US3022825A

US3022825A - Method for sand consolidation

Info

Publication number: US3022825A
Application number: US759511A
Authority: US
Inventors: Weldon O Winsauer; Jack H Edwards
Original assignee: Jersey Production Research Co
Current assignee: Jersey Production Research Co
Priority date: 1958-09-08
Filing date: 1958-09-08
Publication date: 1962-02-27
Anticipated expiration: 1979-02-27

Description

Feb. 27, 1962 w, wlNSAUER ET AL 3,022,825

METHOD FOR SAND CONSOLIDATION Filed Sept. 8, 1958 UNCONSOLIDATED FORMATION TREATED ZONE '1 IO l6 ll V I4 x: I

1I T? z s I4 A I 8 UNCONSOLIDATED cEMENT FORMATION INVENTORS.

WELDON O. WINSAUER,

JACK H. EDWARDS,

ATTORNEY.

United States Patent 3,022,825 METHOD FOR SAND CONSOLIDATION Weldon 0. Winsauer and Jack H. Edwards, Houston,

Tex., assignors, by mesne assignments, to Jersey Production Research Company, Tulsa, Okla., a corporation of Delaware Filed Sept. 8, 1958, Ser. No. 759,511 8 Claims. (Cl. 166-33) This invention is primarily directed to a method for consolidating loose or incompetent formations penetrated by a borehole. More particularly, this invention is directed to an improved method for injecting sand consolidation fluids into subsurface formations in order to consolidate the sands therein.

In producing fluids from subsurface formations, sand is produced along with the formation fluids from loosely consolidated formations. Because production of sand with its attendant accumulation in the well bore or movement to the surface is undesired, various sand control measures have been used to inhibit or prevent sand particles from moving into the well bore. One control measure is the use of porous setting plastics which bind the sand particles together while permitting flow of well fluids therethrough. Particularly good consolidating plastics of this type make use of the resin-forming properties of the reaction between a water soluble aldehyde and a low molecular weight hydroxy aryl compound catalyzed by an alkaline or acidic catalyst. When these compounds are injected into a sand formation, a resin forms which cements the particles of the formation together. Although any water soluble aldehyde may be used, formaldehyde, acetaldehyde, propionaldehyde, or mixtures thereof are preferred. The low molecular weight hydroxy aryl compound may include phenol, cresol, beta naphthol, resorcinol, or cresylic acid, or mixtures thereof. Suitable alkaline catalysts which may be used include guanidine salts such as guanidine carbonate and amino-guanidine bicarbonate; alkali metal hydroxides and carbonates such as sodium hydroxide or sodium carbonate; aliphatic amines such as ethyl amine and triethyl amine; aromatic amines such as aniline; and aliphatic diamines such as ethylene diamine. Suitable acidic catalysts which may be used include acidic salts such as stannous chloride or magnesium chloride; mineral acids such as hydrochloric acid or sulfuric acid; acid anhydrides such as maleic 'anhydride; aromatic acids such as picric acid or benzene sulfonic acid or sulfanilic acid; and polynuclear aromatic acids or acid salts such as alpha naphthylamine sulfonic acid or sodium- 1-naphthylamine-3,6,8 trisulfonate.

In order to insure that no plastic is left in the well bore and to increase the permeability of the consolidated formation, it is desirable to overflush the formation; that is, displace the treating resin forming liquid into the formation with oil. However, when oil is displaced into the formation, the eflectiveness of the consolidation treatment is reduced and the critical area directly adjacent to the well bore remains unconsolidated because some components of the resin-forming mixture are soluble in oil. A high degree of consolidation around the well bore is advantageous in order to prevent the well from producing sand.

