RU2308475C1 - Composition for acid treatment of critical zone of formation (variants) - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: invention provides composition for chemical dissolution of rocks and mudding deposits in critical zone of oil, gas, and gas-condensate formation, which composition may also be used as process fluid when performing perforation and hydraulic rupture of formations. Composition is constituted by, vol %: (1) technical lignosulfonates 20-35, isopropyl alcohol or bottom residues of butyl alcohol production 3-5, 80% acetic acid 3-5, water-soluble demulsifier 2-4, and 20-28% aqueous hydrochloric acid solution - the rest; or (2) technical lignosulfonates 0.5-1, isopropyl alcohol or bottom residues of butyl alcohol production 3-5, Neonol "AF_9-12" or "ML-81", or "ML81B", or "FLEK-DG-002" 0.5-2, 80% acetic acid 3-5, water-soluble demulsifier 2-4, and 20-28% aqueous hydrochloric acid solution - the rest; or (3) technical lignosulfonates 0.5-1, isopropyl alcohol or bottom residues of butyl alcohol production 3-5, 80% acetic acid 3-5, water-soluble demulsifier 2-4, 70% aqueous hydrofluoric acid solution 6-10, and 20-28% aqueous hydrochloric acid solution - the rest; or (4) technical lignosulfonates 0.5-1, isopropyl alcohol or bottom residues of butyl alcohol production 3-5, 80% acetic acid 3-5, water-soluble demulsifier 2-4, 3-5% aqueous polyacrylamide solution or 3-5% aqueous solution of modified starch 3-10, and 20-28% aqueous hydrochloric acid solution - the rest.

EFFECT: widened control range for carbonate rock dissolution rate, dynamic viscosity, complete prevention of precipitation of mudding gel-like deposits, emulsification and complete withdrawal of reaction products from formation during well development operations.

4 cl, 2 tbl, 4 ex

Description

The proposal relates to the field of oil production, in particular to compositions for the acid treatment of formations, and can be used for chemical dissolution of rocks and clogging deposits in the bottomhole zone of an oil, gas and gas condensate formation, and can also be used as a process fluid for perforating a casing and hydraulic fracturing.

The closest to the proposed technical solution for the intended purpose and technical essence is the composition for the acid treatment of the bottomhole formation zone containing an aqueous solution of hydrochloric acid, technical lignosulfonates and water-soluble aliphatic alcohols (see RF patent No. 20133530, IPC ЕВВ 43/27, publ. 30.05. 94 g. Bull. No. 10). The known composition has a 13.7-32.7 times lower reaction rate in relation to carbonates, reduces filtration in the spent state, stabilizes the spent acid solution in relation to ferric iron, has 2.1-13 times higher viscosity values in comparison with traditional acid formulations.

The disadvantages of the known composition are:

1. A relatively narrow range of changes in the rate of dissolution of the carbonate rock and the viscosity of the composition, which limits its scope. For various geological and physical conditions of well operation, the ability to control the dissolution rate of carbonates from ordinary (very high) values (15000-20000 g / m ² · h) to very small values (200-500 g / m ² · h) is required. This property allows you to adjust the pace and depth of processing of the reservoir. The same applies to viscosity values. Practice shows the need to regulate this indicator from the viscosity of almost pure acid (within 1-5 MPa · s) to highly viscous compositions (with a viscosity of up to several thousand MPa · s). This range allows you to adjust the coverage of acid exposure to formations of virtually any structural type, with any dissection and heterogeneity in permeability.

2. An insufficient degree of neutralization of ferric ions, given the very high iron content in the tubing string, through which the acid composition is pumped into the reservoir. In addition, it must be borne in mind that the acid is additionally saturated with iron ions in reactions with rock formations. As a result, the resulting dispersed iron hydroxide precipitates in the pore space of the reservoirs and clogs the filter channels. The neutralizing ability of lignosulfonates is clearly insufficient to prevent this negative phenomenon.

