An iron ion stabilizer for oil field fracturing and its preparation method and application

Abstract

The present invention belongs to the field of oil production technology, and in particular to a kind of iron ion stabilizer for oilfield fracturing and its preparation method and application. The preparation method is as follows: add cyanuric chloride and water in a reactor, add iminodi(methylphosphonic acid), stir evenly, and adjust to pH6-7; continue to add 2-aminonicotinic acid, stir evenly, heat to 30-40°C, and adjust to pH7-8; continue to add amine cinnamic acid, stir evenly, heat to 60-70°C, adjust to pH8-9, and continue to stir for 2-4h; after the reaction is completed, cool to below 10°C, precipitate solid, filter and dry, and obtain the product iron ion stabilizer. The iron ion stabilizer of the present invention has the advantages of good effect and high temperature resistance.

Description

Technical Field

[0001] The invention belongs to the technical field of oil extraction, and in particular relates to an iron ion stabilizer for oil field fracturing and a preparation method and application thereof. Background Art

[0002] As oilfield exploitation enters the middle and late stages, the difficulty of exploitation is increasing. At present, the direction of oil and gas exploitation is developing towards deep wells, ultra-deep wells and unconventional oil and gas reservoirs. These oil and gas reservoirs are usually characterized by deep burial, low permeability and high temperature, and require fracturing. Before the fracturing process, the oil reservoir usually needs to be acidified to reduce the difficulty of fracturing.

[0003] Acidizing is one of the main measures to stabilize and increase production of oil and gas wells, and stabilize and increase injection of water injection wells. It uses acid to remove pollution near the bottom of production wells and water injection wells, restore the permeability of the formation or dissolve the formation rock cement to increase the permeability of the formation, and dredge the fluid seepage channel, thereby restoring and improving the well's productivity.

[0004] In the acidizing operation of oil and water wells, the acid must react with the surface equipment, the metal pipe column downhole and the iron-containing minerals in the formation. Although corrosion inhibitors are used, some iron will be dissolved. These dissolved irons generally exist in a divalent or trivalent state. As the acid continues to interact with the formation, the acid concentration will gradually decrease. When the pH value of the acid rises to 2.2, the trivalent iron ions will begin to produce flocculent Fe(OH)3 precipitation; when the pH value of the acid rises to 3.2, all the dissolved trivalent iron will precipitate.

[0005] In order to prevent iron precipitation when the acid becomes residual acid, iron ion stabilizers are often added to the acid in acidizing technology to prevent the formation of gel-like iron hydroxide precipitation when the acid becomes residual acid, thereby preventing damage to the oil and gas layers and improving the acidizing treatment effect.

[0006] CN105295887A discloses an excellent iron ion stabilizer for acidification operation and a preparation method thereof. +The concentration continues to decrease, and the pH value continues to increase, so that the iron originally existing in an ionic state begins to precipitate, blocking the oil and gas seepage channels in the formation, causing secondary pollution, and leading to a decrease in the recovery rate. Therefore, an iron ion stabilizer needs to be added to make the iron always exist in the residual acid in a soluble state. The technical scheme of the invention is: sodium isoascorbate, NTA, citric acid, EDTA disodium salt and water are added to the container in proportion, and the mass fraction of each component is: sodium isoascorbate 5% to 16%, NTA 1% to 3%, citric acid 2% to 5%, EDTA disodium salt 2% to 5%, and the remainder is water; control a certain temperature and stir to completely dissolve it, cool it to room temperature, transfer it to a volumetric flask and make up the volume to obtain the iron ion stabilizer. The iron ion stabilizer has a low production cost. However, the iron ion stabilization capacity of the invention is only about 40mg / ml, and the iron ion stabilization capacity is low.

