Selectively plugging subterranean formations with a hydrocarbon soluble fluid

Claim 2

A process for selectively plugging a highly permeable zone of a subterranean formation vertically bounded by a relatively less permeable zone comprising the steps of: (a) dissolving a solid melamine in an aqueous formaldehyde solution to form a melamine/formaldehyde solution; (b) combining said melamine/formaldehyde solution with a monohydric or polyhydric alcohol comprising at least about 6 carbon atoms to form a substantially hydrophobic emulsion wherein the moles of said formaldehyde exceed the moles of said melamine; (c) injecting said emulsion into said highly permeable zone via a well in fluid communication with said highly permeable zone; (d) displacing said emulsion along the interface between said highly permeable zone and said relatively less permeable zone; and (e) reacting said emulsion in situ at the pressure of said subterranean formation, at a temperature of from about 80° C. to about 250° C. and for a time of from about 1 to about 4 days to produce a resin which is substantially impermeable to fluids and which substantially plugs said highly permeable zone.

Claim 3

The process of claim 1 wherein the molar ratio of formaldehyde to melamine is at least about 2:1 in said emulsion.

Claim 4

The process of claim 2 wherein the concentration of said melamine is from about 0.5% to about 10% by weight and said formaldehyde is from about 0.5% to about 10% by weight in said emulsion.

Claim 5

The process of claim 3 wherein the concentration of said melamine is from about 1% to about 2% by weight and said formaldehyde is from about 1% to about 2% by weight in said emulsion.

Claim 6

The process of claim 1 wherein the pH of said emulsion is adjusted from about 7 to about 12 prior to injecting said emulsion by adding a base to said emulsion.

Claim 7

The process of claim 5 wherein the pH of said emulsion is adjusted from about 8 to about 9 prior to injecting said emulsion by adding a base to said emulsion.

Claim 8

The process of claim 1 wherein the pH of water within said formation is adjusted to from about 7 to about 5 after the reaction of step (c) is initiated by injecting an acid into said formation.

Claim 9

The process of claim 7 wherein said acid is injected into said formation from about 12 to about 24 hours after said emulsion is injected into said zone.

Claim 10

The process of claim 1 wherein said emulsion is reacted at a temperature of from about 100° C. to about 200° C.

Claim 11

The process of claim 1 wherein said emulsion is reacted for a time of from about 1 to about 2 days.

Claim 12

The process of claim 1 wherein said solid melamine is dissolved in said aqueous formaldehyde solution under basic conditions.

Claim 13

The process of claim 1 wherein said highly permeable zone contains water.

Claim 14

A process for selectively plugging a highly permeable water-containing zone of a subterranean formation, said formation having a relatively less permeable zone substantially permeable to gases but substantially impermeable to liquids, bounded on one side by said highly permeable water-containing zone, and bounded on the other side by a second highly permeable zone, said process comprising the steps of: (a) dissolving a solid melamine in an aqueous formaldehyde solution to form a melamine/formaldehyde solution; (b) combining said melamine/formaldehyde solution with a monohydric or polyhydric alcohol comprising at least about 6 carbon atoms to form a hydrophobic emulsion wherein the molar ratio of formaldehyde to melamine is at least about 2:1; (c) injecting said emulsion into said highly permeable water-containing zone via a well in fluid communication with said water-containing zone; (d) displacing said emulsion along the interface between said highly permeable water-containing zone and said relatively less permeable zone; (e) injecting steam into said second highly permeable zone via a well in fluid communication with said second highly permeable zone; (f) displacing said steam across said relatively less permeable zone and along the interface betweentn said relatively less permeable zone and said water-containing zone; and

Claim 15

A process for selectively plugging a highly permeable water-containing zone of a subterranean formation, said formation having a relatively less permeable zone substantially permeable to gases but substantially impermeable to liquids, bounded on one side by said highly permeable water-containing zone, and bounded on the other side by a second highly permeable zone, said process comprising the steps of: (a) dissolving a solid melamine in an aqueous formaldehyde solution to form a melamine/formaldehyde solution; (b) combining said melamine/formaldehyde solution with a monohydric or polyhydric alcohol comprising at least about 6 carbon atoms to form a hydrophobic emulsion wherein the molar ratio of formaldehyde to melamine is at least about 2:1; (c) injecting said emulsion into said highly permeable water-containing zone via a well in fluid communication with said water-containing zone; (d) displacing said emulsion along the interface between said highly permeable water-containing zone and said relatively less permeable zone; (e) injecting steam into said second highly permeable zone via a well in fluid communication with said second highly permeable zone; (f) displacing said steam across said relatively less permeable zone and along the interface betweentn said relatively less permeable zone and said water-containing zone; and