3. The main negative process is not taken into account, namely, the possibility of the formation of direct and inverse emulsions in the reservoir, which clog the filtration channels and pores. Components of known composition and, in general, practically all acidic compounds mixed with oil, formation water, reaction products, as a rule, form highly viscous blocking mixtures and emulsions.

4. The lack of ability to carry the reaction products from the reservoirs after treatment and, as a result, a decrease in the final processing efficiency. This composition provides for a decrease in the filtration of the spent composition from cracks into the rock matrix, but this effect is not enough to completely remove the reaction products. To do this, it is necessary to reduce surface interfacial tension at the rock-fluid interface, disperse, wet, and remove fine particles and reaction products during washing and well development after treatment.

The technical task of the proposed solution is to create a universal, multi-purpose acid composition with improved technological properties by increasing the range of regulation of the rate of reaction of the dissolution of carbonate rock, dynamic viscosity, completely preventing the precipitation of clogging gel-like sediments, inhibiting the process of emulsion formation and the complete removal of reaction products from the formation during development .

This problem is solved by the known composition for the acid treatment of the bottomhole formation zone, containing an aqueous solution of hydrochloric acid, technical lignosulfonates and water-soluble aliphatic alcohols.

According to the first option, the new one is that the composition additionally contains acetic acid of 80% concentration and a water-soluble demulsifier, and as an aqueous solution of hydrochloric acid of 20-28% concentration, isopropyl alcohol or bottoms of butyl alcohols as water-soluble aliphatic alcohols in the following ratio of ingredients, vol.%:

technical lignosulfonates 20-35 isopropyl alcohol or bottoms of butyl alcohol 3-5 acetic acid of 80% concentration 3-5 water soluble demulsifier 2-4 aqueous solution of hydrochloric acid of 20-28% concentration rest

According to the second variant, the composition additionally contains acetic acid of 80% concentration, a water-soluble demulsifier and a water-soluble surfactant, which are used as neonol AF _9-12 , or ML-81, or ML-81B, or FLEK-DG-002, and as an aqueous solution of hydrochloric acid of 20-28% concentration, as water-soluble aliphatic alcohols - isopropyl alcohol or bottoms of butyl alcohols in the following ratio of ingredients, vol.%:

technical lignosulfonates 0.5-1 isopropyl alcohol or bottoms of butyl alcohol 3-5 neonol AF _9-12 , or ML-81, or ML-81 B, or FLEK-DG-002 0.5-2 acetic acid of 80% concentration 3-5 water soluble demulsifier 2-4 aqueous solution of hydrochloric acid of 20-28% concentration rest

According to the third option, the composition additionally contains acetic acid of 80% concentration, a demulsifier of water-soluble and an aqueous solution of hydrofluoric acid of 70% concentration, and as an aqueous solution of hydrochloric acid of 20-28% concentration, isopropyl alcohol as water-soluble aliphatic alcohols or still bottoms of butyl alcohols in the following ratio of ingredients, vol.%:

technical lignosulfonates 0.5-1 isopropyl alcohol or bottoms of butyl alcohol 3-5 acetic acid of 80% concentration 3-5 water soluble demulsifier 2-4 aqueous solution of hydrofluoric acid 70% concentration 6-10 aqueous solution of hydrochloric acid of 20-28% concentration rest

According to the fourth variant, the composition additionally contains acetic acid of 80% concentration, a water-soluble demulsifier and a polymer, which is used as an aqueous solution of polyacrylamide or an aqueous solution of modified starch, and as an aqueous solution of hydrochloric acid of 20-28% concentration, as water-soluble aliphatic alcohols - isopropyl alcohol or distillation residues of butyl alcohols in the following ratio of ingredients, vol.%:

technical lignosulfonates 0.5-1 isopropyl alcohol or bottoms of butyl alcohol 3-5 acetic acid of 80% concentration 3-5 water soluble demulsifier 2-4 an aqueous solution of polyacrylamide 3-5% concentration or aqueous solution of modified starch 3-5% concentration 3-10 aqueous solution of hydrochloric acid of 20-28% concentration rest

The principal difference of the proposed composition lies in the presence in the formulations of an unconventional component: a water-soluble demulsifier in combination with well-known ingredients - hydrochloric acid, acetic acid, hydrofluoric acid, water-soluble alcohols, water-soluble surfactants. At the same time, acetic acid performs an unconventional function of a neutralizer of iron ions, thereby preventing a number of negative processes of sedimentation of substances in the pores and the formation of mud.

