SU1316568A3 - Method of regeneration of crude oil from underground oil formation - Google Patents

Abstract

The invention relates to the oil industry, is designed to develop oil fields with the use of surface-active substances (SAS) and allows to increase the efficiency of the method. Before injecting an anionic surfactant solution into an oil-bearing formation, an aqueous dispersion of surfactant soluble in oil is introduced into it. Two aqueous dispersions are sequentially injected into the oil-bearing formation through at least one well. The first dispersion contains a non-ionic oil-soluble surfactant with a concentration of 0.05-50 g / l in an amount of 0.01-0.7 pore volume. In this case, ethoxylated alcohols and alkenephenols (ethoxylated nonylphenol, ethoxylated bitanol, ethoxylated dodecylphenol and ethoxylated octylphenol) containing 1–30 groups of ethylene oxide are used. The second dispersion contains an aqueous solution of an anionic surfactant, it is initially dissolved in the aqueous phase with a concentration of 0.05-50 g / l in an amount of 0.01-0.7 pore volume. Water is then injected, which transports the initially injected surfactant dispersions through the oil-bearing formation in the direction of the α-oil recovery tank. Sulfurilated, sulfated, carboxymethylated, phosphated and / or phosphorylated derivatives of surfactants of the first dispersion, which contain 1-30 groups of ethylene oxides, are used as an anionic agent. 2 hp f-ly, 3 tab. O): oe sd o 00 sn

Description

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The invention relates to the oil industry, in particular to the development of oil fields using surfactants.

The purpose of the invention is to increase the efficiency of the method.

Before the injection of the solution of anionic surfactant (surfactant) into the oil-bearing formation, an aqueous dispersion of surfactant soluble in oil is introduced into it.

The proposed method of regeneration includes the following technological stages.

The non-ionic, preferably oil-soluble surface active agent is injected into the formation in the aqueous phase, where such agent is in the form of a dispersion.

In the second stage, an anionic, preferably water-soluble surface-active agent is injected into the oil reservoir in the form of an aqueous solution.

Aggregates of the specified surfactant move through the reservoir in the direction from the injection reservoir to the reception reservoir through conventional flooding.

Depending on the actual properties of the oil-bearing formation, all known methods for controlling mobility and reducing adsorption losses can be used in conjunction with the proposed method in order to increase the effectiveness of the yKasa aggregates of the surface-active agent and to improve the method of oil recovery.

According to a laboratory study, the following has been established: a non-ionic, predominantly oil-soluble surface-active agent can be used in relatively low concentrations; the anionic predominantly water-soluble surface-active agent can be used in a relatively low concentration; Due to the fact that relatively low concentrations of the surfactant are used, a significant amount of excess oil can be regenerated, therefore, favorable economic advantages can be achieved even when agf5

0

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surfactant regatta are used in a relatively large pore volume; the mass of surfactant required for

5 for producing 1 meter of excess oil is 12-25 kg, while in the known methods the characteristic value is 30-70 kg / m.

In the proposed method, numerous surface-active agents can be used, both nonionic predominantly soluble in oil and anionic predominantly soluble in water. Thus, for example, ethoxylated alcohols and phenols containing 1-30, preferably 1-15, ethylene oxide groups can be used as non-ionic surface-active agents. Sulfurized, sulfated, carboxymethylated, can be used as the anionic surfactant. phosphatiro-j. baths and phosphorylated derivatives of the same surface-active agents. The two specified surfactants injected into the reservoir may be the same or different with respect to their basic chemical structure. In the latter case, the chemical and physical difference between such agents is exclusively related to the nature of the ionic group, which is connected to the main non-ionic

