Abstract: Cementing compositions for oil wells or the like comprise between 30% and 100% (by weight of cement) of rubber particles, with grain size in the 40-60 mesh range. Adding rubber particles in accordance with the invention produces a low density slurry while keeping the cement permeability low. Compositions of the invention are particularly advantageous for cementing zones subjected to extreme dynamic stresses such as perforation zones and the junctions of branches in a multi-sidetrack well.

Abstract: Cementing compositions for oil wells or the like comprise between 30% and 100% (by weight of cement) of rubber particles, with grain size in the 40-60 mesh range. Adding rubber particles in accordance with the invention produces a low density slurry while keeping the cement permeability low. Compositions of the invention are particularly advantageous for cementing zones subjected to extreme dynamic stresses such as perforation zones and the junctions of branches in a multi-sidetrack well.

Abstract: The invention relates to a method and to a tool for treating at least one wall in a critical zone of a borehole, in particular a borehole for development of a hydrocarbon, water, gas or analogous field, the method consisting in reinforcing the wall of the critical zone by a coating obtained from a base fluid which is pumped from the surface to a tool (1) to be projected against the wall of the critical zone where it forms the coating once it has set, the method being characterized in that it consists in storing at least one additive or activator in liquid form in a reservoir (R) of the tool (1), and in projecting the additive simultaneously with the base fluid against the wall of the critical zone via at least one injector (I) in order to activate setting of the base fluid.

Abstract: The slurries were prepared using a reference slurry having a density of 16.4 lb/gal(US) (1.965 g/cm3) of cement, with porosity of 55.18%. The cement was a class G Dickerhoff North cement. The slurries were prepared in the presence of on agent at a concentration of 0.4% by weight of cemenit (BWOC) and of an anti-foaming agent at a concentration of 0.03 gallons per (94 pound) sack of cement (gps); (a concentration of 0.1 gps corresponds to 0.90 liters of anti-foaming agent per 100 kg of cement). The suspension agent was added to the mixing water, and mixing took place at 4000 revolutions.

Abstract: The present invention provides a cementing composition for an oil or analogous well, essentially constituted by a solid fraction suspended in a liquid medium. The solid fraction is constituted by a coarse fraction with a packing volume fraction .PHI..sub.1 which, according to the invention, is maximised, and a fines fraction x with a packing volume fraction .PHI..sub.2 which is less than or equal to the volume fraction x.sub.0 such that ##EQU1## The invention also provides a method of maximising the value of .PHI..sub.1. The invention can minimise fluid loss whatever the materials selected for a cementing composition.

Abstract: The present invention concerns a cementing composition for an oil (or similar) well, based on an aluminous hydraulic cement, fine particles, hollow microspheres, water in a quantity such that the porosity is in the range 25% to 50%, a dispersing agent, a setting accelerator for the aluminous cement and optionally, other conventional additives. The invention is of particular application to cementing conductor pipes in arctic zones or in deep-water wells.

Abstract: 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.