Process for recovering hydrocarbons by thermally assisted gravity segregation

Claim 2

A process for recovering hydrocarbons from a subterranean hydrocarbon-bearing formation, the formation having at least one high permeability region and at least one low permeability region, the low permeability region containing liquid hydrocarbons having volatile components and the high permeability region having a gas-filled upper portion, a liquid-filled lower portion, and a gas/liquid interface, the process comprising: injecting a hot light gas into the formation via at least one injection well in fluid communication with the formation, thereby heating at least the upper portion of the formation; and producing liquid and gas via at least one production well in fluid communication with the formation, the liquid and gas produced from below the gas/liquid interface at a rate sufficient to cause gas to cone near the at least one production well.

Claim 3

The process of claim 1 wherein said light gas is selected from the group consisting of steam, produced residue gas, flue gas, CO 2 , N 2 , and mixtures thereof.

Claim 4

The process of claim 1 wherein said heat is provided at a temperature between about 400° F. and about 1100° F.

Claim 5

The process of claim 1 wherein said high permeability regions comprise a fracture network.

Claim 6

The process of claim 1 wherein said at least one injection well and said at least one production well are a common well.

Claim 7

The process of claim 1 wherein said produced gas comprises at least a portion of said volatile component of said liquid hydrocarbons in said matrix blocks.

Claim 8

The process of claim 1 wherein a production tubing string is positioned in said at least one production well so as to allow production from a vertical zone below said gas/liquid interface.

Claim 9

The process of claim 7 wherein said process additionally comprises monitoring said gas/liquid interface to determine changes in the depth of said interface.

Claim 10

The process of claim 8 wherein the depth of said vertical zone is adjusted in response to changes in the depth of said interface.

Claim 11

The process of claim 8 wherein said depth of said interface is adjusted by changing the rate at which said hot gas is injected into said formation.

Claim 12

The process of claim 8 wherein said depth of said interface is adjusted by changing the rate at which said liquid and gas are produced.

Claim 13

The process of claim 1 wherein said at least one high permeability region comprises a fracture network, and said at least one low permeability region comprises matrix.

Claim 14

A process for recovering hydrocarbons from a subterranean hydrocarbon-bearing formation, the formation having at least one high permeability region and at least one low permeability region, the low permeability region and the high permeability region containing liquid hydrocarbons having a substantial fraction of volatile components, the process comprising: injecting a first light gas via at least one injection well in fluid communication with the formation, thereby forming a gas cap and a gas/liquid interface within the high permeability regions in the upper portion of the formation; injecting a second, hot, light gas via the at least one injection well into the formation, thereby heating at least the upper portion of the formation; and producing liquid and gas via at least one production well in fluid communication with the formation, the liquid and gas produced from below the gas/liquid interface via at least one production well penetrating the formation, the liquid and gas produced at a rate sufficient to cause gas to cone near the at least one production well.

Claim 15

A process for recovering hydrocarbons from a subterranean hydrocarbon-bearing formation, the formation having at least one high permeability region and at least one low permeability region, the low permeability region and the high permeability region containing liquid hydrocarbons having a substantial fraction of volatile components, the process comprising: injecting a first light gas via at least one injection well in fluid communication with the formation, thereby forming a gas cap and a gas/liquid interface within the high permeability regions in the upper portion of the formation; injecting a second, hot, light gas via the at least one injection well into the formation, thereby heating at least the upper portion of the formation; and producing liquid and gas via at least one production well in fluid communication with the formation, the liquid and gas produced from below the gas/liquid interface via at least one production well penetrating the formation, the liquid and gas produced at a rate sufficient to cause gas to cone near the at least one production well.

Claim 16

The process of claim 13 wherein said first light gas is selected from the group consisting of N 2 , methane, ethane, produced residue gas, flue gas, CO 2 , and mixtures thereof.

Claim 17

The process of claim 13 wherein said second light gas is selected from the group consisting of steam, produced residue gas, flue gas, CO 2 , N 2 , and mixtures thereof.

Claim 18

The process of claim 13 wherein said heat is provided at a temperature between about 400° F. and about 1100° F.

Claim 19

The process of claim 13 wherein said high permeability regions comprise a fracture network.

Claim 20

The process of claim 13 wherein said injection of said first light gas to create said gas cap and said injection of said second hot light gas to heat said formation are combined.

Claim 21

The process of claim 13 wherein said first light gas is injected prior to said injection of said second light gas.

Claim 22

The process of claim 13 wherein said at least one injection well and said at least one production well are a common well.

Claim 23

The process of claim 13 wherein said produced gas comprises at least a portion of said volatile component of said liquid hydrocarbons in said at least one low permeability region.

Claim 24

The process of claim 13 wherein a production tubing string is positioned in said at least one production well so as to allow production from a vertical zone below said gas/liquid interface.

Claim 25

The process of claim 22 wherein said process additionally comprises monitoring said gas/liquid interface to determine changes in the depth of said interface.

Claim 26

The process of claim 23 wherein the depth of said vertical zone is adjusted in response to changes in the depth of said interface.

Claim 27

The process of claim 23 wherein said depth of said interface is adjusted by changing the rate at which said hot gas is injected into said formation.

Claim 28

The process of claim 23 wherein said depth of said interface is adjusted by changing the rate at which said liquid and gas are produced.

Claim 29

The process of claim 13 wherein said at least one high permeability region comprises a fracture network, and said at least one low permeability region comprises matrix.

