Ultra-low resistance acid-type microemulsion plugging removal and stimulation technology for low permeability oil well

Abstract

The invention relates to a plugging removal and stimulation method for a low permeability oil well. The ultra-low resistance acid-type microemulsion is prepared by the following components: 10%-25% of acid, 5%-20% of oil, 5%-25% of alcohol, 0.5%-5% of surfactant, 0.5%-3% of inorganic salt, 0.3-1.5% of corrosion inhibitor and the balance water. The method comprises the following steps: injecting the prepared microemulsion in the oil bearing reservoir of the oil well, closing the oil well to react for 4-10h, cleaning the oil well, flowing the reaction exhaust liquor back, and completing the oilwell to perform normal production. The ultra-low resistance acid-type microemulsion used by the invention has thermodynamic stability, is a high dispersive acid-type microemulsion with good solubilization capacity, has ultra-low surface and interfacial tensions and good solubilization capacity and can increase the dispersive capacity of crude in water and the emulsification and peeling function to oil film; the microemulsion also has good dissolubility in water or oil and good fluidity due to high carrying capability and low seepage resistances so that the oil yield of the oil well is increased and the water content is reduced; the liquid surface tension in oil reservoir is reduced and the flow resistance of the crude is lowered so that the mining rate of the crude is increased and the plugging removal and stimulation of the oil well can be realized.

Description

technical field

[0001] The invention relates to a crude oil extraction technology, in particular to a method for removing plugs and increasing production of oil wells in low-permeability oil fields. Background technique

[0002] Microemulsion technology, essentially a liquid nanomaterial preparation technology, is an emerging material science and technology. This dispersion system has a high interface area, strong solubilization properties, stable thermodynamic properties and strong solubility for insoluble substances, and has excellent dispersion, penetration, dissolution, adsorption, and transmission functions. Because of its heat and mass transfer function, it is widely used in cutting-edge fields such as biopharmaceuticals, coatings, cleaning, fuel, oil displacement in tertiary oil recovery, and nanomaterial research.

[0003] Acidizing plugging removal technology is one of the main production stimulation technologies in oilfield exploitation. It is recorded in relevant...

Examples

Embodiment 1

[0020] Example 1. The W9-14 oil well in an ultra-low permeability oilfield in Changqing, the average formation permeability of the well is 4.659×10 -3 μm 2 , using ultra-low-resistance acid microemulsion to remove plugging and increase production:

[0021] First of all, the components of the liquid preparation are transported to the oil well operation site in the oil field, added to the liquid storage tank in turn, fully stirred and mixed evenly, and 15 cubic meters of plugging solution liquid is prepared, and it is left to stand for 15 minutes for reaction. Preparation of the plug-removing agent liquid used in the present invention is to use the mixed acid solution of sulfamic acid, hydrochloric acid, acetic acid, citric acid: 10% (mixed concentration), fuel oil: 20%, isopropanol: 5%, sulfonates ZF-SA16 and polyoxyethylene ether OP-10 surfactant: 5.0%, corrosion inhibitor: 0.5%, ammonium chloride: 1.5%, and water to prepare high dispersion, ultra-low surface and ultra-low in...

Embodiment 2

[0023] Example 2. D75-20 oil well in a low-permeability oilfield in Changqing, the average formation permeability of the well is 18.393×10 -3 μm 2 , using ultra-low-resistance acid microemulsion to remove plugging and increase production:

[0024] Firstly, according to the design of the oil well stimulation operation project, the components of the liquid preparation are transported to the site of the plugging removal and production increase operation of the oil well in the oil field, and then added to the liquid storage tank in turn, fully stirred and mixed evenly, and 25 cubic meters of the plugging removal agent liquid is prepared, and the reaction is left for 60 minutes. use. Prepare the plug-removing agent liquid used in the present invention, specifically the mixed acid solution of hydrochloric acid, hydrofluoric acid, formic acid and citric acid: 25% (mixed concentration), n-heptane and crude oil mixed solution: 5%, ethanol: 25%, α olefin and fluorocarbon surfactant: 0...

