# US 2021/0230989 A1 · Methods for Tight Oil Production Through Secondary Recovery

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- Number: US 2021/0230989 A1
- Document ID: US20210230989A1
- Status: Published application
- Kind: A1
- Application number: 17/157,209
- Filed: 2021-01-25
- Published: 2021-07-29
- Earliest claimed: 2020-01-24
- Inventors: Xuebing Fu
- Web page: https://patentgrep.com/patent/US20210230989A1

## CPC

- E21B 43/162: {Injecting fluid from longitudinally spaced locations in injection well}
- E21B 43/166: {Injecting a gaseous medium; Injecting a gaseous medium and a liquid medium (CO2 injection E21B43/164; steam injection E21B43/24)}
- E21B 43/14: Obtaining from a multiple-zone well
- E21B 43/26: by forming crevices or fractures
- E21B 43/267: reinforcing fractures by propping
- E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS

## Abstract

Some methods of production hydrocarbons from a formation comprise drilling two or more horizontal wellbores in the formation, at least a portion of each extending in a direction that is within 20 degrees of parallel to a direction of maximum horizontal stress of the formation. The horizontal wellbores can include one or more producer wellbores and one or more injector wellbores, each of the producer wellbore(s) separated from at least one of the injector wellbore(s) by a formation-permeability-dependent well spacing. Some comprise comprising creating one or more longitudinal fractures that are in communication with the formation in each of the horizontal wellbores, injecting a recovery fluid comprising gas into at least one of the injector wellbore(s) such that the recovery fluid flows into the formation, and receiving hydrocarbons from the formation into at least one of the producer wellbore(s).

## Claims

### Claim 1

A method of producing hydrocarbons from a formation, the method comprising:
drilling two or more horizontal wellbores in the formation, wherein:
at least a portion of each of the horizontal wellbores extends in a direction that is within 20 degrees of parallel to a direction of maximum horizontal stress of the formation; and
the horizontal wellbores include one or more producer wellbores and one or more injector wellbores, each of the producer wellbore(s) separated from at least one of the injector wellbore(s) by a well spacing, wherein:
the well spacing is between 50 and 300 feet, and the average permeability of the formation is between 0.001 and 0.005 millidarcy (mD);
the well spacing is between 100 and 800 feet, and the average permeability of the formation is between 0.005 and 0.01 mD;
the well spacing is between 150 and 1,500 feet, and the average permeability of the formation is between 0.01 and 0.05 mD;
the well spacing is between 200 and 2,000 feet, and the average permeability of the formation is between 0.05 and 0.10 mD;
the well spacing is between 500 and 3,000 feet, and the average permeability of the formation is between 0.10 and 0.50 mD; or
the well spacing is between 800 and 4,000 feet, and the average permeability of the formation is between 0.50 and 2.0 mD;
creating one or more longitudinal fractures that are in communication with the formation in each of the horizontal wellbores;
injecting a recovery fluid into at least one of the injector wellbore(s) such that the recovery fluid flows into the formation, wherein the recovery fluid comprises gas; and
receiving hydrocarbons from the formation into at least one of the producer wellbore(s).

### Claim 2 (depends on 1)

The method of claim 1, wherein:
the one or more producer wellbores comprise two or more producer wellbores, each positioned closer to at least one of the injector wellbore(s) than to each other of the producer wellbores; and/or
the one or more injector wellbores comprise two or more injector wellbores, each positioned closer to at least one of the producer wellbore(s) than to each other of the injector wellbores.

### Claim 3 (depends on 2)

The method of claim 2, wherein each of the producer wellbore(s) is spaced apart from a closest one of the injector wellbore(s) by the well spacing.

### Claim 4 (depends on 1)

The method of claim 1, wherein the well spacing is less than or equal to 900 feet.

### Claim 5 (depends on 4)

The method of claim 4, wherein the average permeability of the formation is less than or substantially equal to 0.10 mD.

### Claim 6 (depends on 1)

The method of claim 1, wherein a depth of each of the horizontal wellbores is within 5% of a depth of each other of the horizontal wellbores.

### Claim 7 (depends on 1)

The method of claim 1, wherein drilling is performed such that at least two of the horizontal wellbores extend from a common vertical wellbore.

### Claim 8 (depends on 1)

The method of claim 1, wherein at least one of the producer wellbore(s) and/or at least one of the injector wellbore(s) has a length that is at least 10% shorter than a length of another one of the horizontal wellbores.

### Claim 9 (depends on 1)

The method of claim 1, wherein the gas comprises methane, ethane, propane, butane, carbon dioxide, and/or nitrogen.

