FR2595752A1 - PROCESS FOR IMPROVING VISCOUS RAW PETROLEUM PRODUCTION - Google Patents

Abstract

FORMATION OF AN OIL-IN-WATER EMULSION WITH VISCOUS CRUDE OIL AND 20 TO 80 BY WEIGHT OF WATER IN THE PRESENCE OF 170 TO 4000 PARTS BY WEIGHT PER MILLION PARTS BY WEIGHT OF OIL OF A MIXTURE OF SURFACTANTS. THIS MIXTURE OF SURFACTANTS CONSISTS OF 30 TO 70 PARTS BY WEIGHT OF ANIONIC OR AMPHOTERIC SURFACTANT AND 30 TO 70 PARTS BY WEIGHT OF A NON-IONIC SURFACTANT. APPLICATION: OIL-IN-WATER EMULSION IS USED IN A PROCESS TO IMPROVE MOBILITY AND PIPELINE TRANSPORTATION OF VISCOUS CRUDE OIL.

Description

! The present invention relates to methods for improving the

  production capacity of a viscous crude oil by formation of an oil-in-water emulsion

  with mixtures of some surfactants.

  The pumping of petroleum from the production plant and the subsequent pipeline transport are

  difficult because of the low mobility of oil.

  Previous methods of overcoming this problem have included the addition of lighter hydrocarbons, such as kerosene or light condensate, and the heating of crude oil. These methods of the prior art are expensive

and waste energy.

  Still another method for decreasing the viscosity of heavy crude oils is using an oil-in-water emulsion. The following patents disclose such methods using various agents to form emulsions therefor: U.S. Patent No. 3,380,531; U.S. Patent No. 3,467,195; U.S. Patent No. 4,108,193; U.S. Patent No. 4,152,290; U.S. Patent No. 4,153,573; U.S. Patent No. 4,153,575; U.S. Patent No. 4,162,989; U.S. Patent No. 4,192,767 and

  U.S. Patent No. 4,214,999.

  However, each of these processes has serious drawbacks in that, for example, the emulsion obtained is still relatively viscous, they require heating to obtain a sufficiently low viscosity emulsion, or the subsequent separation of the

oil is difficult.

  U.S. Patent No. 4,239,052 discloses the use of a mixture of an ethoxylated alkylphenol and a low molecular weight alkarylsulfonate to reduce the viscosity of viscous hydrocarbons. U.S. Patent No. 4,246,919 discloses a process using a mixture of an ethoxylated alkylphenol and an ethoxylated polypropylene glycol. U.S. Patent No. 4,249,554 discloses an emulsion obtained using a mixture of an ethoxylated alkylphenol and a salt of an ethoxylated alcohol sulfate. U.S. Patent No. 4,265,264 discloses a process using a mixture of a salt of an ethoxylated alcohol sulfate and certain polyoxyethylene-polyoxypropylene copolymers or an ethoxylated alcohol. U.S. Patent No. 4,285,356 teaches a method for decreasing the viscosity of viscous hydrocarbons by forming an emulsion with a combination of certain ethoxylated alkylpolyethersulfates and a

alcohol-ether sulphate.

  The subject of the present invention is a process which has clear advantages over those of the prior art in that oil-water emulsions of very low viscosity at ambient temperature are obtained, which provides a significant improvement in the productivity of wells producing viscous crude oils. Thus, the present invention discloses a method for improving the mobility of a viscous crude oil and a method for conveying a viscous crude oil through a pipeline, each of which comprises forming an oil-in-water emulsion with the oil viscous crude and 20 to 80% by weight of water in the presence of 170 to 4000 parts by weight of a surfactant mixture per million parts by weight of petroleum (ppcni-near), said elagenecompetent to 70 parts by weight of an anionic or amphoteric surfactant (A) which is selected from those of formulas Ar (OCH 2 CH 2) nOSO 3 H, Ar (OCH 2 CH 2) nOCH 2 COOH,

(A1) (A)

  R (OCH 2 CH 2) nOCH 2 COOH, 2 2 n (A4) (A)

S03H SO CH2CO 2 CH2CH2OCH2COOH

(A4) (A)

  one of its sodium and ammonium salts; and 30 to 70 parts by weight of a nonionic surfactant selected from those of formulas (B) Ar (OCH 2 CH 2) pOH, or (C) H (OCH 2 CH 2) r (OCH 2 CH) wherein said surfactant (C) having a value hydrophilic-lipophilic balance of 10 to 20; Ar being an octyl or nonylphenyl group, n being a number from 2 to 10, p being a number from 10 to 100, m being a number from 20 to 40, r being a number from 20 to 50, R 1 being a C8 to C18 alkyl group and

2 8 1

  R being a C12-C18 alkyl group.

  The present invention also relates to

  the emulsion formed by the above methods.

  In the above emulsion and methods for its use, a particularly preferred amount of water present in the emulsion is from 25 to 50% by weight of the viscous crude oil. A particularly preferred surfactant mixture comprises 50 parts by weight of said

  surfactant (A) and 50 parts by weight of said surfactant (B) or said surfactant (C).

  A particularly preferred amount of said surfactant mixture used in the emulsion is from 200 to 1500 parts by weight of the mixture per million parts

by weight of viscous crude oil.

