Societe Nationale Elf Aquitaine

Elf Aquitaine

Alain Donche

Rosangela Pirri

Yves Huet

Patrick Isambourg

Alain Ladret

Alain Vaussard

Base composition for water-based drilling muds allowing the number and the amount of the other constituents of the mud to be restricted. In addition to the base solvent, fresh water, sea water or salt water, the said base composition comprises scleroglucan as viscosity agent, the mycelium which produced it and bentonite or an equivalent in limited amount.

Scleroglucan based drilling mud

The present inventors found that the addition of scleroglucan, in particular of unrefined scleroglucan, to the water employed as drilling fluid for drilling wells requiring a high flow rate made it possible to limit formation leaching and improved the removal of cuttings. The invention may be applied to drilling of large-diameter wells.

Application of muds containing scleroglucan to drilling large diameter

Application of scleroglucan muds to drilling deviated wells

The present invention is directed to a process for improving the dispersibility and the filterability of scleroglucan powders, in which a surfactant is incorporated in the coagulated polymer. The powder obtained according to the process has a dispersibility and a filterability after drying of the coagulum which are greatly superior to those of a powder treated after drying with the same quantity of surfactant or of a powder in solution treated with this same quantity of surfactant. The present invention is also directed to methods for preventing the sudden rush of well water into the strata of petroleum fields, to methods for modifying the injection profile, and to methods for improved hydrocarbon recovery from petroleum fields.

Process for enhancing oil recovery using scleroglucan powders

Use of scleroglucan alone or of mixtures of scleroglucan with a polyalcohol or a dialdehyde as cementation spacers during oil drilling operations.

Scleroglucan-based compositions and their use as a cementation spacer

Process for improving the dispersibility and the filterability of scleroglucan powders, in which a surfactant is incorporated in the coagulated polymer. The powder obtained according to the process has a dispersibility and a filterability after drying of the coagulum which are greatly superior to those of a powder treated after drying with the same quantity of surfactant or of a powder in solution treated with this same quantity of surfactant.

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Jurancon, France

Alain Donche