Schlumberger Technology Corporation

Dowell, a Division of Schlumberger Technology Corporation

Clariant Corporation

Dowell Schlumberger Incorporated

Pierre Maroy

Jean-Pierre Feraud

Andre Garnier

Philippe Dejeux

Herve Perthuis

V&eacute;ronique Barlet-Gouedard

Veronique Barlet-Gouedard

Hugo Hendriks

Bruno Drochon

Arnaud Cadix

Bruno Langlois

Florence L'Alloret

Slaheddine Kefi

Roland Reeb

Ilias Iliopoulos

Volker Frenz

Bernard Dargaud

Aranka Tardi

Jack Maberry

Jean-Francois Baret

Frederik Nilsson

Françoise LaFuma

Coralie Simonet

Fabien J Brand

Reinhard J Oswald

Juergen Tonhauser

Dominique Hourdet

Anne-Marie Schulz

Joseph Janca

Roland Audebert

Water-based fluids that can viscosify under shear or can produce a gel or form a gel under shear are obtained by dissolving polymers in an aqueous phase. These polymers comprise three types of functional groups: non-ionic functional groups that are hydrosoluble at the temperature under consideration, ionic functional groups, and functional groups that are hydrophobic at the temperature under consideration. These three types of functional groups can be distributed or spread in a random distribution along the polymer chain. A slightly block distribution is acceptable. For applications to oil wells, functional groups are used which exhibit LCST (Lower Critical Solution Temperature) behavior (i.e., a low critical solution temperature) instead of hydrophobic functional groups. At temperatures below the LCST, the functional groups are hydrophobic.

Polymer solutions with shear reversible properties

The present invention concerns a cement slurry with high permeability and good compressive strength, comprising a solid fraction constituted by: 35% to 80% (by volume) of particles with a mean size in the range 100 microns (&#x3bc;) to 800&#x3bc;; 0% to 15% (by volume) of particles with a mean particle diameter in the range 0.1 microns to 10 microns; and 10% to 40% (by volume) of particles with a mean particle diameter in the range 20&#x3bc; to 50&#x3bc;; a fraction of said-solid particles being constituted by a cement, and preferably a further fraction by self-destructive particles; a liquid fraction in a water/solid ratio in the range 38% to 50% by volume; and a percentage of cells, provided by a gas or a liquid which is not miscible with water, in the range 30% to 60% of the final volume of the slurry.

Permeable cements

Method of well cementing with a foamed slurry having a very low water content. When based on ordinary cement, the solid fraction of the slurry includes (by volume) 20-35% Portland cement, 35-65% particles ranging from 200 &#x3bc;m to 600 &#x3bc;m, and 5% to 25% of fine particles in the range 0.5 &#x3bc;m to 5 &#x3bc;m and the water content is less than 50% by volume. When based on micro-cement, the solid fraction includes (by volume) 50-75% micro-cement, 15-40% fine particles in the range 0.5 &#x3bc;m to 5 &#x3bc;m, and 0-20% particles in the rang 3 nanometers to 60 nanometers and the water content is less than 72% by volume.

Cementing compositions and application of such compositions to cementing oil wells or the like

Cementing compositions which are particularly suitable for squeeze cementing operations, comprise an aqueous phase, and a micro-cement, the aqueous phase including an aqueous suspension comprising a vinyl acetate type polymer obtained by chemically cross-linking a polyvinyl compound, a nanolatex and an anionic surfactant with a cloud point of more than 80&deg; C.

Cementing composition and application thereof to cementing oil wells or the like

A cementing composition comprising a hydraulic cement powder dispersed in a solvent that is miscible both with water and hydrocarbons to make a slurry. The cement powder can be made up simply of hydraulic cement materials or can be a mixture of such materials with particles that are inert or reactive with cement. The composition can also include surfactants or retarders. The composition is used to plug water production in a well while leaving hydrocarbon production unaffected.

Water-selective cementing composition

The present invention provides a water-based fluid, in particular for drilling, completion or for any other intervention in a well such as a hydrocarbon well, in which the viscosity is controlled by a system constituted by precipitated silica nanoparticles (A) associated with a water-soluble copolymer (B) comprising one or more water-soluble co-monomers (I) having little or no affinity for silica and one or more co-monomers (II) which absorb onto the silica. The invention is of particular application to the secondary recovery of hydrocarbons.

