US4083407A — Spacer composition and method of use

Claim 1

Independent Claim 109 words

In a method for injecting a fluid into a borehole containing a drilling mud, wherein the fluid is not compatible with the mud, and wherein injection of the fluid is preceded by injection of a spacer composition compatible with both the mud and the fluid, the improvement comprising: injecting a sufficient quantity of said spacer to separate said mud and said fluid, said spacer comprising (a) water (b) a water soluble alkali metal silicate; and (c) a water soluble metal compound capable of releasing a multivalent metal cation to react with the water soluble silicate; said components (a)-(c) being provided in amounts effective to form an aqueous pumpable gel.

Claim 2

Dependent Claim 109 words

In a method for injecting a fluid into a borehole containing a drilling mud, wherein the fluid is not compatible with the mud, and wherein injection of the fluid is preceded by injection of a spacer composition compatible with both the mud and the fluid, the improvement comprising: injecting a sufficient quantity of said spacer to separate said mud and said fluid, said spacer comprising (a) water (b) a water soluble alkali metal silicate; and (c) a water soluble metal compound capable of releasing a multivalent metal cation to react with the water soluble silicate; said components (a)-(c) being provided in amounts effective to form an aqueous pumpable gel.

Claim 3

Dependent Claim 28 words

The method of claim 1 wherein the spacer also includes a water dispersible cellulose compound and an inert particulate which together impart fluid loss control to said spacer.

Claim 4

Dependent Claim 43 words

The method of claim 2 wherein said cellulose compound is present in an amount of from about 0.5 to about 1.5 percent BWOW, and said fluid loss control-providing particulate is present in an amount of from about 1 to about 100 percent BWOW.

Claim 5

Dependent Claim 30 words

The method of claim 3 wherein the amounts of cellulose compound and said fluid loss control-providing particulate present in said spacer are from about 0.75-1.25 and 5-15 percent, respectively, BWOW.

Claim 6

Dependent Claim 53 words

The method of claim 1 wherein said silicate is present in an amount of from about 0.1-5 percent BWOW, and the metal compound is present in an amount sufficient to release from about 30-130 percent of the molar equivalents of the polyvalent metal cation stoichiometrically required to react with the alkali metal silicate.

Claim 7

Dependent Claim 47 words

The method of claim 5 wherein the silicate is present in an amount of from about 0.5-3 percent BWOW, and the metal compound is present in an amount sufficient to release from about 70-100 percent of the polyvalent metal cation stoichiometrically required to react with the silicate.

Claim 8

Dependent Claim 11 words

The method of claim 1 wherein the silicate is sodium metasilicate.

Claim 9

Dependent Claim 34 words

The method of claim 1 wherein the metal compound is selected from the group consisting of the water soluble oxides, salts, and hydroxides of alkaline earth metals, aluminum, calcium, copper, zinc, iron, and chromium.

Claim 10

Dependent Claim 13 words

The method of claim 8 wherein the metal compound provides Ca ++ .

Claim 11

Dependent Claim 82 words

The method of claim 1 wherein the spacer contains: (a) about 0.1-5 percent BWOW sodium metasilicate; (b) from about 70-100 percent of the amount of calcium chloride stoichiometrically required to react with the silicate; (c) from about 0.5-1.5 percent BWOW a water dispersible cellulose compound; and (d) from about 1-100 percent BWOW an inert particulate having a particle size diameter of from about 1 to about 100 microns, which cooperates with the cellulose compound to impart fluid loss control to said spacer.

Claim 12

Dependent Claim 31 words

The method of claim 10 wherein the spacer contains about 1 percent BWOW carboxymethylcellulose and about 10 percent BWOW silica flour of less than about 200 mesh for fluid loss control.

Claim 13

Dependent Claim 20 words

The method of claim 10 wherein the spacer also contains a weighting material to increase the density of the spacer.

Claim 14

Dependent Claim 27 words

The method of claim 10 wherein the spacer also contains a weak chelating agent for polyvalent metal cations, in an amount up to about 2 percent, BWOW.

Claim 15

Dependent Claim 18 words

The method of claim 1 wherein the mud is a water based mud or an oil-in-water emulsion mud.

Claim 16

Dependent Claim 113 words

In a well treating method for displacing drilling mud from a borehole having a conduit therein so that fluid may be injected down the inside of said conduit and back to the surface via the annulus surrounding said conduit, or vice versa, the improvement which comprises displacing said mud with an aqueous pumpable gel prepared from components including (a) water (b) a water soluble alkali metal silicate; and (c) a water soluble metal compound capable of releasing a multivalent metal cation to react with the water soluble silicate; said components (a)-(c) being provided in amounts effective to form a pumpable gel which does not react with the mud to form an unpumpable mass.

Claim 17

Dependent Claim 113 words

In a well treating method for displacing drilling mud from a borehole having a conduit therein so that fluid may be injected down the inside of said conduit and back to the surface via the annulus surrounding said conduit, or vice versa, the improvement which comprises displacing said mud with an aqueous pumpable gel prepared from components including (a) water (b) a water soluble alkali metal silicate; and (c) a water soluble metal compound capable of releasing a multivalent metal cation to react with the water soluble silicate; said components (a)-(c) being provided in amounts effective to form a pumpable gel which does not react with the mud to form an unpumpable mass.

