Cementing compositions and application of such compositions to cementing oil wells or the like
AssigneeSchlumberger Technology Corporation
InventorsAndre Garnier, Slaheddine Kefi, Pierre Maroy
Life of this patent
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Abstract
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 μm to 600 μm, and 5% to 25% of fine particles in the range 0.5 μm to 5 μm 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 μm to 5 μm, and 0-20% particles in the rang 3 nanometers to 60 nanometers and the water content is less than 72% by volume.
Claims12
A method of cementing an oil well or the like, comprising:
- a) forming a cement slurry comprising:
- i) a solid fraction constituted by
- 35% to 65% by volume particles with an average diameter in the range 200 μm to 600 μm,
- 20% to 45% by volume ordinary Portland cement, and
- 5% to 25% by volume particles with an average diameter in the range 0.5 μm to 5 μm;
- ii) a surfactant;
- and
- iii) water, the water content of the slurry being less than 50% by volume of the slurry;
- b) foaming the slurry by introduction of gas;
- and
- c) injecting the slurry into the well and allowing it to set;
- characterized in that the water content of the slurry is less than 50% by volume before foaming.
The method of claim, 5, whereby the step of foaming is carried out so that the gas bubble size is less than 3 millimeters.
A method of cementing an oil well or the like, comprising:
- a) forming a cement slurry comprising:
- i) a solid fraction constituted by
- 50% to 75% by volume micro-cement having a maximum particle size in the range 6 μm to 12 μm, and a specific surface area per unit weight, determined by the air permeability test of more than 0.6 m2/g,
- 15% to 40% by volume particles with an average diameter in the range 0.05 micrometers to 0.5 micrometers, and
- 0 to 20% by volume particles with an average dimension in the range 3 nanometers to 60 nanometers:.
- ii) a surfactant;
- and
- iii) water;
- the water content of the slurry being less than 72% by volume of the slurry;
- b) foaming the slurry by introduction of gas;
- and
- c) injecting the slurry into the well and allowing it to set.
The method of claim, 7, whereby the step of foaming is carried out so that the gas bubble size is less than 7 millimeters.
Dependencies are inferred from the claim text.