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Seawater-based acid liquid system

A seawater and liquid technology, applied in drilling compositions, chemical instruments and methods, etc., can solve problems such as difficult prevention and control, insignificant acid-dissolving effect, avoid secondary damage, fast dissolving speed, and reduce acidification construction. cost effect

Active Publication Date: 2020-07-28
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Compared with fluoride precipitation, the acid-soluble effect of fluorosilicate precipitation is not obvious, so it is more difficult to prevent and control

Method used

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  • Seawater-based acid liquid system
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  • Seawater-based acid liquid system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0057] Example 1 Preparation of seawater-based acid solution system for sandstone reservoirs

[0058] Including four slugs of pre-acid, main acid, post-acid and displacement fluid, among which,

[0059] The component of pre-acid preparation is as follows (gross weight 100g): diethylenetriaminepentamethylenephosphonic acid 2g, industrial hydrochloric acid 48.39g (containing HCl 15g) of mass concentration 31%, Mannich base 1g, citric acid 1g, Polyoxyethylene polyoxypropylene stearyl ether 1g, diethylamine hydrochloride 1g, filtered seawater 45.61g.

[0060] The components of preparing the main acid are as follows (100g by total weight): 3.75g of hydrofluoric acid (containing 1.5g of HF) with a mass concentration of 40%, 2g of hydroxyethylidene diphosphonic acid, 2g of 2-hydroxyphosphonoacetic acid, and 31% of mass concentration 32.26g of industrial hydrochloric acid (containing 10g of HCl), 1g of Mannich base, 1g of citric acid, 1g of polyoxyethylene polyoxypropylene stearyl et...

Embodiment 2

[0071] Example 2 Preparation of seawater-based acid solution system in sandstone reservoirs

[0072] Including four slugs of pre-acid, main acid, post-acid and displacement fluid, among which,

[0073] The component of preparing pre-acid is as follows (gross weight 100g): polyepoxysuccinic acid 4g, 31% industrial hydrochloric acid 38.71g (containing HCl12g), propynyl alcohol 1.5g, EDTA 1.5g, polyoxyethylene polyoxypropylene polyoxyethylene Ether 1.5g, tetramethylammonium chloride 1.5g, filtered sea water 51.29g.

[0074] The components of preparing the main acid are as follows (100g of total weight): 2.5g of ammonium bifluoride, 3g of ethylenediaminetetramethylenephosphonic acid, 3g of hexamethylenediaminetetramethylenephosphonic acid, 38.71g of 31% industrial hydrochloric acid (containing HCl 12g) , propynyl alcohol 1.5g, EDTA 1.5g, polyoxyethylene polyoxypropylene polyether 1.5g, tetramethylammonium chloride 1.5g, filtered seawater 46.79g.

[0075] The components for prepa...

Embodiment 3

[0085] Example 3 Preparation of seawater-based acid liquid system suitable for sandstone reservoirs with high clay content

[0086] Including four slugs of pre-acid, main acid, post-acid and displacement fluid, among which,

[0087] The components of pre-acid preparation are as follows (gross weight 100g): 2g of diethylenetriaminepentamethylenephosphonic acid, 48.39g of 31% industrial hydrochloric acid (containing HCl 15g), Mannich base 1g, citric acid 1g, polyoxygen Ethylene polyoxypropylene stearyl ether 1g, diethylamine hydrochloride 1g, filtered seawater 45.61g.

[0088] The component of preparation main body acid is as follows (total weight 100g): 40% fluoroboric acid aqueous solution 20g (containing HBF 4 8g), hydroxyethylidene diphosphonic acid 2g, 2-hydroxyphosphonoacetic acid 6g, 31% industrial hydrochloric acid 32.26g (containing HCl 10g), Mannich base 1g, citric acid 1g, polyoxyethylene polyoxypropylene eighteen 1g of alcohol ether, 1g of diethylamine hydrochlori...

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Abstract

The invention discloses a seawater-based acid liquid system which is composed of four slugs: a front acid, a main acid, a rear acid and a displacement liquid. The front acid comprises the following components in percentage by weight: 10%-15% of HCl, 2%-10% of a calcium sulfate precipitation inhibitor, 1%-2% of a corrosion inhibitor, 1%-2% of an iron ion stabilizer, 1%-2% of a demulsifying agent, 1%-2% of a clay stabilizer and the balance of seawater. The main acid is composed of 1.5%-10% of fluoride, 5%-15% of supporting acid, 2%-4% of a fluoride precipitation inhibitor, 2%-8% of a fluosilicate precipitation inhibitor, 1%-2% of a corrosion inhibitor, 1%-2% of an iron ion stabilizer, 1%-2% of a demulsifier, 1%-2% of a clay stabilizer and the balance of seawater. The composition of the rearacid is the same as that of the front acid. The displacement liquid is selected from seawater. The seawater-based acid liquid system disclosed by the invention can be directly prepared by using filtered seawater, has the advantages of high dissolving speed, good compatibility, small secondary damage and the like, can greatly improve the offshore acidification construction efficiency and reduce theacidification construction cost, and provides a technical support for realizing offshore large-scale acidification construction.

Description

technical field [0001] The invention relates to a seawater-based acid liquid system, which can be used for acidizing operations in offshore oil fields. Background technique [0002] Acidizing technology is one of the most commonly used measures for increasing production and injection in offshore oilfields. During the acidizing operation, the clear water, acid solution and other additives used in the liquid preparation are all from land. Generally, the amount of liquid used to acidify a production well is about 30-100 m3, while for water injection wells, the amount of liquid required for acidification is about 100-150 m3. The transportation cost of transporting such a large amount of dosing water from land to offshore platforms hundreds of nautical miles away is enormous. In addition, the water flooding recovery rate of offshore oilfields is usually only 18% to 25%, which is much lower than that of onshore oilfields. Increasing the amount of acid solution, strengthening th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/74
CPCC09K8/74
Inventor 李侠清贾庆升张星孙玉海秦延才刘廷峰宋菲卢占国冯震冯雷雷
Owner CHINA PETROLEUM & CHEM CORP