RU2386664C1 - Composition for increasing oil production - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to the oil extraction industry, particularly to compositions for increasing oil production. The composition for increasing oil production contains a polymer from the acrylic family, a non-ionic surfactant, a cross-linking agent and water. The said polymer from the acrylic family is an all-weather aqueous polymer, and the non-ionic surfactant is a waxy low-melting commodity form - SNO-3B, and the cross-linking agent is still waste liquid or calcium chloride or magnesium chloride with the following ratio of ingredients in wt %: all-weather aqueous polymer 3-10, SNO-3B 1-5, still waste liquid or calcium chloride or magnesium chloride 5-10, water - the rest.

EFFECT: more effective action of the precipitate-forming composition on waterlogged oil-bearing strata.

5 tbl, 2 ex

Description

The invention relates to the field of the oil industry, in particular, compositions for increasing oil production from a heterogeneous oil reservoir by regulating the coverage of the reservoir by water flooding and redistributing filtration flows by reducing the permeability of water-permeable zones of the reservoir.

A known composition for oil production from a heterogeneous oil reservoir based on aqueous polymer solutions with a concentration of 0.03-0.05% (Surguchev M.L. Secondary and tertiary methods of increasing oil recovery. - M .: Nedra, 1985, p.156-165 )

The disadvantage of the composition is its relatively low efficiency due to the adsorption of the polymer and its destruction by mineralized waters.

Closest to the proposed technical essence is a gel-forming composition for increasing oil production, containing givpan, hydrochloric acid, distiller liquid and nonionic surfactant (US Pat. RF No. 2215131, IPC 8 Е21В 43/22, publ. 10.27.03 g. )

However, the use of this composition is not effective enough due to the partial destruction of the gel in the bottomhole formation zone, at high gradients of the filtration rate of the composition. In addition, the use of the composition is limited at sub-zero temperatures.

The objective of the invention is to increase the efficiency of oil production by injecting a stable composition in its entirety, completely blocking highly permeable zones of the formation, redistributing the filtration flows, increasing the coverage of the formation by water flooding and applying it in any climatic conditions.

The technical result of the invention is to increase the effectiveness of the impact of sediment-forming composition on flooded oil-containing formations.

The technical result is achieved in that the composition for increasing oil production containing an acrylic polymer, nonionic surfactant (nonionic surfactant), a crosslinking agent and water, according to the invention, contains an all-weather aqueous polymer (PVA) as an acrylic polymer and a low curing polymer low-melting commercial form of nonionic surfactants - CHO-ZB, as a cross-linking agent - distillation liquid (J), or calcium chloride, or magnesium chloride in the following ratio of ingredients, wt.%:

All-weather water polymer (PVV) 3-10 Low hardening commercial form of nonionic surfactants SNO-3B 1-5 Distiller fluid or calcium chloride, or magnesium chloride 5-10 Water Rest

The proposed composition was tested in laboratory conditions. The following reagents were used:

1. As a polymer - an all-weather aqueous polymer (PVV) with a pour point of not higher than minus 15 ° C.

PVV reagent is intended for use in oil production processes according to TU 2216-002-75821482-2006. The PVV reagent is available in liquid form and is a low-viscosity water-soluble polymer of the acrylic series.

The reagent PVV belongs in accordance with GOST 12.1.007 to hazard class IV.

2. As nonionic surfactants - low-hardening commercial form of nonionic surfactants SNO-3B - oil-displacing system based on nonionic surfactants, type AF _9-12 in the form of low-curing low-melting marketable form containing 60% AF _9-12 , 30% isobutyl alcohol and 10% water. Available in accordance with TU 39-579-4688-001-88 Rev. 1.

3. Distiller liquid is a waste of soda production, is produced according to TU 2152-032-002 04872-97, contains calcium hydroxide and calcium salt in the composition.

4. Technical calcium chloride in accordance with GOST 450-77.

5. Technical magnesium chloride in accordance with GOST 4209-77.

To prepare the composition, the reagents PVV and CHO-3B are mixed in the required ratio according to the claims. The prepared mixture is stored for a long time without crosslinking. When a mixture of PVV and nonionic surfactants SNO-3B, distillation liquid, or calcium chloride, or magnesium chloride is injected into the formation and mixed with formation fluids, the PVV, SNO-3B polymer with divalent Ca ⁺⁺ and Mg ⁺⁺ cations of formation water and distiller liquid are crosslinked. with the formation of a viscoelastic precipitate or a crosslinked structure of the modified polymer. The latter blocks the channels of the porous medium in which it was formed from the penetration of injected water, changing its direction in poorly developed oil-saturated zones, i.e. allows you to regulate the development of an oil field by water flooding.

Example 1. In volumetric test tubes, 10 ml of a mixture of PVV with a mass concentration of 3, 5, 10% and nonionic surfactants CHO-3B with a mass concentration of 1, 2.5, 5% with 10 ml of distillation liquid, or calcium chloride, or magnesium chloride with mass concentration of 5, 7.5, 10%. After thorough mixing, the composition is left for 2 hours to form a precipitate, after which the volume of the precipitate and its stability over time are measured. The results of the experiments are given in table. 1-3.

Laboratory studies indicate that the sediment-forming composition has advantages in its precipitation-forming properties over the prototype, i.e. sediment-forming ability is higher by 20-23%. The precipitate formed is more resistant to destruction. So, after 168 hours, the sediment volume in the known composition decreased by 43-47%, while in the proposed composition it was only 2.5-8.9%, in the case when the precipitating agent is a distillation liquid (Table 1).

Thus, the proposed composition exceeds the sediment-forming properties of the known composition.

