Abstract: Systems (20) and methods for monitoring a well (10) are configured to identify or analyze various issues affecting the well (10) including corrosion, cement quality, inflow, and fluid migration.

Abstract: Systems (20) and methods for monitoring a well (10) are configured to identify or analyze various issues affecting the well (10) including corrosion, cement quality, inflow, and fluid migration.

Abstract: A method for identifying fluid migration or inflow associated with a wellbore tubular, comprises measuring strain of the wellbore tubular with a system comprising at least one string of interconnected sensors that is arranged such that the sensors are distributed along a length and the circumference of the wellbore tubular; establishing a baseline that is a function of steady state strain measurements within a first time period; and identifying fluid migration or inflow where strain measurements substantially deviate from the baseline within a second time period.

Abstract: A system for use in a wellbore, comprises a length of casing, a structure that is configured to deform with deformation of the casing, said structure being affixed to the length of casing at substantially the same radial position along the length of casing, and a sensing device that is configured to measure deformation of the structure, said device comprising a plurality of sensors that are distributed with respect to at least one of the length of said structure and the periphery of said structure.

Abstract: A transmitter system for inducing a transient electromagnetic field in an earth formation comprises an inductive element to generate an electromagnetic field in response to a flow of electric current through the inductive element. Furthermore, switching means arranged to interrupt the flow of electric current through the inductive element, which switching means comprises a primary switch and an auxiliary switch arranged in series connection with each other. The auxiliary switch has a lower breakdown voltage than the primary switch. This induces a transient electromagnetic field in the earth formation. Delay circuitry may impose a time delay between switching of the auxiliary switch relative to switching of the primary switch. A transient electromagnetic response signal may be recorded, and used in a method of producing a mineral hydrocarbon fluid.

Abstract: A system (20) for monitoring deformation of a substantially cylindrical casing (14). The system (20) includes at least two strings (22) of interconnected sensors (24) that are wrapped around the casing (14) so as not to intersect one another. At least one of the strings (22) includes a series of at least two segments (S). The series of segments (S) includes a segment (S) arranged at one wrap angle (?) and another segment (S) arranged at a different wrap angle (?).

Abstract: A down-hole tool provided with a transmitter system for inducing a transient electromagnetic field in an earth formation has an induction coil with a number of windings to generate essentially a magnetic dipole field. The number of windings is divided into two or more groups of windings arranged to cooperatively generate the essentially magnetic dipole field when energized. Switching means are arranged to essentially simultaneously terminate the energizing of the groups of windings. The groups of windings are electrically isolated from each other or connected in parallel to each other, at least when the energizing is terminated. A transient electromagnetic field may thus be induced in an earth formation by essentially simultaneously terminating energizing each group of windings by operating the switching means. A transient electromagnetic response signal may be recorded, and used in a method of producing a mineral hydrocarbon fluid.

Abstract: In accordance with the present disclosure, a system and a method are disclosed for measuring a time varying magnetic field. In one aspect, a system comprises a plurality of induction coils arranged to measure the time varying magnetic field using at least one voltage induced in at least one of the induction coils in the plurality of induction coils, a plurality of snubber circuits connected to the plurality of induction coils, each of the snubber circuits of the plurality of snubber circuits arranged to suppress a resonance of a respective one of the induction coils of the plurality of induction coils, and a summing circuit connected to each of the snubber circuits of the plurality of snubber circuits, the summing circuit arranged to sum voltages induced in each of the induction coils in the plurality of induction coils.

Abstract: A method for obtaining information about a subsurface formation from acoustic signals that contain information about to the subsurface formation, comprises: providing a fiber optic having a proximal end and a remote end, with the proximal end being coupled to a light source and a proximal photodetector, wherein said fiber optic cable includes randomly spaced impurities and selectively placed Bragg gratings and wherein the fiber optic cable is acoustically coupled to the subsurface formation so as to allow the acoustic signals to affect the physical status of at least one grating: transmitting at least one light pulse into the cable; receiving at the photodetector a first light signal indicative of the physical status of at least one first section of the cable, and outputting at least one item of information to a display.

Abstract: Method and apparatus of analyzing a fluid from an earth formation using a downhole tool. In the method, the downhole tool is conveyed down a borehole in the earth formation, and a fluid drawn into a measurement portion of the downhole tool, where a spectroscopic measurement of the fluid is made in a terahertz radiation domain. The method may be part of a method of producing a mineral hydrocarbon material from an earth formation.