The improvement of the present invention resides in incorporating with the oil used to displace the resin-forming mixture a low molecular weight hydroxy aryl compound. Addition of this compound to the oil prevents extraction of the oil-soluble compounds from the resin mixture and allows the formation immediately adjacent the well bore to consolidate. Additionally, it permits the total volume of the formation treated to have a greater strength than otherwise could be obtained. The displacing oil may include crude oil, diesel oil or any other petroleum fraction. Preferably, the hydroxy aryl compound to be used with the displacing oil includes cresol, phenol, or cresylic acid. The amount of the hydroxy aryl compound to be employed is approximately 5% by volume of the oil. The optimum amount to be used in any particular application may be determined, for, as appreciated by those familiar with this art, the technique involves establishing equilibrium between the concentration and solubility of the hydroxy aryl compound in the two solvents, i.e., the aldehyde of the resin-forming liquids and the diesel oil of the overflush liquids. The equilibrium is dependent upon the partition coefficient. The principles of the equilibrium by application of the partition coefficient as well as the dependence of the partition coefficient on temperature is discussed in The Principles of Chemical Equilibrium by Kenneth Denbigh, Cambridge University Press, 1955, pages 254 and 255 under 8.7 Nernsts Law. Thus, the best concentration of the hydroxy aryl compound in the overflush to fit a particular field condition is ascertainable by experiments in which incremental additions of the hydroxy aryl compound to the overflush oil and extraction of the resin solution with the oil are made until a concentration is found in which there is no exchange of the hydroxy aryl compound between the two different solutions.

Thus, an object of this invention is to provide an improved method for consolidation of sands in wells through injection of sand consolidation fluids into the formations.

For a more complete understanding of the invention, reference is now made to the drawing wherein:

FIG. 1 is a cross-sectional view of a borehole penetrating a subsurface formation illustrating the results of displacing into the formation a resin solution with oil containing no hydroxy aryl compound; and

FIG. 2 is a cross-sectional view of a borehole pene trating a subsurface formation illustrating the results of displacing into the formation a resin solution with oil containing hydroxy aryl compound.

Referring to the drawing in greater detail, in FIGS. 1 and 2 is shown a borehole 10 penetrating an unconsolidated formation 11. A casing 12 perforated adjacent formation 11 and cemented in place by means of cement 13 is arranged in borehole 10. The perforations designated 14 extend through casing 12 and cement 13 into formation 11, as shown.

Referring specifically to FIG. 1, when a resin solution is displaced into formation 11 through perforations 14 with an oil containing no hydroxy aryl compound, the areas designated 15 remain unconsolidated after a resin solution treatment of a zone 16. Therefore, the volume of sand designated 15 will be produced when production is started.

Referring specifically to FIG. 2, when a resin solution is displaced into formation 11 with an oil containing hydroxyl aryl compound, no unconsolidated areas 15 remain after treatment. All the sand contacted with the resin solution is consolidated and the well will produce no sand when production is started. Additionally,

the strength of treated zone 16 is greater when an oil,

containing hydroxy aryl compound is employed.

The practice of the invention is illustrated by the following experimental procedures:

PROCEDURE I Treatment employing acidic catalyst Sand was packed in a 1% inch diameter glass column equipped with heads and suitable connections to permit fluids to flow through the column and saturated with 10% sodium chloride solution. Then, the sand was flushed with diesel fuel to a low water saturation and the glass column was placed in a 130 F. water bath. Thereafter, the sand was flushed with an aqueous solution which consisted of one part stannous chloride and 10 parts water (2 pore volumes). A plastic solution composed of 2 parts formalin, 1 part phenol-cresol and 6% by weight stannous chloride then was injected into the sand column after which the sand was flushedwith either diesel fuel or diesel fuel containing by volume cresol or crude oil containing 5% cresol (2 pore volumes). The plastic injection and the oil flushing steps were repeated after a lapse of 3 hours. The column remained in the water bath 24 hours after which it was removed for testing.

PROCEDURE II Treatment employing alkaline catalyst The initial steps of procedure II, up to and including placing the glass column in the 130 F. water bath, were the same as those of procedure I. Following these steps the sand was flushed with methanol (2 pore volumes). A plastic solution composed of 4 parts formalin, 1 part cresol, guanidine carbonate and 3% sodium hydroxide (4 pore volumes) then was injected into the sand. Thereafter, either diesel fuel or diesel fuel containing 5% by volume cresol (2 pore volumes) was injected into the sand and after remaining 24 hours in the water bath the column was removed therefrom for testing.

The technique of flushing with methanol prior to injection of the resin forming solution is embodied in copending patent application Ser. No. 759,442, entitled Method for Consolidation of Sand, by R. E. Williams and H. H. Spain, filed September 8, 1958.

