Schlumberger Technology Corporation

Timothy Gareth John Jones

Gary John Tustin

Li Jiang

Oliver Clinton Mullins

Trevor Lloyd Hughes

Bhavani Raghuraman

Gale Hyslip Gustavson

Jian Zhou

Rogerio Tadeu Ramos

Christopher Harrison

Kosta Ladavac

Ronald E G Van Hal

Andrew Meredith

Jimmy Lawrence

Robert Seth Hartshorne

Benoit Couet

Jonathan Webster Brown

Albert Ballard Andrews

Clive Edward Hall

Markus Pagels

Philip Fletcher

Andrew Gilbert

Jesse Ching-Wang Lee

Amilra Prasanna De Silva

Nathan Scott Lawrence

Xu Wu

Andrew L Kurkjian

Christopher Alan Sawdon

Vladimir Vaynshteyn

Anthony Robert Holmes Goodwin

Richard Guy Compton

Christian Besson

Andreas Manz

A Ballard Andrews

Philip Rabbito

Gregory George Wildgoose

Sarah Elizabeth Pelham

Kay Robinson

Boris Matveev

Ratna Tantra

Loic Regnault De La Mothe

James Francis Westwood

Hemant Kuman Jethalal Ladva

Maria Violante De Paz Banez

Malingappagari Pandurangappa

This invention relates to methods and apparatus for determination of ion concentrations, particularly in downhole water from hydrocarbon wells, aquifers etc. It is useful in a wide range of applications, including predicting the formation of scale and fingerprinting waters from different sources. More particularly, the invention relates to the use of ligands whose electronic configuration is altered by the binding of the scaling ions within a water sample. These alterations are detected electrochemically by applying varying potential to electrodes and measuring current flow as potential is varied, from which is derived the concentration of scaling ions in the fluid.

Apparatus and method for measuring concentrations of scale-forming ions

The present invention provides aqueous viscoelastic compositions comprising a cleavable anionic surfactant which is a sulphonate and possibly also an electrolyte. The cleavable surfactants useful in the present invention comprise a chemical bond, which is capable of being broken under appropriate conditions, to produce oil soluble and water soluble products typically having no interfacial properties and surface activity compared with the original surfactant molecule. Further, the rheological properties of the aqueous viscoelastic composition are usually altered upon cleavage of the cleavable surfactant generally resulting in the elimination of the viscosifying, viscoelastic and surfactant properties of the composition. Aqueous viscoelastic compositions in accordance with the present invention are suitable for use in oil-field applications, particularly for hydraulic fracturing of subterranean formations. Thus, the present invention also relates to a wellbore service fluid and a method of fracturing a subterranean formation.

Viscoelastic compositions

An electro-chemical sensor for methane is described having a catalyst to react methane or other low molecular weight hydrocarbons and a detector to detect the turnover or reaction rate and using such information to determine the concentration of the methane or other low molecular weight species. The sensor is preferably used for measurements in a wellbore.

Electro-chemical sensor

Methods and related apparatuses and mixtures are described for detecting hydrogen sulfide in a formation fluid downhole. A detection mixture is combined with the formation fluid downhole. The detection mixture includes metal ions for reacting with hydrogen sulfide forming a metal sulfide, and charged nanoparticles sized so as to inhibit significant aggregation of the metal sulfide so as to enable spectroscopic detection of the metal sulfide downhole. The combined mixture and formation fluid is then spectroscopically interrogated so as to detect the presence of the metal sulfide thereby indicating the presence of hydrogen sulfide in the formation fluid. The mixture also includes chelating ligands for sustaining thermal endurance of the mixture under downhole conditions.

Downhole spectroscopic hydrogen sulfide detection

A wellbore tool has an electrochemical sensor for measuring the amount of hydrogen sulphide or thiols in a fluid downhole in a wellbore. The sensor comprises a temperature- and pressure-resistant housing containing a flow path for the fluids. The fluids flow over one side of a gas permeable membrane the other side of the membrane being exposed to a chamber containing at least two electrodes and containing a reaction solution which together with the hydrogen sulphide or thiols create a redox reaction resulting in an electrical current dependent upon the amount of hydrogen sulphide or thiols in the fluid. Measurement is made by passing formation fluid along the flow path and repeatedly applying varying potential to one electrode and measuring the peak current flowing between that electrode and a second electrode.

Measurement of hydrogen sulphide and thiols in fluids

A water-based wellbore treatment fluid contains: one or more viscoelastic-gelling carboxylic acids and/or alkali metal salts thereof; and one or more solubilizing alkylolamines. The carboxylic acids and/or alkali metal salts and the alkylolamines are present in the fluid in respective amounts such that, at 25&#xb0; C., the alkylolamines solubilize a sufficient portion of the carboxylic acids and/or alkali metal salts to render the fluid viscoelastic. A remaining portion of the carboxylic acids and/or alkali metal salts forms a suspension of solid particulates in the fluid.

Wellbore treatment fluid

A method and system is disclosed for monitoring one or more characteristics associated with a fluid. An insulating layer comprising non-conducting diamond is positioned within a housing and has a surface exposed directly or indirectly to the fluid. A plurality of microelectrodes made of electrically conducting diamond each have a surface exposed directly or indirectly to the fluid. An electrical circuit in electrical communication with each of the microelectrodes is adapted to convert electrical signals from the microelectrodes into at least one signal associated with a characteristic being monitored. The sensing system is well suited to hydrocarbon wellbore related applications, but can also be used in other applications.

System and method for sensing using diamond based microelectrodes

The invention relates to the use of one or more water-soluble reactive liquid component capable of subsequent polymerization or cross-linking to form a solid to improve the zonal isolation and alleviate the impacts of cracks and fissures in the cement sheath around a completed subterranean well. It includes the steps of injecting a wellbore fluid carrying the reactive component or additive into the wellbore, injecting a cementitious composition as slurry into the wellbore and letting said reactive liquid component pass through at least one of the interfaces between cement and formation, cement and filter cake, and filter cake and formation before forming a solid of said reactive liquid component that traverses said at least one of the interfaces.

Methods and materials for zonal isolation

A subterranean location accessed via a wellbore is treated with an oilfield fluid containing a viscosifying agent which is a polymer and a cross-linking agent which can undergo the Diels-Alder reaction to form a gel. Conditions at the subterranean location alter fluid viscosity by bringing about the Diels-Alder reaction to increase viscosity or the retro Diels-Alder reaction to decrease the viscosity of the gel.

Reversible polymeric gelation for oilfield applications

An electro-chemical sensor is described having two molecular redox systems sensitive to the same species and having an detector to detect relative shifts in the voltammograms of the two redox systems.

A powder composition comprising viscoelastic surfactant forms, in aqueous solution, a viscoelastic wellbore treatment fluid.

Powder composition

A treatment of a subterranean formation which contains a hydrocarbon-bearing zone, is carried out using a hydrocarbon-responsive fluid thickened with an oligomeric surfactant consisting of from 2 to 8_linked surfactant monomer subunits. The process of treatment comprises

Wellbore treatment with hydrocarbon-responsive fluid containing oligomeric viscoelastic surfactant

An optical sensor for pH is described using a cross-linked network of bisilanes to immobilize a pH sensitive chromophore to a surface potentially exposed to a high pressure, high temperature environment such as wellbore effluents at a downhole location.

Optical pH sensor

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Cottenham, United Kingdom

Timothy Gareth John Jones