RU2255215C1 - Method for processing face-adjacent bed zone - Google Patents

Abstract

FIELD: oil industry.

SUBSTANCE: method includes feeding reversed oil emulsion into bed and also water solution of acid, as reversed emulsion, emulsion is used, containing following components, in percents of total: hydrocarbon liquid 26-40, oil-soluble nitrogen-containing emulsifier Sonkor-9601 or Sonkor-9701 0.4-5, water solution of inhibited 10% hydrochloric acid or argillaceous acid or water solution 1-10% of chlorine calcium or chlorine sodium the rest. As hydrocarbon liquid diesel fuel is used or liquid oil hydrocarbons of paraffin row, or unstable gas benzene, or light oil. Reversed emulsion maintains stability during 6-35 hours at temperature from 60 to 100°C during filtering through bed model with penetrability more than or equal to 0.2 mcm². Time of feeding of reversed emulsion with filtering into bed should not exceed emulsion stability preservation time.

EFFECT: higher efficiency.

4 cl, 3 tbl

Description

The invention relates to the oil industry and can be used for acid treatment of the bottomhole formation zone, represented by heterogeneous permeability carbonate or terrigenous reservoirs of oil or gas, as well as fracturing and perforation wells.

There is a method of developing an oil deposit, characterized in that after water cut of the produced products more than 50%, a plugging material is pumped into the reservoir, which is used as an oil emulsion (RU No. 2096600, class E 21 B 43/22, 1997). The disadvantage of this method is not sufficiently deep penetration of the emulsion into the reservoir.

A known method of processing the bottom-hole zone of a well in a multilayer reservoir (RU No. 2092686, class E 21 B 43/27, 43/14), comprising injecting an oil emulsion and an acid solution. Before the injection of the acid solution, the waste from the production of isoprene, which dissolves the oil component of the oil emulsion, is pumped. The disadvantage of this method is the complexity of the technology and low efficiency due to the small depth of penetration of the oil emulsion into the reservoir.

The closest in technical essence and the achieved result is a method of processing the bottom-hole zone of the well, including the injection into the reservoir of an inverse oil emulsion and an aqueous solution of acid (RU No. 2084622, class E 21 B 43/27, 1996). The main disadvantage of this method is its low efficiency when used on highly permeable and fractured reservoirs, due to the small depth of penetration of the oil emulsion into the reservoir and the inability to control its stability at a temperature of 60-100 ° C.

The objective of the invention is to increase the efficiency of the method of processing the bottom-hole zone of the formation by increasing the penetrating ability of the reverse emulsion with the aim of deeper delivery into the formation and regulating stability in the temperature range of 60-100 ° C.

This goal is achieved by the fact that in the method of processing the bottom-hole zone of the formation, including the injection into the formation of an inverse oil emulsion and an aqueous solution of acid, an invert emulsion using an emulsion containing the following components,% vol .:

Hydrocarbon Liquid 26-40

Oil Soluble Nitrogen Emulsifier

Soncor-9601 or Soncor-9701 0.4-5

An aqueous solution of inhibited 10% hydrochloric acid

acid or clay acid or aqueous solution

1-10% calcium chloride or sodium chloride

As the hydrocarbon liquid, diesel fuel or paraffin liquid petroleum hydrocarbons, or unstable gas gasoline, or light oil are used.

The inverse emulsion remains stable for 6-35 hours at a temperature of from 60 to 100 ° C when filtered through a reservoir model with a permeability greater than or equal to 0.2 μm ² .

The time of injection of the inverse emulsion during filtration into the formation should not exceed the time of maintaining the stability of the emulsion.

The problem is solved by sequentially injecting a reverse emulsion into the formation with adjustable stability at a temperature of 60-100 ° C and an aqueous acid solution. In the inventive method, the inverse emulsion serves as a selective and temporary insulating material that clogs highly permeable layers of the oil reservoir. The aqueous acid solution injected after this enters the low-permeability interval of the formation, reacts with the formation rock and colmatizing compounds and increases permeability. In the inventive method, the inverse emulsion may contain an aqueous solution of inhibited hydrochloric or clay acid. In this case, there is no direct contact of the acid with the formation rock; the acid located inside the hydrophobic emulsion can be pumped deeper into the formation without losing its activity. After a certain time, which is governed by the concentration of the emulsifier, the temperature and composition of the internal phase, the emulsion breaks down into two phases (water and hydrocarbon), performs useful work to increase the permeability of the rock, after which oil can freely flow into the well from both low and from high permeability formation intervals. As a result of these processes, the overall permeability of the treated interval increases and levels out.