The sodium hydroxide was employed as a co-catalyst in order to accelerate the rate at which the resin solidifies.

The data obtained from these experiments are shown in the following table:

an increase from 40 to 480 p.s.i. As to permeability, run No. 2 shows an increase from 692 md. to 717 md. Further, in runs 2 and 3, maximum strength at the inflow end of the tube was shown, whereas in run N0. 1, the inflow end of the tube was unconsolidated.

Field runs which illustrate the practice of the invention are shown in the following table:

TABLE II.-FIELD RESULTS The field results also reflect the improved results. When employing cresol in the displacing oil, no sand was produced whereas when employing only the oil some sand was produced when production started. The field results were predictable from the laboratory results.

Having fully described the objects, method, and apparatus of the invention, we claim:

1. A method for consolidating the sands of an incompetent subsurface oil-bearing formation comprising introducing into said formation a mixture of resin-forming liquids comprising a low molecular weight hydroxy aryl compound, a water-soluble aldehyde, and a catalyst, which liquids react and set in said formation and bind the sand particles thereof together; and then overflushing the formation by introducing oil containing a low molecular weight hydroxy aryl compound into the formation following introduction into the formation of the resin-forming liquids and prior to the reaction and setting of the resin-forming liquids, the hydroxy aryl compound in the oil being in an amount sufiicient to prevent extraction of the hydroxy aryl compound from the resin-forming mixture by the overfiush oi-l.

TABLE L-LABORATORY RESULTS Results of consolidation Bun Consolidation treatment Composition of oil used to Remarks No. displace the resin solution Mar. com- Permeprcsslve ability, stren th md.

1.--- A field sand treated with 2 stages of phenol- Diesel fuel 89 692 Inflow end of tube was unconsolicresol lormaldehyde plastic solution, SnCh dated. catalyst, at 130 F. temperature. 2 do Diesel fuel containing 5% 8 M1. 716 717 Maximum strength at inflow end cresol by volume. of tube. 8 do Crude oil containing 6% 3 M.P. 1,020 in Do.

cresol by volume. 4--.. Field sand treated with methyl alcohol, 1 stage Diesel incl 40 m cresol-iormalln plastic solution, NaOH-Gunnidine Carbonate Catalyst. 5 do Diesel fuel containing 5% cresol by 480 8, 200

volume.

1 Not measured.

1 Norn.-p.s.t.pounds per square inch; md.-millldarciea.

The addition of a low molecular weight hydroxy aryl compound to the overfiush oil in runs 2, 3, and 5, show the advantageous results for compressive strength and permeability. As to compressive strength, run No. 2 shows an increase from 89 to717 p.s.i.; run No. 3 shows 2. A method as recited in claim 1 including employing an acidic catalyst as said catalyst.

3. A method as recited in claim 1 including employing an alkaline catalyst as said catalyst.

4. A method as recited in claim 1 including employing an increase from 89 to 1020 p.s.i.; and run No. 5 shows cresol as the hydroxy aryl compound in the oil overflush.

5. A method as recited in claim 1 including employing 8. A method as recited in claim 7 including employing phenol-cresol as the low molecular weight hydroxy aryl sodium hydroxide in the catalyst. compound, formaldehyde as the aldehyde, and stannous chloride as the catalyst. References Cited in the file of this patent 6. A method as recited in claim 1 including employing 5 UNITED STATES PATENTS cresol as the hydroxy aryl compound in the resin-forming mixture. 2,378,817 Wrightsman et'al June 19, 1945 7. A method as recited in claim 1 including employing 2,457,160 Kurtz et a1. Dec. 28, 1948 cresol as the hydroxy aryl compound, formaldehyde as 2,476,015 Wrightsman July 12, 1949 the water-soluble aldehyde, and guanidine carbonate as 10 2,513,614 Barkhuff July 4, 1950 the catalyst in the resin-forming mixture. 2,714,929 Nowak Aug. 9, 1955

Claims

1. A METHOD FOR CONSOLIDATING THE SANDS OF AN INCOMPETENT SUBSURFACE OIL-BEARING FROMATION COMPRISING INTRODUCING INTO SAID FORMATION A MIXTURE OF RESIN-FORMING LIQUIDS COMPRISING A LOW MOLECULAR WEIGHT HYDROXY