Liquid compositions which reversibly viscosify or gel under the effect of shear

Systems for retarding setting in an oilfield well cement slurry comprise a solution of a phosphonate selected from methylene phosphonic acid derivatives and a phosphate, in particular selected from the following salts or the corresponding acids: mono-phosphates (ortho-phosphates PO ; meta-phosphates PO ), acyclic poly-phosphates (pyrophosphates P O , tripolyphosphates P O ) or cyclic poly-phosphates. The system preferably may also comprise a retarder booster and is more particularly applicable to cementing at low or medium temperatures.

Retarding systems and application to oil well cementing

Methods of treating wells for cementing operations and for improving placement of cement in wells containing water swelling clays include treatment of the well with a fluid containing clay precipitating agents capable of coagulating clays in the well. The coagulating fluid can contain quaternary ammonium salts, aqueous salts of potassium or cesium, or silicates as the clay coagulating agent. The coagulating fluids can be applied to convert soft mud cake into hard mud cake prior to placement of cement.

Method of cementing a well in geological zones containing swelling clays or mud residues containing clays

The invention concerns cementing compositions, particularly for squeeze cementing, comprising a liquid phase and a solid phase constituted by particulate materials which are insoluble in said liquid phase, in particular a microcement. The compositions of the invention comprise additives of a nature and composition such that variations in viscosity of the composition due to fluid loss are minimized. Preferably, the compositions comprise at least one &ldquo;very fine&rdquo; additive formed from particles which are smaller than the cement, with a ratio of the average grain sizes of the particles of said additive and those of the cement in the range 5 to 100, preferably about 10, the respective proportions of the solid particles corresponding to a packing volume fraction close to the maximum, and the porosity of the solid mixture being such that the mixture is in a state of hindered settling.

Cementing compositions and the application of such compositions to cementing oil or analogous wells

Well cementing aids

In the presence of certain crude oils, when ferric iron exists in very acidic fluid, it practically instantaneously forms precipitates known as sludges which lead to irreversible damage. Iron control compositions and acid fluids containing such iron control compositions are disclosed. For acid fluids containing up to 15% acid, the iron control composition includes a reducing agent selected from a substituted and unsubstituted thiourea compounds, and a reduction catalyst including a copper (cuprous or cupric) compound. When the acid fluid contains more than 15% acid, for example from 15 to 28% acid, the reducing agent is again selected from substituted or unsubstituted thiourea compounds, and the reduction catalyst is a combination of a copper (cuprous or cupric) compound and iodine (iodine or iodide ions). The invention also includes a process for treatment of oil, water, gas, geothermal or analogous wells using an acid fluid containing an iron control composition according to the present invention, and an industrial cleaning process using a cleaning fluid including an acid fluid containing an iron control agent according to the present invention.

Process for controlling iron

The invention relates to a new, chemically crosslinked PVA. Its application is that of a fluid loss control agent in fluids used in the oil industry, in particular cement slurries, separating fluids, or 'spacers', and drilling muds. Its advantages are that it does not delay the setting of the cement, that it has high temperature properties that are relatively insensitive to external conditions.

Cement composition containing chemically crosslinked polyvinyl alcohol

The invention relates to iron control in an acid medium for forestalling the formation of precipitates known as 'sludges' (asphaltic products) in contact with certain crude oils. Use is made of compounds comprising a mercaptan function non miscible in water and, in combination, a selection of catalysts. Application to acid treatments for oil, gas, water, geothermal and analogous wells, as well as to industrial cleaning.

New compositions for iron control in acid treatments for oil wells

The particulate phase of fluids according to the present invention comprises particles which have specifically adapted size ranges or granulometries. All the essential properties of fluids and their cost are very clearly improved. The technique may be applied to all well operations in oil wells or the like, such as in matrix treatment and the like.

Fluids for oilfield use having high-solids content

The invention relates to the cementing of high temperature wells. The retarder consists of a methylene phosphonic acid derivative and of a boric acid or a borate at least as acid as borax in an aqueous solution, in particular, Na pentaborate, in a preferred ratio of 0.08 to 0.92 parts by weight. A long setting time and a very swift compressive strength development are obtained at the same time.

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Buc, France

Pierre Maroy