Foamable composition for well development

 

(57) Abstract:

The invention relates to the oil and gas industry, namely, foam compositions, and is intended for completion and stimulation fluids from the reservoir. Improving the efficiency of recovery of the permeability of the formation, reduction of costs at completion is achieved due to the content in the foam composition of ammonium chloride 30,0 35,4 wt. nitrite alkali or alkaline earth metal initiator reaction of the halide or sulfate of iron or aluminum, SAC 0.04 to 0.50 wt. CMC or PAA 0.3 to 0.8 wt. and the rest of the water. Foamable composition can be used both in solid and in liquid state and can be used to obtain foam, foam, light weight drilling fluids, cement compositions of the wells are completed, cleaning and washing of the bottomhole zone of the formation, and other processes of intensification of oil and gas. 8 table.

The invention relates to the oil and gas industry, in particular foaming compositions, and is intended for completion and stimulation fluids from the formation.

Known composition for insulation of water in the well containing the hydrolyzed polyaki the high efficiency in the development wells.

Known self-evolving foam system containing ammonium chloride, nitrite, alkali or alkaline earth metal initiator of the reaction of an organic acid, a surfactant, and water [1] the Disadvantage of using this system is the low efficiency of recovery of the permeability of the reservoir, the high cost of development wells.

The purpose of the invention increase the efficiency of recovery of the permeability of the reservoir, reducing the cost of development wells. This is achieved by the fact that well-known self-evolving foam system containing ammonium chloride, nitrite, alkali or alkaline earth metal, surfactant, initiator of the reaction of organic acid and water, it additionally contains a water-soluble structure-forming agent is carboxymethylcellulose (CMC) or polyacrylamide (PAA), and as an initiator of the reaction, the halide or sulfate of iron, aluminum in the following ratio, wt. Ammonium chloride 30,0-35,4

Nitrite or alkaline

alkaline-earth metal 38,8-45,7

The halide or sulfate of iron, aluminium, 11,2-22,5 CMC or PAA 0,3-0,8 SAC 0.04 to 0.50 in Water the Rest

Gassing and foaming occurs spontaneously due to thermal energy of the reservoir through the line between the UB>Cl+Me(NO2)n__ nN2+MeCln+2nH2O

(1) where IU alkali or alkaline earth metal;

n index the chemical formula of a molecule of a substance.

Gasanalysis solution and foam formation during the interaction of chloride of ammonium and nitrite alkali or alkaline earth metal according to the scheme (1) occurs when the temperature of the reaction medium above 80aboutC.

In order to increase the flow rate of this chemical reaction and thermal regulation of health foam system in the reaction mixture is further added, the reaction initiator (catalyst).

In the proposed composition of the initiator of a chemical reaction is a Lewis acid, salts formed from the remnants of a strong acid and weak base. These salts are hydrolyzed in aqueous solution and form acids and low in the water hydroxides of metals. For example, iron chloride (III) when interacting with water forms hydrochloric acid and iron hydroxide (III) the chemical equation balance:

FeCl3+3H2O Fe(OH)3+3HCl

(2)

Hydrochloric acid plays the role of catalyst in the reaction gas-emitting reagents according to the scheme (1) as follows:

Me(NO2)n
The dependence of pH on the concentration of the chlorides of iron and aluminum in water at a temperature of 20aboutListed in the table.1.

Introduction in the reaction environment even a minor amount of the reaction initiator promotes expansion foam (the speed of a chemical reaction) and the decrease in pH of the solution.

The dependence of the health of a foamable composition from the concentration of the initiators of the reaction are shown in table.2.

Increasing the concentration of initiator, the reaction speeds up the process of foam formation and increases the concentration in the reaction mixture of nitrous acid on the chemical equation (4), which in turn affects the temperature regime health foaming composition. For example, the introduction of ferric chloride in the reaction medium in an amount of 0.27 wt. the foam is formed by a multiplicity of 3 and above at a temperature of 70aboutIn order to obtain a foam of the same characteristics for the composition not containing the initiator of the reaction, it is necessary to maintain the temperature regime at the level of 95-100aboutC.

Gasanalysis solution is carried out with gaseous nitrogen according to the equation (5) and allocated a large amount of heat, about 300 kJ per one mole of NH4NO

Technology of application of the foam composition provides two ways of realization of technological operations on the well completion.

The first method. Prepare an aqueous solution containing ammonium chloride, nitrite, alkali or alkaline earth metal, a surfactant, and bring it to the borehole bottom. The reaction initiator is prepared in the form of a cylindrical briquettes, made from a doughy mixture containing 100%-aqueous solution of structure-forming agent and a catalyst. The estimated number of briquettes consistently throw inside the tubing (tubing) through the gland-lubricator installed on the wellhead.

