CN1333038C - High performance sludge inhibitor - Google Patents

Abstract

The invention provides an acidified anti-sludge agent with high adaptability, which is formed by mixing polyoxyethylene alkyl alcohol ether sodium propylene sulfonate, isoascorbic acid, thiourea and water, and the mass percentages of each component are respectively Polyoxyethylene alkyl alcohol ether sodium propylene sulfonate: 10% to 20%, isoascorbic acid: 10% to 20%, thiourea: 10% to 30%, water: 40% to 60%, each component The sum of the mass percentages is 100%. The general structural formula of polyoxyethylene alkyl alcohol ether sodium propylene sulfonate is RO(CH ₂ CH ₂ O) _n CH ₂ CH ₂ CH ₂ SO ₃ Na, where R is an alkyl group, and n is the number of chain members of oxyethylene , n=1～10. The anti-sludge agent provided by the invention can be adapted to prevent the formation of acid-induced sludge and iron-induced sludge, and has wide adaptability.

Description

an anti-sludge agent

Technical field:

The invention relates to an additive used in the acidizing process of oil fields.

Background technique:

During the acidizing process of oil wells, after some crude oil is in contact with acid liquid, (soft) solids with colloids and asphaltene as the main components will be produced in the system, some are like viscous asphalt, and some are brittle carbon-like substances. called acidified sludge.

The deposition of acidizing sludge in the formation can block pore throats, earthworm holes and natural fractures, impairing or even counteracting the effect of acidification. Small acidified sludge particles can also gather on the interface between acid liquid and crude oil, increase the rigidity of the interface film, stabilize the acid-in-oil emulsion, and make it difficult to flow back the poor acid.

Acidification sludge is mainly divided into acid-induced sludge and iron-induced sludge. Iron-induced sludge is mainly caused by Fe ³⁺ contained in the acid solution; acid-induced sludge can be formed without iron ions in the acid solution, and the sludge can be formed when the acid solution contains iron ions generation is intensified. To prevent the formation of iron-induced acidification sludge, iron ion control agents can be used, such as chelating agents acetic acid, citric acid, EDTA, NTA and reducing agents thiourea, hydroxylamine hydrochloride, gluconic acid and ^erythorbic acid, etc. Combine or reduce Fe ³⁺ to Fe ²⁺ to prevent sludge. To prevent acid-induced sludge, in addition to the use of iron ion control agents, it is also necessary to add surfactants, which stabilize the colloidal system of crude oil by adsorbing on the surface of colloidal asphaltenes. Commonly used surfactants for anti-acidification sludge include fatty acids, alkylbenzenesulfonic acids, etc., among which alkylbenzenesulfonic acids have the best effect. However, alkylbenzenesulfonic acid is an oil-soluble surfactant, which is unevenly distributed in the acid solution. In order to improve the acid solubility of alkylbenzenesulfonic acid, US5084192 proposes to replace dodecylbenzenesulfonic acid with polyoxyethylene dodecylbenzenesulfonate, but the anti-sludge effect is reduced. The structural formula of polyoxyethylene dodecylbenzenesulfonate is as follows:

(polyoxyethylene dodecylbenzenesulfonate, n: 1~10)

Invention content:

The object of the present invention is to provide a class of anti-sludge agent which has good preventive effect on iron-induced sludge and acid-induced sludge. The main component of the anti-sludge agent is composed of a kind of non-ionic-anionic amphoteric surfactant with good dissolving ability in acid liquid and reducing agent with different reducing ability. It has high temperature resistance and can be used Prevention of sludge during high temperature acidification.

The object of the present invention is achieved in that the anti-sludge agent is mixed by polyoxyethylene alkyl alcohol ether sodium propylene sulfonate, isoascorbic acid, thiourea and water, and the mass percent of each component is respectively polyoxyethylene alkanol Alcohol ether sodium propylene sulfonate: 10% to 20%, erythorbic acid: 10% to 20%, thiourea: 10% to 30%, water: 40% to 60%, the sum of the mass percentages of each component is 100%.

The polyoxyethylene alkyl alcohol ether sodium propylene sulfonate of the present invention has a general structural formula of RO(CH ₂ CH ₂ O) _n CH ₂ CH ₂ CH ₂ SO ₃ Na, wherein R is an alkyl group, and n is The number of chain members of oxyethylene, n=1-10, preferably 2-6.