  A particularly preferred class of surfactant mixtures is that wherein (A) is an anionic surfactant selected from (A 1), (A2) and (A3), as defined above, or a sodium or ammonium salt thereof , and said nonionic surfactant is a surfactant (B) as defined above; also included in this class are mixtures in which (A) is the anionic surfactant (A1) as defined above, and the nonionic surfactant is a surfactant

  (C), as defined above, but having a hydrophilic-lipophilic balance value of 12 to 16.

  Particular surfactant mixtures which are particularly preferred for the preparation of emulsions of the present invention and for carrying out the processes of the invention are those having equal weights of the following active ingredients: 1. (A 1) Salt sodium or ammonium salts of 4-C9H9C6H4 (OCH2CH2) 4OSO3H and (B) 4-C8H17C6H4 (OCH2CH2) 70o; 2. (A ') The sodium or ammonium salt of 4-C9H19C6H4 (OCH2CH2) 40503H and

(B) 4-C8H17C6H4 (OCH2CH2) 30OH; 30

  3. (A1) The sodium or ammonium salt of 4-C9H19C6H4 (OCH2CH2) 4OSO3H and (C) H (OCH2CH2) 23 (OCH2CH2) 210H having a hydrophilic-lipophilic balance CH3 value of 16; 4. (A1) Sodium or ammonium salt of 4C9H 9C6H4 (OCH2CH2) 40SO3H and (B) 4-C9H19C6H4 (OCH2CH2) 10OH; 5. (Al) Sodium or ammonium salt of 4-C9H19C6H4 (OCH2CH2) 4OSO3H and (B) 4C8H17C6H4 (OCH2CH2) 100H; 6. (A5) The sodium or ammonium salt of the amphoteric surfactant R, dan, in (CSoO CH 2 CH 2 OCH 2 COO O where R 2 is a C 12 to C 8 alkyl group and 112 18 (B) 4 -C 8 H 7 C 6 H 4 (OCH 2 CH 2) 7. (A4) The disodium salt of R 9 O 9, wherein R is C 1 -C 18 alkyl and SO 3 H SO 3 H

(B) 4-C9H19C6H4 (OCH2CH2) 100OH;

  8. (A2) The sodium or ammonium salt of 4C8H7C6H4 (OCH2CH2) 4OCH2COOH and

(B) 4-C8H17C6H4 (OCH2CH2) 30OH;

  9. (A3) Sodium or ammonium salt of C10H21 (OCH2CH2) 4OCH2COOH and

4-C8H17C6H4 (OCH2CH2) 30OH.

  As noted above, the present invention is directed to a process for increasing the productivity of a viscous crude oil by improving the mobility of oil at the wellhead and its transportation by pipelines by forming an oil emulsion. -in-water with some

new surfactant mixtures.

  The surfactants and mixtures thereof have initially been determined in the laboratory to have the ability to form oil-in-water emulsions of substantially reduced viscosity at room temperature and also having adequate stability to transport the emulsion to the site. oil recovery. Of course, the preferred emulsions are not stable enough for subsequent oil separation to be difficult. Thus, the ideal emulsion is an emulsion which is highly mobile at room temperature at the wellhead and during transport, and allows for virtually complete separation of the oil from the well.

recovery site.

  The laboratory test was conducted by forming oil-in-water emulsions with samples of various viscous crude oils and measuring their viscosity and the stability of the emulsion by methods well known in the art. These tests were conducted using water or brine as the aqueous phase. The brines used were natural brines obtained at a drilling site or simulated synthetic brines.

  those which are in the natural state.

  As a result of these tests, it has been found that mixtures of certain known anionic or amphophilic surfactants herein referred to as surfactant (A) with certain known nonionic surfactants, referred to herein as the surfactant ( B) or surfactant (C), give water-in-oil emulsions which exhibited a mobility greater than the ambient temperature and which had the stability

desired, mentioned above.

  The anionic or amphoteric surfactant referred to as (A) in the surfactant mixtures referred to above is selected from those of formulas (A1): Ar (OCH 2 CH 2) n OSO 3 H, wherein Ar is octylphenyl or nonylphenyl and n is a number of 2 to 10 which represents the average number of ethylene oxide units, one of its sodium or ammonium salts; (A): Ar (OCH2CR2) nOCH2COOH, one of its sodium or ammonium salts, wherein Ar and n are as defined for (A1) above; (A3): R1 (OCH2CH2) nOCH2COOH, a sodium or ammonium salt thereof, wherein R is straight or branched C8 C18 alkyl; 10 (A4) R j o one of its salts

S03E S03H

  sodium or ammonium, wherein R is a straight or branched straight chain C8-C18 alkyl group; 85 1 and (A5) -% J

E

CR2C00 CR2CH2OCR2COOE

  one of its sodium or ammonium salts, in which R2

  is a straight chained or branched C12-C18 alkyl group.

  The nonionic surfactant referred to as (B) in the above-mentioned surfactant mixtures is selected from those of formula Ar (OCH 2 CH 2) pOH wherein Ar is as defined above and p is a number from 10 to 100 which represents the average number of reasons

ethylene oxide.

