RU2616637C1 - Solid foaming agent for removal of liquid formation fluid from gaseous and gas-condensate wells - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: solid foaming agent for removal of liquid formation fluid from gaseous and gas-condensate wells, containing following by wt %: suspended methyl methacrylate copolymer with methacrylic acid of 354 K methacryl brand 5-20, polyvinyl pyrrolidone 10-25, neonol AF 9-12 10-25, calcium hydroxide 5-20, water - the rest.

EFFECT: improved efficiency of liquid formation fluid removal from gaseous and gas-condensate wells.

2 dwg, 1 tbl, 4 ex

Description

The invention relates to the field of gas and gas condensate production. The analysis of the prior art showed the following:

- known solid foaming agent for removing liquid formation fluid from gas and gas condensate wells in the following ratio of ingredients, wt. %:

Lutensol AT 25 or AT 50 40-80 Polyvinylpyrrolidone 20-60

(see RF patent No. 2442814 from 06/07/2010, according to CL C09K 8/536, C09K 8/94, publ. 02.20.2012).

The disadvantage of this solid foaming agent is the following. The dissolution rate of this solid foaming agent is 5.4-6.2 g per hour at a temperature of 55 ° C (see example No. 7). As is known, the rate of dissolution of a solid foaming agent affects the volume of fluid transferred to a unit mass of a solid foaming agent, which also reduces the efficiency of removing liquid formation fluid from wells. At such a dissolution rate, a supersaturated surfactant solution will form in the well in a short period of time with the consumption of the largest amount of solid foaming agent with the first portions of the removed formation fluid. The main volume of liquid formation fluid remains in the well and will require the introduction of an additional amount of solid foaming agent. As a result, this will lead to an overrun of the solid foaming agent, a reduction in the inter-operational period, since new portions of the fluid that will enter the well will not be covered by the action of the specified solid foaming agent. The temperature range of the solid foaming agent is up to 72 ° C. The specified solid foaming agent is ineffective in removing liquid formation fluid from wells whose products contain produced water with a salt content of up to 300 g / l at a temperature of up to 85 ° C and a hydrocarbon condensate content of up to 50 vol. % the following reasons. Under these conditions, the surfactant used in the formulation of the solid foaming agent has a low cloud point, which will lead to the formation of a stable emulsion in a mineralized environment. The cloud point depends on the mineralization of the liquid being removed, and with the increase in the latter the cloud point decreases, which makes the specified solid foaming agent inoperative;

- known solid foaming agent for removing liquid from gas and gas condensate wells in the following ratio of ingredients, wt. %:

KSSB powder base 39-49 Surfactant surfactant based on alkyl phenol 50-60 Ammonium tartrate 0.5-0.95 Sodium carbonate 0.05-0.5

(see RF patent No. 2173694 of 06/18/1999 g according to class C09K 7/08, E21B 43/00, publ. 09/20/2001).

The disadvantage of this solid foaming agent is the following. According to the data given in the description of the invention, the removal of fluid is 20-74.6% (see table). In particular, in the absence of gas condensate, the liquid removal is 66.6-74.6%, with a gas condensate content of 20%, the liquid removal is 28.1-39.1%, and when the gas condensate is 50%, the liquid removal is makes up 20-22%. Based on the melting temperature of the starting ingredients (the alkylphenol-based surfactant has a melting point of 43-45 ° C), the solid foaming agent is operable at temperatures up to 68 ° C.

In high-temperature wells (above 75 ° C), due to the low melting point of the solid foaming agent, due to the low temperature range of stability, the near-surface layer of the core of the solid foaming agent can melt with the formation of a viscous melt, it deposits on the walls of the tubing and when loading the next portions rods may form a plug. As a result, work to remove the liquid reservoir fluid will be ineffective. In addition, in the manufacture of a solid foaming agent, it is necessary to strictly control the temperature in a narrow range, since a slight excess will lead to uncontrolled and uneven gas formation, to the inability to form a microporous structure with a closed type of pore.

The technical result that can be obtained by implementing the present invention: improving the efficiency of removing liquid formation fluid from gas and gas condensate wells, the products of which contain formation water with a salt content of up to 300 g / l at a temperature of up to 85 ° C and a hydrocarbon condensate content of up to 50 vol . %, due to the use of a prolonged-action solid foaming agent with improved foaming and tolerant properties.

