Abstract: An aqueous gellable composition capable of producing gels resistant to syneresis in the presence of divalent ions, contains:a water-soluble acrylamide polymer or copolymer,a crosslinking agent formed by a water-soluble aldehyde, or a water-soluble aldehyde and a water-soluble phenol,a water-soluble anti-syneresis agent selected from: organic carboxy acids, organic hydroxy acids and aminoacids, or among aminophosphonic acids and their alkali-metal or ammonium salts.When malonic acid is used, a delay in aqueous composition gelation is additionally obtained.

Abstract: Particular hydrocarbon composition constituted by saturated species, alkylbenzenes and polyaromatics, useful for dissolving asphaltenic residues present in oil wells.

Abstract: Aqueous drilling muds effective at high temperature containing complexes, preformed or formed in situ, of tetravalent zirconium with one or more organic acids, or relative salts, of general formula (I) ##STR1## where R.sub.1 and R.sub.2, which can be the same or different, represent --H, --COOH, --CH.sub.3, --CH.sub.2 COOH or --CH(OH)COOH, or R.sub.1 and R.sub.2 jointly represent an oxo group (.dbd.O).

Abstract: A method for monitoring the state of, and for locating any detachment of, the protective covering of immersed or buried pipelines or other metal structures subjected to cathodic protection with constant current, on the basis of the overall electrical resistance offered by the pipeline/covering/ground system, consisting of applying local sinusoidal wave excitation currents of different frequencies to the pipeline and measuring the corresponding voltage responses, then comparing the measured responses of the system to determine, on the basis of response differences or coincidences at the various frequencies, whether within the portion under consideration there is detachment with corrosion underway or whether there is simple covering decay.

Abstract: A method for separating and analyzing the hydrocarbons, particularly heavy hydrocarbons, contained in sedimentary rocks, comprising:A) loading a sample tube with the sample of sedimentary rock and one or more inert solvents;B) preheating the sample tube;C) removing the solvent and the hydrocarbons previously contained in the rock;D) condensing the vapour and feeding it to a separation and analysis device.The invention also comprises an apparatus for implementing separating and analyzing method.

Abstract: Particular hydrocarbon composition constituted by saturated species, alkylbenzenes and polyaromatics, useful for dissolving asphaltenic residues present in oil wells. Such useful hydrocarbon blends for dissolving asphaltenic residues present in oil wells, are characterized in that said blends are essentially constituted by a composition selected from those which, on a ternary chart, in which the vertex (A) represents 100% of polyaromatics with z<-6, the vertex (B) represents 100% of saturated species, and the vertex (C) represents 100% of alkylbenzenes with z=-6, are comprised between:the vertex (A), i.e., 100% of polyaromatics with z<-6;the point, along the side AB, corresponding to 77% of polyaromatics with z<-6 and 23% of saturated species;the point, along the side AC, corresponding to 45% of alkylbenzenes and 55% of polyaromatics with z<-6;with the further constraint that the initial boiling point of the above said hydrocarbon blend is higher than 150.degree. C.

Abstract: A technique is disclosed for obtaining the true capillary pressure curve directly from experimental measurements. The above said technique is based on the use of a small-size sample being into capillary contact with the sample to be tested, with the usual tail effects being thus prevented. The resulting experimental data does not require complex mathematical processing yielding approximate results.

Abstract: An aqueous gellable composition having a delayed gelling time presettable within wide time and temperature ranges, contains a water-soluble organic polymer crosslinkable with chrome ion and a crosslinking/retardant system definable by the formula:Cr(L).sub.m.nL'wherein:Cr is a trivalent chrome ion;L is an organic ligand consisting of a monocarboxylate or dicarboxylate ion, optionally bearing one or more amino or hydroxy functional group(s), in form complexed with chrome ion;L' is an organic ligand consisting of a monocarboxy or dicarboxy acid, optionally bearing one or more amino or hydroxy functional group(s), in form not complexed with chrome ion;m has a value comprised within the range of from 1 to 3, depending on the nature of the ligand L;n has a value comprised within the range of from 0.5 to 100;with the proviso that in the crosslinking/retardant system, the ligand L is different from the ligand L'.

Abstract: A process is disclosed, for pumping a multi-phase gas-liquid mixture by using a pump as the thrusting machine, and at least two pumping vessels alternatively performing functions of intake and functions of compression/delivery.

Abstract: Gellable compositions containing:(a) water;(b) a water-soluble organic polymer bearing special chelating functional groups;(c) a multi-valent metal ion capable of causing the polymer to crosslink,are useful to recover oil from a oil field.Said compositions make it possible gels to be obtained which are endowed with improved physical properties and show a higher stability under the conditions prevailing in the oil field.