The second method. Prepare 3-10% aqueous solution of structure-forming agent and leave it to swell for 3-4 hours Crushed original components separately to powder and are based on a 3-10% solution structure-forming agent three doughy mixture:

mixture "And" get under stirring nitrite alkali or alkaline earth metal and surfactant in the solution structure-forming agent;

mixture B contains ammonium chloride;

the mixture In the reaction initiator.

The mixture form VA briquettes cook until the bottom hole in the same way, as in the first method, the initiator of the reaction. Last injected briquettes containing the initiator of the reaction.

The preparation of a mixture containing both ammonium chloride and nitrite, alkali or alkaline earth metal is not excluded, but the manufacture of briquettes from this mixture and storage of finished products will entail certain difficulties. When heated and hit any initiator reaction these briquettes can explode and cause irreparable damage.

Well close to the reaction and incubated for 20-60 min, then gradually release the pressure through the tubing or annulus, carry out the call flow of fluid from the reservoir.

The proposed composition for completion allows you to obtain a foam with adjustable speed gas release up to 100 l/s, or at least 120,0 m3gaseous product at the well bottom for 1 ton of briquettes "a" and "b".

In table.3 shows the content of components in the mixture "A".

The largest quantity of water are those mixtures that contain less water-soluble alkaline earth metal nitrites.

Mixture "B" consists of 90.0 wt. of ammonium chloride, the rest 3-10% aqueous solution of structure-forming agent.

P R I m e R 1. Foamable composition experience in a laboratory setup, which is a model of the well, at a temperature of 60aboutC. Prepare a solution containing ammonium chloride, sodium nitrite at their stoichiometric ratio according to equation (1), surfactant, and water, wt. Ammonium chloride 15.0 sodium Nitrite 19,4 surfactant 1,0 Water 64,6

Pressed into cylindrical briquettes initiator reaction of the pasty mixture containing, by weight. Aluminium chloride 90,0 Water 9,0 CMC 1,0

Placed on the bottom of the model well 20,0 ml gas-emitting solution and introduce the initiator of the reaction in the form of rods.

The results of laboratory tests are shown in table.4.

From the data table. 4 it follows that intensive foaming occurs when the concentration of aluminium chloride are higher than 0.9% of Foaming is quite active when the content in the foam composition of ammonium chloride and 6.7 wt. and sodium nitrite to 8.6 wt. below these concentrations, the efficiency of gas saturation of the solution is not satisfactory.

The upper boundary conditions of the ratios of the starting components for the liquid composition determines the solubility of ammonium chloride at 20aboutWith 100 g of water soluble 37,2 g of ammonium chloride.

P R I m m e R 2. Gataullina NP-3), CMC and water in the following ratios, wt. Sodium nitrite 94,5 surfactant of 0.5 CMC 0,2 Water 4,8

Terminal "B" consists of 90.0 wt. of ammonium chloride, the rest 5% aqueous solution of CMC.

Terminal "B" contains in its composition 90.0% of aluminum chloride, and 1.0% CMC and the rest is water.

Test of SS in the form of rods are held in a laboratory setup at a temperature of 25aboutC. the Weight ratio of briquettes "a" and "B" when the tests should be 1,22:1,00 (specific example), then the contents of the components briquettes "a" and "B" on the bottom hole will be, by weight. Sodium nitrite 52,5 ammonium Chloride 40,5 Sultanol NP-3 0,3 CMC 0,3 Water 6,4.

The results of laboratory tests are given in table.5.

From which it follows that:

foamable composition, made in the form of rods, manifests its greatest efficiency at a temperature of 25aboutIf the specific consumption per ton of liquid briquettes (rods) "a" and "b" above 60,0 kg and briquettes (initiator reaction) not less than 15,0 kg;

the rods are completely dissolved in water for 20-40 min;

the weight ratio of the gas-emitting composition (terminals "a" and "B") and initiator of the reaction (aluminium chloride) rods "In" should be not less than 3,0-7,0;
offer foamable composition is not bad performance both in liquid and solid form;

the application of this composition is economically feasible in comparison with the known compounds with the same intensity of foaming;

manufacturer of SS in the form of a cylindrical briquettes feasible stationary or in the factory at any distance from the object of the application;

the use of the composition in solid form is possible year-round, regardless of the ambient temperature;

the process is characterized by its simplicity, low labor costs and development wells can be made at any positive temperature reservoir.

For call flow of fluid from the formation with the well development water content of 90% with the reservoir pressure at 60, the temperature at the bottom hole 65aboutC and equipped with 50-mm tubing, it is necessary to determine by calculation the amount of foamable composition, made in the form of a cylindrical briquettes to get 50,0 m3the gaseous product in the bottomhole formation zone within 20/30 minutes

Prepare a foamable composition in the form of a cylindrical briquettes three Maroc,0.