The technical result is achieved using a solid foaming agent for removing liquid formation fluid from gas and gas condensate wells, containing a copolymer of suspension methyl methacrylate with methacrylic acid of the brand methacryl - 354 K, polyvinylpyrrolidone, neonol AF 9-12, calcium hydroxide and water in the following ratio of ingredients, wt. %:

Methyl Methacrylate Suspension Copolymer with methacrylic acid brand methacryl - 354 K 5-20 Polyvinylpyrrolidone 10-25 Neonol AF 9-12 10-25 Calcium hydroxide 5-20 Water rest

For the preparation of a solid foaming agent, a methyl methacrylate suspension copolymer with methacrylic acid of the methacrylate brand - 354 K (M-354K), molecular weight 90000-100000 according to TU 6-01-1228-80, (hereinafter M-354K copolymer), polyvinylpyrrolidone FS 42-1194- 98 series 039012001, calcium hydroxide according to GOST 9262-77, neonol AF 9-12 (ethoxylated monoalkylphenol) according to TU 2483-077-05766801-98.

The combined use in the recipe of the proposed solid foaming agent of the ingredients in the specified ratio provides an increase in the efficiency of removing liquid formation fluid from wells whose products contain formation water with a salt content of up to 300 g / l at a temperature of up to 85 ° C and a hydrocarbon condensate content of up to 50 vol. %, due to the use of a prolonged-action solid foaming agent with improved foaming and tolerant properties. The achievement of the technical result is provided by a new set of essential features. The use of ingredients in the formulation of a solid foaming agent, characterized by structural features, the presence of chemically active functional groups - hydroxyl (OH), carbonyl (C = O) and hydroxy (-O-) groups, by the mutual influence of the ingredients, explains the effect of a solid foaming agent. The formation of a solid foaming agent occurs due to the following physicochemical processes. In the process of manufacturing rods of a solid foaming agent, a three-dimensional structure is formed due to the following reactions: the reaction is the interaction of the hydroxyl groups of the copolymer M-354K with polyvinylpyrrolidone macromolecules, the formation of hydrogen bonds between neonol AF 9-12 and polyvinylpyrrolidone, the formation of additional bonds between the chains of the copolymer and polyvinylpyrrolidone in the presence of calcium hydroxide. The use of the copolymer M-354K allows one to obtain a viscous structured system characterized by an increase in structural properties over time. At moderate temperatures, linear copolymer macromolecules are able to coagulate due to intramolecular interactions of chain segments; at high temperatures, they form more developed conformations due to the breaking of weak non-covalent intramolecular bonds, while exerting a higher thickening effect on the system. Upon contact of the solid foaming agent with the liquid formation fluid, the formation of the interfacial surface will slow down, which leads to increasing resistance to detachment of the surfactant particles from the surface of the solid foaming agent, and this helps to slow the dissolution of the latter. The dissolution of the solid foaming agent occurs slowly, since the binding energy between the particles that make up the polymer skeleton is higher than the binding energy of the hydrophilic groups of the foaming agent partially shielded by hydrocarbon radicals and water molecules. Since the dissolution of the solid foaming agent is slow, the release of the surfactant is also slowed down, which allows the concentration of the foaming agent to be maintained at the critical micelle concentration for a long period of time, while obtaining the maximum volume of foam. Due to the delayed solubility, the saturation of the liquid with a foaming agent occurs gradually; further dissolution of the foaming agent leads to the removal of the next microvolume of the formation liquid fluid until it is completely removed. The prolonged action of the solid foaming agent is due to the interaction of the ingredients included in its formulation in the claimed quantitative ratios. Polyvinylpyrrolidone has a high adsorbing and complexing ability, binding many substances (Sidilkovskaya F.P. Chemistry of N-vinylpyrrolidone and its polymers // Publishing House "Science", M. 1970, S. 99).

