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A treatment method for underinjection wells in tight oil reservoirs

A technology for tight oil reservoirs and well injection, applied in chemical instruments and methods, earthwork drilling and production, wellbore/well components, etc., can solve the problems of short effective period of measures, low efficiency of measures, and difficult treatment, so as to improve preservation level, solve the speed sensitivity, and ensure the effect of long-term stable production

Active Publication Date: 2018-06-01
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the existing methods of plugging removal and injection enhancement applied to under-injection wells in tight oil reservoirs, resulting in short effective period of measures, low efficiency of measures, and continuous occurrence of under-injection, which cannot fundamentally solve the under-injection in this area problems, difficult problems to govern

Method used

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Examples

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Effect test

Embodiment 1

[0017] The invention provides a treatment method for under-injection wells in tight oil reservoirs, including preventive means and treatment means, wherein the preventive means are to remove sulfate ions in the injection water by using nanofiltration desulfation technology and adding depressurization and increased injection to the injection water agent to prevent the clay from hydration swelling and particle migration, resulting in a decrease in reservoir permeability;

[0018] The treatment method is to add polyhydrochelated acid liquid system to the injected water, carry out measures to increase injection, and use the surface pressurization system to pressurize under-injection wells, and at the same time put in long-acting increase injection agent to improve the formation permeability.

[0019] The invention provides a new method for treating under-injection wells in tight oil reservoirs. According to the characteristics of reservoirs in this area and the mechanism of high-pr...

Embodiment 2

[0023] The depressurizing injection agent is composed of the following components in parts by weight, 20 parts of biological acid, 50 parts of expansion agent, and 10 parts of scale inhibitor, wherein, the biological acid is phytic acid, and the expansion agent is polyester Dimethyl diallyl ammonium chloride, nitrogen-containing organic polyphosphonic acid is selected as the antiscalant.

[0024] The hydrochelating acid liquid system is composed of the following components in parts by weight: 30 parts of hydrochloric acid, 5 parts of hydrofluoric acid, 15 parts of chelating agent, 4 parts of corrosion inhibitor, 2 parts of steering agent, and 10 parts of clay stabilizer , 10 parts of surfactant, the concentration of hydrochloric acid is 35%, the concentration of hydrofluoric acid is 40%, the chelating agent is aminotriacetic acid, the corrosion inhibitor is indole triacetate, and the diverting agent is sulfamic acid , what the clay stabilizer selects is polynuclear hydroxy bri...

Embodiment 3

[0030] The pressure-reducing and increasing injection agent is composed of the following components by weight, 30 parts of biological acid, 60 parts of expansion agent, and 13 parts of scale inhibitor. The biological acid is phytic acid, and the expansion agent is polyethylene dimethyl Diallyl ammonium chloride, and the scale inhibitor is nitrogen-containing organic polyphosphonic acid.

[0031] The hydrochelating acid liquid system is composed of the following components in parts by weight: 40 parts of hydrochloric acid, 16 parts of hydrofluoric acid, 18 parts of chelating agent, 6 parts of corrosion inhibitor, 4 parts of steering agent, and 13 parts of clay stabilizer , 12 parts of surfactant, the concentration of hydrochloric acid is 35%, the concentration of hydrofluoric acid is 40%, the chelating agent is aminotriacetic acid, the corrosion inhibitor is indole triacetate, and the diverting agent is sulfamic acid , what the clay stabilizer selects is polynuclear hydroxy bri...

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Abstract

The invention provides a dense oil reservoir under injection well treatment method. The method comprises a prevention means and a treatment means. According to the prevention means, sulfate ions in injection water are removed with the nanofiltration de-sulfation technique, a decompression and augmented injection agent is added into the injection water, and the situation that reservoir permeability is reduced due to hydration expansion and particle migration of clay is prevented. According to the treatment means, a multi-hydrogen chelation acid liquor system is added into the injection water, measure augmented injection is conducted, pressurization of an under injection well is conducted by means of a ground pressurization system, and a long-acting augmented injection agent is added at the same time to improve in-place permeability. According to the method, under injection well treatment is conducted in terms of prevention and treatment according to the characteristics of the oil reservoir of a certain oil field and the high-pressure under injection mechanism, and the method has important significance in increasing the formation pressure preservation level and guaranteeing long-term stable production of the oil reservoir and solves the problems of velocity sensitivity and water sensitivity of minerals in the reservoir.

Description

technical field [0001] The invention belongs to the technical field of injection water development in oilfields, and in particular relates to a treatment method for under-injection wells in tight oil reservoirs. Background technique [0002] The development characteristics of tight oil reservoirs are as follows: (1) The reservoir is mainly composed of feldspathic lithic sandstone, the pore type of sandstone is mainly micropore, and its permeability is 0.5-1.0×10 -3 um 2 The porosity is between 7% and 15%, which belongs to the low porosity and ultra-low permeability tight sandstone reservoir, and there is strong heterogeneity. (2) The content of rock interstitials is relatively high, and mica has a strong hydration effect, which is prone to hydration expansion and blocked pore throats; the content of kaolinite and illite is high, which is prone to velocity-sensitive and water-sensitive reactions. (3) The injected water of the reservoir is mainly from the Luohe layer, and th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B43/20C09K8/58
CPCC09K8/58C09K2208/12E21B43/20
Inventor 宋昭杰巨亚锋张随望陆小兵王勇隋蕾王尔珍邓志颖何汝贤王薇
Owner PETROCHINA CO LTD
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