[0007] CN1067912A discloses an iron ion stabilizer for formation acidification, which is directly mixed with a reducing agent, sugar and its fermentation product at room temperature. It stabilizes Fe(III) ions in acid solution through the dual effects of reduction and chelation to protect the formation from damage by acidification operation. It is characterized in that the reducing agent is sodium isoascorbate, the sugar is glucose, and the fermentation product is calcium 2-ketogluconate, and when the weight ratio of sodium isoascorbate: glucose: calcium 2-ketogluconate is 100: 5-120: 5-120, it has the effect of obviously stabilizing iron ions in acid. However, the active ingredients in the invention are glucose and its derivatives, which will undergo obvious chemical changes when the temperature exceeds 120 degrees, so the high temperature resistance is insufficient. Summary of the invention

[0008] In view of the deficiencies in the above-mentioned prior art, the present invention provides an iron ion stabilizer for oilfield fracturing and a preparation method and application thereof. The iron ion stabilizer of the present invention has the advantages of good effect and high temperature resistance.

[0009] One of the purposes of the present invention is to disclose a method for preparing an iron ion stabilizer for oil field fracturing, and the specific steps of the preparation method are as follows:

[0010] (1) Add cyanuric chloride and water into a reactor, stir and slurry, cool it to below 5°C with ice water, add iminobis(methylphosphonic acid), stir evenly, add sodium hydroxide solution dropwise, and adjust the pH to 6-7 and no longer drop;

[0011] (2) Continue to add 2-aminonicotinic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 30-40°C, and adjust the pH to 7-8 and no longer drop;

[0012] (3) Continue to add cinnamic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 60-70°C, adjust the pH to 8-9 and do not drop any more, and continue stirring for 2-4 hours;

[0013] (4) After the reaction is completed, adjust the pH to 2-3 with hydrochloric acid, cool to below 10°C, precipitate the solid, filter and dry to obtain the product iron ion stabilizer.

[0014] In the present invention, preferably, based on 1 mole of cyanuric chloride, the amounts of iminobis(methylphosphonic acid), 2-aminonicotinic acid and cinnamic acid are 0.8-1.2 mole, 0.4-0.6 mole and 0.8-1.2 mole, respectively.

[0015] In the present invention, preferably, in step (1), the mass ratio of the water to the mass ratio of cyanuric chloride is 20-30:1.

[0016] The synthesis reaction equation of the iron ion stabilizer of the present invention is as follows:

[0017]

[0018]

[0019]

[0020] Another object of the present invention is to disclose an iron ion stabilizer for oil field fracturing, wherein the molecular structure of the iron ion stabilizer is as follows:

[0021] .

[0022] The third object of the present invention is to disclose the application of the above-mentioned iron ion stabilizer in oil field fracturing.

[0023] The iron ion stabilizer of the present invention has the following principles for stabilizing iron ions. First, the carboxylic acid functional group and the phosphoric acid functional group contained in the present invention have a chelating effect on iron ions, can chelate iron ions, and can greatly reduce free iron ions. The secondary amine cinnamic acid has a certain reducing effect, which can reduce the oxidation of divalent iron ions into trivalent iron ions. Thirdly, the present invention contains multiple secondary amines and tertiary amines, which can form coordination bonds with iron ions to further reduce free iron ions.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] (1) The iron ion stabilizer of the present invention has a strong ability to stabilize iron ions, reaching 175 mg / g or more at room temperature;

[0026] (2) The iron ion stabilizer of the present invention has strong temperature resistance. After being kept at 220°C for 4 hours, the iron ion stabilization capacity is still maintained above 170 mg / g. DETAILED DESCRIPTION

[0027] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0028] The present invention will be further described below with reference to specific embodiments.

[0029] In the present invention, the devices or equipment used are all conventional devices or equipment known in the art and are commercially available.

[0030] In the following examples and comparative examples, unless otherwise specified, all reagents used were commercially available chemically pure reagents.

[0031] Example 1

[0032] (1) Add 0.05 mol of cyanuric chloride and 185 g of water into a reactor, stir and slurry, cool to below 5°C with ice water, add 0.04 mol of iminobis(methylphosphonic acid), stir evenly, add sodium hydroxide solution dropwise, and adjust the pH to 6-7 and no longer drop;

[0033] (2) Continue to add 0.02 mol of 2-aminonicotinic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 30°C, and adjust the pH to 7-8 and no longer drop;

[0034] (3) Continue to add 0.04 mol of cinnamic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 60°C, adjust the pH to 8-9 and do not drop, and continue stirring for 2 hours;

[0035] (4) After the reaction is completed, adjust the pH to 2-3 with hydrochloric acid, cool to below 10°C, precipitate the solid, filter and dry to obtain the product iron ion stabilizer.

