Propping agent and method of propping open fractures in the walls of a bored well

A propping agent for fractures produced in the walls of a bored well, comprising a product in granular form which, on an oxide basis, contains up to 85% by weight zirconium oxide ZrO.sub.2, silica SiO.sub.2 in a quantity such that the weight ratio (ZrO.sub.2 /SiO.sub.2) is at least equal to 1.5, alumina Al.sub.2 O.sub.3 in a quantity such that the weight ratio (Al.sub.2 O.sub.3 /SiO.sub.2) is from 0 to 1.5 and a quantity of sodium oxide Na.sub.2 O such that the weight ratio (Na.sub.2 O/SiO.sub.2) is from 0 to 0.4, said product further containing at least one of the oxides MgO and CaO in a quantity such that the weight ratio (MgO/SiO.sub.2) is between 0 and 1 and the weight ratio (CaO/SiO.sub.2) is between 0 and 1.45.

A propping agent for fractures produced in the walls of a bored well, comprising a product in granular form which, on an oxide basis, contains up to 85% by weight zirconium oxide ZrO.sub.2, silica SiO.sub.2 in a quantity such that the weight ratio (ZrO.sub.2 /SiO.sub.2) is at least equal to 1.5, a quantity of sodium oxide Na.sub.2 O such that the weight ratio (Na.sub.2 O/SiO.sub.2) is from 0 to 0.04, and alumina Al.sub.2 O.sub.3 in a quantity such that the weight ratio (Al.sub.2 O.sub.3 /SiO.sub.2) is between 0.1 and 1.

A method of propping open fractures produced in the walls of a bored well, comprising injecting into the well a fluid suspension of a propping agent comprising a product in granular form containing crystallized zirconium oxide embedded in an amorphous mineral binding material, the product having a composition which, on an oxide basis, comprises up to 85% by weight zirconium oxide ZrO.sub.2, silica SiO.sub.2 in a quantity such that the weight ratio (ZrO.sub.2 /SiO.sub.2) is at least equal to 1.5, a quantity of alumina Al.sub.2 O.sub.3 such that the weight ratio (Al.sub.2 O.sub.3 /SiO.sub.2) is from 0 to 1.5, and a quantity of sodium oxide Na.sub.2 O such that the weight ratio (Na.sub.2 O/SiO.sub.2) is from 0 to 0.04.

A propping agent for fractures produced in the walls of a bored well, comprising a product in granular form which, on an oxide basis, consists essentially of up to 85% by weight zirconium oxide ZrO.sub.2, silica SiO.sub.2 in such a quantity that the weight ratio (ZrO.sub.2 /SiO.sub.2) is at least equal to 1.5, aluminum oxide Al.sub.2 O.sub.3 in such a quantity that the weight ratio (Al.sub.2 O.sub.3 /SiO.sub.2) is from 0.1 to 1, sodium oxide Na.sub.2 O in such a quantity that the weight ratio (Na.sub.2 O/SiO.sub.2) is from 0 to 0.04, and at least one of the oxides MgO and CaO in a quantity such that the weight ratio (MgO/SiO.sub.2) is from 0 to 1 and the weight ratio (CaO/SiO.sub.2) is from 0 to 1.45.

A propping agent for fractures produced in the walls of a bored well, comprising a product in granular form which, on an oxide basis, consists essentially of up to 85% by weight zirconium oxide ZrO.sub.2, silica SiO.sub.2 in such a quantity that the weight ratio (ZrO.sub.2 /SiO.sub.2) is at least equal to 1.5, aluminum oxide in such a quantity that the weight ratio (Al.sub.2 O.sub.3 /SiO.sub.2) is from 0.1 to 1, sodium oxide Na.sub.2 O in such a quantity that the weight ratio is from 0 to 0.04, magnesium oxide MgO in such a quantity that the weight ratio (MgO/SiO.sub.2) is approximately 0.4 and, calcium oxide CaO in such a quantity that the weight ratio (CaO/SiO.sub.2) is approximately 0.82.