The peptide-like structure of polyvinylpyrrolidone determines its ability to form complexes with neonol AF9-12 due to the formation of a hydrogen bond between the functional group of polyvinylpyrrolidone> N-C = O and the hydroxy group of the neonol molecule and form a secondary structure in which these substances are in a condensed state in the form of associates. The latter may have a branched or annular structure. Such an association leads to an increase in the melting temperature, the heat of vaporization, as well as to a change in the mutual dissolving ability of substances. With increasing temperature, hydrogen bonds break, but this process for this composition is stretched over a relatively wide temperature range and increased in time, which leads to the prolonged action of the proposed solid foaming agent. In FIG. 1 is a diagram of the formation of a bond between neonol AF 9-12 macromolecules and polyvinylpyrrolidone.

The connection of polyvinylpyrrolidone with the M-354K copolymer is carried out due to the forces of the Van der Waals type. Despite the weakness of this interaction, this bond ensures the stability of the resulting molecular complexes. Van der Waals forces are responsible for the formation of the spatial structure. In contrast to the chemical bond, the hydrogen bond (between polyvinylpyrrolidone and neonol AF 9-12) is not so strong, and Van der Waals (between polyvinylpyrrolidone and M-354K copolymer) is even weaker. However, they have a significant effect on many physical properties (temperature characteristics), as well as on the quantitative characteristics of some chemical processes (activation energy of the formation and decomposition of molecular complexes, complex ion molecules). Dispersion forces of attraction between particles of polyvinylpyrrolidone and copolymer M-354K are the weakest bonds of all intermolecular interactions. Therefore, in the process of dissolution, upon contact of the solid blowing agent with formation water, the M-354K copolymer first passes into the solution and only then neonol AF 9-12, therefore, its concentration in the water-gas condensate system increases gradually, which also ensures the prolonged action of the solid blowing agent.

In FIG. 2 is a diagram of the formation of a bond between the molecules of polyvinylpyrrolidone and the copolymer M-354K.

The use of calcium hydroxide as a builder makes it possible to obtain a polymer matrix with a certain structure, playing the role of crystallization centers and lowering the surface tension at the phase boundary. The content of calcium hydroxide in the solid foaming agent promotes the binding of the ingredients to a durable complex due to the formation of additional cationic anionic bonds between the chains of the copolymer and polyvinylpyrrolidone. This is due to the fact that the surface of the particles of the mineral builder (calcium hydroxide) has a complex structure, most of them are hydrophilic and well wetted by the medium, while there are hydrophobic areas on the surface of calcium hydroxide particles, due to which they can contact the copolymer M-354K with hydrophobic parts of the surface. Physico-chemical processes occurring at the stage of production of the rods form a slowly soluble system with a high cohesion density. The melting point of polyvinylpyrrolidone is 150-180 ° C, the melting point of the M-354K copolymer is 190 ° C. The content of these ingredients in the composition leads to an increase in the temperature range of stability of the proposed solid foaming agent, provides a synergistic effect and the possibility of using a solid foaming agent to remove liquid formation fluid from wells at temperatures up to 85 ° C. Moreover, its dropping temperature is 90 ° C.

The high endurance of the proposed solid foaming agent is provided by the formation of an unstable foam emulsion system when foaming a water-gas condensate mixture. The formation of complex neonol - polyvinylpyrrolidone micelles prevents the formation of a stable microemulsion adsorption layer on the surface of gas condensate droplets.

