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US 4,921,820 AGranted
Lightweight proppant for oil and gas wells and methods for making and using same
AssigneeNorton-Alcoa Proppants
InventorsDavid S. Rumpf, Paul R. Lemieux
Life of this patent
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AssigneeNorton-Alcoa Proppants
InventorsDavid S. Rumpf, Paul R. Lemieux
Estimating the term…
A lightweight oil and gas well proppant made by simultaneously mixing and compacting a mixture of kaolin clay which has been calcined at a temperature low enough to prevent the formation of mullite and crystobalites to an LOI of 12 or less when tested at 1400.degree. C., and amorphous to microcrystalline silica both of which have been milled to an average agglomerated particle size of 7 microns or less to form green pellets, and then drying, screening, and sintering the pellets to form proppant pellets having a specific gravity of 2.7 or less, the proppant having a conductivity of at least 3,000 millidarci-feet as measured by the Stim-Lab Technique after 50 hours at 8,000 psi and 275.degree. F. in the presence of deoxygenated aqueous 2% solution of KCl using sandstone shims.
A low density proppant comprising solid sintered ceramic pellets which prior to sintering consist essentially of a mixture of a kaolin clay and amorphous to microcrystalline silica, said clay being substantially free of quartz and, prior to sintering, having been maintained at a temperature low enough to prevent a phase transformation of said kaolin clay to mullite and crystobalite, said pellets having specific gravity of less than 2.70, such proppant having a conductivity of at least 3,000 md-ft after 50 hours at 8,000 psi and 275.degree. F. in the presence of deoxygenated aqueous 2% solution of KCl as measured by the Stim-Lab Technique using sandstone shims.
A low density proppant comprising solid ceramic pellets consisting essentially of mullite and crystobalite and having a dry specific gravity of about 2.6 or less, said proppant having a conductivity of at least 3,000 md-ft after 50 hours at 8,000 psi and 275.degree. F. in the presence of a deoxygenated aqueous 2% solution of KCl as measured by the Stim-Lab Technique using sandstone shims.
A low density proppant comprising sintered pellets consisting essentially of mullite and at least 35% crystobalite and which prior to sintering consist essentially of a mixture of between 0 w/o to 90 w/o calcined kaolin clay and 10 w/o to 100 w/o amorphous to microcrystalline silica, said kaolin clay containing less that 2 w/o quartz and less than 1 w/o iron, said mixture being substantially free of mullite and crystobalite prior to sintering, said pellets having a density of less than about 2.6, said calcined kaolin clay and silica having been milled to an average particle size of less than 7 microns.
A low density proppant comprising about from 35 w/o to about 60 w/o mullite and about 35 w/o to about 60 w/o crystobalite, having a specific gravity of less than 2.70, and having a conductivity of at least 3,000 md-ft after 50 hours at 8,000 psi and 275.degree. F. in the presence of deoxygenated aqueous 2% solution of KCl as measured by the Stim-Lab Technique using sandstone shims, with less than 10% of said proppant being a glassy phase.
Dependencies are inferred from the claim text.