  The nonionic surfactant, alternatively, referred to as (C) in the surfactant mixtures mentioned above is selected from those of the formula H (OCH 2 CH 2) r (OCH 2 CH) m OH wherein r represents the average CH 3 number of ethylene oxide units and m represents the number

  medium of propylene oxide units.

  Examples of suitable surfactants (A), above, which are commercially available include Alipal CO-433 and AlipaG C0436 available from GAF Corporation, New York, NY 10020. Other surfactant suppliers (Ai in which the average value of n is between 2 and 10 include Witco Chemical Corporation, New York, NY 10022; Onyx Chemical Company, Jersey City, NJ 07302; Conoco Chemicals, Houston, Texas and Rohm & Haas Co., Philadelphia,

PA 19105.

  Examples of suitable surfactants (A2), above, which are commercially available are HUls BW 1142 and its homologs, available from Chemische Werke Hils AG, Postfach 1230, D-4370, Marl,

Federal Republic of Germany.

  Examples of suitable surfactants (A3), above, which are commercially available are Hals BW 1109 and its counterparts, also available.

from Chemische Werke HUls AG.

  Examples of suitable surfactants (A4), above, which are commercially available include Eleminol R M0N-7 from Sanyo Chemical Industries, Ltd., Kyoto, Japan; and Dowfax 2A0, 2A1, and 3B2 surfactants from Dow Chemical U.S.A., Specialty Chemicals

  Department, Midland, Michigan 48640.

  Examples of suitable surfactants (A5), above, which are commercially available include Mirano # zC2MSF, Miranol H2M, Miranol L2M-SF, Miranol 02M and Miranol C2M available from Miranol Chemical Company, Dayton. NJ 08810; and Cycloteric \ DC-SF from Cyclo Chemical Corp.,

Miami, Florida.

  Suitable nonionic surfactants (B) which are commercially available include Triton X-100, Triton X-305, Triton X-405, Triton X-705 and Triton N-998, respectively containing an average number 10, 30, 40, 70 and 100 oxyethylene units, available from Rohm & Haas Co., Philadelphia, PA 19105; T-DET N-407 and T-DET 507 from Thompson Hayward, Kansas City, KS 66110 and Tergitol NP-40 from Union Carbide Corp.,

Danbury, CT 06817.

  Commercially available nonionic surfactants (C), which are suitable above, include several Pluronic surfactants from BASF Wyandotte Corp., Wyandotte, Michigan 48192, including Pluronic

  L35 (EHL 18.5), L43 (EHL12), L44 (EHIL16), P65 (EHL17), L64 (EHL17), L63 (EHL11), P75 (EHL16.5), P85 (EHL) 16)

  P84 (EHL 14), P94 (EHL 13.5), P104 (EHL 13) and P105 (EHL 15).

  As is well known in the art of surfactants, EHL is the hydrophilic-lipophilic balance, which is a measure of the relative simultaneous attraction of an emulsifier for both phases (oil and water) in an emulsion . Higher EHL values indicate

a superior hydrophilicity.

  Assuming easy separation of the phases in each case, it is recognized by those skilled in the art that the higher the oil content of the emulsions of the present invention, the more efficient the recovery process. Thus, effective emulsions of the present invention are those containing from 20 parts by weight of petroleum and 80 parts by weight of water to those containing 80 parts by weight of petroleum and 20 parts by weight of water. Particularly preferred emulsions are those containing 50 to 75 parts by weight of oil and 25 to 50 parts by weight of water. Of course, as indicated above, the "water" used in the emulsion may be pure water, containing little or no dissolved solids, or brine, containing relatively high levels (up to 15%). Z by weight) total dissolved solids (TDS), including ordinary salt. In most cases, the "water" used in the emulsion is the water produced in the well at the same time

as heavy crude oil.

  In some cases, the liquid produced by a well is a very viscous water-oil emulsion. It has been found that by introducing a surfactant mixture of the present invention into the annulus of the well with a moderate downward mixture, the viscous water-oil emulsion is inverted, forming an emulsion.

  oil-in-water of very low viscosity.

  Although the contents of the surfactant mixture, which is based on the weight of the oil, may vary over a wide range, the preferred levels are those between 170 and 4000 parts by weight of surfactant mixture per million parts by weight of oil. , and the preferred mixtures are those containing 200 to 1500 parts by weight of surfactant per million

parts by weight of oil.

  In all cases of this submission, the

  Surfactant parts refer to the active ingredient parts, excluding inert diluents commonly used in their formulations, for example water.

  The preferred surfactant mixtures are those containing 30 to 70 parts by weight of surfactant (A) and 70 parts by weight of surfactant (B) or surfactant (C) and the preferred mixtures are those containing 50 parts by weight of each active ingredients above, (A)

and (B) or (A) and (C).

  The following examples are intended to illustrate

the present invention.

! 1

EXAMPLE 1

  Viscosity reduction and stability of the emulsion of a California crude oil, API 13,5-15 density, with

various emulsifying agents.

  Process: The crude oil sample, 280 g, the brine *, 120 g, and the emulsifier, 0.224 g (800 ppm based on the weight of the oil), were placed in a blender and mixed at a speed high shear for 30 seconds. The viscosity of the obtained emulsion was measured with a Brookfield LVTD viscometer at shaft speeds of 6, 12, 30 and 60 rpm. All the

  Viscosity readings were approximately the same.