35 structure. It has been found that it is best to use ethoxylated oxyphenol, n-phenylphenol, dodecylphenol containing 3-6 ethyloxy groups, as well as ethoxylated heptyl alcohol, octyl alcohol, nonyl alcohol

alcohol, dodecyl alcohol containing 5-9 ethylene oxide groups as non-ionic surface-active agents. Best results are obtained when

 using the following anionic agents: ethoxylated nonylphenol sulfonate, nonylfeiol sulfate,. nonylphenol phosphonate, nonylphenol phosphate, dodecylphenol sulfonate, dode50 cyclphenol phosphate having 3-b ethyloxy groups, or ethoxylated nonanol sulfate, non-nanol sulfate, etc., having 5-9 ethyloxy groups.

thirty

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The effectiveness of the proposed method can be improved if it is used in conjunction with effective mobility control. In common 31

In this combination, the motility agent is injected into the oil reservoir after two surface active agents, and the entire extruded system moves through the formation from the injection reservoir in the direction of the collection reservoir under the influence of conventional hydration. As a result of an increase in viscosity, the following effects can be achieved: the amount of hydrodynamic dispersion of an aggregate of a surface-active agent (mainly anionic) is significantly reduced, while the stability of an aggregate in a porous system is greatly improved, therefore, the effect of solutions of such agents is that their action extends to a greater length over the reservoir: in watered reservoirs, the spreading efficiency over the area and along the vertical of the reservoir significantly increases.

All sequential injections of non-ionic, anionic surface-active agents and agents that regulate mobility, as well as any other modifiers of this process, fall within the scope of the proposed shadow invention. Virtually all water-soluble organic and inorganic compounds can be considered as viscosity enhancing agents or regulating mobility. Preferably, high molecular weight, water soluble polymers (polyacrylamides, cellulose derivatives and polyethylene oxides, polysaccharides, etc.) should be used, as well as organic and inorganic compounds capable of crosslinking or gel formation (for example, partially hydrolyzed polyacrylamides, derivatives cellulose, lignosulfonates, silicates, phosphates, etc.). The concentration of viscosity-enhancing or mobility-regulating agents in an aqueous solution introduced into the reservoir after surface-active agents can lie in the range of 0.05-90 g / l, preferably 0.1 to 50 g / l. The volume of the buffering agent may be 0.05-1.00, preferably 0.1-0.5 pore volumes, depending on the nature of the system, as determined by the proposed method.

In addition, a water solution of a non-ionic or anionic surfactant84

the active agent, preferably both of these solutions, contain viscosity-increasing or motility-regulating agents in order to increase the effectiveness of the action of said aggregates of surfactants. The combined use of surface-active or mobility regulating agents in the same solution does not replace the use of a buffer aggregate, but only complements such use successfully.

Thus, the proposed method is based on the dissolution of the viscosity-increasing or mobility regulating agents in a solution of a non-ionic or anionic agent, preferably in both solutions. Almost all

water-soluble organic and inorganic compounds can be used to increase the viscosity or to reduce the mobility of these surfactant solutions.

agents. However, it is preferable to use high molecular weight water-soluble polymers (polyacrylamides, cellulose derivatives and polyethylene oxides, biopolymers, etc.),

as well as organic or inorganic chemicals capable of crosslinking in situ and gelling (for example, partially hydrolyzed polyacrylamides, cellulose derivatives, lignosulfonates, silicates, phosphates, etc.). The concentration of such additives in the solution of the surfactant, depending on the nature of the chemical itself, may

be 0.05-90 g / l, preferably 0 to 1-50 g / l.

The proposed regeneration method is combined with pre-profile alignment, for example, with the homogenization of layers having different permeability with respect to homogeneous injection.

In addition, solutions of surface-active agents are separated from the natural brine, which may contain inorganic salts in high concentrations.

