Method for extracting oil by utilizing indigenous microbe of oil pool subjected to polymer flooding

A technology of original microorganisms and polymers, applied in drilling compositions, chemical instruments and methods, and production fluids, etc., can solve problems such as unfavorable reservoir protection and ground environmental protection, high cost of bacterial fermentation, and increased technical difficulty. Achieve the effects of enhancing residual oil recovery, increasing injection water sweep efficiency, and reducing permeability

Inactive Publication Date: 2014-04-02
YANGTZE UNIVERSITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantage of this invention is that the exogenous microorganisms are not suitable for the reservoir conditions after polymer flooding, and the fermentation cost of the bacterial solution is high and uneconomical
At the same time, when combined with polymer protection slugs and chemical flooding, the compatibility problem must be

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] The development area of ​​the North Second West East Block of Daqing Oilfield is 7.63km 2 , geological reserves 6598.9×10 4 t, was put into development in 1964, an infill adjustment was carried out in 1981, a second infill adjustment was completed in 1994, and the first group of polymer flooding wells in Pu was put into production. The average single-well sandstone thickness is 19.9m, the effective thickness is 12.1m, the original formation pressure is 10.91MPa, the original saturation pressure is 9.83MPa, and the fracture pressure is 13.1MPa. The viscosity of crude oil underground in the oil layer is 9.3mPa s, the specific gravity of crude oil is 0.859, and the original oil-gas ratio is 47.4m 3 / t, the salinity of the original formation water is 7000mg / L. In December 1995, polymers were invested in this block, and in April 2003, the follow-up water flooding was launched. The polymer consumption in the whole process was 757PV.mg / L, and the current cumulative oil produ...

Embodiment 2

[0029] Experimental method is the same as embodiment 1.

[0030] In the indoor simulation experiment of Beierxi oil reservoir, water flooding was firstly carried out to a water cut of about 80%, and the recovery rate of water flooding was about 30.7%. Then polymer (0.15% polyacrylamide solution) flooding was carried out to a water cut of about 95%. %, the recovery rate of polyflooding is about 16.3%, and the cumulative recovery rate is 47%; then the original microbial oil flooding is carried out, and 0.5PV of the original microbial activator (activator solution B, specifically (g / L): dihydrogen phosphate Ammonium 1.5, sodium nitrate 2, molasses or sucrose 60, compound amino acid 10, ammonium molybdate 0.03, copper sulfate 0.2, ferric chloride 0.25, zinc sulfate 0.023, the compound amino acid consists of equal weight of threonine, serine, arginine acid, lysine and histidine), closed the well and cultivated for 3 days (the original bacteria after detection and activation include...

Embodiment 3

[0032] The original bacterium and activator used are the same as in Example 1.

[0033] The inorganic gel in this profile control and oil displacement system is aluminum salt solution and urea, aluminum salt solution such as aluminum trichloride, aluminum sulfate, aluminum iron sulfate, aluminum potassium sulfate, etc., urea is slowly hydrolyzed under reservoir conditions to produce hydrogen and oxygen Root ions, combined with aluminum ions to produce aluminum hydroxide precipitates, resulting in inorganic gel plugging in the large pores deep in the reservoir.

[0034] The core flooding simulation test of Daqing Beierxi oil reservoir shows that water flooding is carried out first, and the recovery rate is about 33%, and then polymer flooding (same as Example 1), the cumulative recovery rate after polymer flooding is about 48.4%, and then injected Inorganic gel slug 0.3PV (8% inorganic gel aqueous solution), then use the original bacterium activator C (specifically (gram / liter)...

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PUM

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Abstract

The invention relates to a method for extracting oil by utilizing indigenous microbes of an oil pool subjected to polymer flooding. In the method, a method activating the indigenous microbes of the oil pool is adopted, and an activating agent comprises diammonium phosphate, sodium nitrate, molasses or cane sugar, compound amino acid, ammonium molybdate, copper sulfate, ferric chloride and zinc sulfate; and plugging can be further carried out on a deep channel and a roaring channel of the oil pool by injecting controlled-release nutritional agents and inorganic gel slugs. The method for extracting oil by utilizing the indigenous microbes of the oil pool subjected to the polymer flooding has obvious extraction rate enhancement effect, relatively low-cost used raw material and ground and underground dual environmental protection without increasing the difficulty of the post processing of produced fluids.

Description

technical field [0001] The invention belongs to the field of microbial oil recovery in tertiary oil recovery in oil and gas field development, and specifically relates to a method for improving residual oil recovery after polymer flooding by using an original microbial activator, slow-release nutrient and / or inorganic gel slug. Background technique [0002] my country's Daqing Oilfield, Dagang Oilfield, Shengli Oilfield, Henan Oilfield and Karamay Oilfield have all used polymer flooding on a large scale, that is, injecting high-concentration and high-molecular-weight polyacrylamide aqueous solution to flood oil, and achieved great success. However, when polymer flooding is followed by water flooding, the water content of the oil well rises to 100% very quickly, and about 50% of the residual oil cannot be produced in the reservoir with the existing technology. For example, there are currently 6,000 oil wells in Daqing Oilfield after polymer flooding with high water cut (more ...

Claims

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Application Information

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IPC IPC(8): E21B43/22C09K8/582
Inventor 佘跃惠张凡舒福昌王正良孔淑琼喻高明周玲革马莎莎韩春春董浩
Owner YANGTZE UNIVERSITY
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