US4126181A — Method and apparatus for formation fracturing wit…

Claim 1

Independent Claim 142 words

A method of treating a subsurface earth formation penetrated by a well bore with a foam comprising the steps of: blending a proppant with a foamable carrier thereby forming a slurry; pressurizing the slurry to a desired pressure; introducing the pressurized slurry into a centrifugal separator which can separate out some of the carrier thereby concentrating the amount of proppant per volume of slurry; removing an amount of the carrier from the separator per volume of slurry until the desired proppant concentration is obtained in the concentrated slurry; discharging the concentrated slurry from the separator; adding a surfactant to the slurry either prior to or after pressurizing said slurry and at a stage prior to the formation of foam; adding a pressurized gas to the discharged concentrated slurry, thereby forming a pressurized foam; and injecting said pressurized foam into the well bore.

Claim 2

Independent Claim 142 words

A method of treating a subsurface earth formation penetrated by a well bore with a foam comprising the steps of: blending a proppant with a foamable carrier thereby forming a slurry; pressurizing the slurry to a desired pressure; introducing the pressurized slurry into a centrifugal separator which can separate out some of the carrier thereby concentrating the amount of proppant per volume of slurry; removing an amount of the carrier from the separator per volume of slurry until the desired proppant concentration is obtained in the concentrated slurry; discharging the concentrated slurry from the separator; adding a surfactant to the slurry either prior to or after pressurizing said slurry and at a stage prior to the formation of foam; adding a pressurized gas to the discharged concentrated slurry, thereby forming a pressurized foam; and injecting said pressurized foam into the well bore.

Claim 3

Dependent Claim 14 words

The method of claim 1 wherein said surfactant is added to the pressurized slurry.

Claim 4

Dependent Claim 14 words

The method of claim 1 wherein said surfactant is added to the unpressurized slurry.

Claim 5

Dependent Claim 13 words

The method of claim 1 wherein said carrier comprises water plus guar gum.

Claim 6

Dependent Claim 10 words

The method of claim 4 wherein said proppant is sand.

Claim 7

Dependent Claim 35 words

The method of claim 1 and further including drawing off some of the pressurized slurry before the slurry is concentrated; mixing the drawn off slurry with surfactant; and combining the mixture with the concentrated slurry.

Claim 8

Dependent Claim 22 words

The method of claim 6 wherein foaming gas is added to the concentrated slurry before combination thereof with said drawn off slurry.

Claim 9

Independent Claim 137 words

A method for producing a foam for treating a subsurface earth formation penetrated by a well bore comprising the steps of: blending a proppant with a foamable carrier which comprises a liquid, thereby forming a slurry; pressurizing the slurry to a pressure that is great enough for introduction into the well bore; introducing the pressurized slurry into a centrifugal, mechanical separator of the type that can concentrate the amount of proppant in the carrier by removing some of the liquid; discharging the concentrated slurry from the separator and removing an amount of substantially proppant free liquid from the separator to get the desired proppant concentration in the slurry; adding a surfactant to the mixture at a stage prior to the formation of foam; and adding a pressurized gas to the concentrated slurry to form the pressurized foam.

Claim 10

Independent Claim 137 words

A method for producing a foam for treating a subsurface earth formation penetrated by a well bore comprising the steps of: blending a proppant with a foamable carrier which comprises a liquid, thereby forming a slurry; pressurizing the slurry to a pressure that is great enough for introduction into the well bore; introducing the pressurized slurry into a centrifugal, mechanical separator of the type that can concentrate the amount of proppant in the carrier by removing some of the liquid; discharging the concentrated slurry from the separator and removing an amount of substantially proppant free liquid from the separator to get the desired proppant concentration in the slurry; adding a surfactant to the mixture at a stage prior to the formation of foam; and adding a pressurized gas to the concentrated slurry to form the pressurized foam.

Claim 11

Dependent Claim 170 words

The method of claim 8 wherein said slurry is concentrated in a substantially horizontally extending separator having an internal rotor, said rotor comprising intake impellers, discharge impellers, and an internal passageway connecting said intake and discharge impellers and said rotor defining a concentric channel between the outer separator walls and the rotor, said concentration being accomplished by imparting a spin to the slurry as the slurry is introduced into said separator; transmitting a fraction of the spinning slurry radially inwardly into said internal passageway with said intake impellers, transmitting the remainder of the slurry axially through said concentric channel to a discharge point; removing substantially all of the proppant from said fraction of slurry to said channel thereby concentrating said axially transmitted slurry and producing a substantially proppant free carrier; discharging said concentrated slurry from said separator at a rate so as to control the pressure inside said separator; and discharging said carrier from said separator at a rate so as to control the proppant concentration of said concentrated slurry.

