrode, and one electrode constructed of the material to be monitored (the working electrode). Even though the two electrodes will have different galvanic potentials, by reducing the DC current to zero the electronic circuitry is able to avoid galvanic effects. Furthermore, the voltage potential can be monitored between the inert current reference electrode, and a third electrode also constructed of an inert material. As corrosion activity occurs on the working electrode, both current noise and voltage noise may then be monitored simultaneously.