Thus, viscosity-enhancing or motility-regulating agents capable of extracting porous layers with different permeability are introduced into the oil-bearing

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reservoir rocks injection units of surface-active agent. A large number of water-soluble organic or inorganic compounds can be selected for pre-injection. High molecular weight water soluble polymers (polyacrylamides, cellulose derivatives and polyethylene oxides, biopolymers, etc.) as well as those capable in situ for crosslinking or gelation of organic and inorganic chemicals (for example, partially hydrolyzed polyacrylamides, cellulose derivatives, lignosulfonates, silicone, phosphates, etc., can be used as agents that increase viscosity or regulate mobility. The concentration of the above materials in the pre-injection solution may be 0.05-90 g / l, preferably 0-50 g / l. The volume of the aqueous solution of the aggregate that is injected in front of the solution of the surface-active agent in order to level the porous layer having different permeabilities can be 0.05-0.5 of pore volume, preferably 0.05-0.3 of pore volume.

When the concentration of non-ionic or anionic surface-active agents, preferably both, changes in time periodically or continuously, is covered by the proposed method. Typically, the three concentration programming stages satisfy the requirements of the practice. When using more than ten stages for one unit, stepwise programming does not give any advantages in comparison with the continuous concentration programming. A possible stepwise concentration programming that was effective in the laboratory for both non-ionic and anionic aggregates is as follows:

Concentration, g / l Pore volume

Step 1 0.01-50 0.01-0.5 Preferably 0.5-10 0.05-0.2

Step 2 0.01–40 0.01–0.5 Preferably 0.5–7 0.05–0.2

Stage 3 0.01-30 0.01-0.5 Preferably 0.5-5 0.05-0.2

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In the proposed regeneration method, not only surface-active agents, but also other chemical compounds and additives in the pre-injection injection unit and the buffer unit, are introduced into the oil-bearing formation with gradually varying concentrations.

The effectiveness of the method of regeneration

JO oil can be further enhanced if special inorganic or organic compounds, preferably an aqueous solution of silicates or phosphates, are injected

5 into the oil reservoir before the introduction of a solution of a non-ionic, oil-soluble or anionic, water-soluble surface-active agent in order to reduce the adsorption losses in the porous system. Concentration such chemical compounds in the pre-injection solution may be 0.01-50 g / l, preferably 0.5-10 g / l.

 Special additives are present in the solution in addition to chemical compounds in order to reduce the adsorption loss of surface-active agents and can reduce the retention of agents that increase the viscosity or regulate mobility in the porous system. Finding their chemical nature, additives used to reduce adsorption or retention of surface -active agents and motility regulating agents may be the same or different. Chemical compounds used to reduce adsorption

40 losses may be introduced into the formation before injecting the aqueous dispersion of a non-ionic, predominantly oil-soluble surfactant, or together with an anionic one.

45 predominantly water-soluble surface-active compound dissolved in the same solution. I

5o In the proposed method, special inorganic and organic compounds are added with a concentration of 0.01-50 g / l, preferably 0.5 to 10.0 g / l, in an aqueous dispersion of a non-ionic, mainly oil-soluble agent , or in an anionic aqueous solution, predominantly a water-soluble surface-active agent, in both systems for the purpose of

lower adsorption losses of such active materials in the porous system.

Numerous organic and inorganic compounds can be used to reduce the adsorption and retention of surfactants and motility regulating agents. Among them, water-soluble polymers with low or medium molecular weight (e.g., polyacrylamides), inorganic silicates (ortho, meta-half-polysilicates of sodium), inorganic and organic phosphates, and their mixtures in an aqueous solution are the most effective.

The geological structure and physicochemical nature of the hydrocarbon containing formation may differ from each other.

Claims (3)