The sodium polyoxyethylene alkyl alcohol ether propylene sulfonate in the formula can generate polyoxyethylene alkyl alcohol ether propylene sulfonic acid in the acid solution, which can be adsorbed on the surface of colloid and asphaltene in crude oil, preventing Colloids and asphaltenes in crude oil aggregate after contact with acid liquid. Compared with alkylbenzene sulfonic acid, polyoxyethylene alkyl alcohol ether propylene sulfonic acid has enhanced acid solubility due to the introduction of oxyethylene chains in the molecule, and can be more evenly distributed in the process of acid solution preparation and injection. Dispersed in the liquid phase, the ability to prevent acid sludge is obviously better than that of alkylbenzenesulfonic acid. Both erythorbic acid and thiourea in the formula are strong reducing agents. Erythorbic acid can quickly reduce Fe ³⁺ introduced into the acid solution to Fe ²⁺ , and the reduction rate of Fe ³⁺ by thiourea increases with the increase of temperature. In the invention, the cascade reduction system composed of erythorbic acid and thiourea can ensure the reduction of Fe ³⁺ in the acid liquid to be in contact with crude oil to Fe ²⁺ , and prevent the induction of Fe ³⁺ on acidified sludge.

Detailed ways:

The composition and preparation process of the present invention will be described in detail below in conjunction with the examples.

The anti-sludge agent is formed by mixing polyoxyethylene alkyl alcohol ether propylene sulfonate sodium, erythorbic acid, thiourea and water, and the mass percentages of each component are respectively polyoxyethylene alkyl alcohol ether propylene sulfonate sodium: 10%-20%, erythorbic acid: 10%-20%, thiourea: 10%-30%, water: 40%-60%, the sum of the mass percentages of each component is 100%.

The surfactant required by the present invention can be prepared according to the following steps: 1. add quantitative polyoxyethylene alkyl alcohol ether and a certain amount of toluene in a 100ml there-necked flask equipped with a water separator, and remove the water separation after azeotropic distillation dehydration device. Under the protection of dry nitrogen flow, add a little excess sodium block, raise the temperature to 110°C and react for about 24 hours to prepare sodium polyoxyethylene alkyl alcohol ether. ② After cooling down to room temperature, add propane sultone dissolved in refined toluene dropwise, and the reaction will exotherm at this time. After reacting at room temperature for 1 to 2 hours, the temperature is raised to 50 to 60° C., and the reaction is completed after another 3 to 4 hours. The toluene was distilled off under reduced pressure, and the yield of the product was about 80%. The reaction equation is as follows:

2R-OCH ₂ CH ₂ O _n H+2Na→2R-OCH ₂ CH _{2 On} Na+H ₂

The polyoxyethylene alkyl alcohol ether used in the preparation method can be polyoxyethylene lauryl alcohol ether, polyoxyethylene cetyl alcohol ether or polyoxyethylene stearyl alcohol ether, preferably polyoxyethylene dodecyl alcohol ether Alcohol ether; the chain number n of oxyethylene can be selected from 1 to 10, preferably 2 to 6.

Example: Add 1000kg of water into the activated ^3m3 reactor, raise the temperature to 60°C, stir at a low speed, slowly sprinkle 200kg of polyoxyethylene alkyl alcohol ether sodium propylene sulfonate, stir and dissolve, then cool down to 40°C, Then add 200kg of isoascorbic acid and 600kg of thiourea, stir until dissolved, and pack in barrels.

The formula provided by the invention can be adapted to the formation of acid-induced sludge and iron-induced sludge, has wide adaptability, and can be used to prevent acidified sludge when oil layers are acidified at 150°C.

Claims (1)

1. An anti-sludge agent is characterized in that it is formed by mixing polyoxyethylene alkyl alcohol ether propylene sulfonate sodium, isoascorbic acid, thiourea and water, and said polyoxyethylene alkyl alcohol ether propylene sulfonate The general structural formula of sodium sulfonate is RO(CH ₂ CH ₂ O) _n CH ₂ CH ₂ CH ₂ SO ₃ Na, where R is an alkyl group, n is the number of chain members of oxyethylene, n=1~10, each group The mass percentages are polyoxyethylene alkyl alcohol ether sodium propylene sulfonate: 10%-20%, isoascorbic acid: 10%-20%, thiourea: 10%-30%, water: 40%-60% , the sum of the mass percentages of each component is 100%.