Claim 12

Independent Claim 150 words

A system for treating a subsurface earth formation penetrated by a well bore with a foam comprising: means for blending a proppant with a foamable carrier so as to form a slurry; means connected to said blending means for pressurizing the slurry to a desired pressure; a centrifugal separator connected to the discharge of the pressurizing means, said separator being capable of separating out some of the carrier thereby concentrating the amount of proppant per volume of slurry, of discharging an amount of the carrier per volume of slurry until the desired proppant concentration is obtained in the concentrated slurry, and of discharging the concentrated slurry; means for adding a surfactant to the mixture at a stage prior to the formation of foam; means for adding a pressurized gas to the discharged concentrated slurry, thereby forming a pressurized foam; and means for injecting said pressurized foam into the well bore.

Claim 13

Independent Claim 150 words

A system for treating a subsurface earth formation penetrated by a well bore with a foam comprising: means for blending a proppant with a foamable carrier so as to form a slurry; means connected to said blending means for pressurizing the slurry to a desired pressure; a centrifugal separator connected to the discharge of the pressurizing means, said separator being capable of separating out some of the carrier thereby concentrating the amount of proppant per volume of slurry, of discharging an amount of the carrier per volume of slurry until the desired proppant concentration is obtained in the concentrated slurry, and of discharging the concentrated slurry; means for adding a surfactant to the mixture at a stage prior to the formation of foam; means for adding a pressurized gas to the discharged concentrated slurry, thereby forming a pressurized foam; and means for injecting said pressurized foam into the well bore.

Claim 14

Dependent Claim 21 words

The system as claimed in claim 10 wherein said surfactant adding means is connected to the discharge of said pressurizing means.

Claim 15

Dependent Claim 19 words

The system as claimed in claim 10 wherein said surfactant adding means is connected upstream of said pressurizing means.

Claim 16

Dependent Claim 15 words

The system as claimed in claim 10 wherein said carrier comprises water plus guar gum.

Claim 17

Dependent Claim 12 words

The system as claimed in claim 13 wherein said proppant is sand.

Claim 18

Dependent Claim 43 words

The system as claimed in claim 10 and further including means for drawing off some of the pressurized slurry before the slurry is concentrated; means for mixing the drawn off slurry with surfactant; and means for combining the mixture with the concentrated slurry.

Claim 19

Dependent Claim 40 words

The system as claimed in claim 15 wherein said gas adding means is connected between said separator and said combining means such that said foaming gas is added to the concentrated slurry before combination thereof with said drawn off slurry.

Claim 20

Independent Claim 151 words

A system for producing a foam for treating a subsurface earth formation penetrated by a well bore comprising: means for blending a proppant with a foamable carrier which comprises a liquid, thereby forming a slurry; means connected to said blending means for pressurizing the slurry to a pressure that is great enough for introduction into the well bore; a centrifugal, mechanical separator of the type that can concentrate the amount of proppant in the carrier by removing some of the liquid, the intake of said separator connected to the discharge of said pressurizing means, said separator removing an amount of substantially proppant free liquid to get the desired proppant concentration in the slurry and discharging the concentrated slurry; means for adding a surfactant to the mixture at a stage prior to the formation of foam; and means for adding a pressurized gas to the concentrated slurry to form the pressurized foam.

Claim 21

Independent Claim 151 words

A system for producing a foam for treating a subsurface earth formation penetrated by a well bore comprising: means for blending a proppant with a foamable carrier which comprises a liquid, thereby forming a slurry; means connected to said blending means for pressurizing the slurry to a pressure that is great enough for introduction into the well bore; a centrifugal, mechanical separator of the type that can concentrate the amount of proppant in the carrier by removing some of the liquid, the intake of said separator connected to the discharge of said pressurizing means, said separator removing an amount of substantially proppant free liquid to get the desired proppant concentration in the slurry and discharging the concentrated slurry; means for adding a surfactant to the mixture at a stage prior to the formation of foam; and means for adding a pressurized gas to the concentrated slurry to form the pressurized foam.

Claim 22

Dependent Claim 169 words

The system as claimed in claim 17 wherein said separator comprises a substantially horizontally extending vessel, an internal rotor, said rotor comprising intake impellers, discharge impellers, and an internal passageway connecting said intake and discharge impellers and said rotor defining a concentric channel between the outer separator walls and the rotor, said concentration being accomplished by imparting a spin to the slurry as the slurry is introduced into said separator; transmitting a fraction of the spinning slurry radially inwardly into said internal passageway with said intake impellers, transmitting the remainder of the slurry axially through said concentric channel to a discharge point; removing substantially all of the proppant from said fraction of slurry to said channel thereby concentrating said axially transmitted slurry and producing a substantially proppant free carrier; discharging said concentrated slurry from said separator at a rate so as to control the pressure inside said separator; and discharging said carrier from said separator at a rate so as to control the proppant concentration of said concentrated slurry.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1981-11-20	1982-05-22	1982-11-21	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1985-11-20	1986-05-22	1986-11-21	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1989-11-20	1990-05-22	1990-11-21	$7700.00	Window Closed / Lapsed

Method and apparatus for formation fracturing with foam having greater proppant concentration

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