It is known that in the presence of gas condensate in the reservoir fluid, the foaming agent's endurance decreases, since part of it is spent on emulsification of the gas condensate. A prerequisite for the removal of gas condensate is the formation of an unstable foam emulsion system. Used in the formulation of the proposed solid foaming agent, polyvinylpyrrolidone has a fairly loose packaging of molecular chains, which ensures the formation of an unstable microemulsion adsorption layer on the surface of gas condensate droplets. He also has a pronounced ability to form complexes, thereby increasing their hydrophilicity, due to which the proposed solid foaming agent effectively removes formation fluid with a gas condensate content of up to 50 vol. % In addition, the hydrophilic-lipophilic balance of neonol AF 9-12 is 14, which indicates that this surfactant is a stabilizer of the oil-in-water emulsion, and the presence of a hydroxide in the composition of a solid calcium foaming agent enhances the adsorption of surfactant substances on the molecules of water and gas condensate, and due to this, it is effective to remove formation fluid with a gas condensate content of up to 50 vol. % The activity of the solid foaming agent in mineralized water does not decrease, since neonol AF 9-12 forms complexes with calcium and magnesium ions. An important and determining factor in foaming ability is the high rate of formation of the interfacial surface and the excess free energy of adsorption of surfactants on the surface of gas condensate droplets and air bubbles in dynamic conditions. In the case of a low adsorption rate of surfactants, the formation of the interfacial surface will slow down and the endurance of the foaming agent is reduced. The high refresh rate of the interfacial surface during foaming of the gas-gas condensate mixture is provided by the proposed solid foaming agent due to the ingredients included in its formulation. In this case, the high endurance of the solid foaming agent is ensured by the synergistic effect during the formation of a mixed adsorption layer of neonol AF 9-12 molecules - polyvinylpyrrolidone on gas condensate globules and air bubbles formed due to intermolecular interaction in neonol-polyvinylpyrrolidone binary mixtures. The formation of mixed micelle complexes between these ingredients leads not only to a synergistic effect - an increase in the foaming properties of the solid foaming agent, but also to a decrease in the effect of elevated temperature on the cloud point of neonol AF 9-12, since the solubility of the latter decreases in the complexes and it does not form a separate phase when high temperature. Another significant point is that the neonol - polyvinylpyrrolidone complex does not form Winsor systems with the claimed mineralization of the removed liquids. In a wide range of formation fluid mineralization, a hydrophilic (light) foam emulsion is formed with high tolerance, which in turn will increase the efficiency of removing liquid formation fluid from gas and gas condensate wells, the products of which contain formation water with a salt content of up to 300 g / l at a temperature up to 85 ° С and hydrocarbon condensate content up to 50 vol. %

In more detail, the essence of the claimed invention is described by the following examples.

Examples (laboratory)

Example 1

To obtain a solid foaming agent, 6.5 ml (50 wt.%) Of water is poured into the mixer at room temperature, 1.3 g (10 wt.%) Of calcium hydroxide are added and mixed. To the resulting solution, 1.3 g of copolymer M-354K, 1.96 g (15 wt.%) Of neonol AF 9-12, (which is 1.87 ml, density ρ = 1046 kg / m ³ ) are added successively with stirring, 1 96 g (15 wt.%) Polyvinylpyrrolidone. Mixing is carried out until a homogeneous mass is obtained, which is loaded into the molds and kept at a temperature of 120-125 ° C until the rods are melted and then kept at room temperature for 72 hours.

A molded rod with a density of ρ = 1090 kg / m ³ weighs 13 g. The carrying capacity of a solid foaming agent is determined on the model of the well, which is a glass tube 2.3 m high and 0.032 m in diameter. The lower part of the column to a depth of 0.7 m is placed in a water bath , the set temperature in which is supported by a heat heater. Heated air at a speed of 0.5 m / s is supplied from below through a column of liquid. The endurance of a solid foaming agent is defined as the ratio of the volume of the removed fluid to the initial volume of the investigated fluid in percent. For research, formation water is used with a total salinity of 296.57 g / l and a density of 1705 kg / m ³ .

The liquid formation fluid is thermostated at 50 ° C, 70 ° C, 85 ° C.

The composition of the reservoir fluid: 100 vol. % water, gas condensate is absent, at the temperature of temperature control:

50 ° C, an endurance of 80%, a dissolution rate of 0.70 g / h;

70 ° С; endurance 85%; dissolution rate 0.72 g / h;

85 ° C, 90% tolerance, 0.75 g / hour dissolution rate.

The composition of the reservoir fluid: 50 vol. % gas condensate, 50 vol. % water, at a temperature of temperature control:

50 ° С, endurance 72%, dissolution rate 0.33 g / h;

70 ° С; endurance of 75%; dissolution rate of 0.45 g / h;

85 ° С; endurance of 77%; dissolution rate of 0.60 g / hour.

Example 2

To obtain a rod weighing 13 g using the following ingredients, g / wt. %:

Suspension copolymer methyl methacrylate with methacrylic acid brand methacryl - 354 K 1.3 / 10 Polyvinylpyrrolidone 1.3 / 10 Neonol AF 9-12 1.3 / 10 (use 1.24 ml ρ = 1046 kg / m ³ ) Calcium hydroxide 1.3 / 10 Water 7.8 / 60

Perform all operations, as in example 1.

A molded rod with a density ρ = 1078 kg / m ³ .

