CN106645558A - Test method for chelating ability of chelated acid to metal magnesian ions - Google Patents

Abstract

The invention provides a test method for chelating ability of a chelated acid to metal magnesian ions. The method comprises the steps of taking a raw acid solution of the chelated acid, in the presence of a buffer solution, titrating by a Mg<2+> standard solution to a final point, then calculating the chelating ability of the chelated acid to the metal magnesian ions according to a formula (1), and expressing by using amount of magnesian ions chelated by a sample: shown in the description, in the formula, omega (Mg) is magnesian ions chelating ability, mg/g; V is consumed magnesium standard solution volume (mL); W is sample weight (g); the test method provided by the invention is simple to operate, fast, good in repeatability, and easy to popular and use.

Description

A kind of chelated acid is to magnesium metal ion chelating capacity method of testing

Technical field

The present invention relates to petrochemical industry, is to be related to a kind of chelated acid to magnesium metal ion chelating capacity specifically Method of testing.

Background technology

Acidizing treatment is to ensure oil field development volume increase, an important measures of augmented injection.Sandstone acidizing dominant mechanism is hydrogen fluorine Calcium hydroxide precipitation is likely to form in acid and aluminosilicate, the reaction of fluoaluminate, but the course of reaction.Can therefore realize right Precipitating ion effectively chelating is the important indicator for investigating chelating acid energy.

At present the conventional sequestering power method of testing of laboratory experiment is mainly mixed with sodium carbonate and calcium chloride solution by acid solution Homogeneous reaction observation precipitation status are closed, the process needs to iterate through the pH value for adding sodium hydroxide solution to adjust mixed liquor, examination Operating difficulties is tested, test operation result is difficult accurately to be judged, causes easily not reaching test to the judgement of magnesium ion stabilizing power Determine purpose.

The content of the invention

It is an object of the invention to provide a kind of chelated acid is to magnesium metal ion chelating capacity method of testing, its operation side Just, quickly, accurate, easy to spread use is tested.

Be up to above-mentioned purpose, the invention provides a kind of chelated acid is to magnesium metal ion chelating capacity method of testing, wherein, Methods described includes：Chelating acid solution is taken, in the presence of buffer solution, Mg is used²⁺Standard liquid is titrated to terminal, then according to formula (1) chelated acid is calculated to magnesium ion sequestration ability, and the amount for chelating magnesium ion with sample is represented：

In formula：ω (Mg)-chelated magnesium ion energy, mg/g；

The magnesium standard solution volume (mL) of V-consumption；

W-example weight (g).

According to some specific embodiments of the invention, wherein, methods described includes：Chelating acid solution is taken, is deposited in buffer solution Under, Mg is used²⁺Standard liquid is titrated to muddy for terminal.

According to some specific embodiments of the invention, wherein, it is to use Mg²⁺Standard liquid is titrated to muddy maintenance more than 30s, As terminal.

According to some specific embodiments of the invention, wherein, the buffer solution is NH₃-NH₄Cl cushioning liquid.

According to some specific embodiments of the invention, wherein, the buffer solution consumption is to be adjusted to chelated acid pH value of solution 10-13。

According to some specific embodiments of the invention, wherein, the buffer solution consumption is to be adjusted to chelated acid pH value of solution 11。

Wherein it is understood that described here be adjusted to 10-13 by chelated acid pH value of solution, refer to and buffer solution is added into chela In closing acid solution, until the pH value of chelating acid solution (chelating acid solution and buffer solution mixed liquor) is 10-13.

According to some specific embodiments of the invention, wherein, NH₃-NH₄The cushioning liquid of Cl is in every 1000mL distilled water NH containing 6g₄Cl and 414-450 milliliter ammoniacal liquor.

According to some specific embodiments of the invention, wherein, the mass-volume concentration of described chelating acid solution is 1%- 3%.

According to some specific embodiments of the invention, wherein, the Mg²⁺Concentration of standard solution is 0.5-1.0mol/L.

