RU2669213C1 - Composition for insulation of water inflow to producing oil wells and intensification of oil production - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: invention relates to the oil industry, in particular to the compositions used to isolate the inflow of water into production oil wells and intensify oil production. Composition comprises 5–30 % by weight of oleic acid, 1–5 % by weight of a mixture of organic sulphonic acids with 10–18 carbon atoms, 20–30 % by weight of an aliphatic alcohol, 3–10 % by weight of ethanolamine, and fresh water with the remainder.EFFECT: technical result is an increase in the efficiency of conducting waterproofing works and intensification of oil production due to the use of a homogeneous composition of selective action to the water-saturated areas of terrigenous and carbonate reservoirs.3 cl, 3 ex, 3 tbl

Description

The invention relates to the oil industry, in particular to compositions used to isolate the influx of water into producing oil wells and to intensify oil production.

Currently, one of the main requirements for water-insulating compositions is the selectivity of the impact on the reservoir. They must isolate the influx of formation water, that is, pass the hydrocarbon component (gas, oil, gas condensate) through themselves and cut off the water coming from the formation.

A known composition for the selective isolation of formation water in oil and gas wells, consisting of organosilicon compounds of polyphenylethoxysiloxane and sodium ethylsiliconate GKZH-10 or sodium methylsiliconate GKZH-11 (SU 1078036, publ. 07.031984).

A known composition for isolating formation water, including an organosilicon liquid and an aqueous solution of polyvinyl alcohol with a volume ratio of 1: 1 (RU 2032068, publ. 03/27/1995).

Known waterproofing composition containing gidrofobiziruyuschy organosilicon liquid GKZH-10 or GKZH-11, an aqueous solution of polyvinyl alcohol and aluminosilicate microspheres (RU 2211306, publ. 27.08.2003).

The disadvantages of these organosilicon compounds are their low selectivity and the high cost of work in the isolation of formation water, when the costs of chemicals for a single operation to isolate water increase many times.

A known method of limiting water inflow and oil-water emulsion used in the method, including the injection into the reservoir of a hydrophilic oil-water emulsion containing an aqueous solution of diethanolamide fatty acids with 10-16 carbon atoms and a dispersed phase - oil (SU 726305, publ. 04/05/1980). The disadvantage of this method is the watering of wells in a short period of time due to insufficient viscosity released during the decay of the oil emulsion.

Closest to the proposed invention for the technical task and chemical composition is a composition for isolating water inflow into producing oil wells, which is an aqueous solution of fatty acid ethanolamide, secondary alcohol - isopropanol and polyhydric alcohol - ethylene glycol (RU No. 2527996, publ. 03.07.2013 g. ., prototype). The effectiveness of the composition is achieved by selective isolation of the waterlogged intervals of the oil reservoir while maintaining the permeability of oil-saturated. However, the prototype composition does not effectively block the washed zones in highly permeable fractured reservoirs, since it does not provide sufficient adsorption of the hydrophobizing component on the rock surface, which ultimately affects the efficiency of limiting water inflow and oil recovery.

The search for new effective compounds for limiting water inflow into producing oil wells, expanding the arsenal of known means of this purpose, is an urgent task.

The technical result of the claimed invention is to increase the efficiency of waterproofing works and the intensification of oil production through the use of a homogeneous composition of selective action to water-saturated areas of terrigenous and carbonate reservoirs.

The technical result is achieved by using a homogeneous composition for isolating water flow to production wells and intensifying oil production, including oleic acid, a mixture of organic sulfonic acids with 10-18 carbon atoms, aliphatic alcohol - methanol or isopropanol, ethanolamine and fresh water in the following ratio of components, wt. %:

Oleic acid 5-30 A mixture of organic sulfonic acids 1-5 Ethanolamine 3-10 Aliphatic alcohol 20-30 Fresh water  rest.

The selective action mechanism of the claimed composition is based on the selective formation of a clogging insulating screen in contact with formation water. In oil saturated intervals, when in contact with oil, the composition does not form an insulating material. Thus, the composition itself “finds” in the formation a zone of formation water inflow into the well and blocks it. Selective isolation of the waterlogged intervals of the oil reservoir is achieved due to the different solubilities of the resulting ethanolamine fatty acid salt in produced water and oil. The homogeneity of the composition is achieved by the presence of a certain amount of aliphatic alcohol, and its high adsorption on the surface of the rock is achieved due to organic sulfonic acids, which are surface-active substances.

In the inventive composition, the ingredients used are available cheap reagents:

Technical oleic acid in accordance with GOST 7580-91,

Ethanolamines according to TU 2423-159-00203335-2004,

Technical methanol in accordance with GOST 2222-95,

Isopropyl alcohol according to GOST 9805-84,

A mixture of organic sulfonic acids according to TU 2481-001-13002012-2017.

The composition is obtained by mechanically mixing weighed quantities of ingredients.