1) Two solutions are injected into the cyclic oil reservoir, i.e. c-mass non-ionic and anionic surface-active agents are introduced into the formation in more than one cycle. Each cycle consists of sequentially injecting a portion of the solution of a non-ionic agent and a portion of the solution of an anionic surfactant agent. The surfactant system moves through the oil formation under the action of the mobility of a buffering agent or conventional flooding. 2) In the case of a layered formation, injection walls can be perforated in one or more layers when the injection of solutions of surface-active agents is carried out through one perforation or simultaneously through several perforations in one wall. 3) The proposed method can be used as a primary, secondary or tertiary method in a process carried out in one or more cycles in order to regenerate one or several oil-bearing formations simultaneously. The use of the proposed method provides improved oil recovery, enhances displacement, and improves penetration efficiency, resulting in improved oil recovery. Example 1. Comparative displacement experiments were performed on artificially fortified samples. 165688 Porous rock, which has approximately the same chemical composition as the natural rocks of the oil-bearing formation, using 5 average temperatures and pressures characteristic of hydrocarbon formations. Experimental data and parameters of porous models are the following Core length, cm 120 10 square cross 6.2-6.4 Permeability to brine, m Porosity Experimental pressure, MPa Experimental temperature, s 0.173-0.210 0.28-0.30 - 20 95 Sample Alf 2 Oil from Medium Oil Tank Brine sample Alg 2 brine Frontal displacement speed, m / day 0.5 Each time before the experiments, the displacement is carried out by the initial saturation of the oil, the usual water-oil method and carried out the extrusion brine 1.0 then. The average oil content of the core after the displacement of brine is 33/37% of the pore volume, i.e. 47-53% of the original 5 oil content (O.O.I.P). The amounts of recovered excess oil are calculated as a percentage of O.O.I.P. in the core sample. The first series of laboratory experiments proved that the proposed method provides a more efficient displacement of oil in comparison with the known methods of oil recovery, based on the use of water 5 solutions containing both non-ionic and anionic surface-active agents. In tab. Table 1 shows data on the quality of surface-active agents, the ratio of surface-active agents, their concentrations, the size of aggregates, as well as the amount of excess oil produced, and also shows the results obtained in examples 1-11. Examples 1-5 (table. 1) demonstrate the results of experiments on the displacement of various pairs of 913 anionic and non-ionic surface-active agents, when the concentration ratios are maintained at 1: 1, it has been established that the amounts of excess oil obtained in each case are less than 10% of 0.0.1.R. In experiment 11, in which surface-active agents (non-ionic and anionic) are injected in separate solutions, the amount of excess oil is 36.4% 0.0.1.R., although the quality and absolute amount of surface-active agents are the same as in the example one. The lesser amount of excess oil obtained in Examples 1-5 is due to the fact that the ratio of surface active agents in the water-driven aggregates is not optimal. In examples 6-8, the ratio of surface active agents (used in example 1 to obtain a relatively good result) is changed so that the total concentration of surface active agents remains constant. The amount of excess oil produced is significantly increased when the ratio of surface active agents shifts to the side of the predominant content of non-ionic substance, however, even in Example 8, which is better by results, the amount of excess oil is almost 10% less than in Experiment 11. The amount of excess oil that can be obtained under the action of this pair of surface-active agents, to a large extent depends on the concentration of the solutions. Therefore, experiments 9 and 10, on the one hand, demonstrate how the amount of excess oil depends on the concentration of a pair of surface-active agents used together, and on the other hand, these experiments answer the question whether it is possible to obtain the same amount of excess oil by increasing these concentrations. It has been established that increasing the total concentration of surface-active agents from 5-8 to 10 g / l leads to an increase in the amount of excess oil from 22.4-31.8 to 34.8% 0.0.01 .., however, these results are still lower value of 36.4% 0.0.1. P., obtained by the proposed method. In addition, the unit cost of surface-active1656810 a lethal agent (1 kg of surface-active agent per 1 m of excess oil) is also important, as can be seen from the following data: 5 Experiment Specific consumption of surface-active agent, kg / m iO oil 732.5 9 10 11 34.8 41.0 20.5 Based on the data presented in Table. 