RU2526943C1 - Compound for control of development of inhomogeneous oil stratum - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: compound for control of development of inhomogeneous oil stratum includes stabilised latex, silicic acid derivative and water. As a silicic acid derivative is contains siliceous that represents a finely dispersed system based on silicone dioxide with silica modulus 100. It contains water activated electrochemically with pH 5.4 at electric conductivity of 3.7 mS. The compound includes the following component ratio, wt %: stabilised latex (on dry basis) 2-5, siliceous with silica modulus 100 in quantity of 2-5, the above water activated electrochemically - the remaining part.

EFFECT: increasing oil displacement efficiency.

2 dwg, 1 tbl

Description

The invention relates to the oil industry, in particular to compositions for increasing oil recovery of oil fields by regulating the development of heterogeneous formations.

There is a method of regulating the waterflooding front of oil reservoirs, which includes stopping at least one injection well and holding technological shutter speed to restore the current reservoir pressure in the bottomhole zone of the well, followed by pumping in rims that limit the filtration of the composition containing polymer, sodium silicate, fresh and mineralized water , with an increase in injection pressure and a change in the concentration of the composition in each rim, in which the filter-limiting composition additionally contains latex, said composition prepared by mixing a composition comprising, in weight.%:

polymer 0.005-2.0 sodium silicate 0.1-10.0 latex 0.01-15.0 fresh water rest

and mineralized water with a volume ratio varying within 1: 1-1: 30, and the injection pressure is increased by at least 1%, not exceeding the maximum allowable for each individual well, where Alcoflood 1175A polyacrylamide manufactured by the company is used as the polymer BASF in the amount of 0.072 t, liquid glass is used as sodium silicate - a derivative of silicic acid with a silicate module of 2.3-3.6 in accordance with GOST 13078-81, and unstabilized nonionic surfactant latex of the SKS-65 GP grade is used as latex ( GOST 1056 4-75) in an amount of 3.6 t 7.66 m ³ (RU Patent No. 2290504, IPC E21B 43/22, C09K 8/88, 2006).

The disadvantage of this object is the lack of effectiveness of the composition associated with its low stability, and, as a consequence, insufficient penetration into the pore space of a heterogeneous oil reservoir.

A known composition for regulating the development of a heterogeneous oil reservoir containing a water-soluble organic polymer stabilized by a nonionic surfactant latex and water, for example, various types of polyacrylamide, a polyacrylamide copolymer or a water-soluble cellulose derivative, for example, carboxymethyl cellulose, can be used as a water-soluble organic polymer as a latex stabilizer use, for example, neonol or sinterol, in the following ratio comrade, wt.%:

water soluble organic polymer 0.005-1.0 stabilized latex 0.05-10.0 water rest

(RU Patent No. 2172821, IPC 7 ЕВВ 43/22, 2001).

The disadvantage of this object is the lack of effectiveness of the composition associated with its low stability, and, as a consequence, insufficient penetration into the pore space of a heterogeneous oil reservoir.

The closest in technical essence is the composition for regulating the development of a heterogeneous oil reservoir containing latex, a derivative of silicic acid and water, as a derivative of silicic acid contains liquid glass with a silicate module of 2.3-3.6 in the following ratio of components, wt.%:

water glass (in terms of sodium silicate) 0.1-10.0 latex (in terms of dry matter) 0.01-10.00 water rest

(RU Patent No. 2194158, IPC 7 E21B 43/22, 2002).

The composition contains liquid glass - a derivative of silicic acid with a silicate module of 2.3-3.6 in accordance with GOST 13078-81. The composition contains latex stabilized with a nonionic surfactant. Latex is an aggregatively stable fine emulsion of synthetic or natural rubbers in water, for example, SKS-65 GP or SKS-65 GPB.

The composition is prepared by mixing the components of the composition in fresh or mineralized water with a density of not more than 1010 kg / m ³ or in a mixture thereof.

A disadvantage of the known composition is the lack of aggregate stability when interacting with the formation water of highly flooded sections of a layered heterogeneous oil reservoir, which helps to reduce the oil displacement coefficient.

The objective of the invention is to increase the coefficient of oil displacement by increasing the aggregate stability of the composition when interacting with formation water of highly watered sections of a heterogeneous oil reservoir.

The technical problem is solved in that the composition for regulating the development of a heterogeneous oil reservoir, including stabilized latex, a derivative of silicic acid and water, contains silica as a derivative of silicic acid, which is a highly dispersed system of silicon dioxide with silicate module 100, and as water contains electrochemically activated water with a pH of 5.4 at a conductivity of 3.7 mS, with the following ratio of components, wt.%:

stabilized latex (in terms of dry matter) 2-5 silica with silicate module 100 2-5 specified electrochemically activated water rest

The solution of the technical problem allows to increase the oil displacement coefficient up to 4.8%.