Briquettes "B" on the basis of 4.0% aqueous CMC solution containing ammonium chloride to 90.0 wt.

Briquettes "In" the initiator of the reaction, contains in its composition, wt. Aluminium chloride 90,0 CMC 1,0 Water 9,0

For development wells consistently throw the estimated amount of the foaming composition in the form of pellets inside the tubing through the gland-lubricator installed on the wellhead.

The sequence of input briquettes "A" or "B" is not regulated, briquettes "In" initiator reaction thrown in last.

On the basis of the General scheme (1) chemical interaction of initial gas-emitting components comprise chemical equation:

NH4Cl+NaNO2__ N2+NaCl+2H2O Determine the molecular weight of the reacting substances:

NH4Cl 14 + 4 + 35,5 of 53.5 g/mol

NaNO223 + 14 + 2 x 16 69,0 g/mol. Under normal conditions, 1 mole of nitrogen gas occupies a volume of 22.4 l, then in terms of 1 g of the original substance will stand out:

V 0,1829 l/g To determine the weight ratio of pellets a and B find the ratio of molecular masses of gas-emitting components:

NH4Cl:NH4Cl - 1,00

NaNO2:NH4Cl - 1,29

Therefore, when the content in the briquette is>/BR>A B 1,23 1,00

Gas-emitting composition in such a weight ratio of briquettes will contain, by weight. Ammonium chloride 40,4 sodium Nitrite 51,8 surfactant of 0.5 CMC 0,3 Water 7,0

Per 1 ton of pellets a and B is formed gaseous nitrogen by volume: Q (NH4Cl + +NaNO2x 1000 x V, where NH4Cl; NaNO2a single share of gas-emitting components of the composition; V is the volume of gas per 1 kg of the gas-emitting components of the composition, m3.

Q (0,404 + 0,518) x 1000 x 0,1829

168,6 m3. To get on the conditions of the problem 50,0 m3gases at the bottom of the borehole must 296,6 kg PS or briquettes a and B are each individually:

A 163,6 kg

B 133,0 kg

The initiator of the reaction it is necessary to carry out this operation when the weight ratio of gas-emitting composition and briquettes In 7,0 1,0 (PL.5):

B 42,4 kg

Thus, the foamable composition will have a ratio of initial components, wt. Ammonium chloride 35,3 sodium Nitrite 45,5 aluminium Chloride and 11.2 surfactant (OP-10) 0,4 CMC Water 0,5 7,1

The rate of gas saturation of the solution will be about

V/t where V is the volume of the gas at the conditions of the problem, l;

t response time, s

27.8 l/s

Well close to the reaction and incubated for 20-30 min, then release the pressure through the ageny to bottom-hole formation zone finish 1,0-3,0 m3water.

Instead of sodium nitrite can be used nitrites other alkaline or alkaline earth metals, and instead of aluminium chloride are another initiator response (Lewis acid and so on).

The formation of foam in these cases is no different from the interaction of nitrite with ammonium chloride. The difference is only quantitative proportions, which are calculated according to the chemical equation (1).

In table.6 and 7 shows the mass ratio of the components of the foamable composition, the weight ratio of the briquettes, the estimated volumes of gases, which are formed under normal conditions per unit gas-emitting component and a foaming composition, the initiator of the reaction of aluminium chloride.

In table.6 presents the data with a minimum content in briquettes And gas-emitting component, in table.7, when the maximum content of this component.

In table.8 shows the ratio of initial components for foaming the composition in the liquid state.

The proposed method of producing a foaming composition for completion not time consuming and does not require special equipment that can be used in obtaining the mevki bottom-hole formation zone, completion, the elimination of traffic jams in the wells and the intensification of the processes of oil and gas. This foamable composition can be used both in solid and in liquid state.

Offer the source reagents are cheap and available, do not require special conditions during the transportation and storage industry produces large capacity and are widely used.

FOAMABLE COMPOSITION FOR well DEVELOPMENT, including ammonium chloride, nitrite, alkali or alkaline earth metal, a reaction initiator, surfactant and water, characterized in that it further contains a foam stabilizer a carboxymethyl cellulose or polyacrylamide, and as an initiator of the reaction, the halide or sulfate of iron or aluminum in the following ratios, wt.

Ammonium chloride 30,0 35,4

Nitrite, an alkaline or alkaline earth metal 38,8 45,7

The halide or sulfate of iron or aluminum 11,2 22,5

The carboxymethyl cellulose or polyacrylamide 0,3 0,8

Surfactant 0,04 0,5

Water The Rest

 

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