Claim 16

(g) contacting said emulsion with said steam at the interface at the pressure of said subterranean formation, at a temperature of from about 100° C. to about 250° C., and for a time of from about 1 to about 4 days to produce a resin substantially impermeable to said gases and liquids and which substantially plugs said highly permeable water-containing zone.

Claim 17

(g) contacting said emulsion with said steam at the interface at the pressure of said subterranean formation, at a temperature of from about 100° C. to about 250° C., and for a time of from about 1 to about 4 days to produce a resin substantially impermeable to said gases and liquids and which substantially plugs said highly permeable water-containing zone.

Claim 18

A process for steamflooding a highly permeable hydrocarbon-bearing zone of a subterranean formation to produce said hydrocarbon therefrom, said formation having a relatively less permeable zone substantially permeable to gases but substantially impermeable to liquids, bounded on one side by said highly permeable hydrocarbon-bearing zone and bounded on the other side by a highly permeable water-containing zone, said process comprising the steps of: (a) dissolving a solid melamine in an aqueous formaldehyde solution to form a melamine/formaldehyde solution; (b) combining said melamine/formaldehyde solution with a monohydric or polyhydric alcohol comprising at least about 6 carbon atoms to form a hydrophobic emulsion wherein the molar ratio of formaldehyde to melamine is at least about 2:1; (c) injecting said emulsion into said highly permeable water-containing zone via a well in fluid communication with said water-containing zone; (d) displacing said emulsion along the interface between said highly permeable water-containing zone and said relatively less permeable zone; (e) injecting steam into said highly permeable hydrocarbon-bearing zone via a well in fluid communication with said hydrocarbon-bearing zone; (f) displacing said steam across said relatively less permeable zone and along the interface between said relatively permeable zone and said water-containing zone; (g) contacting said emulsion with said steam at the interface at the pressure of said subterranean formation, at a temperature of from about 100° C. to about 250° C., and for a time of from about 1 to about 4 days to produce a resin substantially impermeable to said gases and liquids and which substantially plugs said highly permeable water-containing zone; and (h) steamflooding said highly permeable hydrocarbon-bearing zone to produce said hydrocarbon therefrom.

Claim 19

A process for steamflooding a highly permeable hydrocarbon-bearing zone of a subterranean formation to produce said hydrocarbon therefrom, said formation having a relatively less permeable zone substantially permeable to gases but substantially impermeable to liquids, bounded on one side by said highly permeable hydrocarbon-bearing zone and bounded on the other side by a highly permeable water-containing zone, said process comprising the steps of: (a) dissolving a solid melamine in an aqueous formaldehyde solution to form a melamine/formaldehyde solution; (b) combining said melamine/formaldehyde solution with a monohydric or polyhydric alcohol comprising at least about 6 carbon atoms to form a hydrophobic emulsion wherein the molar ratio of formaldehyde to melamine is at least about 2:1; (c) injecting said emulsion into said highly permeable water-containing zone via a well in fluid communication with said water-containing zone; (d) displacing said emulsion along the interface between said highly permeable water-containing zone and said relatively less permeable zone; (e) injecting steam into said highly permeable hydrocarbon-bearing zone via a well in fluid communication with said hydrocarbon-bearing zone; (f) displacing said steam across said relatively less permeable zone and along the interface between said relatively permeable zone and said water-containing zone; (g) contacting said emulsion with said steam at the interface at the pressure of said subterranean formation, at a temperature of from about 100° C. to about 250° C., and for a time of from about 1 to about 4 days to produce a resin substantially impermeable to said gases and liquids and which substantially plugs said highly permeable water-containing zone; and (h) steamflooding said highly permeable hydrocarbon-bearing zone to produce said hydrocarbon therefrom.