[0036] Example 2

[0037] (1) Add 0.05 mol of cyanuric chloride and 276 g of water into a reactor, stir and slurry, cool to below 5°C with ice water, add 0.045 mol of iminobis(methylphosphonic acid), stir evenly, add sodium hydroxide solution dropwise, and adjust the pH to 6-7 and no longer drop;

[0038] (2) Continue to add 0.022 mol of 2-aminonicotinic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 40°C, and adjust the pH to 7-8 and no longer drop;

[0039] (3) Continue to add 0.055 mol of cinnamic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 62 °C, adjust the pH to 8-9 and do not drop, and continue stirring for 4 hours;

[0040] (4) After the reaction is completed, adjust the pH to 2-3 with hydrochloric acid, cool to below 10°C, precipitate the solid, filter and dry to obtain the product iron ion stabilizer.

[0041] Example 3

[0042] (1) Add 0.05 mol of cyanuric chloride and 214 g of water into a reactor, stir and slurry, cool to below 5°C with ice water, add 0.04 mol of iminobis(methylphosphonic acid), stir evenly, add sodium hydroxide solution dropwise, and adjust the pH to 6-7 and no longer drop;

[0043] (2) Continue to add 0.025 mol of 2-aminonicotinic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 35°C, and adjust the pH to 7-8 and no longer drop;

[0044] (3) Continue to add 0.045 mol of cinnamic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 65°C, adjust the pH to 8-9 and do not drop, and continue stirring for 3 hours;

[0045] (4) After the reaction is completed, adjust the pH to 2-3 with hydrochloric acid, cool to below 10°C, precipitate the solid, filter and dry to obtain the product iron ion stabilizer.

[0046] Example 4

[0047] (1) Add 0.05 mol of cyanuric chloride and 266 g of water into a reactor, stir and slurry, cool to below 5°C with ice water, add 0.06 mol of iminobis(methylphosphonic acid), stir evenly, add sodium hydroxide solution dropwise, and adjust the pH to 6-7 and no longer drop;

[0048] (2) Continue to add 0.026 mol of 2-aminonicotinic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 32°C, and adjust the pH to 7-8 and no longer drop;

[0049] (3) Continue to add 0.05 mol of cinnamic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 70°C, adjust the pH to 8-9 and do not drop any more, and continue stirring for 3 hours;

[0050] (4) After the reaction is completed, adjust the pH to 2-3 with hydrochloric acid, cool to below 10°C, precipitate the solid, filter and dry to obtain the product iron ion stabilizer.

[0051] Example 5

[0052] (1) Add 0.05 mol of cyanuric chloride and 258 g of water into a reactor, stir and slurry, cool to below 5°C with ice water, add 0.055 mol of iminobis(methylphosphonic acid), stir evenly, add sodium hydroxide solution dropwise, and adjust the pH to 6-7 and no longer drop;

[0053] (2) Continue to add 0.028 mol of 2-aminonicotinic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 36°C, and adjust the pH to 7-8 and no longer drop;

[0054] (3) Continue to add 0.06 mol of cinnamic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 63 ° C, adjust the pH to 8-9 and do not drop, and continue stirring for 2 hours;

[0055] (4) After the reaction is completed, adjust the pH to 2-3 with hydrochloric acid, cool to below 10°C, precipitate the solid, filter and dry to obtain the product iron ion stabilizer.

[0056] Example 6

[0057] (1) Add 0.05 mol of cyanuric chloride and 264 g of water into a reactor, stir and slurry, cool to below 5°C with ice water, add 0.05 mol of iminobis(methylphosphonic acid), stir evenly, add sodium hydroxide solution dropwise, and adjust the pH to 6-7 and no longer drop;

[0058] (2) Continue to add 0.03 mol of 2-aminonicotinic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 38°C, and adjust the pH to 7-8 and no longer drop;

[0059] (3) Continue to add 0.055 mol of cinnamic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 68 ° C, adjust the pH to 8-9 and do not drop, and continue stirring for 4 hours;

[0060] (4) After the reaction is completed, adjust the pH to 2-3 with hydrochloric acid, cool to below 10°C, precipitate the solid, filter and dry to obtain the product iron ion stabilizer.