In contrast to the known method, the inventive hydrophobic emulsion is stabilized by effective nitrogen-containing emulsifiers (Soncor-9601 or Soncor-9701). Soncor-9601 or Soncor-9701 - reaction products of amines and tall oil fatty acids with solvents and additives. As additives, they include nonionic surfactants (AF ₉ -6 or AF ₉ -12). The introduction of n-surfactant into Soncor-9601 or Soncor-9701 leads to the formation of a synergistic mixture of the reaction products of amines and fatty acids of tall oil with n-surfactant, which has a greater polarity and interphase activity. Thus, Sonkor-9601 or Sonkor-9701 are a combination of surfactants, which gives them a wider range of controlled properties, in particular lower interfacial tension of hydrocarbon solutions of nitrogen-containing emulsifiers Sonkor-9601 or Sonkor-9701. The lower interfacial tension of hydrocarbon solutions of nitrogen-containing emulsifiers Sonkor-9601 or Sonkor-9701 than that of the known composition helps to reduce the size of the globules of the dispersed phase of the emulsion. The latter factor contributes to a deeper uniform delivery of the composition to both low- and highly permeable formation fractures. The use of effective emulsifiers made it possible to create reverse emulsions with predetermined (predicted) stability over a wide temperature range. In addition, the presence of metal cations (Ca ⁺⁺ , Na ⁺ ) promotes the exchange reaction of the formation of metal soaps of higher carboxylic acids, which are present in the composition of emulsifiers, and this leads to a decrease in interfacial tension and more effective emulsification and regulation of the stability of the emulsion.

To implement the method using the following reagents and commercial products containing them.

Soncor-9601 (TU-2415-009-00151816-98) or Soncor-9701 (TU 2415-006-00151816-2000), which are a mixture of the reaction products of amines with tall oil fatty acids with a solvent and additives, were used as oil-soluble nitrogen-containing emulsifiers. , Emultal (TU 6-14-1035-79) - a mixture of complex monoesters of tall oil acids and triethanolamine, Neftenol-NZ grade 40 (2483-007-1719778-97) - a hydrocarbon solution of esters of oleic, linolenic, and resin acids and triethanolamine. Sonkor-9601 and Sonkor-9701 are produced by JSC "Neftekhim Experimental Plant" in Ufa, Emultal and Neftenol-NZ grade 40 are produced by JSC "Himeko Gang".

Inhibited hydrochloric acid (TU 48 1482), or clay acid (TU 601147888), or solutions of calcium chloride or sodium chloride were used as the aqueous phase.

The hydrocarbon liquid used was diesel fuel, liquid paraffin-type petroleum hydrocarbons, for example BFLH (a wide fraction of low-boiling light hydrocarbons), unstable gas gasoline or light crude oil.

For a comparative assessment of the effectiveness of the developed and known method, the compositions according to the invention and prototype are tested.

The inverse emulsion in the present method is prepared in the following way. The required amount of emulsifier (Soncor-9601 or Soncor-9701 and others) is dissolved in the calculated amount of hydrocarbon liquid with vigorous stirring, and the calculated amount of an aqueous acid solution or an aqueous solution of CaCl ₂ or NaCl is introduced in portions of 3-4 doses. The mixing time of the emulsion composition is 5 minutes at a mixing speed of 5000 rpm.

The compositions in the method according to the prototype are prepared by mixing marketable oil, emulsifier and produced water in the quantities described in the prototype.

Evaluation of the effectiveness of the method is checked in laboratory conditions to determine the stability of the reverse emulsion in the temperature range 60-100 ° C, viscosity, to measure the interfacial tension of hydrocarbon solutions of the emulsifier and to determine the permeability of the core, in which the emulsion is not destroyed.

The stability of the emulsion was evaluated at a certain temperature in time until the aqueous phase in the lower layer was isolated. Stable emulsion has 100% aggregative stability at Vn ₂ about = 0. Aggregate stability is calculated by the formula:

V _em - the volume of the emulsion;

Vн ₂ о - volume of released water.

The viscosity was determined on a Brookfield rotational viscometer at a shear rate of 73.2 sec ^-1 .