Nonionic surfactants CHO-3B, adsorbed on polymer molecules, stabilize it from premature crosslinking with formation Ca ⁺⁺ and Mg ⁺⁺ ions of produced water. In addition, nonionic surfactants CHO-3B is a displacing agent. As parameters of the filtration properties of the composition, characterizing the viscoelastic and insulating properties, we used the values of the factor and residual resistance factor, a decrease in the permeability of the channels washed with water, and an increase in the displaced oil.

Example 2

In the experiment, bulk reservoir models were used. The characteristics of reservoir models are presented in table. 4. As a porous medium, disintegrated sandstone of the Arlan deposit was used.

Experiment progress: the reservoir model was saturated with an isoviscose oil model of the Arlan field, consisting of degassed oil, in which 30% of kerosene was added. The viscosity of isoviscous oil is 19.5 MPa * s.

After filtering the produced water (salt content 140 g / l) through the porous medium until the oil displacement is completely stopped and the differential pressure is stabilized, the mixture of PVV and CHO-3B was sequentially filtered in the amount of 30% of the pore volume, followed by the delivery of 20% distillation fluid and 10% reservoir water. Then the filtration was stopped for 10-12 hours for gelation at a reservoir temperature of 24 ° C. After stopping, the filtration of injected water was resumed, while the pressure drop was measured immediately after exposure, as well as after injection of 5 pore volumes of injected water. The results of filtration studies are presented in table. 5.

As can be seen from the table. 5, as a result of filtration after 12 hours of gelation at a temperature of 24 ° C, the pressure drop during pumping of the proposed composition increased by 25-32.9 times (experiment 1, 2, 3 of Table 2), while the residual resistance factor was 13 -16, while when filtering the composition according to the prototype, the pressure drop increased 10.9 times, and the residual resistance factor amounted to 5.8.

As can be seen from the data presented, the inventive composition has a higher resistance factor, which characterizes its effectiveness for increasing oil recovery.

Thus, the composition for increasing oil production, based on the use of an all-weather aqueous polymer (PVV), low-hardening salable form CHO-3B and distillation liquid, or calcium chloride, or magnesium chloride, has a number of technological advantages compared to the prototype.

1. The composition to increase oil production when mixed with produced water forms a gel stable in time and volume.

2. The composition is all-season, which is one of the most important advantages for the climatic conditions of the Ural-Volga region and Western Siberia.

3. The composition does not require the use of non-standard, expensive equipment. All processes of dissolving and pumping reagents are carried out on serial equipment. Reagents are environmentally friendly, biodegradable. Hazard Class IV.

4. The reagents PVV, CHO-3B, chlorides of alkaline earth metals do not adversely affect the collection and preparation of oil.

Table 1 The effect of distiller liquid (DJ) * on sedimentation in the PVV + nonionic surfactant system СНО-3Б. Structure The concentration of ingredients,% Volume fraction of precipitation,% In 2 hours after 168 hours In 2 hours after 168 hours PVV 3 41 38 45 41 Nonionic surfactants SNO-3B one PVV 5 47 44 fifty 46 Nonionic surfactants SNO-3B 2.5 PVV 10 40 39 44 40.5 Nonionic surfactants SNO-3B 5 5 Givpan-10 10 33 22 (bundle) 35 21.8 (layering) Hydrochloric acid fifteen JJ Nonionic surfactants SNPCH-4410 0.05 (prototype) * The concentration of J - 5.10%. The aging (aging) time of precipitation is 7 days. table 2 The effect of calcium chloride * on sedimentation in the PVV + nonionic surfactant system СНО-3Б. Structure The concentration of ingredients,% Volume fraction of precipitation,% In 2 hours after 168 hours In 2 hours after 168 hours PVV 3 63 58 70 64 Nonionic surfactants SNO-3B one PVV 5 77 71 85 80 Nonionic surfactants SNO-3B 2.5 PVV 10 one hundred 95 one hundred 97 Nonionic surfactants SNO-3B 5 5 * The concentration of calcium chloride is 5, 10%. The aging (aging) time of precipitation is 7 days. Table 3 The effect of magnesium chloride * on sedimentation in the PVV + nonionic surfactant system СНО-3Б. Structure The concentration of ingredients,% Volume fraction of precipitation,% In 2 hours after 168 hours In 2 hours after 168 hours PVV 3 75 68 78 68.1 Nonionic surfactants SNO-3B one PVV 5 88 81.3 93 88.7 Nonionic surfactants SNO-3B 2.5 PVV 10 one hundred one hundred one hundred one hundred Nonionic surfactants SNO-3B 5 * The concentration of magnesium chloride is 5, 10%. The aging (aging) time of precipitation is 7 days. Table 4 Characterization of reservoir models Experience number Model length, cm Tube diameter, cm Pore volume, bp Air permeability, microns ² Porosity,% one thirty 2.9 63.0 1.3 31.8 2 thirty 2.9 59.6 1.23 30.1 3 31.3 2.9 66.3 1.37 32.1 four 30.5 2.9 64.0 1.29 31.8 5 30,2 2.9 61,4 1.35 30.8 6 30.3 2.9 62.0 1.31 31,0

Claims (1)

Composition for increasing oil production, containing an acrylic polymer, nonionic surfactant (nonionic surfactant), a crosslinking agent and water, characterized in that the composition contains an all-season aqueous polymer (PVV) as an acrylic polymer and a low-melting low-melting commodity polymer the form of nonionic surfactants - CHO-3B, as a crosslinking agent - distillation liquid (J), or calcium chloride, or magnesium chloride in the following ratio of ingredients, wt.%:
All-weather water polymer (PVV) 3-10 Low hardening commercial form of nonionic surfactants SNO-3B 1-5 Distiller fluid or calcium chloride, or magnesium chloride 5-10 Water Rest