RU2071555C1 - Composition for control of oil-field development - Google Patents

Abstract

FIELD: oil production; particularly, isolation control of water inflow to oil wells, change of filtering characteristics of non-uniform strata. SUBSTANCE: composition contains, mas.%: water-soluble polymer, 0.03-20.0; lacer, 0.02-3.0; wood flour, 0.1-7.0; water, the balance. EFFECT: higher efficiency. 2 tbl

Description

 The invention relates to the oil industry, in particular to compositions for regulating the development of oil fields, and can be used to isolate water inflow to oil wells, eliminate casing flows, and also to change the filtration characteristics of heterogeneous formations.

 Known gel-forming grouting composition for regulating the development of oil fields by eliminating absorption in wells, including hydroxyethyl cellulose, trivalent chromium salt, bentonite clay powder, alkali and water (Aut. St. N 1592473, class E 21 B 33/138, 1990).

 The disadvantage of this composition is its instability to erosion under conditions of highly porous and fractured reservoirs due to the fact that after gel formation in reservoir conditions, clay particles continue to swell, reducing the strength of the gel.

 Known gel-forming composition for regulating the development of oil fields, including carboxymethyl cellulose, lignosulfonates, chromates and water (Aut. St. N 1472643, CL E 21 B 33/138, 1989).

 However, this composition is not very effective in highly permeable formations, because possesses insufficiently high structural and mechanical properties due to the lack of filler, and to achieve high strength characteristics requires a large consumption of expensive reagents.

 The closest in technical essence and the achieved effect is a composition for regulating the development of oil fields, including polyacrylamide, chrome alum, bentonite clay and water (Avt. St. N 1731942, class E21 B 43/22, 1992).

 However, the known composition has insufficiently high structural and mechanical properties, this is due to the fact that the introduction of clay, which has a greater degree and time of maximum swelling, significantly exceeding the gelation time, leads to the appearance of overvoltages in the gel formed, i.e. internal defects in the structure. Therefore, such a system undergoes destruction under the influence of a high-pressure flow of water in the reservoir.

 The basis of the present invention is to create a composition for regulating the development of oil fields with high structural and mechanical properties.

 The proposed composition contains a water-soluble polymer, a filler, a crosslinker, for example, chrome alum and water, moreover, wood flour is used as a filler in the following ratio of components, wt.

water soluble polymer 0.03 20.0
Wood flour 0.1 7-0
Stapler 0.02 3.0
Water rest
The composition is prepared as follows.

 In an aqueous polymer solution prepared directly at the well or under industrial conditions, with constant mechanical stirring, add the calculated amount of wood flour, then a crosslinker.

 When preparing the composition by this method, a spatially cross-linked network of polymer macromolecules is formed. Wood flour, being an active filler, enters into intermolecular physical interaction with the polymer with the formation of hydrogen bonds and due to physical forces. Due to the fact that the swelling time of wood flour in water is less than or comparable with the gelation time, the resulting crosslinked polymer-filled system is devoid of internal overvoltages in its structure and has increased structural and mechanical properties. This allows you to effectively use it in technological processes aimed at regulating the development of oil fields.

 A new set of claimed essential features allows to obtain a new technical result, namely, to increase the efficiency of the processes of regulation of oil field development through the use of a material with high structural and mechanical properties.

As water-soluble polymers can also be used, for example:
domestic polyacrylamides (PAA) according to TU 6-16-2531-81 TU 6-01-1049-81, TU 14-6-121-75, imported with a molecular weight of (3-15) 10 ⁶ , as well as Gipan acrylic polymers "according to TU 6-01-166-77," Metasol "according to TU 6-01-254-74," Comet "according to TU 6-01-622-76;
technical lignosulfonates technical lignosulfonate (LST) in accordance with TU 13-0281036-05-89, condensed sulphite-alcohol stillage hydrolysis product (KSSB in accordance with TU 13-0281036-05-89, sulphite-yeast mash concentrate (KDB) in accordance with TU 81-04- 225-79;
cellulose ethers carboxymethyl cellulose (CMC) according to TU 6-55-36-90, hydroxyethyl cellulose (OEC) according to TU 6-55-221-565-88, 6-55-221-317-88, imported brands Tylosa, Nubrosol.