1, it can be concluded that the effectiveness of the proposed method (the amount of excess oil and the specific consumption of surface-active agent) is significantly better than the efficiency of processes based on the combined use of non-ionic and anionic surface-active agents (mixture). An example hydrosatural fluid system. 11 is not optimized. Laboratory experiments show that the application of the proposed method, in addition, the combination with other methods that contribute to increased efficiency, can provide even better results. In tab. 2 summarizes the results of experiments in which the volumes of consecutive liquid aggregates modified while maintaining absolute amounts of surface-active agents at a constant value — and this method is combined with exposure to polyacrylamide buffer in order to control mobility; From the results of examples 12-15 (Table 2), it can be concluded that according to the invention — sequential injection of aqueous solutions of a non-ionic and anionic surfactant — it becomes possible to achieve 40% O.O.I.Pi in excess oil production when combined with other methods to increase efficiency and optimize the composition of the water mill system. In the laboratory experiment 13, the displacement was 44.6% 0.0.1.R. excess oil and the specific consumption of surfactant was reduced to 12.5 g / m of oil .. The significant recovery of excess oil is not limited to the pairs of surfactants from components A and B., which are used in most of the examples. All surface active couples used in Examples 16–20 yielded excess oil recovery of more than 30% 0.0.1.Р ,, although the quality of the optimal pair of surface-active agents essentially depends on the type and quality of this crude oil, brine, oil grade foot layer, etc. Examples 21-24 in the table. 3 illustrates the effect of limiting concentrations and fringe size. From the results presented in the examples, it can be seen that Lara of surfactants A and B can provide an additional amount of oil even when using only 0.05 g / l in an amount and a volume of 0.01 pore volume, although its absolute value low (2.3%). The results obtained with the introduction of MB with a higher pore volume (0.7 pore volume) and low concentration indicate the effect of pore volume on productivity, but even in this case, the amount of excess oil is small. Examples 23 to 24 present the results of studying the limiting value of a different concentration as well in order to establish a mechanism. At a concentration of 50 g / l and even a volume of 0.01 pore volume, it is possible to provide a significant excess of oil (15.7%), whereas with the highest volume of 0.7 pore volume, the resulting excess of 43.3% cannot be considered as optimum. These experiments, designed to study the effect of limiting concentrations and pore volume, were carried out without the use of a polymer buffer. It is obvious that practical use of the limiting concentration is possible. 3. Method pop, 1, characterized in that sulfurized, sulfated, carboxymethylated, phosphated, and / or phosphorylated derivatives of surfactants, peroxides, are used as the animate water-soluble surface active agent. radios and pore volume, but in these cases-. The decisive role is played by the ecological and numerical ones in Clause 2, which contain all the calculations. Although the use of 1-30 groups of ethylene oxide. surfactants with a very high concentration and pore volume is effective, but the additional yield is disproportionate to the mass of chemicals injected into the well, so the economic indicators for industrial use are below the permissible limit. Invention Formula 1. A method of regenerating crude oil from an underground oil-bearing formation, which consists in injecting through at least one injection well into the oil-bearing formation successively two water dispersions, different TeMj that, In order to increase the efficiency of the method, the first dispersion contains a non-ionic oil-soluble surface-active agent with a concentration of 0.05–50 g / l in an amount of 0.01–0.7 pore volume, and the second dispersion contains an aqueous solution of anionic surface-active agent, which dissolves in the aqueous phase, a concentration of 0.05-50 g / l B in an amount of 0.01-0.7 pore volume, after which water is injected, which transfers the initially injected dispersions of surface-active agents through the oil-bearing formation in the direction of the reservoir l collecting oil. 2. Method as described in, wherein ethoxylated alcohols are preferably used as non-ionic oil-soluble surfactants. alkenephenols (etrxylated nonylphenol, ethoxylated butanol, this is xylated dodecylphenol, and ethoxylated octylphenol.) containing 1-30 groups of ethylene oxide. 3. Method pop 1, characterized in that the sulfonic, sulfated, carboxymethylated, phosphated and / or phosphorylated derivatives of the surfactants listed in 2 are used as anionic water-soluble surface active agent, - 30 groups of ethylene oxide. Note. Surface active agent - partially hydrolyzed polyacrylamide Compiled by I. Lopakova Editor S. Patrusheva Tehred V. Kadar Proofreader M. Sharoshi Order 2374/58 Circulation 532 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, ul, Proektna, 4 Continuation of table 2 Table 3