Embodiment 3

[0025] Example 3. The Y64-33 oil well in a certain ultra-low permeability oilfield, the average formation permeability of the well is 6.94×10 -3 μm 2 , using ultra-low-resistance acid microemulsion to remove plugging and increase production:

[0026] First, according to the engineering design of the oil well stimulation operation, the components of the liquid preparation are transported to the site of the plugging removal and production increase operation site of the oil well in the oil field, and then added to the liquid storage tank in turn, fully stirred and mixed evenly, and 20 cubic meters of the plugging removal agent liquid is prepared, and the reaction is allowed to stand for 120 minutes. use. Prepare the plug-removing agent liquid used in the present invention, specifically the mixed acid solution of hydrochloric acid, hydrofluoric acid, acetic acid, citric acid: 18% (mixed concentration), n-dodecane: 5%, wood alcohol: 15%, alkanol Amide and phosphoric acid ester su...

technical field

[0001] The invention relates to a crude oil extraction technology, in particular to a method for removing plugs and increasing production of oil wells in low-permeability oil fields. Background technique

[0002] Microemulsion technology, essentially a liquid nanomaterial preparation technology, is an emerging material science and technology. This dispersion system has a high interface area, strong solubilization properties, stable thermodynamic properties and strong solubility for insoluble substances, and has excellent dispersion, penetration, dissolution, adsorption, and transmission functions. Because of its heat and mass transfer function, it is widely used in cutting-edge fields such as biopharmaceuticals, coatings, cleaning, fuel, oil displacement in tertiary oil recovery, and nanomaterial research.

[0003] Acidizing plugging removal technology is one of the main production stimulation technologies in oilfield exploitation. It is recorded in relevant...

Examples

Embodiment 1

[0020] Example 1. The W9-14 oil well in an ultra-low permeability oilfield in Changqing, the average formation permeability of the well is 4.659×10 -3 μm 2 , using ultra-low-resistance acid microemulsion to remove plugging and increase production:

[0021] First of all, the components of the liquid preparation are transported to the oil well operation site in the oil field, added to the liquid storage tank in turn, fully stirred and mixed evenly, and 15 cubic meters of plugging solution liquid is prepared, and it is left to stand for 15 minutes for reaction. Preparation of the plug-removing agent liquid used in the present invention is to use the mixed acid solution of sulfamic acid, hydrochloric acid, acetic acid, citric acid: 10% (mixed concentration), fuel oil: 20%, isopropanol: 5%, sulfonates ZF-SA16 and polyoxyethylene ether OP-10 surfactant: 5.0%, corrosion inhibitor: 0.5%, ammonium chloride: 1.5%, and water to prepare high dispersion, ultra-low surface and ultra-low in...

Embodiment 2

[0023] Example 2. D75-20 oil well in a low-permeability oilfield in Changqing, the average formation permeability of the well is 18.393×10 -3 μm 2 , using ultra-low-resistance acid microemulsion to remove plugging and increase production:

[0024] Firstly, according to the design of the oil well stimulation operation project, the components of the liquid preparation are transported to the site of the plugging removal and production increase operation of the oil well in the oil field, and then added to the liquid storage tank in turn, fully stirred and mixed evenly, and 25 cubic meters of the plugging removal agent liquid is prepared, and the reaction is left for 60 minutes. use. Prepare the plug-removing agent liquid used in the present invention, specifically the mixed acid solution of hydrochloric acid, hydrofluoric acid, formic acid and citric acid: 25% (mixed concentration), n-heptane and crude oil mixed solution: 5%, ethanol: 25%, α olefin and fluorocarbon surfactant: 0...

Embodiment 3

[0025] Example 3. The Y64-33 oil well in a certain ultra-low permeability oilfield, the average formation permeability of the well is 6.94×10 -3 μm 2 , using ultra-low-resistance acid microemulsion to remove plugging and increase production:

[0026] First, according to the engineering design of the oil well stimulation operation, the components of the liquid preparation are transported to the site of the plugging removal and production increase operation site of the oil well in the oil field, and then added to the liquid storage tank in turn, fully stirred and mixed evenly, and 20 cubic meters of the plugging removal agent liquid is prepared, and the reaction is allowed to stand for 120 minutes. use. Prepare the plug-removing agent liquid used in the present invention, specifically the mixed acid solution of hydrochloric acid, hydrofluoric acid, acetic acid, citric acid: 18% (mixed concentration), n-dodecane: 5%, wood alcohol: 15%, alkanol Amide and phosphoric acid ester su...