Nano liquid for decompression and augmented injection of tight oil water-flooding and preparation method and application thereof

A dense oil, hydrophobic nanotechnology, applied in chemical instruments and methods, drilling compositions, etc., can solve the problems of high cost, application limitation, environmental pollution, etc., and achieve the effects of low cost, convenient preparation and environmental friendliness

Active Publication Date: 2015-10-28
CHINA UNIV OF PETROLEUM (EAST CHINA)
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Chinese patent document CN102502663A utilizes the hydrolysis of silicon tetrachloride to prepare a kind of hydrophobic nano-silica by in-situ modification method. The disadvantage is that it needs to be dispersed with organic solvents such as carbon tetrachloride, toluene, diesel oil and liquid paraffin.
However, organic solvents such as diesel oil and carbon tetrachloride are required to disperse, and the cost is high and it is easy to cause environmental pollution
Moreover, the radius of pore throats in low-permeability reservoirs is micron-scale, while tight reservoirs are mostly micro-nano-scale pores, so the application in tight oil depressurization and injection enhancement is also limited

Method used

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  • Nano liquid for decompression and augmented injection of tight oil water-flooding and preparation method and application thereof
  • Nano liquid for decompression and augmented injection of tight oil water-flooding and preparation method and application thereof
  • Nano liquid for decompression and augmented injection of tight oil water-flooding and preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0048] Embodiment 1: the preparation of hydrophobic nano silicon dioxide

[0049] Put 6g of nano-silica in a three-necked flask, stir and dry in an oil bath at 100-120°C for 1-3h, remove the moisture on the surface of nano-silica; cool down to 50°C, add 150g of absolute ethanol, and continue stirring 20min, to form a uniform dispersion of nano-silica; add 0.3g dimethyl dichlorosilane modifier and 0.15g water, adjust the oil bath temperature to 75-80°C, and react with nitrogen for 4h; centrifuge the reaction solution, And wash the precipitate 4-6 times with absolute ethanol to remove the residue; dry the washed precipitate in a vacuum drying oven at 100° C. for 24 hours, and grind to obtain hydrophobically modified nano silicon dioxide.

Embodiment 2

[0050] Example 2: The development of tight oil water injection nano-fluid for pressure reduction and injection increase, the composition of the raw materials is as follows:

[0051] The hydrophobic nano silicon dioxide 2g that embodiment 1 prepares,

[0052] Dispersant PEG600 4g,

[0053] Dispersion aid NaOH 1g,

[0054] Water 993g.

[0055] Preparation steps:

[0056] Take 4g of dispersant PEG600 and add it to 993g of water, stir mechanically at room temperature for 5min, after stirring evenly, add 2g of modified hydrophobic nano-silica, add 1.0g of dispersing aid NaOH at the same time, continue stirring for 5min, and continue to mix in a water bath at 60°C Stir the mixed solution for 20 minutes to obtain the depressurized and increased injection nano-liquid.

[0057] The particle size distribution of hydrophobic nano-silica in the gained step-down and increase-injection nano-liquid is as follows: figure 1 As shown, the particle size is between 14-21nm, and the median part...

Embodiment 3

[0058] Example 3: The development of tight oil water injection nano-fluid for depressurization and increasing injection, the composition of the raw materials is as follows:

[0059] The hydrophobic nano silicon dioxide 3.5g that embodiment 1 prepares,

[0060] Dispersant PEG600 6g,

[0061] Dispersion aid NaOH 1.5g,

[0062] Water 989g.

[0063] The preparation steps are the same as in Example 2, except that the mixed solution is continuously stirred for 20 minutes under the condition of a 65°C water bath to obtain the reduced-pressure and increased-injection nano-liquid.

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Abstract

The present invention relates to a nano liquid for decompression and augmented injection of tight oil water-flooding, and a preparation method and application thereof. The nano liquid for decompression and augmented injection is composed of 0.1-1% of hydrophobic nano-silica, 0.3-3% of a dispersant, 0.2-1% of a dispersing aid and the balance of water. The hydrophobic nano-silica has particle size between 12-22 nm, and median diameter between 16-18 nm; and the hydrophobic nano-silica is prepared from fumed nano silica and an organic silicon compound by a wet modification method. The dispersant is octylphenyl polyoxyethylene ether, polyethylene glycol 400, polyethylene glycol 600 or glycerin. The dispersing aid is NaOH, Na2SiO3 or n-butanol. The nano liquid for decompression and augmented injection employs water base dispersion and has the advantages of environment-friendliness, simple preparation and good stability. Under the action of stratum water salt ions, the hydrophobic nano-silica is adsorbed on the surface of the rock, so that wetting conversion generates on the rock surface to produce hydrophobic slip effect and reduce flow resistance and injection pressure.

Description

technical field [0001] The invention belongs to the technical field of oilfield chemicals, and relates to a nano-fluid for pressure-reducing and increasing-injection development of tight oil water injection, a preparation method and application thereof. Background technique [0002] Tight oil refers to oil that exists in source rocks in an adsorbed or free state, or interbeds with source rocks, or in tight sandstones, tight carbonate rocks, and other reservoir rocks that have not undergone large-scale long-distance migration. accumulation of oil". Known as "black gold" by the oil industry. However, due to the severe low porosity and low permeability characteristics (porosity φ<10%, matrix overburden permeability k<0.1×10 -3 μm 2 , pore throat diameter <0.5μm), it is difficult to develop. [0003] Due to the lack of energy in tight oil formations, water injection is mainly used for development after fracturing operations. Under the long-term immersion of formati...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/584
CPCC09K8/584C09K2208/10
Inventor 戴彩丽王世禄李玉阳由庆赵明伟高明伟刘逸飞方吉超赵光杨帅
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
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