The composition uses SKS-65 GPB synthetic latex stabilized with a nonionic surfactant, specification in accordance with TU 38.103111-83 (see http: /b2b.sibur.ru/pages_new_ru/catalog/catalog_product.jsp? Portal = SYNRUB & prod = 1308 & level = 110); as a derivative of silicic acid, the composition contains silica with silicate module 100 of the KZ-TM 20 brand, specification in accordance with TU 2145-004-12979928-2001 (see http://www.compass-kazan.ru/products/64/) . As electrochemically activated water, the composition contains anolyte obtained by treating water with sodium chloride in an electrochemical activation unit STEL-10AK. The initial slightly salted water has a pH of 5.75 and an electrical conductivity of 2.5 mS. Electrochemically activated water used in the composition according to examples 1 and 2, has a pH of 5.4 with a conductivity of 3.7 mS. The composition of the claimed object is prepared by mixing stabilized latex (latex SKS-65 GPB) and silica with silicate module 100 in the specified electrochemically activated water.

The composition according to examples 3 and 4 is prepared by mixing stabilized latex (SCS-65 GPB latex) and silica with silicate module 100 in electrochemically activated water, which has a pH of 6.4 at a conductivity of 3.5 mS.

The composition according to examples 5 and 6 is prepared by mixing stabilized latex (SCS-65 GPB latex) and silica with silicate module 100 in electrochemically activated water, which has a pH of 4.4 at a conductivity of 3.9 mS.

The data in examples 1-6 and the prototype are summarized in table 1.

The composition obtained in this way is pumped into the reservoir using the technology of areal impact (from cluster pumping stations) or using a one-time technology (in separate wells).

The inventive composition allows you to create a waterproofing screen at a greater distance from the injection well, and thereby increase the coverage of the formation by oil-displacing effects (Figure 2, where the positions 3, 4, 5 correspond to the formation models farthest from the injection well). In the study of the effectiveness of the composition for regulating the development of a heterogeneous oil reservoir, the data on filtration resistance are important.

The increase in oil recovery of highly watered layered heterogeneous formations when using sediment-gel-forming compositions is proportional to an increase in filtration resistance or the so-called residual resistance factor, and thereby increase the oil displacement coefficient (Gazizov A.A. : LLC Nedra-Business Center, 2002, p.317).

Bulk models are used to simulate highly flooded sections of a layered heterogeneous formation, each of which is a cylindrical hollow metal body 15 cm long, 30 mm in diameter with a wall thickness of 6 mm, closed on both sides with plugs having through holes. These cylindrical hollow models (tubes) are filled with acid-washed quartz sand. Next, the models are sequentially interconnected using adapter couplings. Filtration resistance, or the so-called residual resistance factor, is determined on the models according to the claimed object and the prototype according to the generally accepted technique (Lozin E.V., Khlebnikov V.N. Use of colloidal reagents to increase oil recovery. - Ufa, ed. Bashnipineft, 2003, p. one hundred).

The order of injection of agents filtered by the reservoir model is as follows: first, mineralized water of a certain density is pumped with an amount of 2-3 pore volumes (p.o.) until the pressure drop stabilizes, then a buffer of 0.1 b.p., composition of 0.19 b.p. , buffer 0.1 bp and a rim of saline water 0.36 bp The filtration is stopped for 2 days to complete the coagulation processes, after which the mineralized water is filtered until the pressure drop stabilizes at about 3.0 bp. In this case, determine: the initial (k ₁ ) and final (k ₂ ) permeability of the reservoir models in water; pressure drop (p) that occurs during filtration; flow rate of filtered water at the outlet of the reservoir model (Q); the volume of oil displaced by water from the reservoir model at the maximum oil saturation with this water (V _HB ) and the initial volume of oil contained in the reservoir model (V _HH ), as a result, the residual resistance factor and oil displacement coefficient are calculated.

The residual resistance factor in the case of steady filtration and constant viscosity of the filtered water after exposure to the waterproofing composition of water is determined by the formula

, $$R_{OCT}=\frac{k_{\mathrm{one}}}{{\mathrm{<figure-callout\; id="2"\; label="k"\; filenames="00000004.png,00000005.png"\; state="\{\{state\}\}">k</figure-callout>}}_2}$$

,

where k ₁ and k ₂ - the permeability of the porous medium in water before and after exposure, respectively, determined by the formula

, $$k=\frac{Q\cdot l\cdot \mu }{\Delta P\cdot S}$$

,

where Q is the fluid flow rate, m ³ / s; ΔP is the pressure drop, Pa; µ is the dynamic viscosity of water, Pa · s; l is the length of the reservoir model clogged by the porous medium, m; S is the cross-sectional area of the reservoir model clogged by the porous medium, m ² .