According to some specific embodiments of the invention, wherein, the Mg²⁺Standard liquid is magnesium chloride hexahydrate or magnesium chloride The aqueous solution.

According to some specific embodiments of the invention, wherein, the Mg²⁺Standard liquid is that mass concentration is 8%-12%'s Magnesium chloride brine；Wherein it is more preferably the magnesium chloride brine that mass concentration is 10.15%.

According to some specific embodiments of the invention, wherein, counted with chelated acid total solution weight as 100%, the chelating Acid solution is made up of following weight percent composition：Ammonium fluoride 5.0-15.0%, hydrochloric acid 5.0-20.0%, corrosion inhibiter 2.0- 10.0%th, chelating agent 3.0-15.0% and balance of water.

According to some specific embodiments of the invention, wherein, the corrosion inhibiter is selected from triethanolamine, mercaptan amine, acetophenone By 1:(1-2):(1-3) it is configured to the aqueous solution that concentration is 15.0%-25.0%.

According to some specific embodiments of the invention, wherein, the corrosion inhibiter is selected from triethanolamine, mercaptan amine, acetophenone By 1:1:1 is configured to the aqueous solution that concentration is 25.0%.

According to some specific embodiments of the invention, wherein, the chelating agent is pressed selected from citric acid, complexon I (2-4):1 aqueous solution for being configured to 20.0%-25.0%.

According to some specific embodiments of the invention, wherein, the chelating agent presses 2 selected from citric acid, complexon I: 1 is configured to 25.0% aqueous solution.

According to some specific embodiments of the invention, wherein, methods described includes：

Step 1：2g chelating acid solutions are weighed, distilled water diluting is added to 50mL；

Step 2：Measure the NH of 5mL₃-NH₄The cushioning liquid of Cl, in adding the chelating acid solution of dilution；

Step 3：Use 0.5mol/L Mg²⁺Standard liquid is titrated to muddy (continuing more than 30 seconds), as terminal；

Step 4：Chelated acid is calculated magnesium ion sequestration ability by formula (1)：

In formula：ω (Mg)-chelated magnesium ion energy, mg/g；

The magnesium standard solution volume (mL) of V-consumption；

W-example weight (g).

In sum, the invention provides a kind of chelated acid is to magnesium metal ion chelating capacity method of testing.The present invention's Method has the advantage that：

(1) invent that the assay method is simple to operate, quick, reproducible, easy to spread use；

(2) invent the assay method and not there are problems that adding sodium hydroxide solution to adjust pH value repeatedly obtains；

(3) inventing the assay method can quickly and accurately realize stablizing acid solution the evaluation of magnesium ion ability；

(4) the chelating agent energy highly effective chelating Ca is invented²⁺、Fe³⁺、Mg²⁺Deng metal ion, it is to avoid form fluoaluminate, fluorine The secondary precipitations such as silicate；

(5) the invention chelating agent acid fluid system scene can directly dilute and use.

Specific embodiment

The implementation process for describing the present invention in detail below by way of specific embodiment and the beneficial effect for producing, it is intended to which help is read Reader more fully understand the present invention essence and feature, not as to this case can practical range restriction.

Embodiment 1

Preparation of reagents：

0.5mol/L standard liquids：Accurately weigh crystallization magnesium chloride (MgCl₂·6H₂O) 101.5g, with distilled water diluting extremely 1000mL, shakes up standby.

NH₃-NH₄The cushioning liquid of Cl (pH=11)：With the pure NH of distillation water dissolves 6g₄Cl and 414 milliliter of ammoniacal liquor, the buffering Solution ph is 11, with volumetric flask constant volume to 1000mL, is shaken up standby.

It is pure that above reagent is analysis.

Measure of the chelated acid to magnesium metal ion chelating capacity：

Weigh 2g chelating acid solution (ammonium fluoride 10.0%, hydrochloric acid 12.0%, corrosion inhibiter 6.0%, chelating agent 10.0% and Balance of water), it is diluted with water to 50mL, plus 5mL NH₃-NH₄The cushioning liquid of Cl (pH=11).Use 0.5mol/L Mg²⁺Standard Solution is titrated to muddy (continuing more than 30 seconds), as terminal, records volume V (mL) of consumed magnesium standard solution.