  A 100 ml portion of the emulsion was poured into a graduated cylinder and allowed to stand at 25 C. After six hours, each graduated cylinder was inverted three times to redisperse the mixture. The viscosity was measured again and noted as the viscosity after 6 hours. The extent of the decrease in viscosity and the ease of redispersion ability after a rest period are measurements of the degree of coalescence of the oil phase and thus are a measure of the stability of the emulsion. The results are summarized in the table below.

  * The brine contained 10% by weight total dissolved solids (TDS) and had a hardness of 1%.

  Agent Efficiency of emulsion stability, emulsification, thinning, viscosity after 6 hours initial viscosity at 25 C (centipoise) 2 30 at 25 C (centipoise)

None 20,000 N.A.

Surfactant I 9 450 N.A.

  Surfactant II 200 4,200 Surfactant III 250 5,200 Surfactant IV 200 5,000 Surfactant V 180 6,800 Agent Stability effectiveness of the emulsifying emulsion1 fluidification, viscosity after 6 hours initial viscosity at 250C (centipoise) 2 at 25 C (centipoise) Surfactant VI 400,500 (US Pat. No. 4,239,052) Surfactant VII 320,5,840 (US Pat.

No. 4,249,554)

  Mixture I (I + III) 200 4 400 Mixture 2 (I + II) 300 I 100 Mixture 3 (I + V) 300 1 700 1800 ppm active surfactant below, based on

oil weight.

  Surfactant Chemical Name and Formula I Nonylphenoxytri (Ethyleneoxy) Ethanol Sulfate

C9H19C6H4 (OCH2CH2) 3OCH2CH2OSO 3H.

  II Octylphenoxypoly (ethylenoxy) ethanol (30 moles of ethylene oxide)

C8H17C6H4 (OCH2CH2) 300H.

  III Octylphenoxypoly (ethylenoxy) ethanol (70 moles of ethylene oxide) C8H17C6H4 (OCH2CH2) 70 OHIV Nonylphenoxypoly (ethylenoxy) ethanol (100 moles of ethylene oxide)

C9H19C6H4 (OCH2CH2) 100OH.

  V Block copolymer of ethylene oxide and propylene oxide (40% ethylene oxide),

EHL = 16 *.

  VI Dodecylbenzenesulfonate and nonylphenoxypoly (ethylenoxy) ethanol mixture of C12H25C6H4SO3H and CY-19C6H4 (OCH2CH2) 400H

in the 50/50 ratio.

  VII Alfonic mixture 1412-A C12 14H -29

  C12_14_-29 (OCH2CH2) 30S03NH43 plus T-DET-N407 '[C9H19C6H4 (OCH2CH2) 400H] in the ratio 50/50 (w / w).

  Surfactant Chemical Name and Formula Mixture 1 50/50 mixture (w / w) of Surfactants I and III above. Mixture 2 50/50 mixture (w / w) of surfactants I and II above. Blend 3 50/50 mixture (w / w) of surfactants I and V above. NA = not applicable

* Pluronic L-44, BASF Wyandotte.

  ** Alfonic is a registered trademark of Conoco Chemicals. T-DET is a registered trademark of Thompson Hayward Chemical Co.

EXAMPLE 2

  The effect of the variation in the ratio of the supercharging ratio of the mixture 2 of Example 1 was determined using the same heavy crude oil from California, hereinafter referred to as Type A Oil, and a second

  California heavy crude oil, Type B, by the method of Example 1, except that the ratio of surfactants in the mixture is as indicated below.

  Surfactant Ratio I / II Type of Stability Efficiency of (total: 800 ppm) petroleum fluidification1 emulsion2

0/100 to 200 4200

25/75 to 240 3100

/ 50 to 300 1100

/ 25 to 7280 N.A.3

/ 0 to 9450 N.A.3

/ 50 B4 300 700

Notes:

  Initial viscosity at 25 C, centipoise.

  2Viscosity after a rest at 25 for six hours, centipoises. 3N.A. = not applicable 4Crude heavy oil from California, API 11-12 density,

  viscosity at 33 C equal to 15,000 centipoise.

EXAMPLE 3

  The effect of the variation of the total weight of the surfactants using the mixture 2 of Example 1 was observed with a heavy crude oil of Central California of 12 API, having a Brookfield viscosity (centipoise) having the following values: C greater than 20,000 cps at 33 C 18,500 cps at 40 C 6,320 cps

  and a paraffin / asphaltene ratio of 10.9. The method used was that of Example 1, except that the stability of the emulsion was determined after a two-hour rest, instead of six hours. The percentage of separation of the phases after the emulsion has been at rest for two hours has also been noted. The results are summarized below.

