Abstract: A device (53) comprises an enclosure (63) and means (65, 67) for circulating a drilling mud in the enclosure (63). The inventive device is also provided with means (69) for introducing a gas carrier into the enclosure (63), which comprises a pipe (113) provided with a unit (121) for adjusting the gas carrier flowrate. The device (53) comprises a gas extracting pipe (71) open into the enclosure (63). The gas introducing means (69) comprise a sensor (123) for measuring a pressure at a point located downstream of the adjusting unit (121) and means (117) for controlling the flowrate of the gas carrier injected through said adjusting unit (121) according to the difference between a pressure measured by the sensor (123) and a determined gas extraction pressure.

Abstract: Method of calibration intended to be used in a process of determining the content of a plurality of compounds contained in a drilling fluid, the method comprising obtaining a calibration mud; performing a gas extraction from said calibration mud with at least two extraction stages in order to obtain at least two extracted gases; measuring parameters representative of the quantities of said calibration compounds in said extracted gases; and calculating correction factors using said measured parameters, the correction factors being intended to be used in said process.

Abstract: The method includes extraction of gases contained in a mud, in order to obtain a gas stream of extracted gases containing hydrocarbons to be analyzed and at least one parasitic compound. The method includes transporting the gas stream through a transport line (54) and passing it through a separation column (121) in order to separate the hydrocarbons to be analyzed according to their elution times in the separation column (121). The parasitic compound is likely to have an elution time in the separation column (121) between the elution time for the first hydrocarbon to be analyzed and the elution time of the final hydrocarbon to be analyzed. The method includes passing the gas stream over a surface (141) for chemical and/or physical interaction with the parasitic compound in order to selectively retain the or each parasitic compound without retaining the hydrocarbons to be analyzed.

Abstract: This device comprises a means (111) for forming a gaseous flow from the sample, and a means (121) for separation by means of selective retention each gaseous constituent. It comprises a means (113) for combustion of the gaseous flow in order to form a gaseous residue from each constituent, and a means (115) for quantifying the content of each constituent to be analysed in the gaseous flow. The quantification means (115) comprise an optical measurement cell (127) which is connected to the combustion means (113), and a means (161) for introducing a laser incident optical signal into the cell (127). The quantification means (115) also comprise means (133) for measuring a transmitted optical signal resulting from an interaction between the optical signal and each gaseous residue in the cell (127), and means (125) for calculating said content on the basis of the transmitted optical signal.

Abstract: This device includes a stage for forming a gaseous flow from the sample, and a column for separation by selective retention of each gaseous constituent. It includes an oven for combustion of the gaseous flow in order to form a gaseous residue from each constituent, and a quantification unit for quantifying the content of each constituent to be analyzed in the gaseous flow. The quantification unit includes an optical measurement cell connected to an oven, and a mirror for introducing a laser incident optical signal into the cell. The quantification unit also measures a transmitted optical signal resulting from an interaction between the optical signal and each gaseous residue in the cell, and calculates the content on the basis of the transmitted optical signal.

Abstract: This mandrel (10) comprises a body (16; 22) and a radially expandable annular sealing element (18) which comprises a centring arrangement (46) and a closure arrangement (44) which can be deployed radially between a contracted configuration and a dilated configuration. It further comprises an anchoring element (20) which is positioned at a longitudinal distance from the sealing element (18) and is radially expandable between a retracted state and a deployed state. The mandrel (10) comprises sequencing means (24) which are capable of radially deploying the closure arrangement (44) after the anchoring element (20) and the centring arrangement (46). In an at least partly deployed configuration, the centring arrangement (46) defines at least one axial passage (64) which extends through the annular sealing element (18). The closure arrangement (44) closes the or each axial passage (64) as it is deployed.

Abstract: A device and method for measuring electromagnetic signals that can be used to take measurements at or near the sea floor. The device comprises a central housing, a data management system located within the housing and at least two arms extending outwards from the housing. Each arm comprises a flexible elongate sheath attached to the housing, a sensor head, a flexible electrical cable attached to the sheath and connecting the sensor head to the data management system and a rod which is removeably locatable within the sheath. The rod is connectable relative to the housing at one end and connectable relative to the sensor head at the end remote from the housing.

Abstract: The invention relates to a safety device for an oil well and to the associated safety installation. The inventive device comprises a valve housing (40) which defines a fluid flow passage (52). The aforementioned housing (40) comprises a valve (48) which is used to seal the passage and which can move between an open position and a closed position and means for permanently biasing the valve towards the closed position thereof. The housing (40) also comprises releasable means (54) for connecting same to a working line with tubing that is intended to move the housing (40) in the conduit. In addition, the device comprises retractable means (42) for supporting the valve (58) in the open position and hydraulic means (44, 46) for actuating the support means (42) in order to activate same upon reception of a valve open control signal. The aforementioned support means (42) and actuation means (44, 46) are solidly connected to the housing (40) such that they can be moved simultaneously under the control of the line.

Abstract: A method and device includes measuring a multiple-phase fluid flowing through a pipe. The inventive method includes the following steps in which: a fluid is illuminated using a first coaxial probe placed in contact with the liquid phase of the fluid, and a first electromagnetic wave is emitted at a high frequency. The admittance at the interface between the first probe and the fluid is measured, and the fractions of at least two constituents of the liquid phase are calculated in order to obtain the effective permittivity (?1) of the phase. The method also includes the following steps in which: the fluid is illuminated using a second coaxial probe and a second electromagnetic wave is emitted at a low frequency. The admittance at the interface between the second probe and the liquid is measured, and the thickness (e) of the liquid is measured. The aforementioned calculation is performed on the basis of the calculated effective permittivity (?1) and the admittance measured by the second probe.

