Abstract: Buoyancy unit comprising a body (14) in which there are formed a buoyancy chamber (20) and a chamber (22) which is intended to become filled with water. According to the invention, the wall of the chamber (22) has at least two openings (24, 28), at least one opening of which comprises a nozzle (24, 28) allowing the passage of water between the chamber (22) and the outside, the nozzle being dimensioned in such a way as to appreciably slow the flow of water. The unit may form a buoyancy column intended to hold the deck of a floating rig up out of the water.

Abstract: The method consists in using a first interpreted horizon (H.sub.0) extracted from a seismic block migrated with at least a first value of a velocity (V) known with an uncertainty (.DELTA.V), and is characterized in that it consists in performing the following steps:a) making a second interpreted horizon (H.sub.1) by migration of the first horizon (H.sub.0) using a second value (V+.DELTA.V) of the velocity, equal to the first value (V) plus the uncertainty (.DELTA.V);b) making a third interpreted horizon (H.sub.2) by migration of the first horizon (H.sub.0) using a third value (V-.DELTA.V) of the velocity, equal to the first value (V) less the uncertainty (.DELTA.V);c) selecting a positioning point (X.sub.0) for the well on the said first horizon (H.sub.0) and plotting a vertical (D) which passes through the said point (X.sub.0) and intersects the second and third horizons(H.sub.1 and H.sub.2) at migrated points (X.sub.1, X.sub.2);d) on the said first interpreted horizon (H.sub.

Abstract: A seismic reflection data acquisition and processing method and device for prospecting in tectonically complex environments are disclosed. In particular, the seismic reflection data acquisition and processing method is useful for providing a summation rate tensor field and a 3D image unit, e.g. in 3D earth seismics or complex tectonics.

Abstract: A method for the determination of migration velocities in seismic processing in which a blasting point S is associated with receivers (R.sub.1 to R.sub.n) which are separated by offsets such that in a given speed range, a first set of traces derived from the blasting point and registered on the receivers, and a second set of traces in constant and colinear offset to the first set are migrated. Two migrated images of the part of the site corresponding to the two sets of traces are obtained. The two images are correlated by means of a spatial two-dimensional correlation, the result thereof determining the deviation between the migration used and the investigated velocity. The result is particularly useful in the seismic prospection of a site.

Abstract: Measuring device comprising a flow meter (26) provided with an inlet and an outlet which are each intended to be connected to a conduit in which a polyphase outflow to be measured flows, originating, for example, from an oil well, and a first valve (28) arranged below the flow meter (26), the flow meter being mounted generally vertically. According to the invention, the device furthermore comprises a branch passage (34), provided with a second valve (36), opening above the flow meter, so that it can be filled selectively with liquid using this branch passage (34).

Abstract: An electric pump including a linear motor consisting of a stator and a moving element driven by the electromagnetic field generated by the stator, and a pump piston driven by the linear motor, is disclosed. The piston is arranged inside the stator of the electric pump and forms the moving element of the linear motor. An oil well facility provided with such an electric pump is also disclosed.

Abstract: The subject of the present invention is an oil well production string hanger. A well comprises a production string, or tubing, through which the hydrocarbons flow, and a casing which supports the wall of the well. Between the two, there is an annular space used for control of the well. The tubing hanger fixed at the top of the well generally has two passages allowing communication with the tubing and with the annular space respectively. The invention relates to a tubing hanger with a single passage which gives access both to the tubing and to the annular space and allows the annular space to be plugged using a simple, economical, reliable and reversible method.

Abstract: Functionalized elastomer/bitumen compositions with a broad plasticity range are produced by contacting a bitumen or bitumen mixture with an elastomer, a functionalizing agent and optionally a peroxide compound at 100.degree.-230.degree. C. under stirring conditions. The funtionalizing agent is a thiolcarboxylic acid having 3 or more carbon atoms, a thiolcarboxylic acid ester and specifically a disulphide having carboxylic groupings or carboxylic esters. The compositions may be used either directly or in diluted form to produce bitumous binders for making road surfacings, coated materials and sealing coatings.

Abstract: Bitumen/polymer compositions with a broadened plasticity range are produced by contacting a bitumen or bitumen mixture with a sulphur-cross-linkable elastomer and a sulphur-donating coupling agent, at 100.degree.-230.degree. C. and under stirring conditions, to produce a cross-linked bitumen/polymer composition, then adding to the composition, maintained at 100.degree.-232.degree. C. and under stirring conditions, an acidic additive selected from polyphosphoric acids, acids of formula R--(COO).sub.t --SO.sub.3 H wherein t=0 or 1 and R is a monovalent hydrocarbyl radical having up to 12 carbon atoms, and mixtures of both types of acid separately or jointly with sulphuric acid, and maintaining the resulting reaction medium at 100.degree.-230.degree. C. and under stirring conditions for at least ten minutes. The bitumen/polymer compositions may be used directly or in diluted form to produce bituminous binders for making road surfaces, coated materials or sealing coatings.

Abstract: Installation for pumping a liquid coming from an underground source, comprising a well (10) extending from the surface (12) towards the liquid source (14), the well having a chamber (40) extending substantially over its entire length, at least one tubing (18) passing through the chamber and communicating with the latter, and a set of valves (34), which is intended for putting the chamber selectively in communication with a gas source at a first pressure (36), making it possible for the liquid coming from the source to fill the chamber, and a gas source at a second pressure (38) higher than the first pressure, in order to empty the chamber, the liquid being delivered towards a first outlet (30) by flow through the tubing, characterized in that the said installation comprises, furthermore, a shutter (52), mounted in the tubing (18), and a second conduit (58; 70) leading to a second outlet (74), the shutter being capable of reacting to the density of fluid surrounding it, so that it can deliver a first liquid to

Abstract: For controlling physical quantities in industrial plants, and particularly in the crude oil processing industries, the chemical and papermaking industries and gas, power stations and distribution networks, the value of a controlled physical quantity, subjected to perturbations, is kept between two limit values by modifying an action quantity. The action quantity should have small amplitudes in order to stabilize the downstream flows and should evolve so as to anticipate the perturbations. It is determined by performing fuzzy inference on a set of predefined decision rules, on the basis of values of the controlled physical quantity, of a secondary variable connected with the controlled physical quantity and of a context variable obtained from at least one detection variable or from a combination of detection variables representative of the physical quantities at the origin of the perturbations in the controlled physical quantity.