  Effect of concentration of mixture 2 on viscosity and stability of the emulsion Mix quantity 2, ppm based on oil weight None

400 800 1600

  Initial viscosity, Viscosity after 2 hours (centipoise) at 25 C (centipoise) Percentage separation of phases after 2 hours

> 20,000

180 160

> 20,000

600 400 400

32 20

N Ln -'j hn

EXAMPLE 4

  The effect of various surfactant mixtures, each containing 800 ppm (based on the weight of the oil) on the viscosity and stability of emulsions (oil: water) in the 70:30 ratio of a northern heavy crude oil of Montana was determined by the above method. The heavy crude oil used had the following viscosities: at 22 C (70 F) 12,000 cps at 38 C (100 F) 2,700 cps at 49 C (120 F) I 100 eps In each case, emulsions in The duplicates were prepared in the Waring Blender at 60 C (1400 F) using tap water and brine containing 5% by weight total dissolved solids (TDS). The viscosity of the emulsion was determined after cooling to 25 ° C. and the phase separation per hour was determined after a period of two hours. The results are summarized below Initial viscosity and stability of heavy crude oil emulsions from northern Montana (water / oil 70:30) with various surfactant mixtures at 800 ppm (based on the weight of the oil) Initial viscosity, cps Phase separation (% / H) Surfactant mixture. * H20 tap Brine at 5% STD! _20 tap Brine at 5% STD Blend I 62 74 18 23 Blend 2 214 70 28 31 Blend 4 108 84 21 EXAMPLE 4 (continued) * Mixture I - a 50:50 weight ratio mixture of surfactants I (Alipal CO-436, GAF Corporation, New York, NY 10020) and III ( Triton X-705, Rohm & Haas Co., Philadelphia, PA 19105) of Example I; Mixture 2 - a mixture in the 50:50 weight ratio of surfactant I above, and surfactant II of Example 1 (Triton X-305, Rohm & Haas Co., Philadelphia,

PA 19105);

  Blend 4 - a 50:50 weight ratio mixture of surfactant I, above, and IV surfactant of Example 1, nonylphenoxypoly (ethylenoxy) ethanol (Triton N-998, Rohm & Haas, Philadelphia, PA 19105); Mixture of a 50:50 weight ratio mixture of surfactant I, above, and octylphenoxypoly (ethylenoxy) ethanol, C8H17C6H4O (CH2CH2O) o10H (Triton X100,

  Rohm & Haas, Philadelphia, PA 19105).

EXAMPLE 5

  A heavy crude oil from Peru, heavily asphalted, 280 g, 10% STD brine, 120 g, and 800 ppm 50/50 weight ratio surfactant blend was emulsified and the viscosity Initial Brookfield was measured as in Example 1 to determine the fluidizing efficiency of the surfactant mixture at 25 C. Then the emulsion was shaken for 24 hours at 27 C at a rate of 150 cycles / minute for determine the stability of the emulsion on the basis of the coalescence of the oil by determining the diameter of the oil globules. A cell diameter of less than 2 millimeters under these conditions

  (diameter 1) undergoes the test successfully.

  Efficiency of thinning, viscosity at 25 ° C (centipoise) Stability of the emulsion after 24 hours, shaking test Mixture of surfactants No 112 mg each of nonylphenoxytri (ethylenoxy) ethanol sulfate and ethylene oxide block copolymer, propylene oxide (40% ethylene oxide) (I + IV of Example 1) 112 mg each of ethylene oxide block copolymer, propylene oxide (40% ethylene oxide), (V of Example 1), and [(C 4 H -CH) -4- (sulphonylphenoxy) 3benzegensulfate disodium salt *

> 20,000

not applicable 1-2 o CD l

  * Eleminol MON-7, a registered trademark of Sanyo Chemical KK.

r.> ut% a A 14 A

EXAMPLE 6

  Effect of Total Concentration of Surfactant Mixture 2 on Emulsion Stability with California Heavy Crude Oil Blends of 380 g crude oil, 163 g 10% (w / w) brine, and 100, 200, 400 or 800 ppm by weight, based on the weight of the oil, of 50/50 mixture (weight / weight) of surfactants I and II of Example I were emulsified by pumping the mixture by a 0.25 inch diameter loop tube at a shear rate of 1000 sec -1 minutes. The initial appearance and viscosity were obtained as in Example I and the emulsion was then pumped through the tube at a shear rate at the wall of 500 s-1 and the appearance and separation of the water was noted after a crossing of the tube equal to 7, 62 m. The results are summarized below: Surfactant mixture2, ppm * Emulsion initial viscosity, (centipoise) Appearance of the emulsion After 7.62 m of initial tube separation Water separation uniform considerable coalescence uniform slight uniform coalescence uniform uniform ml, clear after 10 minutes ml, limpid after 30 minutes ml, muddy after 20 hours ml, muddy after 20 hours NN based on the weight of oil r'a 1% O tA re

EXAMPLE 7

  Stability of Emulsion with California Heavy Crude Oil Using a heavy crude oil from Cat Canyon, California, viscosity equal to 7860 cps at 21 C (70oF), oil / brine emulsions in the ratio: 30 (brine). contained 6260 ppm STD, hardness 42 ppm) containing 200 to 1000 ppm surfactant mixture, was prepared by pumping the mixture at 27 C (80 F) for seconds by a 0.635 cm (0.25 in) loop tube. - diameter at a shear rate of 1000 s. Then

  pumping at a speed of 500s-1 shear was continued until the emulsion was broken. The break times of the emulsions tested in this way are summarized below.

