Schlumberger Technology Corporation

Schlumberger Canada Limited

Prad Research and Development Nv

Services Petroliers Schlumberger

Schlumberger Holdings Limited

Prad Research and Development Limited

Prad Research Development Limited

Michel Michaux

Simon James

Sylwia Komocki

Bruno Drochon

Tatiana Pyatina

Jean-Philippe Caritey

Sylvaine Le Roy-Delage

Laurent Gabilly

Clara Carelli

Bernard Dargaud

Michel Ermel

Jean-Francois Baret

John Villar

Sebastien Catheline

Philippe Revil

Andr&eacute; Garnier

Cyril Terrier

James Simon

Sylvaine Le-Roy-Delage

Frédéric Thery

Jean Philippe Caritey

Cement retarders are based on blends of lignosulfonate compounds, borate compounds and gluconate compounds. The compounds are present in certain ratios that allow the retarders to operate at temperatures and pressures up to and exceeding about 176&#xb0; C. and 152 MPa. The retarders may also be provided in liquid form, improving their suitability for use at offshore well-site locations.

Retarded cement compositions and methods for well completions

Spacer fluids that are stable at temperatures up to at least 260&#xb0; C. comprise water, polystyrene sulfonate and a mixture of particulate materials. The particulate materials may be chosen such that the mixture has at least a trimodal particle-size distribution. The fluids may further comprise inorganic clays, mutual solvents and surfactants.

Compositions and methods for completing subterranean wells

This invention relates to methods for servicing subterranean wells, in particular, fluid compositions and methods for remedial operations during which the fluid compositions are pumped into a wellbore and make contact with well cements placed during primary cementing or previous remedial cementing operations.

Silica composition for servicing subterranean wells

Well-cementing compositions for use in high-pressure, high-temperature (HPHT) wells are often densified, and contain weighting agents such as hematite, ilmenite, barite and hausmannite. The weighting agents are usually finely divided to help keep them suspended in the cement slurry. At high temperatures, finely divided weighting agents based on metal oxides react with the calcium-silicate-hydrate binder in set Portland cement, leading to cement deterioration. Finely divided weighting agents based on metal sulfates are inert with respect to calcium silicate hydrate; consequently, set-cement stability is preserved.

Compositions and methods for well completions

A method of cementing a well is disclosed. The method comprising pumping into the well a cement slurry comprising a solid blend including cement, water, and a fluid loss control agent, and allowing the cement slurry to set. The fluid loss control agent comprises a styrene-butadiene latex and a high molecular-weight water-soluble polymer such as a copolymer AMPS-Am. The addition of the water-soluble polymer allows drastic reduction of the quantity of latex required to achieve fluid loss control performance and even gas migration control.

Fluid loss control agents and compositions for cementing oil and gas wells comprising said fluid loss control agent

It is proposed a new fluid loss control agent useful for the cementation of oil or gas wells. This fluid loss control agent consists of a mixture of a styrene-butadiene latex and a high molecular weight water-soluble polymer such as a copolymer AMPS-Am. The addition of the water-soluble polymer allows drastic reduction of the quantity of latex required to achieve fluid loss control performance and even gas migration control.

Fluid compositions containing a silica-particle suspension with no intrinsic cementitious properties may be pumped into a wellbore. Upon making downhole contact with previously placed well cements from primary-cementing or previous remedial-cementing operations, the silica suspension reacts to form a gel that seals voids, cracks or fissures in the cement sheath. Portland cement is the preferred cement with which the silica-particle suspensions interact downhole.

Compositions and methods for servicing subterranean wells

Providing a solution of at least one salt capable of reacting with a set cement to form a solid phase comprising a precipitate or an expanded phase of the cement; contacting a region of the set cement to be repaired with the solution so as to form the solid phase in voids in the region of the set cement to be repaired.

Solids free sealing fluid

Methods for sealing voids and cracks in subterranean-formation rock that contains carbonate minerals, thereby minimizing or stopping fluid flow between the formation rock and the wellbore of a subterranean well, comprise pumping a solution of one or more lattices that contains at least one carboxylated monomer down a well during drilling and allowing it to enter voids (e.g., pores, fractures, vugs and caverns) in the carbonate-containing formation. The solution reacts with divalent cations liberated by the carbonates and forms a plug.

Method for servicing subterranean wells

A cement retarder system for use in underground wells included a borate compound, an organophosphonate salt, and a copolymer formed from AMPS and a monomer selected from the group consisting of acrylic acid, acrylamide and mixtures thereof. A method of using the retarder system in an underground well having a borehole drilled therein with a borehole wall, and further including a casing disposed in said borehole, such that an annulus exists between said casing and said borehole wall, comprising the steps of providing a cement composition and a liquid carrier, providing a retarder system for said cement composition comprising a borate compound, an organophosphonate salt, and a copolymer formed from AMPS and a monomer selected from the group consisting of acrylic acid, acrylamide, and mixtures thereof, mixing a sufficient amount of said retarder system to create a desired induction period with said cement composition and said liquid carrier to form a cement slurry, pumping the cement slurry from the surface down the casing, and causing said slurry to return to the surface in the annulus between the casing and the borehole wall.

Cement retarder systems, and retarded cement compositions

A retarder aid increases the applicable temperature range of phosphonate/borate cement-retarder systems to at least 302&#xb0; C. (575&#xb0; F.), and 207 MPa (30,000 psi). The retarder aid comprises a terpolymer of styrene sulfonate, maleic anhydride and acrylate of ethylene oxide. Cement slurries containing the retarder and retarder aid may be used for both primary-cementing and remedial-cementing applications.

Compositions and methods for well cementing

The invention provides a cementing composition for use in oilfield application, wherein a significant amount of cement is left intentionally un-hydrated when the cement is set; such that said amount of un-hydrated cement becomes hydrated when the set cement is damaged.

Cementing composition comprising within un-reacted cement

Cementing compositions for use in oilfield applications are designed such that, after setting, a significant amount of cement remains unhydrated. After placement in a subterranean well, the unhydrated cement remains dormant. If the cement sheath becomes damaged, the unhydrated cement hydrates upon exposure to formation fluids, thereby restoring zonal isolation in the wellbore. The compositions comprise emulsions that allow a substantial reduction of the water-to-cement ratio, yet the rheological properties remain suitable for placement in the well.

A sealant composition, comprising an alkali metal silicate and a calcium containing inorganic compound, wherein the particles of the calcium containing compound have a mean particle size that is submicron, is useful for sealing cracks, fissures and voids in subterranean wells, thereby restoring zonal isolation. The mean particle size of the calcium containing compound is preferably smaller than 100 nm.

Sealant composition

The use of silicate as a retarder enhancer at appropriate levels to enhance the retarding effect of retarders at high temperatures encountered downhole while accelerating the set of cement at lower temperatures encountered near to the surface.

Growing community of inventors

Verrieres-le-Buisson, France

Michel Michaux