 Mixtures of water soluble polymers may also be used.

 Wood flour is a product of dry grinding of waste from the woodworking industry, GOST 16361-87.

As a stapler can be used, for example:
potassium dichromate, GOST 2652-78,
sodium dichromate, GOST 2651-88,
chromium acetate;
chrome alum, GOST 4162-79.

 When hexavalent chromium compounds are used as a crosslinker, if necessary, a chromium reducing agent is added to the composition from the hexavalent to the trivalent state.

 An analysis of the known solutions selected during the search showed that there is no object in science and technology that is similar to the claimed combination of essential features and has high rates when using formulations to regulate the development of oil fields.

 To prove the compliance of the claimed invention with the criterion of "industrial applicability" provides specific examples of the preparation of the composition and its use in the field at specific fields.

 Example 1

 The required amount of polymer and water are placed in a beaker equipped with a stirrer. Then, after complete dissolution of the polymer, add the calculated amount of wood flour and a crosslinker, the composition is mixed during the induction period of gelation in order to maintain its sedimentation stability. After that, the composition prepared on the basis of PAA and cellulose ethers is poured into the measuring device of the Reogel-001 device and kept for 24-48 hours to complete the gelling process, and the composition prepared on the basis of lignosulfonate is left in a glass, the height of the gel column is at least 45 mm.

The structural and mechanical properties of the claimed and known compositions are evaluated in laboratory conditions according to the following indicators: shear stress at a shear rate of 1 s ^-1 , shear modulus, shear strain for compositions based on polyacrylamide and cellulose ethers using the Reogel-001 device "and the number of penetration for compositions based on lignosulfonates. The determination of the number of panetration is carried out according to GOST 1440-78. One penetration unit is equal to 0.1 mm of the immersion depth of the needle and the larger the number (immersion), the softer, more plastic the composition and, therefore, the lower the gel strength.

 The compositions and their structural and mechanical properties are given in table 1.

 As can be seen from the data given in table 1, the claimed composition has high structural and mechanical properties.

 To determine the effectiveness of using the proposed composition, field tests are conducted at the wells of the Lyantorskoye, Samotlor, Bystrinsky and Druzhnoye fields. The research results are given in table.2.

 Example 2 (table 2, experiment 1).

 In the producing well, work is carried out to isolate the influx of formation or injected water entering the well from productive production horizons, as well as from “foreign” horizons through casing flows. To isolate water, a composition is injected, consisting of 0.5% PAA, 0.3% wood flour, 0.3% potassium dichromate and 98.9% water. Efficiency is estimated by reducing the water content of the extracted products and according to geophysical studies (thermometry and flow metering).

 Example 3 (table 2, experiment 4).

 In the injection well, work is carried out to turn off the washed high-permeability intervals and eliminate the withdrawal of injected water into unexploited horizons (casing flows). For this, a composition is injected consisting of 10.0% LFB, 2.0% wood flour, 30% potassium dichromate and 85.0% water. The insulation efficiency is estimated by the change in injectivity and according to geophysical research.

 Analogously to example 2 and 3, work is carried out on the processing of other producing and injection wells.

 The results show a high efficiency of the application of the claimed composition for regulating the development of oil fields in comparison with the use of the known composition (table 2, experiment 6).

The application of the proposed structure will allow:
more efficiently regulate the development of oil fields characterized by complex mining, geological and field conditions;
use standard equipment during transportation and injection;
Dispose of large-tonnage waste and intermediate products of industrial production.

Claims (1)

 The composition for regulating the development of oil fields, including a water-soluble polymer, a filler, a crosslinker and water, characterized in that it contains wood flour as a filler in the following ratio of components, wt. Water soluble polymer 0.03 20.0
Wood flour 0.1 7.0
Stapler 0.02 3.0
Water Else

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