Abstract: The permeability of high-permeability zones in a oil reservoir can be reduced by using a gellable aqueous composition with delayed gelation. The composition comprises:a) water;b) a high-molecular weight natural or synthetic water-soluble polymer cross-linkable by means of Cr.sup.3+ ions;c) a water-soluble inorganic Cr.sup.

Abstract: An aqueous gellable composition having a delayed gelling time is disclosed, which contains a water-soluble polymer crosslinkable with Cr.sup.3+ and a crosslinking/retardant system containing a Cr.sup.3+ ion and a salicylic acid ligand, wherein said ligand can be in free form, or in the form of a complex with Cr.sup.3+, or partially in free form and partially in complexed form.Such a composition is useful for modifying the permeability in petroleum reservoirs, within a wide range of temperatures, of from about 60.degree. C. to 120.degree. C., or higher temperatures.

Abstract: A multi-section helicopter-borne rotatable beam for supporting at either of its ends range-finder cameras and television focusing cameras for stereophotogrammetric surveys, in which the central tubular section is rotated by means of an electric motor and return springs and supported by two collars mounted rotatably by means of hinged constraints on a base fixed rigidly to the floor of the helicopter cab and the two truncated-cone tubular-structure side sections of the beam are secured to the central section by a telescopic coupling arrangement ensured by half-ring ties co-operating with flanges of the sections and by through pins and safety split pins, the above-mentioned cameras being supported by prismatic box frames in their turn supported, by means of a dampening system comprising springs and double-acting shock absorbers, inside housings or pods with a ventral opening, which can be closed with an internally-sliding door, and a plexiglass portable. Variants are also envisaged.

Abstract: An internal centering device which is particularly suitable for the connection of tube ends wherein there are fitted onto a central supporting member of mainly axial development two hollow mandrels of which at least one is adapted for axial movement and at least one is articulated on the said central body and is provided with at least three radial actuators which are disposed sufficiently remotely from the corresponding articulation, for angular positioning of the mandrel in relation to the said central body, each mandrel having an outer elastic sleeve which is capable of being radially expanded by an internal hydraulic axial actuator having two opposing threads. Also described are particular types of axial actuators as well as alternative embodiments.

Abstract: A system of identifying materials and equipment consisting of small metal plates applied to them on their concealed surface and in which identifying means are provided consisting of incisions or blind holes which are detected under scanning or by multiplex technology using ultrasonic transducers which emit ultrasonic waves and which detect the ultrasonic signals reflected by the concealed surface, which set up a different binary coded sequence of return signals as a function of the markings made on the concealed surface of the small plate which is applied to the material.

Abstract: The permeability of high-permeability zones in a oil reservoir can be reduced by using a gellable aqueous composition with delayed gelation.The composition comprises:a) water;b) a high-molecular weight natural or synthetic water-soluble polymer cross-linkable by means of Cr.sup.3+ ions;c) a water-soluble inorganic Cr.sup.

Abstract: A method for reducing the permeability of a high-permeability zone in a high-temperature oil reservoir comprises:preparing a gellable polymeric aqueous solution, operating on the surface under controlled conditions;injecting said gellable solution into the oil reservoir through a well;moving the solution through the reservoir until it reaches and substantially fills the high-permeability zone to be treated; andgelling the solution in situ with consequent lowering of the permeability in said high-permeability zone, and is essentially characterized in that the gellable solution is an aqueous solution containing a Cr(III) ion cross-linking agent and a water-soluble organic polymer cross-linkable by the effect of said cross-linking agent, said solution being free or substantially free of ligands for the cross-linking agent and having a pH adjusted to a value within the range of 1.5 to 5.5, depending on the desired gelling time.

Abstract: A gellable aqueous compositions able to reduce the permeability of high-permeability zones in an oil reservoir is a aqueous solution containing metered quantities of:a) a water-soluble organic polymer cross-linkable by the effect of a polyvalent metal ion cross-linking agent;b) a Cr(III) ion cross-linking agent; andc) a ligand for the cross-linking agent chosen from water-soluble organic alpha-hydroxy acids and alpha-amino acids.

Abstract: New acrylamide copolymers formed by (meth)acrylamide benzene dicarboxylic monomer units in accordance with the following formula: ##STR1## wherein R is H or CH.sub.3 ; X is H or an alkaline metal or NH.sub.4 ; and wherein the COOX groups may be in ortho-, meta- or para- position in relation to each other, preferably being in ortho- position to each other; and of (meth)acrylamide monomer (II) units.

Abstract: A gellable aqueous composition particularly suitable for reducing the permeability of high-permeability zones in an oil reservoir is an aqueous solution comprising:a) a water-soluble organic polymer cross-linkable by the effect of a polyvalent metal ion cross-linking agent;b) a Cr(III) ion cross-linking agent;c) a buffer agent free or subtantially free of ligand characteristics towards the cross-linking agent, and chosen from organic bases and aromatic carboxylic or sulphonic acids;the solution pH being adjusted to a value within the range of about 2 to about 7.