Abstract: The invention relates to a method and apparatus for start-up, transformation from start-up to normal operation and normal separation of carbon dioxide and other acid gases from methane using a distillation column with a controlled freezing zone. Normally, the feedstream is treated in at least one distillation zone, a controlled freezing zone, and another acid gas stripping apparatus. The freezing zone produces a carbon dioxide slush which is melted and fed into a distillation section and a methane-enriched stream which is fed to a separate stripping unit. Start-up is accomplished by refluxing the product stream from the separate stripping unit to the distillation column. Transformation is accomplished by separating the methane-enriched stream produced by the freezing zone into a liquid component for refluxing to the column and a vapor component to be fed to the separate stripping unit.

Abstract: A method of locating leaks in pipelines and associated facilities and a novel leak-detection test-fluid are disclosed. The novel test-fluid, comprising dimethylsulphide and a mutual solvent, is injected into a pipeline or facility so that the test-fluid escapes through the leak and an odorant which, by virture of its chemical and physical properties, is released from other test-fluid components to be detected in the vicinity of the leak.

Abstract: A method for recovering oil from a subterranean formation is disclosed wherein an aqueous surfactant solution is injected into the formation to reduce the mobility of gas in a gas-flooding process. The gas may include hydrocarbon gas, inert gas, carbon dioxide, and steam, or mixtures thereof. The surfactant is represented by the general formula ##STR1## where R is a linear or branched chain alkyl group with n carbon atoms wherein n ranges from about 6 to about 50, except that if the gas is steam n ranges from about 9 to about 50;Ar is a mononuclear or fused ring dinuclear aryl group;Z is an ionic group consisting of --SO.sub.3.sup.- M.sup.+ or --R'SO.sub.3.sup.- M.sup.+ wherein M.sup.+ is a cation and R' is a linear or branched chain alkyl group of from one to about six carbon atoms;x ranges from 0 to about 20; andy ranges from 3 to about 100.

Abstract: A low noise, magnetotelluric, intercalation electrode is disclosed that is both electronically and ionically conductive and stable in ground water brine. The electrode is comprised of an inert or chemically inactive long cylindrical and porous support shield, a semipermeable membrane located in the shield selectively permeable to the positive ions of a metal selected from the group consisting of Na+ and K+ ions, a brine electrolyte, and an electrode axis located in the brine electrolyte that includes an electronically conductive, metallic material ionically reversible to Na+ and K+. The electrode is sealed and attachable at its electrode axis to a wire leading to another electrode spaced apart therefrom. The wire connection permits voltage measurements and thereby provides a method for determining the resistivity between the electrodes at frequencies that are quite low without being interferred with by noise attendant prior art magnetotelluric electrodes.

Abstract: An improved apparatus is disclosed for setting a deck structure or other marine superstructure using a barge mounted cantilevered support structure. The cantilevered support structure is attached at one end of a floating vessel. The cantilevered support structure extends past the edge of the vessel and, in one embodiment, includes means for rotating parallel support members about the deck of the floating vessel permitting the cantilevered support structure to be raised and lowered while it remains substantially parallel with the top of the offshore platform enabling the superstructure to engage the top of a previously installed offshore platform in a synchronized manner. Alternatively, this superstructure may be aligned directly over the platform. A cantilevered drilling rig is then aligned over the cantilevered support structure and used to lift the deck structure or marine superstructure, permitting the vessel and cantilevered support structure to move.

Abstract: Method and apparatus for generating seismic energy in offshore areas includes energy propagating means for directing energy downwardly vertically into an earth formation. A carrier contains an elongated rigid coupler means that extends from the carrier at the water level to the seat floor. A base plate may be connected to the lower end of the coupler means. The coupler means may be a section of pipe. Driving means on the carrier drives the coupler means to cause sound energy to emanate from the coupler means or base plate into the sea floor. Such means may be a hammer-type device or a vibrator-type device. Alternatively, the lower end of the coupler means or the base plate may be driven by means of a vibrator-type device to cause sound waves to emanate from the coupler means or the base plate directly into the sea floor.

Abstract: The quadrupole shear wave logging device of this invention includes a logging sonde, means for generating a quadrupole shear wave in the earth formation surrounding a borehole containing fluid, and means for detecting in the fluid the refraction of the quadrupole shear wave. In the preferred embodiment, the generating means comprises four similar sectors of a hollow piezoelectric cylinder. The four cylinders are polarized radially. The four sectors are so connected to the sonde that they are in the form of a split cylinder coaxial with the sonde axis. Electrical pulses of similar waveforms are applied across the inner and outer cylindrical surfaces of each sector to vibrate the four sectors. The electrical pulses are of such polarities that, during their initial motions of vibration, two oppositely situated sectors are caused to move outward and the remaining two oppositely situated sectors to move inward substantially simultaneously.

Abstract: A choke arrangement useful in subsea completions in a subsea tree cap. The subsea choke arrangement allows for refitting of existing subsea tree arrangements to allow for the installation of a choke arrangement that can be easily maintained and removed. Also, a choke arrangement is shown that allows the choke to be isolated after failure which permits continued production of the well until repair or replacement operations can be implemented.

Abstract: A method for determining at wellsites the swelling-clay content of cement mixtures by high-frequency dielectric measurements including: grinding a cement mix sample to a size suitable for testing; washing the cement mix sample with a fluid having a water activity substantially less than water, which may contain a soluble cation; packing the washed cement mix sample into a sample cell suitable for dielectric measurement; measuring the dielectric constant at a preselected frequency; and comparing the measured dielectric constant of the cement mix sample to calibration curves.