The increase in the range of controlled technological properties and the field of application of the composition according to the first embodiment is achieved by introducing into the main component (hydrochloric acid) a new set of ingredients with their corresponding quantitative ratio. This gives this composition a new property - the ability to control the reaction rate with carbonates in the range of the required low values of this parameter, in particular, this composition has a 30-100 times lower reaction rate compared to traditional compositions - an aqueous solution of hydrochloric acid, as well as compositions of this solution with alcohols and surfactants.

This effect is based on the ability of technical lignosulfonate components (lignosulfonic acid salts, monosulfite liquor, sugars, cellulose residues, and other high molecular weight compounds) to be adsorbed on the rock surface, creating a screening layer. Vat residues of butyl alcohols and isopropyl alcohol enhance the effect by changing the wettability of the rock surface.

The composition according to the second option allows you to adjust the reaction rate, viscosity, interfacial tension, while slowing down the reaction rate from 2 to 6 times, increasing the dynamic viscosity by 2-4 times, reducing the surface tension by 2-3 times (compared with traditional known compounds) .

The composition according to the third option provides processing of both carbonate rocks with an increased content of clay components, and terrigenous sandstones, polymictic rocks-reservoirs, which significantly expands the scope of use of the composition.

The composition according to the fourth embodiment provides an increase in the range of viscosity control from 50 to several thousand MPa · s at various shear rates, while reducing the reaction rate by 6-15 times compared with the known composition. This technical effect significantly expands the scope of application of the composition both technologically: the efficiency of operations such as directed acid treatments, acid fracturing, deep acid treatments, acid hydromonitor drilling and formation processing and a number of other operations, as well as in terms of geological and physical conditions, increase : from pore-fractured to cavernous-fractured rocks.

The analysis of scientific, technical and patent literature did not allow to identify an identical set of essential features that solve a similar technical problem. Based on this, we believe that our proposed technical solution meets the criteria of "novelty" and "inventive step".

Examples of the preparation of compounds.

Example 1. Concentrated hydrochloric acid was diluted with fresh water to a 20-28% concentration by volume. With technical stirring on a laboratory stirrer, bottoms of butyl alcohol or isopropyl alcohol, a water-soluble demulsifier, acetic acid of 80% concentration were added to technical lignosulfonates. The components were mixed for 1 min. Then, the prepared hydrochloric acid solution was introduced into this solution and stirred for 1 minute until a homogeneous composition was obtained.

Example 2. To technical lignosulfonates, isopropyl alcohol or bottoms alcohol was added with constant stirring, then neonol AF _9-12 , or ML-81, or ML-81B, or FLEK-DG-002, then a water-soluble demulsifier, then an aqueous solution of acetic acids of 80% concentration. Stirred for 1 min. Then, an aqueous solution of hydrochloric acid of 20-28% concentration was introduced into this solution. Stirred for 1 min until a homogeneous composition.

Example 3. Isopropyl alcohol or bottoms alcohol was added to technical lignosulfonates with constant stirring, then a water-soluble, aqueous solution of 80% concentration of acetic acid demulsifier was added with stirring. Stirred for 1 min. Then, an aqueous solution of hydrofluoric acid of 70% concentration was introduced. Stirred for 1 min. Then, an aqueous solution of hydrochloric acid of 20-28% concentration was introduced. Stirred for 1 min until a homogeneous composition.