[0061] Example 7

[0062] (1) Add 0.05 mol of cyanuric chloride and 185 g of water into a reactor, stir and slurry, cool to below 5°C with ice water, add 0.052 mol of iminobis(methylphosphonic acid), stir evenly, add sodium hydroxide solution dropwise, and adjust the pH to 6-7 and no longer drop;

[0063] (2) Continue to add 0.03 mol of 2-aminonicotinic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 33°C, and adjust the pH to 7-8 and no longer drop;

[0064] (3) Continue to add 0.052 mol of cinnamic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 70°C, adjust the pH to 8-9 and do not drop, and continue stirring for 3 hours;

[0065] (4) After the reaction is completed, adjust the pH to 2-3 with hydrochloric acid, cool to below 10°C, precipitate the solid, filter and dry to obtain the product iron ion stabilizer.

[0066] Example 8

[0067] The iron ion stabilizing capabilities N1, N2, and N3 of the iron ion stabilizers (Examples 1-7) of the present invention were tested at room temperature, 160°C, and 220°C. The test method was based on SY / T 6571-2012 "Performance Evaluation Method of Iron Ion Stabilizer for Acidification". The iron ion stabilizer of Shandong Aokai Chemical Co., Ltd. was used for comparative experiments. The test results are shown in Table 1.

[0068] Table 1 Test results of the ability to stabilize iron ions at room temperature, 160°C, and 220°C

[0069]

[0070] From Table 1 we can see that:

[0071] (1) The iron ion stabilizer of the present invention (Examples 1-7) has an iron ion stabilizing capacity of more than 175 mg / g at room temperature, and the highest is 182 mg / g (Example 6); while the iron ion stabilizer of Shandong Aokai Chemical Co., Ltd. in the comparative example has an iron ion stabilizing capacity of 75 mg / g, which is significantly lower than that of the present invention;

[0072] (2) The iron ion stabilizer of the present invention (Examples 1-7) has an iron ion stabilizing capacity of 175 mg / g or more at 160°C, with the highest reaching 180 mg / g; while the iron ion stabilizer of Shandong Aokai Chemical Co., Ltd. in the comparative example has an iron ion stabilizing capacity of 72 mg / g, which is significantly lower than that of the present invention;

[0073] (3) The iron ion stabilizer of the present invention (Examples 1-7) has an iron ion stabilizing capacity of more than 170 mg / g at 220°C, with the highest reaching 178 mg / g; while the iron ion stabilizer of Shandong Aokai Chemical Co., Ltd. in the comparative example has an iron ion stabilizing capacity of 61 mg / g, which is significantly lower than that of the present invention.

[0074] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing an iron ion stabilizer for oil field fracturing, characterized in that: The specific steps of the preparation method are as follows: (1) Add cyanuric chloride and water into a reactor, stir and slurry, cool it to below 5°C with ice water, add iminobis(methylphosphonic acid), stir evenly, add sodium hydroxide solution dropwise, and adjust the pH to 6-7 and no longer drop; (2) Continue to add 2-aminonicotinic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 30-40°C, and adjust the pH to 7-8 and no longer drop; (3) Continue to add cinnamic acid, stir evenly, add sodium hydroxide solution dropwise, heat to 60-70°C, adjust the pH to 8-9 and do not drop any more, and continue stirring for 2-4 hours; (4) After the reaction is completed, adjust the pH to 2-3 with hydrochloric acid, cool to below 10°C, precipitate the solid, filter and dry to obtain the product iron ion stabilizer; Based on 1 mole of cyanuric chloride, the amounts of iminobis(methylphosphonic acid), 2-aminonicotinic acid, and cinnamic acid are 0.8-1.2 mole, 0.4-0.6 mole, and 0.8-1.2 mole, respectively; The molecular structure of the iron ion stabilizer is as follows: 。 2. The preparation method according to claim 1, characterized in that: In step (1), the mass ratio of the water to the cyanuric chloride is 20-30:

1.

3. The iron ion stabilizer prepared by the preparation method according to any one of claims 1-2, wherein the molecular structure of the iron ion stabilizer is as follows: 。 4. Use of the iron ion stabilizer according to claim 3 in oil field fracturing.

Images