The interfacial tension of hydrocarbon solutions of emulsifiers is measured on a stalagmometer equipped with a medical syringe with a micrometer screw, developed in Ufa Research Institute.

Interfacial tension is determined by the formula:

K is the constant of the device;

n is the number of divisions of the micrometer;

d ₁ is the density of water;

d ₂ - density of the investigated fluid.

Experiments on the study of filtration characteristics using the proposed and known method were carried out on linear models 10 cm long and 3.5 cm in diameter, filled with quartz sand. The cores were saturated with diesel fuel, which was replaced by a model of oil. The core permeability was determined for diesel fuel and oil. Then, a composition in a volume of 2 pores was pumped through the core at a filtration rate of 6.8 m / day and mobility was measured with a visual assessment of the stability of the emulsion at the core exit. The calculation of mobility is carried out according to the formula:

λ is the mobility of water (λ = k / μ), μm ² / cPz;

k is the permeability, microns;

μ is the viscosity, cPz;

L is the core length, cm;

Q is the given flow rate, cm ³ / s;

S is the core area, cm ² ;

ΔР - pressure drop, atm.

The test results of the composition in the claimed and known method, taken as a prototype, are presented in table.1-3.

From the data presented in table 1, it follows that in the inventive method, the inverse emulsion has adjustable stability in the temperature range 60-100 ° C for 6-35 hours, while the composition in the prototype method has a stability of only 1-3. When the content of the emulsion of the emulsifier Sonkor-9601 or Sonkor-9701 in an amount of less than 0.4% is impractical, since the emulsion has insufficient stability. The content in the composition of the emulsifier of more than 5% leads to a sharp increase in stability and inability to use as a temporarily insulating material.

As can be seen from the data given in table 2, the interfacial tension of hydrocarbon solutions Sonkor-9601 and Sonkor-9701 is incomparably less than the interfacial tension of hydrocarbon solutions of the emulsifier of the prototype.

The inventive inverse emulsion is filtered without destruction through a core with a permeability of more than 0.2 μm ² , and the emulsion of the prototype through a core with a permeability of more than 18 μm ² .

Thus, the effectiveness of the proposed method is determined by the following advantages compared with the known method:

- the inverse emulsion in the present method has adjustable stability in the temperature range of 60-100 ° C;

- stabilized by effective oil-soluble nitrogen-containing emulsifiers (Sonkor-9601 and Sonkor-9701, etc.) having a low interfacial tension of hydrocarbon solutions, the inverse emulsion in the inventive method has a significantly smaller size of the globules of the dispersed phase, and this provides a deeper penetration into the reservoir.

In practice, the developed method is implemented in the following way.

At a well planned for stimulating work, taking into account the geological and physical characteristics of the formation and current development indicators, the degree of heterogeneity of the formation and its nature in the interval of perforation of the well are determined. Next, the volume of the inverse emulsion is calculated for the effective temporary isolation of the interval over which water breakthrough occurs. Then prepare the estimated volume of the inverse emulsion containing an aqueous solution or an inhibited acid or an aqueous solution of salts. Emulsification of an acid or aqueous solution in a hydrocarbon solution of an emulsifier is carried out in a special mixer or unit UOE-1. Next, the calculated amount of the acid solution is pumped. Liquid injection is stopped for a time corresponding to the stability of the inverse emulsion (table 1). After exposure, the emulsion is destroyed, after which the oil can freely enter the well from both low and high permeability intervals of the reservoir. Then they begin to develop the well.

According to the results of field studies, the use of the proposed method can increase the thickness of the formation by about 3 times in comparison with the known method and will increase oil production while reducing the water cut of the produced products.