Example 4. Isopropyl alcohol or bottoms alcohol was added to technical lignosulfonates with constant stirring, then a water-soluble demulsifier, acetic acid of 80% concentration was added with stirring. Stirred for 1 min. Then, an aqueous solution of hydrochloric acid of 20-28% concentration was introduced. Stirred for 1 min until a homogeneous composition. With stirring, an aqueous polymer solution (polyacrylamide or modified starch) was dosed.

The dynamic viscosity of the composition was determined on a VPZh-4 capillary viscometer and a rotational Reotest-2.

The reaction rate of the composition was evaluated by the mass method, in which a cube of marble with a certain area and weight was placed in the test composition. By changing the mass for a fixed time, the dissolution rate of marble was determined.

The degree of stabilization of the composition with respect to iron ions was determined visually when dosing into the composition of iron oxides and by measuring the volume of precipitated iron hydroxide.

The interfacial activity and penetrating ability of the composition into the pore space of the oil-saturated part of the reservoir were estimated by the magnitude of the interfacial tension at the “composition-oil” interface.

The degree of prevention of formation of highly viscous mixtures and emulsions blocking the formation upon contact of the composition with oil was evaluated visually and by the magnitude of the viscosity of the reaction products.

The composition and properties of the proposed and known prototype compositions are shown in tables 1 and 2.

Table 1 No. of experience Test composition Water soluble alcohols Acetic acid (80%) Demulsifier Water surfactant solution HF (70%) Polymer Tech. lignosulfonates Salt to-that View % vol. % vol. View % vol. View % vol. % vol. View % vol. % vol. End,% % vol. one COBS 3 3 SNPH 2 twenty twenty 72 2 COBS 5 four Reapon 2 25 24 64 3 Isopropyl alcohol 3 5 Din 3 thirty 26 59 four Isopropyl alcohol 5 3 SNPH four 35 28 53 5 Isopropyl alcohol 3 3 REEF 3 AF _9-12 one 0.5 twenty 89.5 6 Isopropyl alcohol four 5 SNPH 2 ML-81 2 one 21 86 7 COBS four four Din 3 ML-81B 1,5 0.5 22 87 8 COBS 5 3 Reapon four FLEK 0.5 one 28 86.5 9 Isopropyl alcohol 5 5 SNPH four 6 0.5 28 79.5 10 Isopropyl alcohol four four Din 3 7 one 27 81 eleven COBS 3 3 REEF 2 8 0.7 26 83.3 12 COBS 3 four Reapon 2 10 one 25 80 13 COBS four four Din four Starch 5% 3 0.5 28 84.5 fourteen Isopropyl alcohol 5 3 REEF 3 Starch 3% 10 0.8 27 78,2 fifteen COBS four 5 Reapon 2 PAA 5% 10 one 26 78 16 Isopropyl alcohol 3 four SNPH 2 PAA 3% 3 0.5 25 87.5 17 COBS 5 5 SNPH 2 PAA 4% 5 one 24 82 eighteen Isopropyl alcohol four 3 Reapon 3 PAA 5% 8 0.5 23 81.5 19 COBS 3 four Din four Starch 4% 5 one 22 83 twenty Isopropyl alcohol 5 5 REEF 2 Starch 3% 8 one twenty 79 Known composition of the prototype 21 Methanol 5 10 fifteen 85 22 Glycerol 7.5 twenty 16.5 72.5 23 Triethylene glycol 10 thirty eighteen 60 24 Ethanol 5 thirty eighteen 65