Abstract: A method of determining the nature of subterranean strata. The transmitter antenna is towed by vessel at a distance h above the sea floor. The antenna omits a wave field whose strength is proportional to the current delivered to the antenna and this is monitored. The input voltage to the antenna is also measured and changes in antenna impedance are calculated. Changes in antenna impedance are used together with seismic information to determine the nature of the subsea strata.

Abstract: A concrete formulation, which undergoes controlled deterioration in water, that can be used for making anchors for releasably tethering submarine devices at the seabed. The anchor may have handles for a device release mechanism or a central hole for a central device release mechanism. The formulation includes additives, which cause the cement to transform into non-binding Thaumasite over a pre-set period of time, leaving only natural material on the seafloor.

Abstract: A source arrangement for generating electrogmagnetic (EM) wavefields, comprising an EM signal generator, at least three electrodes (141-144) connected to the generator, and a control system. The electrodes are spaced apart but not all in line. The control system is arranged to apply non-coincident time-varying signals or transmissions from the generator between different pairs of the electrodes. The non-coincidence can be by applying the signals sequentially or by applying the signals out of phase.

Abstract: The inventive device (53) comprises an enclosure (63), means (65) for supplying the drilling mud into the enclosure (63), and means (67) for discharging the drilling mud from the enclosure (63). The device also comprises means (69) for introducing a carrier gas into the enclosure (63) and a pipe (71), which serves to extract the gas discharging into the enclosure (63) and which is connected to suction means (109). The device (53) additionally comprises selective venting means (72) comprising a vent pipe (115) perforated over the extracting pipe (71) and means (117) for closing the vent pipe (115). These means (117) are designed for opening the vent pipe (115) when the pressure at at least one point (121) of the device is less than a predetermined set value. The invention is used for analyzing the gaseous content of muds from drilling oil wells.

Abstract: A device includes an analyzer (53) and a sampling apparatus (51) for taking a sample of at least one fraction of the gas that has at least one porous membrane element (55). The porous membrane element (55) has a support (63) and a first surface (57) which is in contact with liquid circulating in duct (13) and a second surface (59) which opens out into a duct (61) which is connected to the analyzer (53). The hardness of the first surface (57) is more than 1400 Vickers (kgf/mm2), ranging more particularly between 1400 and 1900 Vickers (kgf/mm2). The device can be used to analyze the gaseous content of oil well boring sludge.

Abstract: The mandrel comprises a body having a longitudinal axis together with a radially-expandable annular assembly. The annular assembly presents a peripheral surface for pressing against a borehole and a peripheral surface for pressing against the body. Around the longitudinal axis, the annular assembly comprises a plurality of radial-expansion blocks. Each block has a first bearing surface, a second bearing surface, and two side surfaces disposed respectively facing a side surface of at least one adjacent block. The block are displaceable relative to one another between a radially-contracted configuration, and a radially-expanded, engagement configuration in which each side surface of a block is in contact with the side surface of the adjacent block.

Abstract: The device relates to an installation comprising a cavity extending from the surface of the ground and provided with at least one electrically conductive tubular element. The device comprises a single-strand smooth cable for supporting an action and/or measurement assembly, which cable is electrically conductive and has a breaking strength greater than 300 daN, and is disposed in the tubular element. The surface of the cable is electrically insulated at least in part from said tubular element. The device includes transmitter means and receiver means for transmitting and receiving an electrical and/or electromagnetic signal, said means being situated in the vicinity of the surface and in the cavity, and being electrically connected to the cable and to the tubular element and/or an underground formation. The invention is applicable to transmitting information and to controlling tools in an oil well.

Abstract: A system for investigating subterranean strata. An electromagnetic field and a seismic event are applied from the same location and the responses are detected using respective receivers both located at a second location spaced from the first. The responses are combined to identify the presence and/or nature of subterranean reservoir. The refracted wave components are used.

Abstract: A method analyzes the hydrocarbon composition of geological strata. The method includes an analysis of gaseous hydrocarbon concentrations contained in drilling muds. According to the method, for a given depth range, gaseous hydrocarbon concentration ratios are established in pairs at essentially-identical depths. Subsequently, a sub-set of the ratios is selected in order to form a signature that is representative of the gaseous hydrocarbon composition of the depth range. The aforementioned signature is defined by the at least one straight line representing the concentration of a first gaseous hydrocarbon in relation to the concentration of a second hydrocarbon. The signature is then compared to reference signatures in order to determine the hydrocarbon concentration of the geological stratum corresponding to the depth range.

Abstract: A method processing an electromagnetic wavefield response in a seabed logging operation. The wavefield is resolved into upgoing- and downgoing components. The downgoing component represents reflections from the sea surface while the upgoing component represents reflections and refractions from subterranean strata. The upgoing component is then subjected to analysis.

Abstract: A method includes the phases of measuring the quantity of a given gas in the gases extracted from a calibration sample of a calibration mud, in at least two stages for extraction under predetermined conditions. A family of curves representing the extraction, under the predetermined conditions, of the given gas from the drilling mud, is established on the basis of the measurements carried out. The method also includes the phases of measuring the quantity of given gas in the gases extracted from an analysis sample of the drilling mud in an extraction stage, under the predetermined conditions; and computing the given gas content of the drilling mud on the basis of the measured quantity of given gas and of a curve of the family.