RU2313566C2 - Method of increasing viscosity and stability of water-oil emulsions - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: invention relates to technology of obtaining high-viscosity and stable water-oil emulsions, which are used to increase oil recovery of formation and also in gas production processes. Method according to invention consists in mixing oil lubricant with water taken in amount by 10-25% larger than critical amount of water in emulsion using electromechanical mixer at 2000-2500 rpm for 40-50 min, after which excess water is removed.

EFFECT: simplified technology and avoided use of emulsifying and stabilizing compounds.

1 tbl, 12 ex

Description

The invention relates to a technology for producing highly viscous and stable water-oil emulsions. Water-oil emulsions are widely used in technologies for producing fuels, increasing oil recovery, for example, in the treatment of highly watered reservoirs, injection and production wells (Mater. 2 nd scientific-practical conference. “Production, preparation, transport of oil and gas.” Tomsk : Publishing House of the SB RAS, 2001), as well as in gas production processes and for temporary isolation of permeability in the bottomhole formation zone (EPO Patent 1198536).

In recent years, structured emulsions have been used in hydraulic fracturing technologies for low-permeable gas and oil bearing formations.

The viscosity, providing structural, phase and mechanical stability of emulsions, is formed using expensive surface-active substances (surfactants), stabilizers and depends on the quality, their content in the composition of the emulsions. For example, in the method for producing emulsions with the composition: 1-70% water in 30-99% oily liquid (esters, acetals, dialeylphenols, hydrocarbons), complex surfactants of the formula H [CH ₂ CH (R) A] _x N (R ) [CH ₂ CH (R) A] _y H, where R is an aliphatic hydrocarbon group C _12-22 ; R '= H or alkyl C _1-3 ; A = NH or O; x + y = 1-3 (Patent US 6218342, C09K 7/00).

Emulsion hydrocarbon fuels are stabilized in the presence of a 0.05-25% ionic or nonionic emulsifier with a hydrophilic-lipophilic balance of 1-40 (US Pat. No. 6,530,964, C10L 1/32) or in the presence of an emulsifier based on a polyacid polymer such as C _4-30 olefins with maleic copolymers anhydride (Patent US 6419714, C10L 1/32).

In the method of producing emulsion fuels of the composition HC: water = (60:40) - (98: 2) with a viscosity of 100 cP (0.1 Pa · s), lower alkyl amines in combination with ethylene oxide are used as emulsifiers (Patent US 5993495, С10L 1 / 32), inorganic compounds containing Na, Mg, Ca, Cl (Patent US 6296676, С10L 1/12), NaOH and CaCl ₂ (Patents US 6066186, 6030424, С10L 1/32).

The viscosity of multi-phase oil / water / oil emulsions based on hydrocarbon feedstocks, water and emulsifiers is further stabilized by dispersed substances, for example carbon (EPO Application 1111027, C10L 1/32), organophilic clay minerals and coke (Patents US 6150425, 6069178, A61K 9 / 113, B01F 3/00, respectively).

The viscosity of a combustible water / hydrocarbon emulsion (kerosene, gasoline) with a water / HC ratio of (5-35) :( 95-65) is controlled by a certain content of paraffins, as well as vegetable, animal or synthetic oils (Application FR 2842820, С10L 1/32 )

In the method for preparing a water-oil emulsion and stabilizing its viscosity, saturated and fatty unsaturated alcohols and acids, saturated and unsaturated hydrocarbons are used (Application DE 19859054, C02F 3/02). Nonylphenol polyethoxylate was proposed to stabilize water-emulsion fuels based on oil residues, and beef tallow dihydrooxyethyl glycinate was used as thermostabilizer of these emulsions when the content of these compounds in the emulsion was from 1.0 to 5.0% (US Patent 6187063, С10L 1/22; French application 2801057, C10L 1/32).

For example, a water-hydrocarbon-based drilling fluid with hydrophobic properties is stabilized by carbolignosulfonate when it is contained in the emulsion from 11.0 to 21.3% (Patent RU 2238297, C09K 7/06).

In order to expand the working range of an inverse emulsion based on bitumen (19.0-98.0%) and water (1.0%), heavy pyrolysis resin is added to it in an amount of 1.0 to 80.0% (RF Patent 2194062, С08L 95/00).

Using stabilizing compounds based on esters of polyhydric alcohols and high molecular weight fractions of synthetic fatty acids, invert emulsions that are heat-resistant up to 190 ° C have been developed for drilling and overhauls (Oil Refining and Petrochemicals, 2003, p. 195).

Salts of hydrocarbon-substituted (8-400 C atoms) succinic acid or its anhydride and ammonium or amine at concentrations of 0.01-15.0% increase the thermal stability of emulsified mixtures of water-fuel compositions and improve their combustion process (Patent US 6648929, С10L 1/22).

