Storable composition and slurries and use of same for cementing oil and gas wells
AssigneePetroleo Brasileiro S.A. - Petrobras
InventorsArnaldo Rodrigues D'Almeida, Cristiane Richard De Miranda, Gilson Campos
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Abstract
Storable compositions and slurries for cementing oil and gas wells are described which comprise blast-furnace slag besides other additives which are usual in the cementing technique. The compositions and slurries are insufficiently activated (or are activated immediately before introducing them into the well), so that they can be stored for at least 72 hours (alternatively they may be stored indefinitely) without the setting of the composition and dispense with the addition of activation inhibitors. The use of the compositions and slurries in the cementing of oil and gas wells is also described.
Claims23
Storable compositions for cementing oil and gas wells containing high-furnace slag as hydraulic material, activators, additives and an aqueous continuous phase forming a cementitious slurry, wherein the amount of activators in said compositions based on the amount of slag is insufficient to effect the setting of the composition for at least 72 hours.
Storable compositions for cementing oil and gas wells containing blast-furnace slag as hydraulic material, activators, additives and an aqueous continuous phase forming a cementitious slurry, wherein the amount of activators is added immediately before pumping the composition to said well, in any amount which is efficient to effect the setting.
Storable compositions for cementing oil and gas wells containing blast-furnace slag as hydraulic material, activators, additives and an aqueous continuous phase forming a cementitious slurry, wherein a portion of the activators is added while said composition is being prepared and the remaining required portion is added immediately before the composition is pumped into the well.
14 Storable compositions according to claim 1, 3 or 5, wherein the activator contains a weak alkali.
15 Storable compositions according to claim 14, wherein the weak alkali comprises a carbonate ion.
Storable compositions according to claim 15, wherein the carbonate ion is a sodium carbonate, a potassium carbonate or a mixture of same, in an amount of 0.01 to 8 weight % based on the amount of slag in the composition, preferably between 0.5 and 2.5 weight %, and still more preferably between 1.5 and 2.5 weight % based on the weight of slag in the cementitious slurry.
Storable compositions according to claim 14, wherein the weak alkali comprises a phosphate ion.
Dependencies are inferred from the claim text.