  Break Time Concentration, Overmix Blending Time i Blending Mixture 2, ppm * Example 1 Example

0.25 --400 0.50 0.6

600 0.75 - 800 1.4 1.5

1000 1.5 1.7

* based on the weight of the oil.

EXAMPLE 8

  Performance with a South American Heavy Crude Oil A South American crude oil with a Brookfield viscosity of 11 000 cps at 20 C and 2800 cps at 27 C, and a paraffin / asphaltene ratio of 4.1, was emulsified in brine containing 6.7% or 9.1%

  dissolved solids with three different surfactant mixtures, as shown below.

  In each case, the emulsions contained 70% petroleum and 30% brine by weight and 800 ppm surfactant mixture. The emulsions were prepared in a Waring blender at 60 ° C, cooled to 25 ° C and the initial Brookfield viscosity was determined using an N 3 rod at 6 rpm. The stability of the emulsion was determined by the diameter of the oil droplets after shaking for 24 hours at 27 ° C., as described in Example 5. The results are summarized below: Viscosity Stability of the emulsion emulsion Surfactant mixture Brine, initial after 24 hours, (800 ppm)% of STD the emulsion, droplet diameter 10 ______________________________________________________________________________________________________________________________________________________________________ Mixture 6-a, mixture in the ratio: 50 (by weight) of Miranol C2MSF * and surfactant II of Example 1 6.7 total coalescence Mixture 4 of Example 4 6.7 420 2-5 mm Mixture 4 of Example 4 9.1 230 2 mm Mixture 7-a mixture in the 50:50 ratio (by weight) of Eleminol M0N-7 ** and IV surfactant of Example 1 9.1 230 I mm Miranol C2M-SF, Miranol Chemical Co., Inc., Dayton, NJ 08810; a copra dicarboxylic derivative of an imidazoline of formula

(C12H25C18H37) N H

  CH 2 CH 2 CH 2 OCH 2 COONa ** Eleminol 1 MON-7, Sanyo Chemical Co., is a 4-alkyl (sulfophenoxy) benzenesulfonate-disodium salt of the formula SO 3 Na SO 3 Na wherein R is a C 4 H 9 to C 18 H 37 group which may be chained

straight or branched.

EXAMPLE 9

  Performance with bitumen from western Canada The process of Example 8 was repeated with a bitumen from western Canada having a Brookfield viscosity of 34,800 cps at 25 C. In addition to the initial viscosity and the stability of the emulsion, the percentage of separation after a rest of 24 hours was determined. The results

  are summarized in the table below.

  Surfactant mixture * (ppm, by weight of oil) Weight ratio oil / water Initial viscosity of the emulsion, cps Stability of the emulsion after 24 hours Diameter of the drops after Percentage of separaagitation by shaking phase, mm Rest Mixture 1 (400) 70/30 180 Mixture I (800) 70/30 100 Mixture 2 (400) 70/30 160 Mixture 2 (600) 70/30 160 Mixture 2 (800) 70/30 60 Mixture 4 (400) 70/30 30 140 Mix 4 (800) 70/30 80 Mix 7 (800) 70/30 50 Mix 2 (800) 80/20 1250 * All surfactant mixtures are 1, 2 and 4 are as defined in

example 8.

-10 <1

-10 <1 <1

-10 <1

100 10

0 '

1-2 100

<1 <3

  in a weight ratio of 50:50. Blends Example 4. Blend 7 is as defined in tA no t; Iu

EXAMPLE 10

  Performance of Surfactant Blends 2, 8 and 9 with Geisinyer Heavy Crude Oil, California Geisinger, California heavy crude oil samples having a Brookfield viscosity greater than 10,000 cps (13.5 API) at 25 C were brine emulsified with 10% total solids dissolved, in a ratio of 70 parts by weight of petroleum and 30 parts by weight of brine, with the surfactant mixtures indicated below at 400 ppm of each component (total mixture surfactants, 800 ppm based on petroleum). The initial viscosity (cps) and the phase separation at rest at 25 ° C. were

  determined. The results are summarized below.

  Initial viscosity mixture Phase separation, surfactant ** of the emulsion, at ml / hour (800ppm) 25 C, cps * ___________No> 10,000 Mixture 2,600 0,9 Mixture 8,300 1,0 Mixture 9,600 1, O * Using a Brookfield viscometer, LVT, stem N 3

at 6 rpm, and 25 C.

  ** Blend 2 is a blend of weight% to surfactants I and II of respective brands Alysal C0436 and Triton.

  X-305, as defined in Example 1.

  Mixture 8 is a mixture of equal weights of Hils BW1142 and Triton X305S; the former is C10R21 (OCR2CH2) OCU2COONa (90% active). The mixture is an equal weight mixture of HIls B 1109 and Triton X-305; Huls BW! 109 meets the formula CIOH21 (OCH2CH2) 40CH2COONa (90% active). HlsBW1109 and BW 1124 are available from Chemische Werke Hils AG,

  Postfach 1230, D-4370 Marl, Federal Republic of Germany, Germany.