Chelated acid is calculated magnesium ion sequestration ability by formula (1)：

In formula：ω (Mg)-chelated magnesium ion energy, mg/g；

The magnesium standard solution volume (mL) of V-consumption；

W-example weight (g).

3 parallel laboratory tests are carried out to chelating acid solution according to this assay method, 1 is as a result seen.As shown in Table 1, the method is surveyed The chelated acid for obtaining is up to 159mg/g, average out to 158mg/g to magnesium ion sequestration ability.

The magnesium ion sequestration ability of table 1

Claims (10)

1. a kind of chelated acid is to magnesium metal ion chelating capacity method of testing, wherein, methods described includes：Chelating acid solution is taken, In the presence of buffer solution, Mg is used²⁺Standard liquid is titrated to terminal, then according to formula (1) calculates chelated acid to magnesium ion sequestration energy Power, and represented with the amount of sample chelating magnesium ion：

$\mathrm{\&omega;}\left(Mg\right)=\frac{12V}{W}---\left(1\right)$

In formula：ω (Mg)-chelated magnesium ion energy, mg/g；

The magnesium standard solution volume (mL) of V-consumption；

W-example weight (g).

2. method according to claim 1, wherein, methods described includes：Chelating acid solution is taken, in the presence of buffer solution, Use Mg²⁺Standard liquid is titrated to muddy for terminal；(preferred muddy maintenance more than 30s, as terminal).

3. method according to claim 1, wherein, the buffer solution is NH₃-NH₄Cl cushioning liquid；(the preferred buffering Liquid consumption is that chelated acid pH value of solution is adjusted to into 10-13, preferably 11).

4. method according to claim 3, wherein, NH₃-NH₄The cushioning liquid of Cl is to contain 6g in every 1000mL distilled water NH₄Cl and 414-450 milliliter ammoniacal liquor.

5. method according to claim 1, wherein, the mass-volume concentration of described chelating acid solution is 1%-3%.

6. method according to claim 1, wherein, the Mg²⁺Concentration of standard solution is 0.5-1.0mol/L；It is preferred that described Mg²⁺Standard liquid is the aqueous solution of magnesium chloride hexahydrate or magnesium chloride；(preferably mass concentration is water-soluble for the magnesium chloride of 8%-12% Liquid；More preferably mass concentration is 10.15% magnesium chloride brine).

7. method according to claim 1, wherein, counted with chelated acid total solution weight as 100%, the chelating acid solution It is made up of following weight percent composition：Comprising ammonium fluoride 5.0-15.0%, hydrochloric acid 5.0-20.0%, corrosion inhibiter 2.0- 10.0%th, chelating agent 3.0-15.0% and balance of water.

8. method according to claim 7, wherein, the corrosion inhibiter presses 1 selected from triethanolamine, mercaptan amine, acetophenone: (1-2):(1-3) it is configured to the aqueous solution that concentration is 15.0%-25.0%.

9. method according to claim 7, wherein, the chelating agent presses (2-4) selected from citric acid, complexon I:1 It is configured to the aqueous solution of 20.0%-25.0%.

10. method according to claim 1, wherein, methods described includes：

Step 1：2g chelating acid solutions are weighed, distilled water diluting is added to 50mL；

Step 2：Measure the NH of 5mL₃-NH₄The cushioning liquid of Cl, in adding the chelating acid solution of dilution；

Step 3：Use 0.5mol/L Mg²⁺Standard liquid is titrated to muddy (continuing more than 30 seconds), as terminal；

Step 4：Chelated acid is calculated magnesium ion sequestration ability by formula (1)：

$\mathrm{\&omega;}\left(Mg\right)=\frac{12V}{W}---\left(1\right)$

In formula：ω (Mg)-chelated magnesium ion energy, mg/g；

The magnesium standard solution volume (mL) of V-consumption；

W-example weight (g).