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.

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.

A bi-directional telemetry system for use in a wellbore environment is provided. The bi-directional telemetry system includes a first acoustic telemetry component and a second acoustic telemetry component that is separate from the first acoustic telemetry component. The first acoustic telemetry component comprises a downhole acoustic transmitter disposed in a wellbore and operable to transmit the first acoustic signal and an uphole acoustic receiver. The second acoustic telemetry component comprises an uphole acoustic transmitter operable to transmit the second acoustic signal and a downhole acoustic receiver.

A bi-directional telemetry system for use in a wellbore environment is provided. The bi-directional telemetry system includes a first acoustic telemetry component and a second acoustic telemetry component that is separate from the first acoustic telemetry component. The first acoustic telemetry component comprises a downhole acoustic transmitter disposed in a wellbore and operable to transmit the first acoustic signal and an uphole acoustic receiver. The second acoustic telemetry component comprises an uphole acoustic transmitter operable to transmit the second acoustic signal and a downhole acoustic receiver.

An apparatus for downhole multi-dimensional imaging includes an acquisition unit configured to acquire a formation resistivity signal, an ultrasonic echo signal and an orientation signal regularly; a sector calculation unit configured to calculate, based on said orientation signal, a sector where a currently acquired signal is from; and a multi-dimensional imaging unit, configured to calculate, based on the signals acquired by the acquisition unit, data of resistivity, distance from a drilling tool to a borehole wall and ultrasonic echo amplitude, and distribute said data into all sectors for feature recognition and extraction, thus obtaining key features characterizing a current formation being drilled, said key features being transmitted to ground for guiding drilling process. The structural complexity and the length of the downhole imaging measurement instrument can be reduced, and feature recognition can be directly performed on the imaging data underground.

An apparatus for downhole multi-dimensional imaging includes an acquisition unit configured to acquire a formation resistivity signal, an ultrasonic echo signal and an orientation signal regularly; a sector calculation unit configured to calculate, based on said orientation signal, a sector where a currently acquired signal is from; and a multi-dimensional imaging unit, configured to calculate, based on the signals acquired by the acquisition unit, data of resistivity, distance from a drilling tool to a borehole wall and ultrasonic echo amplitude, and distribute said data into all sectors for feature recognition and extraction, thus obtaining key features characterizing a current formation being drilled, said key features being transmitted to ground for guiding drilling process. The structural complexity and the length of the downhole imaging measurement instrument can be reduced, and feature recognition can be directly performed on the imaging data underground.

A body defines a central flow passage. A check valve is located within the central flow passage. The check valve is supported by the body. The check valve is arranged such that a fluid flow travels in a downhole direction during operation of the float collar. An auxiliary flow passage is substantially parallel to the central flow passage and is defined by the body. The auxiliary flow passage includes an inlet upstream of the check valve and an outlet at a downhole end of the float collar. A rupture disk seals the inlet of the auxiliary flow passage. The rupture disk is configured to burst at a specified pressure differential.

A body defines a central flow passage. A check valve is located within the central flow passage. The check valve is supported by the body. The check valve is arranged such that a fluid flow travels in a downhole direction during operation of the float collar. An auxiliary flow passage is substantially parallel to the central flow passage and is defined by the body. The auxiliary flow passage includes an inlet upstream of the check valve and an outlet at a downhole end of the float collar. A rupture disk seals the inlet of the auxiliary flow passage. The rupture disk is configured to burst at a specified pressure differential.

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.

A method can be used to determine multi-phase measurements of fluid flowing with respect to a wellbore. Signals can be received, and the signals can be emitted by each variable frequency acoustic emitter of a set of variable frequency acoustic emitters positioned spaced apart in a sensing transducer that is in an interior of a wellbore. The received signals can be converted into a flow rate of each of a set of different fluid phases of a fluid in the wellbore. The multi-phase measurements of the fluid can be determined using the converted flow rate.