The oil displacement coefficient is defined as the ratio of the volume of oil V _HB displaced by water from the reservoir model at the maximum saturation of oil with this water to the initial volume of oil V _HH contained in the reservoir model

. $$K_B=\frac{V_{HB}}{V_{HH}}$$

.

The above formulas are given in the book (A. A. Gazizov. Oil recovery at a late stage of development. - M.: Nedra-Biznescentr LLC, 2002, p. 124, 152).

The experimental results (at a temperature of 20-22 ° C) on reservoir models of the Romashkinskoye field with the determination of the residual resistance factor and oil displacement coefficient depending on the concentration of reagents in the technological solution are presented in table 1.

The results of determining the residual resistance factor and oil displacement coefficient (at a temperature of 20-22 ° C) on the reservoir models of the Romashkinskoye field depending on the concentration of reagents in the injected waterproofing solution are presented in table 1.

Table 1 The composition of the prototype and the claimed object according to examples 1-6, wt.% Residual Resistance Factor Oil displacement ratio,% one 2 3 four Prototype Latex - 0.10 Liquid glass - 0.01 20,2 72.1 Water - 99.89 Latex - 5 Liquid glass - 2 40.5 80,4 Water - 93 Latex - 10 Liquid glass - 10 49.2 81.2 Water - 80 The claimed composition 1. Stabilized latex (in terms of dry matter) - 5.00 Silica sol - 2.00 46.3 85.3 Electrochemically activated water with a pH of 5.4 at a conductivity of 3.7 mS - 93 2. Stabilized latex (in terms of dry matter) - 2,00 Silica sol - 5.00 55.7 85.9 Water electrochemically activated (pH 5.4 at a conductivity of 3.7 mS) - 93 Additional examples one 2 3 four 3. Stabilized latex (in terms of dry matter) - 5.00 Silica sol - 2.00 42.9 82.5 Electrochemically activated water with a pH of 6.4 at a conductivity of 3.5 mS - 93 4. Stabilized latex (in terms of dry matter) - 2,00 Silica sol - 5.00 50,0 83.1 Electrochemically activated water with a pH of 6.4 at a conductivity of 3.5 mS - 93 5. Stabilized latex (in terms of dry matter) - 5.00 Silica sol - 2.00 46.8 86.0 Electrochemically activated water with a pH of 4.4 at a conductivity of 3.9 mS - 93 6. Stabilized latex (in terms of dry matter) - 2,00 56.7 86.0 Silica sol - 5.00 Electrochemically activated water with a pH of 4.4 at a conductivity of 3.9 mS - 93

The results of filtration experiments (at a temperature of 20-22 ° C) on the penetration distance into the interwell zone of a heterogeneous oil reservoir of the Romashkinskoye field with the determination of the residual resistance factor according to the prototype (composition: latex - 5.00 wt.%, Liquid glass - 2.00 wt. %, water - the rest) and for the claimed object, see position 2 of table 1 (composition: latex - 5.00 wt.%, silica sol - 2.00 wt., water electrochemically activated - the rest) are presented in FIG. 1 and FIG. .2 respectively. Positions 1-5 mean the number of the sand-filled formation model in the articulated structure. The farther the model is from the discharge tank, the higher its serial number.

According to the results of the filtration experiments presented in table 1, it can be seen that the claimed object in comparison with the prototype increases the value of the resistance factor and oil displacement coefficient, which is associated with the formation of an insulating screen at the greatest distance from the injection well in the interwell zone of the heterogeneous oil reservoir model, and, as the consequence, by increasing the coverage of the formation due to the involvement of poorly drained sections of the formation in flooding, see Fig. 2, position 3, 4, 5, i.e. The claimed object allows to increase the oil displacement rate up to 4.8%.

Claims (1)

The composition for regulating the development of a heterogeneous oil reservoir, including stabilized latex, a derivative of silicic acid and water, characterized in that it contains silica as a derivative of silicic acid, which is a highly dispersed system of silicon dioxide with silicate module 100, and as water it contains electrochemically activated water with a pH of 5.4 at a conductivity of 3.7 mS, with the following ratio of components, wt.%:
stabilized latex (in terms of dry matter) 2-5 silica with silicate module 100 2-5 specified electrochemically activated water rest

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