To confirm the effectiveness of the application of the claimed composition, studies were conducted on four single models of the oil reservoir with residual oil saturation, which is a metal tube 330 mm long and 33 mm in diameter, filled with ground rock. To create relict water saturation, the models were saturated with formation water under vacuum. To create the initial oil saturation, formation water from the pore space was replaced by oil. The displacement was carried out until the filtration characteristics were completely stabilized at the outlet of the porous medium. When creating residual oil saturation, the models were connected to the pressure vessel and oil was displaced from the pore space of the model with formation water. Oil displacement was carried out until the water cut at the output of the model. All stages of the experiment were carried out at a temperature of 26 ° C.

After creating the residual oil saturation in the pore space of the oil reservoir model, in accordance with the statement of the problem in the experiment, the inventive composition (examples 1-3) was introduced on the reverse side in the amount of 10% of the pore volume of the model and the oil was continued to be displaced with formation water in the initial direction. The results are presented in tables 1-3.

Example 1. The composition contains oleic acid (20 wt.%), A mixture of sulfonic acids (2 wt.%), Monoethanolamine (5 wt.%), Isopropanol (30 wt.%), And water (43 wt.%). Four experiments were carried out with the above composition:

Carbonate model No. 1 was saturated with formation water and oil, selected from a well operating carbon deposits.

Terrigenous model No. 2 was saturated with formation water and oil selected from a well operating carbon deposits.

Model No. 3 carbonate was saturated with formation water and oil, selected from a well operating Devonian sediments.

Model No. 4 terrigenous was saturated with formation water and oil taken from a well operating Devonian sediments.

An analysis of the data in Table 1 indicates a decrease in water permeability of models from 2.94 times (model No. 4) to an almost complete attenuation of filtration (model No. 3).

On models 1 and 2, using produced water and oil taken from a well operating carbon deposits, the decrease in water permeability is 9.4 and 10.4 times, respectively. Residual oil saturation decreased by 21.2-42.1%. Compared with the prototype, water insulation improved almost 2 times, and additional oil recovery increased by 10-15%.

V _then - the pore volume of the model of the oil reservoir, cm ³ ;

k _abs - absolute permeability (gas), μm ² ;

k _water — model water permeability, initial, μm ² ;

S _n - maximum (initial) oil saturation (pore volume of the model occupied by oil),%;

k _nef - oil permeability of the model, μm ² ;

S _ost - oil saturation of the model after displacement by water (in% of the initial oil saturation);

k _{water.ost.n / n} - the permeability of the model with residual oil saturation in water, μm ² ;

S _ost.con - oil saturation of the model after exposure to the reagent and further displacement with water (in% of the initial oil saturation);

k _vod.kon - the permeability of the model after exposure to the reagent and further displacement with water, microns.

Example 2. The composition contains oleic acid (30 wt.%), A mixture of sulfonic acids (5 wt.%), Diethanolamine (10 wt.%), Isopropanol (30 wt.%), And water (25 wt.%).

The experiments were carried out analogously to example 1 on the same models, the results are presented in table 2.

The use of the above composition leads to a more significant (12-13 times) reduction in water permeability, while the oil saturation of the formation decreased by a maximum of 43.3% (model 2). Compared with the prototype, there is a twofold decrease in water permeability. Residual oil saturation (S _ost.kon ) decreased compared with the prototype, additional oil recovery increased to 50%.

Example 3. The composition contains oleic acid (5%), a mixture of sulfonic acids (1%), triethanolamine (3%), methanol (20%), and water (71%). The experiments were carried out analogously to example 1 on the same models, the results are presented in table 3.

The use of the above composition leads to a decrease (6-7 times) in water permeability and a decrease in oil saturation (by 20-40%) of reservoir models 1 and 2. These indicators are almost the same as the prototype. However, given the significantly lower concentration of the active base in the test composition, it can be concluded that the composition has a more effective effect on water permeability and oil displacement.

Thus, a homogeneous selective composition is proposed for isolating the influx of water into producing oil wells, which has a significantly greater waterproofing ability (up to 100%) compared to the prototype and increases the additional extraction of residual oil (up to 50%).

Claims (4)

1. Composition for isolating the influx of water into producing oil wells and stimulating oil production, including fatty acid, aliphatic alcohol and fresh water, characterized in that it further comprises a mixture of organic sulfonic acids with 10-18 carbon atoms and ethanolamine, and as a fatty acid composition contains oleic acid in the following ratio, wt.%: Oleic acid 5-30 A mixture of organic sulfonic acids 1-5 Ethanolamine 3-10 Aliphatic alcohol 20-30 Fresh water Rest 2. The composition for isolating the influx of water into oil producing wells and stimulating oil production according to claim 1, characterized in that ethanolamine is monoethanolamine, diethanolamine or triethanolamine. 3. The composition for isolating the influx of water into producing oil wells and the intensification of oil production according to claim 1, characterized in that the aliphatic alcohol is methanol or isopropanol.