Polymer flooding oil reservoir microbial plugging removal method

A technology of microorganisms and polymers, which is applied in the direction of drilling compositions, chemical instruments and methods, earthwork drilling and mining, etc., to achieve good experimental results, long validity period, and the effect of unblocking

Inactive Publication Date: 2015-03-11
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Application number: CN201010253315.9, "A method for unclogging oil wells using acid-producing bacteria". This patent uses small molecular acids such as acetic acid to unblock oil wells near the well. It has the function of polymer degrading bacteria, and the patent is aimed at the plugging removal in the near-well area of ​​the oil well, not the polymer plugging removal in the deep formation. At present, there is no relevant report on the biotechnology plugging removal of the formation plugging caused by polymer flooding.

Method used

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  • Polymer flooding oil reservoir microbial plugging removal method
  • Polymer flooding oil reservoir microbial plugging removal method
  • Polymer flooding oil reservoir microbial plugging removal method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Implementation 1, taking Block F of Shengli Oilfield as an example

[0030] Block F of Shengli Oilfield is an unconsolidated sandstone reservoir with high permeability, medium-high viscosity, and high salinity. The reservoir temperature is 65°C, the porosity is 34.0%, and the pore volume is 3.6×10 4 m 3 , recoverable reserves 3.6×10 4 t, this block began to implement polymer flooding since August 2009, and the injection pressure before the implementation of polymer flooding was 6.2MPa. As of December 2011, the injection pressure rose to 11.3MPa. In March 2012, the method of the present invention began to be used. The specific implementation steps for oil reservoir plugging removal are as follows:

[0031] (1) Screening of polymer flooding reservoirs

[0032] The reservoir temperature in Block F is 65°C, and the water injection pressure increases by 82.2% before and after polymer injection, which meets the screening conditions for polymer flooding reservoirs.

[0033...

Embodiment 2

[0048] Implementation 2, taking Shengli Oilfield block L as an example

[0049] Block L of Shengli Oilfield is an unconsolidated sandstone reservoir with high permeability, medium-low viscosity, and medium-high salinity. The reservoir temperature is 72°C, the porosity is 33.5%, and the pore volume is 3.1×10 4 m 3 , recoverable reserves 2.1×10 4 t, this block began to implement polymer flooding since December 2004, and the injection pressure before the implementation of polymer flooding was 3.1MPa. As of December 2007, the injection pressure rose to 7.2MPa, and the method of the present invention began to be used in June 2008. The specific implementation steps for oil reservoir plugging removal are as follows:

[0050] (1) Screening of polymer flooding reservoirs

[0051] The reservoir temperature in Block L is 72°C, and the water injection pressure increases by 132.3% before and after polymer injection, which meets the screening conditions for polymer flooding reservoirs. ...

Embodiment 3

[0067] Implementation 3, taking block G of Shengli Oilfield as an example

[0068] Block G of Shengli Oilfield is an unconsolidated sandstone reservoir with high permeability, medium-high viscosity, and high salinity. The reservoir temperature is 75°C, the porosity is 33.0%, and the pore volume is 3.2×10 5 m 3 , recoverable reserves 3.2×10 5 t, this block began to implement polymer flooding since May 2006, and the injection pressure before the implementation of polymer flooding was 3.5MPa. As of December 2009, the injection pressure rose to 8.2MPa. In February 2010, the method of the present invention began to be used. The specific implementation steps for oil reservoir plugging removal are as follows:

[0069] (1) Screening of polymer flooding reservoirs

[0070] The reservoir temperature in Block G is 75°C, and the water injection pressure increases by 134.3% before and after polymer injection, which meets the screening conditions for polymer flooding reservoirs.

[0071...

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Abstract

The invention discloses a polymer flooding oil reservoir microbial plugging removal method. The method specifically comprises the following steps of: screening polymer flooding oil reservoirs and selecting polymer flooding oil reservoirs with oil reservoir temperature being lower than 80DEG C and increase of water injection pressure exceeding 50 percent before and after polymer injection; conducting indigenous microbial plugging removal feasibility analysis, and selecting indigenous plugging removal if indigenous microbial plugging removal conditions are satisfied; conducting exogenous microbes screening if the indigenous microbial plugging removal conditions are not satisfied; optimizing a field injection process to obtain field injection process parameters; conducting field construction and effect tracking. The polymer flooding oil reservoir microbial plugging removal method has the advantages that the method is safe and environmental-friendly and activator used in the method is harmless and nontoxic; the field testing effect is good and the rate of decrease of injection pressure of the oil reservoirs exceeds 50 percent; the construction process is simple, the cost is low, and the effective period is long and is more than 24 months; the acting range is wide, not only can plugging in belts near oil wells be removed, but also plugging at deep positions of the oil reservoirs can be removed, and thus the method can be widely applied to the polymer flooding oil reservoir plugging removal process.

Description

technical field [0001] The invention belongs to the technical field of petroleum exploitation, and in particular relates to a method for removing plugging by microorganisms in polymer flooding oil reservoirs. technical background [0002] After long-term water flooding development in the oil field, large pores have been formed. In order to further enhance oil recovery, a large amount of polymer needs to be injected into the reservoir, but long-term large-scale injection will cause blockage near the well and the formation, resulting in The permeability is greatly reduced, which leads to the increase of water injection pressure and makes it difficult to inject water normally, which eventually leads to a lack of energy in the formation, which seriously affects the subsequent development of the reservoir. [0003] At present, the commonly used methods for removing oil well polymer clogging are as follows: (1) hydrogen peroxide (hydrogen peroxide) method, which will produce a lar...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B37/06E21B43/22C09K8/582
CPCE21B37/06C09K8/52C09K8/582C09K8/588E21B43/16
Inventor 汪卫东林军章王静宋欣段传慧徐闯巴燕刘涛潘永强徐鹏张守献
Owner CHINA PETROLEUM & CHEM CORP
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