EXAMPLE II

  Injection Rejecting Test at Reward Field, McKittrick, Calif. A low-productivity well was used which, during a 26-day preliminary test period, had an average daily oil production of 0.11. with an average API gravity of 12 [0.986 g / cm3] and an average Brookfield viscosity greater than 20,000 cps. The viscosity of various samples of this crude oil was lowered to 130 to 180 cps with 400-800 ppm of surfactant mixture by the method of Example 1. During the 10 day test period, a solution was obtained. Mixture 2, containing 250 ppm of each of the two active surfactants, was continuously injected into the annulus of the well. The liquid produced during this period contained, on average, 36% of aqueous phase and 64% of oil, by weight. Average well fluid production increased by 240% and oil production increased by 450%. 20 Average well head temperature was equal to C. In addition, the pressure of the surface flow line was lowered from pre-test gauge pressure to 2068.5 x 103 Pa at gauge pressure

  during the test period of 179.27 x 103 Pa.

  For a period of 15 days after testing, oil production dropped to 0.19 / day, which

  is always 70% higher than the speed before testing.

  The results are summarized in the table below.

  SUMMARY OF THE AVERAGE RESULTS OBTAINED DURING A REWARD FIELD WELL TEST, MC KITTRICK, CALIFORNIA, WITH THE MIXTURE OF SURFACTANTS 2 (500 ppm) Liquid per day, 'Oil per day, r? Flow line pressure, Pa Viscosity, cps ** Ambient temperature, C maximum / minimum Preliminary test (26 days) Test (10 days)

0.29. 0.97

0.11. 0.62 0.19

  2068.5 x 103 179.27 x 10 1220.4 x 103

000 10-20 41 200

9.5 / -0.6 13/2

  Subsequent trial (28 days) 19/6 0.79 do

  * The surfactant mixture used was a 5% aqueous solution of equal parts by weight of the active ingredients: (A1) nonylphenoxytri (ethylenoxy) ethanol sulfated (Alipalt C0436 from GAF Corporation, New York, NY 10020) and (B) octylphenoxypoly ( ethyleneoxy) ethanol with 30 moles of ethylene oxide (TritorX-305, from Rohm & Haas, Philadelphia, PA 19105). It was pumped into the annulus of the well at a rate calculated to obtain the desired content of surfactant, oil and water mixture.

  ** Using a Brookfield viscometer, LV N 3 rod at 60 rpm, HA N 4 rod at 10 rpm.

-14 us r1,

EXAMPLE 12

  Midway-Sunset Field, Fellows, California injection emulsification test This test was conducted with a well that was already poorly productive, averaging 0.95? of oil per day during the eight-day preliminary test period, having a noticeable Brookfield viscosity at 40 C of 29,000 cps. On the 9th day, the continuous injection of 440 ppm (based on the weight of the oil) of surfactant mixture 2 was undertaken. The viscosity remained high (28,400 cps), the content of the mixture 2 was increased to 650 ppm the day 1010 and 740 ppm the day day, during which the viscosity fell to 12 800 cps (10th day) and 12 cps (the day). Administration was maintained at about 740 ppm until day 13, where it was further increased to 1040 ppm and maintained at 1000 to 1300 ppm until the end of the test period at day 18. From the 18th to the 18th, the viscosity remained

  low (12-90 cps), except for readings of 5200 and 20 2000 on the 12th day.

  During the 10-day trial period, liquid production was increased by 30% and oil production by 63% to an average of 1.55 n per day. During the test period, the temperature of the wellhead was 39 C. The results are

summarized below.

  SUMMARY OF THE AVERAGE RESULTS OBTAINED DURING A MIDWELLSUNSET FIELD, FELLOWS, CALIFORNIA TEST WITH THE MIXTURE OF SURFACTANT52 A 440 AT 1300 ppm Liquid by Oil by Room Temperature Pressure, C, day, n? day, born driving Viscosity, maximum / minimum flow cps, Pa Preliminary test 3 (8 days) 2, U7 0.95 896.35 x 10 29 000 26/7 Run 3 (10 days) 2.70 1, 56 689.5 x 10 540 * 19/7 Post Trial 3 (5 days) 1.91 0.95 1999.55 x 10 21 800 * 19/7

  * Using a Brookfield viscometer, HA N 4 rod at 10 rpm.

  * From the 13th to the 18th day, the viscosity remained in the interval between 12

and 90 cps.

  4 * 4The viscosity during the subsequent test was in the range of

  13,200 cps on the 19th day at 31,360 cps on the 22nd day, the moment of the final reading.

Lnl tu1 o N

Claims (9)

