Sintered spherical pellets containing clay as a major component useful for gas and oil well proppants
First Claim
1. A method of fracturing a subterranean formation located at a depth in excess of 7,000 but less than 14,000 feet, which comprises injecting a hydraulic fluid into said formation at a rate and pressure sufficient to open a fracture therein, injecting into said fracture a fluid containing composite, sintered, spherical pellets having a permeability to brine at about 200°
- F. (93.3°
C.) which decreases not more than about three-fourths when the applied pressure on said pellets is increased from 2,000 to 10,000 psi., (140 to 700 Kg/cm2) said pellets being comprised of clay and a member of the group of bauxite, alumina or mixtures thereof, said pellets being prepared from a mixture containing at least 40 percent on a dry weight basis of clay, said pellets having an alumina to silica dry weight basis ratio from about 9;
1 to about 1;
1, said pellets having an apparent specific gravity of less than 3.40.
4 Assignments
0 Petitions
Reexamination
Accused Products
Abstract
Sintered, spherical composite pellets or particles comprising one or more clays as a major component and bauxite, alumina, or mixtures thereof, are described, along with the process for their manufacture. The pellets may have an alumina-silica (Al2 O3 -SiO2) ratio from about 9:1 to about 1:1 by weight. The use of such pellets in hydraulic fracturing of subterranean formations is also described.
179 Citations
6 Claims
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1. A method of fracturing a subterranean formation located at a depth in excess of 7,000 but less than 14,000 feet, which comprises injecting a hydraulic fluid into said formation at a rate and pressure sufficient to open a fracture therein, injecting into said fracture a fluid containing composite, sintered, spherical pellets having a permeability to brine at about 200°
- F. (93.3°
C.) which decreases not more than about three-fourths when the applied pressure on said pellets is increased from 2,000 to 10,000 psi., (140 to 700 Kg/cm2) said pellets being comprised of clay and a member of the group of bauxite, alumina or mixtures thereof, said pellets being prepared from a mixture containing at least 40 percent on a dry weight basis of clay, said pellets having an alumina to silica dry weight basis ratio from about 9;
1 to about 1;
1, said pellets having an apparent specific gravity of less than 3.40. - View Dependent Claims (4, 5, 6)
- F. (93.3°
-
2. In a hydraulic fracturing method in which a fluid is injected into a subterranean formation to open a fracture therein, said formation being located at a depth in excess of 7,000 but less than 14,000 feet, the improvement wherein the fracture is propped with composite, sintered, spherical pellets having a permeability to brine at about 200°
- F. which decreases not more than about three-fourths when the pressure applied to said pellets is increased from 2,000 to 10,000 psi (140 to 700 Kg/cm2);
said pellets being comprised of clay and a member of the group of bauxite, alumina or mixtures thereof, said pellets being prepared from a mixture containing at least 40 percent on a dry weight basis of clay, said pellets having an alumina to silica dry weight basis ratio from about 9;
1 to about 1;
1, said pellets having an apparent specific gravity of less than 3.40.
- F. which decreases not more than about three-fourths when the pressure applied to said pellets is increased from 2,000 to 10,000 psi (140 to 700 Kg/cm2);
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3. A method for increasing permeability in a subterranean formation penetrated by a well wherein a fluid is pumped into the well to create a fracture in said subterranean formation, the improvement which comprises introducing into a fluid composite, spherical, sintered pellets comprised of clay and a member of the group of bauxite, alumina, or mixtures thereof, said pellets containing on a dry weight basis a major portion of clay, said pellets having an apparent specific gravity of less than 3.40;
- introducing said pellet-containing fluid into a fracture, the compaction pressure of which is between about 280 and about 700 Kg/cm2 (4,000 and about 10,000 psi), to deposit a propping distribution of said pellets, said pellets having an average particle size between 0.1 and 2.5 millimeters.
Specification