A viscous emulsion for the separation of hydrocarbons from underground formations is stabilized by a solid additive, for example, particles of clays, quartz, gypsum, feldspar, coal dust, asphaltenes and polymers (US Pat. No. 5,910,467, C09K 3/00).

The viscosity of the water emulsion in petroleum oil is stabilized by liquid rubber or latex copolymer of diene, vinyl or diene and vinyl monomers with carboxyl-containing monomers (Patent RU 2121495, C10M 173/00). The stabilizing substance is taken in an amount of 0.3-5.0% by weight of the oil, based on dry matter, with a weight ratio of oil and water of 20: 80-80: 20 and a metal compound of the second or third groups 0.09-3.5% by weight of the oil. The stabilizer is used in a mixture with a surfactant taken in an amount of 0.5-3.0% by weight of oil. All applications of emulsions include their operating modes, characterized by high thermomechanical loads (deformations). In most cases, especially when the water content in oil products is more than 30%, emulsions are destroyed by deformation. Therefore, the dynamic viscosity is a quantitative assessment of the stability of the structure and phase composition of emulsions.

An analysis of patents shows that in order to prevent the process of destruction of emulsions, complex mixtures of synthetic stabilizing compounds are introduced into their composition in an amount of 0.3 to 80 wt.% In combination with emulsifiers.

According to the technical nature of the proposed method for increasing the viscosity and stability of water-oil emulsions, the closest method is to stabilize the water emulsion in oil oil according to patent RU 2121495. The disadvantage of this method is the increased content in the emulsion and low efficiency of the stabilizing composition based on rubber or latex of a copolymer of diene, vinyl monomers with carboxyl-containing monomers, as well as in the additional metal content of the second or third groups and emulsifier, which in total amounts to 11.5 wt.%.

The objective of the invention was to develop a technologically simple and effective method for producing water-oil emulsions with higher viscosity and stability without the use of emulsifying and stabilizing compounds.

The technical result is achieved by the fact that petroleum oil of the type 5W40, 10W30, M8V, Kamaz, Avtol, I-12 - I-40, Rimula D Shell and excess water by 10-25% relative to the maximum experimentally a certain amount of water for each type of oil without the addition of special emulsifiers and stabilizers is mixed using an electromechanical mixer at 2000-2500 rpm for 40-50 minutes. After removal of free (non-emulsified) water from the reactor, emulsions with a dynamic viscosity of 3-6 times the viscosity of emulsions with the same water content, but obtained without excess water, are obtained. The stability of emulsions is characterized quantitatively by the method of dynamic viscometry at strain shear rates from 0.16 to 1312 s-1. The shear stress and viscosity of the emulsions are determined using a Reotest-2 device. The average values of the rheological characteristics of emulsions based on 5W40 and 10W30 oils are shown in the table.

As can be seen from the examples with an increase in excess water to 20-24% (examples 1-5) introduced into the emulsion process, the water content in the emulsions decreases, and their dynamic viscosity rapidly increases to 232-331 Pa · s against 41- 72 Pa · s viscosity for emulsions obtained under the conditions of the calculated amount of water. High viscosity emulsions flow at high ultimate shear deformations - 300 Pa. The viscosity of the emulsions does not change when they are heated to 60-70 ° C. With a decrease in excess water, its content in emulsions increases, and the viscosity approaches values close to those for emulsions obtained without excess water.

The developed method for increasing the viscosity and stability of water-oil emulsions is technologically advanced, not burdened by the use of expensive, toxic reagents. In technical and economic terms, the method is many times more effective than the prototype.

Table The viscosity of an emulsion based on 10W30 oil, depending on the method of its preparation Example No. The amount of water taken in the emulsion, wt.% The amount of water included in the emulsion, wt.% The viscosity of the emulsion obtained in excess water, Pa · s Example No. The viscosity of the emulsion obtained with the calculated amount of water, Pa · s one 86.0 62.3 232.4 fourteen 40.6 2 85.7 65.4 323.6 fifteen 55.8 3 85.6 64.9 330.8 16 52.6 four 85.5 63.2 349.3 17 75.9 5 85.4 63.1 344.6 eighteen 71.5 6 85.0 71.0 357.0 19 73.6 7 84.7 72.0 331.0 twenty 86.0 8 84.5 76.2 340.0 21 105.2 9 84.0 78.5 346.0 22 190.0 10 83.0 80.3 405.0 23 297.3 eleven 82.9 81.0 389.7 24 378.0 12 82.7 82.0 548.5 25 451.0 13 82.5 82.5 595.0 26 595.0

Claims (1)

A method of increasing the viscosity and stability of water-oil emulsions by mixing oil oil and water, characterized in that oil lubricating oil and water taken 10-25% more than the critical amount of water in the emulsion are mixed at 2000-2500 rpm for 40-50 minutes then excess water is removed.