Claim 30

A process for recovering hydrocarbons from a subterranean hydrocarbon-bearing formation, the formation having at least one high permeability region and at least one low permeability region, the low permeability region and the high permeability region containing liquid hydrocarbons having a substantial fraction of volatile components, the process comprising: decreasing the pressure of said formation, thereby creating a gas cap and a gas/liquid interface within the high permeability regions in the upper portion of the formation; injecting a hot light gas into the formation via at least one injection well in fluid communication with the formation, thereby heating at least the upper portion of the formation; and producing liquid and gas from below the gas/liquid interface via at least one production well in fluid communication with the formation, thereby producing the liquid and gas at a rate sufficient to cause gas to cone near the at least one production well.

Claim 31

A process for recovering hydrocarbons from a subterranean hydrocarbon-bearing formation, the formation having at least one high permeability region and at least one low permeability region, the low permeability region and the high permeability region containing liquid hydrocarbons having a substantial fraction of volatile components, the process comprising: decreasing the pressure of said formation, thereby creating a gas cap and a gas/liquid interface within the high permeability regions in the upper portion of the formation; injecting a hot light gas into the formation via at least one injection well in fluid communication with the formation, thereby heating at least the upper portion of the formation; and producing liquid and gas from below the gas/liquid interface via at least one production well in fluid communication with the formation, thereby producing the liquid and gas at a rate sufficient to cause gas to cone near the at least one production well.

Claim 32

The process of claim 28 wherein said light gas is selected from the group consisting of steam, produced residue gas, flue gas, CO 2 , N 2 , and mixtures thereof.

Claim 33

The process of claim 28 wherein said heat is provided at a temperature between about 400° F. and about 1100° F.

Claim 34

The process of claim 28 wherein said high permeability regions comprise a fracture network.

Claim 35

The process of claim 28 wherein said at least one injection well and said at least one production well are a common well.

Claim 36

The process of claim 28 wherein said produced gas comprises at least a portion of said volatile component of said liquid hydrocarbons in said matrix blocks.

Claim 37

The process of claim 28 wherein a production tubing string is positioned in said at least one production well so as to allow production from a vertical zone below said gas/liquid interface.

Claim 38

The process of claim 34 wherein said process additionally comprises monitoring said gas/liquid interface to determine changes in the depth of said interface.

Claim 39

The process of claim 35 wherein the depth of said vertical zone is adjusted in response to changes in the depth of said interface.

Claim 40

The process of claim 35 wherein said depth of said interface is adjusted by changing the rate at which said hot gas is injected into said formation.

Claim 41

The process of claim 35 wherein said depth of said interface is adjusted by changing the rate at which said liquid and gas are produced.

Claim 42

The process of claim 28 wherein said at least one high permeability region comprises a fracture network, and said at least one low permeability region comprises matrix.

Claim 43

A process for recovering hydrocarbons from a subterranean hydrocarbon-bearing formation, the formation having substantially parallel first and second high permeability regions containing fluids and having an approximately vertical orientation, the high permeability regions separated by at least one low permeability matrix region containing liquid hydrocarbons having volatile components, the process comprising: injecting a hot light gas into the formation via at least one injection well in fluid communication with the first high permeability region, thereby heating the at least one low permeability matrix region by thermal conduction to vaporize at least a portion of the volatile hydrocarbon components in the low permeability region and causing the vaporized components to flow from the matrix into the second high permeability region and segregate therein into liquid and gas layers separated by a gas/liquid interface; and producing hydrocarbons via at least one production well in fluid communication with the second high permeability region.

Claim 44

A process for recovering hydrocarbons from a subterranean hydrocarbon-bearing formation, the formation having substantially parallel first and second high permeability regions containing fluids and having an approximately vertical orientation, the high permeability regions separated by at least one low permeability matrix region containing liquid hydrocarbons having volatile components, the process comprising: injecting a hot light gas into the formation via at least one injection well in fluid communication with the first high permeability region, thereby heating the at least one low permeability matrix region by thermal conduction to vaporize at least a portion of the volatile hydrocarbon components in the low permeability region and causing the vaporized components to flow from the matrix into the second high permeability region and segregate therein into liquid and gas layers separated by a gas/liquid interface; and producing hydrocarbons via at least one production well in fluid communication with the second high permeability region.

Claim 45

The process of claim 40 wherein said produced hydrocarbons comprise liquid and heavy gas and are produced from below the liquid/gas interface at a rate sufficient to cause heavy gas to cone near the at least one production well.

Claim 46

The process of claim 41 wherein said first high permeability region comprises an injection fracture network and said second high permeability region comprises a production fracture network.

Claim 47

The process of claim 42 wherein a secondary fracture system provides a poor degree of fluid communication between said injection and production fracture networks.

Claim 48

The process of claim 42 wherein said injection fracture network and said production fracture network are substantially in fluid isolation from each other.

Claim 49

The process of claim 40 wherein said light gas is selected from the group consisting of steam, produced residue gas, flue gas, CO 2 , N 2 , and mixtures thereof.

Claim 50

The process of claim 40 wherein said light gas is injected at a temperature between about 400° F. and about 1100° F.

Claim 51

The process of claim 40 wherein said produced hydrocarbons comprise at least a portion of said volatile components of said liquid hydrocarbons in said matrix.

Claim 52

The process of claim 40 wherein a production tubing string is positioned in said at least one production well so as to allow production from a vertical zone below said gas/liquid interface in said second high permeability region.

Claim 53

The process of claim 48 wherein said process additionally comprises monitoring said gas/liquid interface to determine changes in the depth of said interface.

Claim 54

The process of claim 49 wherein the depth of said vertical zone is adjusted in response to changes in the depth of said interface.

Claim 55

The process of claim 49 wherein said depth of said interface is adjusted by changing the rate at which said hydrocarbons are produced.