  A method for improving the mobility of a viscous crude oil, characterized by forming an oil-in-water emulsion with said oil and 20 to 80 percent by weight of water in the presence of 170 to 4000 parts by weight of a surfactant mixture per million parts by weight of petroleum, said mixture comprising 30 to 70 parts by weight of an anionic or amphoteric surfactant (A) selected from those of formulas Ar (OCH2CH2) nOSO 3H, Ar (OCH2CH) nOCH2COOH, R1 (OCH2CH) nOCH22 2 n 3 2 n 2 '2 2 n 2 COOH, O 9 R, and So3H so3H CH2COOCH2CH2OCH2COOH a sodium or ammonium salt thereof; and 30 to 70 parts by weight of a nonionic surfactant selected from those (B) of formula Ar (OCH2CH2) pOH, or (C) of formula H (OCH2CH2) r (OCH2CH) mOH CH3, said surfactant (C) having a hydrophilic-lipophilic balance value of 10 to 20; Wherein Ar is an octylphenyl or nonylphenyl group, n being a number from 2 to 10, p being a number from 10 to 100, m being a number from 20 to 40, r being a number from 20 to 50, R 1 being a lower alkyl group; C to C8 and R2 8 18   being a C12 to C18 alkyl group.   2. A process according to claim 1, characterized in that the water is present in an amount of 25 to 50 percent by weight of said oil, the mixture comprises parts by weight of surfactant (A) and 50 parts by weight of surfactant (B) or surfactant (C), and said surfactant mixture is present in an amount of 200 to 1500 parts by weight per million parts of said oil. 3. A process according to claim 2, characterized in that (a) said surfactant (A) is Ar (OCH2CH2) nOSO3H and said nonionic surfactant is a surfactant (B) or (C) having a hydrophilic balance value lipophilic from 12 to 16; or (b) said surfactant (A) is Ar (OCH2CH 2) n OCH2COOH or R (OCH2CH2) nOCH2COOH and said nonionic surfactant 2 2 n 2 is a surfactant (B).   4. A process for conveying a viscous crude oil in a pipeline, characterized by forming an oil-in-water emulsion with said oil and 20 to 80 percent by weight of water in the presence of 170 to 4000 parts by weight of a surfactant mixture per million parts by weight of petroleum, said mixture comprising 30 to 70 parts by weight of an amphoteric anionic surfactant (A) selected from those of formulas Ar (OCH2CH2) nOSO3H, Ar (OCH2CH2) n OCH2COOH, R1 (OCH2CH2) nOCH2COOH, 2 2 n 2COH R O R \ R2 SO3H SO3H CH2C H2OCH2COOH   or a sodium or ammonium salt thereof; and 30 to 70 parts by weight of a nonionic surfactant selected from those (B) of the formula Ar (OCH 2 CH 2) OH, or (C) of the formula H (OCH 2 CH 2) r (OCH 2 CH) wherein said surfactant (C) having a hydrophilic-lipophilic equilibrium value of 10 to 20; Wherein Ar is an octylphenyl or nonylphenyl group, n being a number from 2 to 10, p being a number from 10 to 100, m being a number from 20 to 40, r being a number from 20 to 50, R 1 being a lower alkyl group; C8 to C8 and 2 8 18   R being a C12-C18 alkyl group.   A process according to claim 4, characterized in that the water is present in an amount of from 25 to 50 percent by weight of said oil, the mixture comprises parts by weight of surfactant (A) and 50 parts by weight of surfactant (B) or surfactant (C) and said surfactant mixture is present in an amount of 200 to 1500   parts per million parts by weight of said oil.   6. A process according to claim 5, characterized in that (a) said surfactant (A) is Ar (OCH2CH2) OSO3H and said nonionic surfactant is a surfactant (B) or 20 (C) having an equilibrium value hydrophilelipophilic from 12 to 16; or (b) said surfactant (A) is Ar (OCH2CH2) nOCH2COOH or R1 (OCH2CH2) nOCH2COOH and said nonionic surfactant 2 2 n 2 is a surfactant (B).   7. Oil-in-water emulsion, characterized in that it comprises 20 to 80 percent by volume of a viscous crude oil, 20 to 80 percent by weight of water and 170 to 4000 parts by weight of a surfactant mixture per million parts by weight of petroleum, said mixture comprising 30 to 70 parts by weight of an anionic or amphoteric surfactant (A) selected from those of formulas Ar (OCH 2 CH 2) nOSO 3 H, Ar (OCH 2 CH 2) n OCH 2 CH, R (OCH2CH2) nOCH2COOH, -2595752   R1 \ t / 2, So3p SO3H CH2COO CH2CH2OcR2COO or a sodium or ammonium salt thereof; and 30 to 70 parts by weight of a nonionic surfactant selected from those (B) of formula Ar (OCH2CH2) pOH, or (C) of formula H (OCH2CH2) r (OCH2CH) mOH, CH3 said surfactant (C) having a hydrophilelipophilic equilibrium value of 10 to 20; Wherein Ar is an octylphenyl or nonylphenyl group, n being a number from 2 to 10, p being a number from 10 to 100, m being a number from 20 to 40, r being a number from 20 to 50, R1; being a C 1 -C 8 alkyl group and R 2   being a C12 to C18 alkyl group.   8. Emulsion according to claim 7, characterized in that the water is present in an amount of 25 to 50 percent by weight of said oil, said mixture comprises 50 parts by weight of surfactant (A) and 50 parts by weight of surfactant (B) or surfactant (C) and said surfactant mixture is present in an amount of 200 to 1500 parts by weight per million parts by weight said oil.   Emulsion according to claim 8, characterized in that (a) said surfactant (A) is Ar (OCH2CH2) nOSO3H and said nonionic surfactant is a surfactant (B) or (C) having a hydrophilelipophilic equilibrium value of 2595752 36   12 to 16; or (b) said surfactant (A) is Ar (OCH2CH2) nOCH2COOH or R1 (OCH2CH2) nOCH2COOH and said nonionic surfactant is   2 a su2factant (B2). a surfactant (B).