table 2 No. of experience from table 1 Properties and parameters of acid composition Viscosity, MPa · s Dissolution rate
kg / m ² · h Hydroxide sediment volume
Fe, cm ³ Interfacial tension, mN / m The viscosity of the reaction products (with oil), MPa · s Application area one 25 0.60 absent 0.9 22 Deep RMS of carbonates, acid fracturing, acid GLP of all types of carbonates 2 31 0.55 absent 0.8 21 3 38 0.41 absent 0.7 23 four 45 0.25 absent 0.55 24 5 eighteen 1.10 traces 0.08 eighteen All types of acidic SCR pore-fractured carbonates 6 twenty 0.98 absent 0.12 12 7 fifteen 1.20 traces 0.14 16 8 10 1.40 absent 0.10 17 9 17 0.35 ^* traces 0.38 23 All types of acidic SCR terrigenous reservoirs 10 19 0.32 ^* traces 0.42 25 eleven 21 0.36 ^* traces 0.43 24 12 23 0.41 ^* traces 0.45 25 13 50-75 1,50 absent 0.71 28 Acid directed SCR, acid fracturing, acid GLP, deep acid exposure, jet-acid treatment of all types of carbonates fourteen 2000-2250 0.70 absent 0.89 24 fifteen 1850-2010 0.72 absent 0.61 29th 16 70-110 1.20 absent 0.42 thirty 17 980-1200 1.10 traces 0.53 31 eighteen 1180-1420 0.98 traces 0.62 28 19 180-310 0.92 traces 0.78 23 twenty 480-920 0.88 traces 0.58 25 21 75 1.51 light precipitate - 0.5 1.29 84 Deep Fractured Carbonate Acid Treatment 22 143 0.82 same - 1.1 1,59 62 23 182 0.64 the same - 0.8 1.88 58 24 197 1.25 same -0.9 1.47 78 ^* - soluble material - terrigenous sandstone, in all other experiments - marble

The following materials were used to prepare the compositions and their tests:

Devonian oil, with a density of 859 kg / m ³ , viscosity of 14-18 mPas;

Technical lignosulfonates are a waste from sulphite pulping at a number of pulp and paper mills in the country and are a by-product after sugar fermentation in sulphite liquors, distillation of alcohol, subsequent evaporation and neutralization with sodium or ammonia hydroxide. According to TU 13-0281036-05-89, TU 13-7308001-453-84 “Black monosulfite liquor” product is a homogeneous viscous liquid of dark brown color with low acidity;

inhibited hydrochloric acid TU 2458-017-12966038-2002; TU 2122-205-00203312-2000;

neonol AF _9-12 TU 38.507-63-171-91;

preparations ML-81, ML-81B TU 2481-007-48482528-99, TU 2481-048-04689375-97;

preparation FLEK-DG-002 TU 2483-004-24084384-00;

modified starch MPK-001;

polyacrylamide TU 6-01-1049-76, imported polyacrylamide PDA-1020, PDA-1041; hydrofluoric acid TU 48-5-184-78; bottoms of butyl alcohols; isopropyl alcohol, water-soluble demulsifiers DIN-4, SNPCH 4501, RIF, Reapon-4v.

The data in tables 1 and 2 indicate that the options of the proposed composition compared with the known composition of the prototype have a wider range of regulation of the reaction rate both in the direction of decreasing the rate of dissolution, and in the direction of increasing the rate of dissolution of the carbonate material of the formation. The dynamic viscosity of the claimed compounds is regulated in the range from 10 to 2250 MPa · s, and in the prototype viscosity is regulated in the range of 75-182 MPa · s. The proposed compositions do not form precipitation of iron hydroxide, which eliminates the clogging of the pore channels of the reservoir. Qualitatively new is the degree of decrease in interfacial tension of the proposed compositions at the border with oil. So, the range of variation of this important parameter is from 0.9 to 0.08 mN / m, while for the known composition it is much higher (1.29-1.88 mN / m). The viscosity of the reaction products in a mixture with oil in the proposed compositions is much lower and comparable with the viscosity of the oil itself (12-31 mPa · s), while the viscosity of the reaction products in the known composition is high (58-84 mPa · s).

The research results showed the optimality of the content of the ingredients of the compositions within the specified limits. The increase in the content of components in the compositions is not advisable, because manufacturability decreases or stabilization of parameters is established at the same level. With a decrease in the content of components in the compositions below the specified limits, a decrease in physicochemical properties is observed.