Table 1 The composition of the emulsion,% wt. Stability Viscosity No. Emulsifier Hydrocarbon fluid Water phase at a temperature of ° C for an hour at shear rate mark qty mark qty composition count 60 80 100 73.2 sec-1 1 prototype 3 2 1 40 2 Soncor 9601 0.2 diz. fuel 26 10% Hcl ing. rest 4 3 2 120 3 Soncor 9601 0.4 diz. fuel 26 10% Hcl ing. rest 10 6 4 160 4 Soncor 9601 1 diz. fuel 26 10% Hcl ing. rest 12 8 6 200 5 Soncor 9601 2 diz. fuel 28 10% Hcl ing. rest twenty 12 8 243 6 Soncor 9601 5 diz. fuel 26 10% clay acid. rest 32 17 14 900 7 Soncor 9601 10 diz. fuel 26 10% Hcl ing. rest stab. stab. 40 1100 8 Soncor 9601 2 light oil 28 10% clay acid. rest 21 thirteen nine 260 nine Soncor 9601 2 ShFLU 28 10% clay acid. rest twenty 12 8 240 10 Soncor 9601 1 diz. fuel 29th 2% CaCl ₂ rest 24 8 6 180 eleven Soncor 9601 2 diz. fuel 28 2% CaCl ₂ rest thirty fifteen 8 265 12 Soncor 9601 2 diz. fuel 40 5% NaCl rest 26 12 6 190 thirteen Soncor 9601 2 light oil 40 5% NaCl rest 27 14 7 230

The composition of the emulsion,% wt. Stability Viscosity No. Emulsifier Hydrocarbon fluid Water phase at a temperature of ° C for an hour at speed mark qty mark count composition qty 60 80 100 shear 73.2 sec-1 14 Soncor-9701 1 diz. fuel 40 10% HCl ing. rest 12 8 6 210 fifteen Soncor 2 diz. 28 10% rest 16 12 nine 455 9701 fuel clay acid. 16 Soncor 2 light 26 1% CaCl ₂ rest 35 twenty 10 280 9701 oil 17 Soncor 2 light 40 2% NaCl rest thirty eighteen 8 270 9701 oil eighteen Emultal 2 diz. 38 10% HCl rest twenty fifteen 7 190 fuel Ing. 19 Neftenol-NZ 2 diz. fuel 28 10% CaCl ₂ rest 32 eighteen 6 670

table 2 №№ Emulsifier brand Emulsifier concentration,
% Interfacial tension at the border with a solution of 2% CaCl ₂ , mn / m Interfacial tension at the border with 10% Hcl, mn / m 1 Prototype emulsifier 1 17 14 2 Prototype emulsifier 2 fifteen 12 3 Prototype emulsifier 5 12 10 4 Soncor 9601 0.02 16 5 5 Soncor 9601 0.04 8 2 6 Soncor 9601 0.12 2 1 7 Soncor-9701 0.02 14 4 8 Soncor-9701 0.04 7 1,5 nine Soncor-9701 0.12 1 0.5

Table 3 №№ Composition No. from table 1 The permeability of the core, microns ² State of emulsion at core exit 1 2 3 stub emulsion 2 3 1 stub emulsion 3 4 1 stub emulsion 4 5 0.5 stub emulsion 5 6 0.2 stub emulsion 6 7 0.2 stub emulsion 7 8 0.2 stub emulsion 8 nine 0.5 stub emulsion nine 10 3.0 stub emulsion 10 eleven 3.0 stub emulsion eleven 12 3.0 stub emulsion 12 thirteen 3.0 stub emulsion thirteen 14 3.0 stub emulsion 14 fifteen 0.5 stub emulsion fifteen 16 3 stub emulsion 16 17 3 stub emulsion 17 5 0.05 The emulsion is stratified into 2 phases eighteen eighteen 4 stub emulsion 19 19 4 stub emulsion twenty prototype eighteen stub emulsion 21 prototype 14 The emulsion is stratified into 2 phases 22 prototype 10 The emulsion is stratified into 2 phases

Claims (4)

1. The method of processing the bottom-hole zone of the formation, including the injection into the formation of a reverse oil emulsion and an aqueous solution of acid, characterized in that as an inverse emulsion using an emulsion containing the following components, vol. %: Hydrocarbon Liquid 26-40 Oil Soluble Nitrogen Emulsifier Soncor-9601 or Soncor-9701 0.4-5 An aqueous solution of inhibited 10% hydrochloric acid acid or clay acid or aqueous solution 1-10% calcium chloride or sodium chloride 2. The method according to claim 1, characterized in that diesel oil, or liquid petroleum hydrocarbons of the paraffin series, or unstable gas gasoline, or light oil is used as a hydrocarbon liquid. 3. The method according to claim 1, characterized in that the inverse emulsion remains stable for 6-35 hours at a temperature of 60-100 ° C when filtered through a reservoir model with a permeability greater than or equal to 0.2 μm ² . 4. The method according to claim 1, characterized in that the injection time of the inverse emulsion during filtration into the formation should not exceed the time for maintaining the stability of the emulsion.