Abstract: An improved surface controlled chemical injection valve and method for injecting chemical fluid into the bore of a tubing string of a well are provided, the chemical injection valve having at least one piston movable in response to the pressure of the chemical fluid, an actuator connected to the piston, and a flow restrictor wherein the pressure of the chemical fluid supplied to the valve from the chemical fluid source acts on the piston to cause the actuator to open the valve and inject the chemical fluid into the tubing string bore. The flow restrictor is mounted downstream of the piston to create sufficient available pressure in the chemical fluid upstream of the flow restrictor to act on the piston and hold the valve in the open position.

Abstract: A method of determining the continuity of a lithographic layer located between two vertical boreholes is disclosed. A seismic source is lowered in the first borehole while simultaneously a receiver pair, preferably a pair of "vertical" geophones spaced apart by about two feet, are lowered in the second borehole to develop a "differenced signal". The recording of high amplitude signals within a layer is an indication of a continuous, low velocity layer. The middle of a layer can also be discovered using a single vertical receiver and finding the place of phase reversal.

Abstract: A method is disclosed for detecting the presence or absence of anisotropy in a subterranean geological formation and for determining its orientation. In a first preferred embodiment, the method utilizes a seismic source which generates circularly polarized shear waves and directs them to a target formation. These waves undergo wave splitting on encountering anisotropic conditions and the resulting components are linearly polarized and are reflected to the surface or to a bore hole where they are detected by receivers. The reflected arrivals are then analyzed to detect the presence and orientation of the linearly polarized arrivals as is known in the prior art. In an alternative preferred embodiment, the use of a circularly polarized source is simulated by generating two orthogonal waves linearly polarized 90.degree. out of phase with respect to each other.

Abstract: A method for the production of bitumen from a subterranean reservoir having a zone of increased effective permeability therein. In particular, a first well is in fluid communication with the zone of increased effective permeability at a first level in the reservoir. Fluid communication is established between a second well and the zone of increased effective permeability at a second level above the first level in the reservoir. In-situ combustion is initiated in the reservoir proximate the second well. Combustion sustaining fluid is injected through the second well into the zone of increased effective permeability so that bitumens in the reservoir are mobilized by the in-situ combustion and flow downward through the reservoir towards the first well, through which they are recovered.

Abstract: Method and apparatus for converting tube waves into body waves downhole for seismic exploration are disclosed, comprising a rotary valve tube wave source for producing swept frequency tube waves that are injected into a tubing or wellbore. The tube waves are converted to body waves by an elongate tube wave converter located at a selected position downhole. The tube wave converter comprises an elongate body that preferably substantially fills the wellbore or tubing and has a preferred shape in order to convert efficiently the tube waves to body waves at the selected position downhole.

Abstract: A marine seismic cable network including cables towed parallel to the surface of the sea at at least two depths for providing time analysis of reflected seismic data to dimensionally clarify characteristics of reflecting surfaces.

Abstract: A method for determining at wellsites the solids content of drilling fluids by high-frequency dielectric measurements including: preparing samples of the drilling fluid, of the drill cuttings from the formation, and of each solids-additives type added to the drilling fluid for uniform dielectric constant measurements at preselected frequencies and obtaining the solids content in accordance with the relationship between the dielectric constant measurements of the drilling fluid-solids, drill cuttings, and each of the solids-additives type. In accordance with the method of the invention two levels of determination are possible. These levels of determination depend upon whether the quantities of solids-additives type added to the drilling fluid are known.

Abstract: A method of deterministically computer generating a model of a response voltage waveform of a seismic receiver employed in a seismic, particularly marine, data gathering system, the model incorporating factors that have been identified as significant contributions to amplitude, such as directivity, divergence, attenuation, interbed multiples, and transmissivity. The model is generated from the mathematical manipulation of well log data and data gathering system characteristics into a seismic range equation, namely: ##EQU1## where E.sub.r (f)=received energy densityE(f)=radiated energy densityD(l.theta..sub.s, .phi..sub.s,f)=source directivity along .theta..sub.s,.phi..sub.s direction at the sourceA.sub.c (.theta..sub.H,.phi..sub.H,f)=Capture area along .theta..sub.H,.phi..sub.H direction at the hydrophone arrayR.sub.T =target reflection coefficientD.sub.

Abstract: An apparatus for positioning a plurality of marine seismic sources in an array. The marine seismic sources are retained in retaining means which are mounted to a frame so that each source is separated from the nearest other source in the array by a predetermined distance. Shock absorbing means are mounted in the frame intermediate each of the retaining means and each other retaining means mounted to the frame.

Abstract: An improved process is described for the separation and recovery of substantially all the propane and heavier hydrocarbon components in a hydrocarbon gaseous feedstream. In this process, the vapor stream from a deethanizer is cooled to liquefaction and contacted with a vapor phase from the hydrocarbon gaseous feedstream. The contact takes place within a direct heat exchanger, and the resulting vapor fraction, which is essentially ethane and methane, is the gaseous product of the process.

Abstract: Method and apparatus for acoustic wave generation and transmission into a subsurface earth formation, particularly adapted for use in borehole shear wave logging. A logging sonde adapted to be suspended in a borehole traversing a formation houses a source of acoustic waves. The source simultaneously generates a plurality of acoustic waves propagating generally radially outward from locations within the sonde housing adjacent the vertical central axis thereof and will interfere to produce multipole acoustic waves in the formation. Detector means within the housing spaced longitudinally from the source detect acoustic energy in the formation resulting from the generated waves. In a preferred embodiment, the source includes a cross-shaped rod assembly comprised of two rods perpendicular to each other and joined at their mid-points through which the central axis passes.