By increasing the range of control of the reaction rate, dynamic viscosity, completely preventing the formation of gumming gel-like precipitates, inhibiting the process of emulsion formation and the complete removal of reaction products from the formation during development, the task is completely solved - universal, multi-purpose acid compositions with improved technological properties are created. They can be used in all known technological operations for acid stimulation of productivity of wells and reservoirs. This leads to high technical and economic efficiency of the proposed compositions for increasing the productivity of oil wells operating in a wide variety of geological and physical conditions of deposits and deposits, both in carbonate and terrigenous reservoirs.

Thus, the proposed technical solution, when widely introduced into the oil and gas industry, will bring significant profit due to the quality of its direct functions to increase hydrocarbon production, integrate operations over time, and save material and labor resources.

Claims (4)

1. The composition for the acid treatment of the bottom of the formation, containing an aqueous solution of hydrochloric acid, technical lignosulfonates and water-soluble aliphatic alcohols, characterized in that it additionally contains acetic acid of 80% concentration and a demulsifier water-soluble, and as an aqueous solution of hydrochloric acid 20-28 % concentration, as water-soluble aliphatic alcohols - isopropyl alcohol or distillation residues of butyl alcohols in the following ratio of ingredients, vol.%: technical lignosulfonates 20-35 isopropyl alcohol or bottoms of butyl alcohol 3-5 acetic acid of 80% concentration 3-5 water soluble demulsifier 2-4 aqueous hydrochloric acid 20-28% concentration rest 2. The composition for the acid treatment of the bottom of the formation containing an aqueous solution of hydrochloric acid, technical lignosulfonates and water-soluble aliphatic alcohols, characterized in that it further comprises acetic acid of 80% concentration, a demulsifier, water-soluble and water-soluble surfactant, which is used as neonol AF _9-12 or ML-81, or ML-81B, or FLEK-DG-002, and as an aqueous solution of hydrochloric acid of 20-28% concentration, isopropyl as water-soluble aliphatic alcohols high alcohol or bottoms of butyl alcohols in the following ratio of ingredients, vol.%: technical lignosulfonates 0.5-1 isopropyl alcohol or bottoms of butyl alcohol 3-5 neonol AF _9-12 or ML-81, or ML-81 B, or FLEK-DG-002 0.5-2 acetic acid of 80% concentration 3-5 water soluble demulsifier 2-4 aqueous hydrochloric acid 20-28% concentration rest 3. The composition for the acid treatment of the bottom of the formation, containing an aqueous solution of hydrochloric acid, technical lignosulfonates and water-soluble aliphatic alcohols, characterized in that it further comprises acetic acid of 80% concentration, a demulsifier, water-soluble and aqueous solution of hydrofluoric acid of 70% concentration, and as an aqueous solution of hydrochloric acid of 20-28% concentration, as water-soluble aliphatic alcohols - isopropyl alcohol or bottoms of butyl alcohols in the following ratio of ingredients, vol.%: technical lignosulfonates 0.5-1 isopropyl alcohol or bottoms of butyl alcohol 3-5 acetic acid of 80% concentration 3-5 water soluble demulsifier 2-4 aqueous solution of hydrofluoric acid 70% concentration 6-10 aqueous hydrochloric acid 20-28% concentration rest 4. The composition for the acid treatment of the bottom of the formation, containing an aqueous solution of hydrochloric acid, technical lignosulfonates and water-soluble aliphatic alcohols, characterized in that it further comprises acetic acid of 80% concentration, a water-soluble demulsifier and a polymer, which is used as an aqueous solution of polyacrylamide or an aqueous solution of modified starch, and as an aqueous solution of hydrochloric acid of 20-28% concentration, isopropyl alcohol as water-soluble aliphatic alcohols RT or distillation residues of butyl alcohols in the following ratio of ingredients, vol.%: technical lignosulfonates 0.5-1 isopropyl alcohol or bottoms of butyl alcohol 3-5 acetic acid of 80% concentration 3-5 water soluble demulsifier 2-4 an aqueous solution of polyacrylamide 3-5% concentration or modified starch aqueous solution 3-5% concentration 3-10 aqueous hydrochloric acid 20-28% concentration rest