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Oil recovery method restraining channeling in CO2 flooding process in low-permeability fractured reservoir through two-stage channeling blocking

A low-permeability and fracture technology, applied in chemical instruments and methods, production fluids, earth drilling and production, etc., can solve problems such as water injection difficulties, plugging adjustment technology is difficult to apply, gas injection expansion and volume loss, etc., to improve oil recovery rate effect

Active Publication Date: 2014-10-29
CHINA UNIV OF PETROLEUM (BEIJING)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Many conduct CO 2 The oil reservoirs flooded are all low-permeability conditions, and it is difficult to inject water normally. However, the injection of CO 2 Escape
In addition, because there are often fractures with a certain density in low-permeability reservoirs, it will cause a great loss to the enlarged swept volume of gas injection.
Obviously, under this condition, due to the difficulty of water injection in the low-permeability matrix, the conventional plugging technology based on high-viscosity gels is difficult to apply; and the plugging of fractures requires gels that not only have high strength, but also have Strong ability to bond with the matrix, but also resistant to CO 2
In the existing literature reports, no technical data that can be directly used to control gas channeling in low-permeability reservoirs where water injection is difficult is found, which is also the main technical difficulty faced by this research work

Method used

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  • Oil recovery method restraining channeling in CO2 flooding process in low-permeability fractured reservoir through two-stage channeling blocking
  • Oil recovery method restraining channeling in CO2 flooding process in low-permeability fractured reservoir through two-stage channeling blocking
  • Oil recovery method restraining channeling in CO2 flooding process in low-permeability fractured reservoir through two-stage channeling blocking

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0049] Experimental conditions

[0050] The size of the physical model is φ400mm×60mm, which is made by drilling, cutting and grinding the natural outcrop. According to the five-point well pattern, one injection and four production well groups are designed.

[0051] Due to the inconsistency in the degree of tightness of the natural outcrop, the permeability from the injection well to the four production wells is also inconsistency, which happens to simulate the site conditions more realistically.

[0052] The physical properties of physical model 1 and the permeability in four directions are shown in Table 1.

[0053] Table 1. Permeability measurement results of the model in Example 1 in each production well direction

[0054]

flow(ml / min)

Differential pressure (KPa)

Matrix permeability (mD)

1 #

0.1

888.39

0.218

2 #

0.4

138.61

5.62

3 #

0.4

122.51

6.39

4 #

0.5

51.81

18.74

...

Embodiment 2

[0080] The physical properties of physical model 2 and the permeability in four directions are shown in Table 3.

[0081] Table 3 Permeability measurement results of the model in Example 2 in each production well direction

[0082]

flow(ml / min)

Differential pressure (KPa)

Matrix permeability (mD)

1 #

0.1

997.63

0.194

2 #

0.4

111.01

7.03

3 #

0.4

168.92

4.63

4 #

0.4

238.01

3.27

[0083] Likewise, at 1 # with 3 # Between the wells, fractures are artificially fractured. The fracture is filled with a small amount of quartz sand with a particle size of about 0.3mm as a fracture proppant, and the measured fracture permeability is 11876.5mD.

[0084] The same two-stage sealing is carried out, and after the crack sealing, the CO 2 After flooding, the channeling of the relatively high-permeability layer in the matrix was blocked by circulation after gas channeling occurred in a ...

Embodiment 3

[0090] The physical properties of physical model 3 and the permeability in four directions are shown in Table 5.

[0091] Table 5 Permeability measurement results of the model in Example 3 in each production well direction

[0092]

flow(ml / min)

Differential pressure (KPa)

Matrix permeability (mD)

1 #

0.4

296.27

2.62

2 #

0.4

350.5

2.23

3 #

0.4

673.82

1.16

4 #

0.4

609.22

1.28

[0093] In order to further investigate the ability of the two-stage channel sealing to control the heterogeneity of the plane, artificial fractures were constructed from the central well to the # well and 2 # The well forms a "V"-shaped fracture, and a small amount of quartz sand with a particle size of about 0.3mm is also filled in the fracture as a fracture proppant. The measured fracture permeability is 12676.8mD.

[0094] Then start the same operation procedure, the model is driven by gas after ...

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Abstract

The invention provides an oil recovery method restraining channeling in the CO2 flooding process in a low-permeability fractured reservoir through two-stage channeling blocking so as to increase the oil recovery ratio. The two-stage channeling blocking technology comprises the steps that a strong adhesive system with a natural modified polymeric material as the main agent is injected and forms a high-strength adhesive through waiting on cement setting to block off a fracture; fatty amine serves as a channeling blocking agent to block off channeling, caused by a relatively high-permeability layer in a low-permeability matrix, of low-viscosity CO2. By means of the two-stage channeling blocking technology, channeling in the CO2 flooding process in the low-permeability fractured reservoir can be effectively controlled, the swept volume can be increased, and therefore the oil recovery ratio can be increased.

Description

technical field [0001] The invention belongs to the technical field of oil and gas stimulation, in particular to two-stage sealing and channeling suppression of CO in low-permeability fractured reservoirs. 2 A method of driving escape to enhance oil recovery. Background technique [0002] With the rapid development of modern industry, the demand for oil and natural gas is increasing day by day, and most old oil fields have entered the stage of medium and high water cut, making it more and more difficult to stabilize production and tap potential. In order to maintain stable crude oil production, the development of low-permeability oilfields has received great attention and has become an important development goal now and in the future. Therefore, there is an urgent need to explore effective means of scientifically developing low-permeability oilfields. At present, there are nearly a hundred proven low-permeability oil reservoirs in my country, and their oil reserves account...

Claims

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Application Information

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IPC IPC(8): E21B33/13E21B43/16
CPCC09K8/588C08F251/00C09K8/594E21B33/138E21B43/164
Inventor 侯吉瑞赵凤兰刘中春
Owner CHINA UNIV OF PETROLEUM (BEIJING)
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