RU2309972C2 - Compound for treatment of carbonate formations - Google Patents

Abstract

FIELD: oil-and-gas producing industry; production of compounds for treatment of carbonate formations for intensification of oil and gas influx from formation.

SUBSTANCE: proposed compound for treatment of carbonate formations contains the following components, mass-%: polyglycols, 8-12; waste of ethyl alcohol production process, 0.1-10; polysaccharides - waste of sugar production process or multi-atom alcohols, 6-10; corrosion inhibitor ИКУ-1, 0.01-1; the remainder being water.

EFFECT: reduced rate of reaction and solvent ability of compound in water-saturated portion of reservoir of formation.

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Description

The invention relates to the oil and gas industry, namely, to obtain compositions for the processing of carbonate formations in order to intensify the influx of oil and gas from the formation.

A well-known solution based on hydrochloric acid (Loginov B.G., Malyshev L.G. and other Guidelines for acid treatment of wells. - M .: Nedra, 1966). The disadvantage of this solution is the high reaction rate with the formation of the maximum number of dissolution channels in the borehole zone to the detriment of the efficiency of its penetration deep into the reservoir, as a result of which the object is not completely covered by the impact.

Also known is a composition (patent RU 2076204, IPC ЕВВ 43/27, publ. 03/27/1997) containing an aqueous solution of 10-12% hydrochloric acid, diethylene glycol and specially prepared to slow down the reaction of an acid with a carbonate rock with a surfactant - foaming agent PO- one. The disadvantage of this solution is the low solubility of the oil-saturated part of the reservoir, resulting in an increase in permeability only in the washed (water-saturated) part of the reservoir, while its oil-saturated part is slightly processed. This leads to a rapid increase in water cut and low efficiency of subsequent treatments.

Closest to the claimed technical solution is the composition (patent RU 2184224, IPC ЕВВ 43/27, publ. 06/27/2002) containing a solution of hydrochloric acid of 13.5% concentration, polyglycols, ethoxylated fatty acids (OFA) and the marketable form of neonol AF9- 12 (СНО-4Б) in the following ratio of components, wt.%:

HCl (13.5% concentration) 96-80 Polyglycols 3.8-15 OZHK 0.1-2 СНО-4Б 0.1-3

The disadvantage of this solution is the low solubility of oil-saturated carbonate rock, in addition, a number of components included in its composition (OLC and CHO-4B) are no longer produced in the Russian Federation, which makes the practical use of this composition difficult.

The technical result is a decrease in the reaction rate and the dissolving ability of the composition in the water-saturated part of the reservoir with a parallel increase in the dissolving ability in its oil-saturated part.

The composition for processing carbonate formations, including polyglycols and water, additionally contains waste from the production of ethyl alcohol, polysaccharides - waste from the production of sugar or polyols and corrosion inhibitor IKU-1 in the following ratio, wt.%:

Polyglycols 8-12 Ethyl alcohol production waste 0,1-10 Polysaccharides 6-10 Corrosion Inhibitor IKU-1 0.01-1 Water Rest

In studies for the preparation of the composition used the following reagents.

Polyglycols - Glycoil reagent, TU 2422-130-05766801-2003, manufactured by OAO Nizhnekamskneftekhim. Polyglycols obtained by hydration of ethylene oxide are a mixture of glycols (diethylene glycol, triethylene glycol, tetraethylene glycol, etc.).

Wastes from the production of ethyl alcohol - concentrate of head impurities of ethyl alcohol (KGPES), TU 9182-478-00008064-2002.

Sugar production waste (OPS) according to GOST 18-385-82.

Wastes from the production of polyhydric alcohols (OPS) according to TU 64-19-1-91.

IKU-1 - a steel corrosion inhibitor, is a quaternary salt based on quinoline and benzyl chloride. Available in accordance with TU-2415-005-12749890-2000 NPF Tribonika.

The laboratory research technique was as follows.

An oil-saturated core sample from the Kashiro-Podolsk deposits of the Vyatka area of the Arlan field was taken as a carbonate rock. It was disintegrated and a 1-2 mm fraction was taken. Studies were conducted both for the conditions of the washed zone of the reservoir, and for the conditions of the initial oil saturation. In the first case, the experiments were carried out on a “clean” surface after grinding. In the second case, the selected fraction for modeling the conditions of the initial oil saturation was placed for some time in oil to form the latter on the surface of the boundary layer. After this, free oil was removed, and the rock was transferred to filtered paper to further remove free oil. The formulation of the investigated compounds are shown in the table.

A portion of the prepared carbonate rock was placed in a flask with the test solution. The yield of carbon dioxide formed during the interaction of solutions with limestone characterized the kinetics of the process. It was recorded using the GSB-400 gas meter.

From the obtained data it follows that the dissolution rate of water-saturated carbonate rock "pure carbonate" when using the proposed composition is reduced in comparison with the composition of the prototype, in addition, the completeness of dissolution of the washed breed is reduced.

In the presence of oil on the surface of the carbonate rock, the use of the proposed composition increases the dissolution rate of oil-saturated rocks compared with the prototype composition with the same skeleton dissolution.

Thus, the use of the proposed composition allows to reduce the dissolution rate of water-saturated interlayers and at the same time increase the dissolution rate and efficiency of oil-saturated parts of the carbonate formation, which under field conditions will achieve the greatest effect from the technology used as a result of the involvement of oil into the displacement during flooding.

The proposed composition has a low surface tension at the interface with hydrocarbon liquids and has a low viscosity. Due to these properties, the penetrating ability of the working agent is improved. The composition due to the addition of a corrosion inhibitor IKU-1 to its composition has a reduced corrosion activity with respect to the well’s oil well. In addition, the composition contains waste from industrial enterprises, which potentially reduces its cost in comparison with the prototype and as a result, the cost of 1 ton of additional oil.

The processing technology does not change compared to the known one and does not require the use of special equipment

Table
Recipe Formulations Compositions The content of components, wt.% Polysaccharides Polyglycols KGPES IKU-1 Water one 10 (OPS) 8 0.1 0.01 81.89 2 9 (OPS) 9 2 0.02 79.98 3 7 VHI 10 5 0.5 77.5 four 6 VHI 12 9 one 72

Claims (1)

Composition for treating carbonate formations, including polyglycols and water, characterized in that it additionally contains waste from the production of ethyl alcohol, polysaccharides - waste from the production of sugar or polyols and corrosion inhibitor IKU-1 in the following ratio, wt.%: Polyglycols 8-12 Ethyl alcohol production waste 0,1-10 Polysaccharides 6-10 Corrosion Inhibitor IKU-1 0.01-1 Water Rest