### Claim 10 (depends on 1)

The method of claim 1, wherein:
the one or more producer wellbores comprise two or more producer wellbores;
drilling is performed such that:
a first one of the producer wellbores is spaced apart from a second one of the producer wellbores by a distance that is at least 150% of the well spacing;
a first one of the injector wellbore(s) is spaced apart from each of the first and second producer wellbores by the well spacing; and
the first injector wellbore is:
drilled in the formation at least one year after the first and second producer wellbores are each drilled in the formation; and
positioned closer to the first producer wellbore and to the second producer wellbore than is the first producer wellbore to the second producer wellbore; and
receiving hydrocarbons from the formation includes receiving hydrocarbons into the first and second producer wellbores before the first injector wellbore is drilled in the formation.

### Claim 11

A method of producing hydrocarbons from a formation, the method comprising:
drilling two or more horizontal wellbores in the formation, wherein:
at least a portion of each of the horizontal wellbores extends in a direction that is within 20 degrees of parallel to a direction of maximum horizontal stress of the formation; and
the horizontal wellbores include one or more producer wellbores and one or more injector wellbores, each of the producer wellbore(s) separated from at least one of the injector wellbore(s) by a well spacing that is within 10% of
1
.
5
⁢
2
⁢
9
⁢
k
⁢
Δ
⁢
p
⁢
T
∅
⁡
(
1
-
S
w
)
⁢
μ
in feet, wherein k is an average permeability of the formation in millidarcies (mD), Δp is a differential between a target production pressure and a target injection pressure in pounds per square inch, T is between 0.5 and 20 years, Ø is an effective porosity of the formation, Sw is a water saturation of the formation, and μ equals a viscosity of the hydrocarbons in the formation in centipoise (cP) plus a viscosity of a recovery fluid in cP divided by two;
creating one or more longitudinal fractures that are in communication with the formation in each of the horizontal wellbores;
injecting the recovery fluid into at least one of the injector wellbore(s) such that the recovery fluid flows into the formation and a pressure within the injector wellbore is within 20% of the target injection pressure, wherein the recovery fluid comprises gas; and
receiving hydrocarbons from the formation into at least one of the producer wellbore(s), wherein a pressure within the producer wellbore is within 20% of the target production pressure.

### Claim 12 (depends on 11)

The method of claim 11, wherein:
the one or more producer wellbores comprise two or more producer wellbores, each positioned closer to at least one of the injector wellbore(s) than to each other of the producer wellbores; and/or
the one or more injector wellbores comprise two or more injector wellbores, each positioned closer to at least one of the producer wellbore(s) than to each other of the injector wellbores.

### Claim 13 (depends on 12)

The method of claim 12, wherein each of the producer wellbore(s) is spaced apart from a closest one of the injector wellbore(s) by the well spacing.

### Claim 14 (depends on 11)

The method of claim 11, wherein the well spacing is less than or equal to 900 feet.

### Claim 15 (depends on 14)

The method of claim 14, wherein the average permeability of the formation is less than or substantially equal to 0.10 mD.

### Claim 16 (depends on 11)

The method of claim 11, wherein a depth of each of the horizontal wellbores is within 5% of a depth of each other of the horizontal wellbores.

### Claim 17 (depends on 11)

The method of claim 11, wherein drilling is performed such that at least two of the horizontal wellbores extend from a common vertical wellbore.

### Claim 18 (depends on 11)

The method of claim 11, wherein at least one of the producer wellbore(s) and/or at least one of the injector wellbore(s) has a length that is at least 10% shorter than a length of another one of the horizontal wellbores.

### Claim 19 (depends on 11)

The method of claim 11, wherein the gas comprises methane, ethane, propane, butane, carbon dioxide, and/or nitrogen.

### Claim 20 (depends on 11)

The method of claim 11, wherein:
the one or more producer wellbores comprise two or more producer wellbores;
drilling is performed such that:
a first one of the producer wellbores is spaced apart from a second one of the producer wellbores by a distance that is at least 150% of the well spacing;
a first one of the injector wellbore(s) is spaced apart from each of the first and second producer wellbores by the well spacing; and
the first injector wellbore is:
drilled in the formation at least one year after the first and second producer wellbores are each drilled in the formation; and
positioned closer to the first producer wellbore and to the second producer wellbore than is the first producer wellbore to the second producer wellbore; and
receiving hydrocarbons from the formation includes receiving hydrocarbons into the first and second producer wellbores before the first injector wellbore is drilled in the formation.