RU2213212C2 - Composition for regulation of oil deposit development - Google Patents

Abstract

FIELD: oil producing industry, particularly, well development of oil deposits. SUBSTANCE: composition includes exopolysacharide containing 1-30 wt.% of uronic acids and produced Azotobacter Vinelandii (Lipman)FTch-1 VKPM V-5933 in form of culture fluid, chrome alum and water. Composition additionally contains surfactant from class of ethoxylated ethers of sorbitan of general formula given in invention description. Composition contains the following amounts of ingredients, wt.%: said exopolysacharide 0.001-1.0; chrome alum 0.002-0.04; said surfactant 0.02- 0.1; the balance, water. EFFECT: improved rheological properties of compositions, its higher flexibility resulting in its needed strength. 1 tbl

Description

 The invention relates to the oil industry, namely to the downhole development of oil fields.

 Known gel-forming composition for treating oil wells containing cellulose ether, an inorganic salt of trivalent chromium, in particular, potassium alum, alkali and water (ed. St. USSR 1392077). The ether used is hydroxyethyl cellulose, glycidated hydroxyethyl cellulose or a mixture of carboxymethyl cellulose with hydroxyethyl cellulose, and additionally the sodium or potassium salt of hydrochloric or nitric acid and the sodium or potassium salt of orthophosphoric acid.

 The main disadvantage of the known composition is its complexity, the complexity of obtaining and high cost. In addition, instant gelation after mixing of the components precludes the injection of the specified composition into low-permeability deep-seated reservoirs.

 To isolate the inflow of formation water into the well, biopolymers are used, for example, solutions of the heteropolysaccharide produced by Xanthomonas campestris (auth. USSR. 1051226) Acinetobacter sp (auth. St. USSR 1726732).

 Known heteropolysaccharides, incl. xanthan, do not provide the required change in filtration resistance with all the variety of geological and physical conditions.

 A known composition for isolating water inflow into a well containing an aqueous solution of polyacrylamide and potassium chromium alum as a crosslinking agent (ed. St. USSR 985255).

 However, this composition is not effective enough at low polymer concentrations and due to the active adsorption of the chromium cation on the threshold at a high polymer concentration, which leads to a decrease in the strength of the crosslinked polymer.

A close technical solution to the present invention is a composition for regulating the development of oil fields, including an exopolysaccharide containing 1-30 wt.% Uronic acids and produced by Azotobacter Vinelandii (Lipman) FC-1 VKPM B-5933 in the form of a culture fluid, chrome potassium alum and water ( Pat. RF 2107811). The ratio of components in the composition, wt.%:
Exopolysaccharide - 0.001 - 1.0
Chromium Alum - 0.002 - 0.04
Water - The rest is up to 100%
However, this composition is not effective enough, because at a high concentration of polymer crosslinked by potassium chromium alum, the composition, when injected into the formation, has reduced strength and brittleness.

 The purpose of this invention is to improve the rheological properties of the composition, increasing the elasticity of the composition, which in turn leads to its strength.

где

+x+y+z =20;
R - монолаурат, монопальмитат, моноалеат, триолеат, линолеат.This goal is achieved in that the composition of the prototype additionally contains a surfactant surfactant from the class of ethoxylated sorbitan esters of the General formula

Where

+ x + y + z = 20;
R is monolaurate, monopalmitate, monoaleate, trioleate, linoleate.

The ratio of the components in the composition is the following, wt.%:
The specified exopolysaccharide is 0.001 to 1.0
Chromium Alum - 0.002 - 0.04
Specified surfactant - 0.02 - 0.1
Water - The rest is up to 100%
Using the proposed surfactant allows you to get a very strong, elastic and volumetric structure, and by changing the ratio of the components included in the inventive composition, you can adjust the time of formation of an elastic volumetric structure in a wide range of changes in the geological and physical conditions of the formation.

 The exopolysaccharide containing 1-30 wt.% Uronic acids and produced by Azotobacter Vinelandii (Lipman) FC-1 VKPM B-5933 in the form of a culture fluid has high gelling properties, which unfortunately cannot be maintained at elevated temperatures and high shear stresses.

 This drawback was eliminated by the use of the specified formula in the surfactant composition, due to which crosslinking of polymer molecules with alum molecules occurred with the formation of a very flexible and branched network in the solution.

The proposed technical solution is illustrated by the following examples.
Example 1
Preliminarily, a biosynthesis of exopolysaccharide with a uronic acid content in the range of 1-30% is carried out using the Azotobacter Vinelandii (Lipman) strain FC-1 VKPM B-5933 in the form of a culture fluid (US Pat. RF 2073712).

Example 2
The preparation of the composition in laboratory conditions was carried out as follows: the exopolysaccharide culture liquid from Example 1 and water were poured into a glass beaker with a stirrer. After thorough mixing, the required amount of potassium alum and surfactant was simultaneously added to the glass. Again mixed until a homogeneous mass. Thus prepared composition was divided into two parts:
the first was thermostated at 20 ^o C, and the second at 60 ^o C. After gelation was completed, the ultimate shear stress was determined on an Rhcogel-90M instrument.

 Examples of the proposed compositions and test results are shown in the table.

 In field conditions, the most obvious evidence of the success of the insulation composition can be either a change in the water content of the produced products (during processing of the production well) or a change in the injectivity profile (during processing of the injection well) during injection of compositions with a subsequent decrease in the water content of the liquid in the production wells.

 The preparation of a solution of the claimed composition in the field was carried out in the tanks of a cementing unit connected to an injection well and equipped with pumps for mixing. After obtaining a homogeneous mass, the pump brings the resulting solution through the tubing string to the bottom of the well and push it into the formation. Fresh water was used as a squeezing liquid.

 Experimental injections at a field in Tataria showed that the use of the proposed formulations provides additional oil production in the amount of 250 tons per 1 ton of injected composition during processing of production wells, while redistribution in the injection profile and reduction of water cut in production wells by 10- 40%

Claims (1)

Composition for regulating the development of oil fields, including exopolysaccharide containing 1-30 weight. % uronic acids and produced by Azotobacter Vinelandii (Lipman) FM-1 VKPM B-5933 in the form of a culture fluid, chrome potassium alum and water, characterized in that the composition additionally contains a surfactant from the class of ethoxylated sorbitan esters of the general formula

Where

+ x + y + z = 20,
R - monolaurate, monopalmitate, monoaleate, trioleate, linoleate, with a ratio of components in the composition, wt. %:
The specified exopolysaccharide is 0.001-1.0
Chromium Alum - 0.002-0.04
The specified surfactant is 0.02-0.1
Water - Else

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