The composition of the reservoir fluid: 100 vol. % water, gas condensate is absent, at the temperature of temperature control:

50 ° C, an endurance of 68%, a dissolution rate of 0.69 g / h;

70 ° С; endurance 69%, dissolution rate 0.71 g / h;

85 ° С, endurance 70%, dissolution rate 0.75 g / h.

The composition of the reservoir fluid: 50 vol. % gas condensate, 50 vol. % water, at a temperature of temperature control:

50 ° С, endurance 60%, dissolution rate 0.32 g / h;

70 ° С; endurance of 61%, dissolution rate of 0.44 g / h;

85 ° C; 68% tolerance; 0.60 g / h dissolution rate.

Example 3

To obtain a rod weighing 13 g using the following ingredients, g / wt. %:

Suspension copolymer methyl methacrylate with methacrylic acid brand methacryl - 354 K 0.65 / 5 Polyvinylpyrrolidone 3.26 / 25 Neonol AF 9-12 3.26 / 25 (use 3.12 ml ρ = 1046 kg / m ³ ) Calcium hydroxide 0.65 / 5 Water 5.2 / 40

Perform all operations, as in example 1.

A molded rod with a density of ρ = 1086 kg / m.

The composition of the reservoir fluid: 100 vol. % water, gas condensate is absent, at the temperature of temperature control:

50 ° С, endurance 73%, dissolution rate 0.80 g / h;

70 ° С; endurance 78%, dissolution rate 0.82 g / h;

85 ° С; endurance of 80%; dissolution rate of 0.85 g / h.

The composition of the reservoir fluid: 50 vol. % gas condensate, 50 vol. % water, at a temperature of temperature control:

50 ° C, an endurance of 62%, a dissolution rate of 0.68 g / h;

70 ° С; endurance 65%; dissolution rate 0.73 g / h;

85 ° С; endurance 70%; dissolution rate 0.78 g / h.

Example 4

To obtain a rod weighing 13 g using the following ingredients, g / wt. %:

Suspension copolymer methyl methacrylate with methacrylic acid brand methacryl - 354 K 2.6 / 20 Polyvinylpyrrolidone 1.3 / 10 Neonol AF 9-12 1.3 / 10 (use 1.24 ml ρ = 1046 kg / m ³ ) Calcium hydroxide 2.6 / 20 Water 5.2 / 40

Perform all operations, as in example 1.

A molded rod with a density ρ = 1144 kg / m ³ .

The composition of the reservoir fluid: 100 vol. % water, gas condensate is absent, at the temperature of temperature control:

50 ° C, an endurance of 67%, a dissolution rate of 0.67 g / h;

70 ° С; endurance 68%, dissolution rate 0.70 g / h;

85 ° С; endurance 69%, dissolution rate 0.76 g / h.

The composition of the reservoir fluid: 50% vol. Gas condensate, 50 vol. % water, at a temperature of temperature control:

50 ° С, endurance 59%, dissolution rate 0.30 g / h;

70 ° С; endurance 60%; dissolution rate 0.42 g / h;

85 ° С, endurance 67%, dissolution rate 0.68 g / h.

The results of the studies are presented in the table.

The content in the solid foaming agent of the copolymer M-354 K in an amount of less than 5 wt. % or more than 20 wt. %, polyvinylpyrrolidone in an amount of less than 10 wt. % or more than 25 wt. %, neonol AF 9-12 in an amount of less than 10 wt. % or more than 25 wt. %, calcium hydroxide in an amount of less than 5 wt. % or more than 20 wt. % does not provide the ability to form rods. Thus, according to the above, the proposed combination of essential features ensures the achievement of the claimed technical result.

Claims (2)

A solid foaming agent for removing liquid formation fluid from gas and gas condensate wells, containing a copolymer of suspension methyl methacrylate with methacrylic acid of the brand methacryl - 354 K, polyvinylpyrrolidone, neonol AF 9-12, calcium hydroxide and water in the following ratio of ingredients, wt. %: Methyl Methacrylate Suspension Copolymer with methacrylic acid brand methacryl - 354 K 5-20 Polyvinylpyrrolidone 10-25 Neonol AF 9-12 10-25 Calcium hydroxide 5-20 Water rest

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