Claim 18

Dependent Claim 18 words

The method of claim 15 wherein the mud is of the water based type or oil-in-water emulsion type.

Claim 19

Dependent Claim 12 words

The method of claim 15 wherein the silicate is a sodium silicate.

Claim 20

Dependent Claim 13 words

The method of claim 17 wherein the metal cation is Ca ++ .

Claim 21

Dependent Claim 11 words

The method of claim 17 wherein the silicate is sodium metasilicate.

Claim 22

Dependent Claim 12 words

The method of claim 19 wherein the metal compound is calcium chloride.

Claim 23

Dependent Claim 33 words

The method of claim 15 wherein the components from which the gel is prepared include a water dispersible cellulose compound and an inert particulate which together impart fluid loss control to said gel.

Claim 24

Dependent Claim 36 words

The method of claim 21 wherein from about 0.5-1.5 percent said cellulose compound, BWOW, and from about 1-100 percent said particulate, BWOW, are employed in preparing said gel to impart fluid loss control to said gel.

Claim 25

Dependent Claim 53 words

The method of claim 22 wherein the cellulose compound is selected from the group consisting of an alkyl cellulose, a carboxyalkyl cellulose, a hydroxyalkyl cellulose, and a carboxyalkyl hydroxyalkyl cellulose, and wherein the particulate is selected from the group consisting of silica flour, pozzolan, flyash, dictomaceous earth, calcium carbonate, barium sulfate, and talc.

Claim 26

Dependent Claim 38 words

The method of claim 23 wherein from about 0.75-1.25 percent BWOW carboxymethylcellulose, and from about 5-15 percent BWOW silica flour having an average particle size diameter of from about 1 to 100 microns are employed in the gel.

Claim 27

Dependent Claim 53 words

The method of claim 15 wherein from about 0.1 to about 5 percent BWOW silicate, and a sufficient amount of the metal compound to release from about 30-130 percent of the molar equivalents of the polyvalent metal cation stoichiometrically required to react with the silicate, are employed in the preparation of the gel.

Claim 28

Dependent Claim 62 words

The method of claim 25 wherein the gel is prepared from components including water and: about 0.5-3 percent BWOW anhydrous sodium metasilicate; about 70-100 percent of the amount of calcium chloride stoichiometrically required to react with the sodium metasilicate; about 1 percent BWOW carboxymethylcellulose; and about 10 percent BWOW silica flour having an average particle size less than of about 200 mesh.

Claim 29

Dependent Claim 29 words

The method of claim 26 wherein the gel includes a weighting agent effective to increase the density of the gel to greater than that of the mud being displaced.

Claim 30

Dependent Claim 117 words

In a method for cementing a conduit in a borehole containing a drilling mud wherein at least part of the mud is displaced from the borehole by a spacer fluid and the cement is circulated into position immediately following the spacer fluid, the improvement which comprises: employing as the spacer fluid, a pumpable gel prepared from components including (a) water; (b) a water soluble alkali metal silicate; and (c) a water soluble metal compound capable of releasing a multivalent metal cation to react with the water soluble silicate; said components (a)-(c) being provided in amounts effective to form a pumpable gel which does not react with either the mud or the cement to form an unpumpable mass.

Claim 31

Dependent Claim 117 words

In a method for cementing a conduit in a borehole containing a drilling mud wherein at least part of the mud is displaced from the borehole by a spacer fluid and the cement is circulated into position immediately following the spacer fluid, the improvement which comprises: employing as the spacer fluid, a pumpable gel prepared from components including (a) water; (b) a water soluble alkali metal silicate; and (c) a water soluble metal compound capable of releasing a multivalent metal cation to react with the water soluble silicate; said components (a)-(c) being provided in amounts effective to form a pumpable gel which does not react with either the mud or the cement to form an unpumpable mass.

Claim 32

Dependent Claim 56 words

The method of claim 28 wherein components (b) and (c) are provided in the following amounts, respectively: (b) from about 0.1-5 percent BWOW, and (c) in an amount sufficient to release from about 30 to about 130 percent of the molar equivalents of the polyvalent metal cation stoichiometrically required to react with the alkali metal silicate.

Claim 33

Dependent Claim 28 words

The method of claim 28 wherein the spacer also includes a water dispersible cellulose compound and an inert particulate which together impart fluid loss control to said gel.

Claim 34

Dependent Claim 81 words

The method of claim 30 wherein the spacer is prepared from water and: from about 0.1-5 percent BWOW alkali metal silicate; the metal compound in an amount sufficient to release from about 30 to about 130 percent of the molar equivalents of the polyvalent metal cation stoichiometrically required to react with alkali metal silicate; from about 0.5-1.5 percent BWOW the cellulose compound; and from about 1-100 percent BWOW particulate having a particle size diameter of from about 1 to 100 microns.

Claim 35

Dependent Claim 27 words

The method of claim 31 wherein the spacer also contains a weak chelating agent for polyvalent metal cations, in an amount up to about 2 percent, BWOW.

Claim 36

Dependent Claim 16 words

The method of claim 32 wherein the spacer also includes a material for preventing lost circulation.

Claim 37

Dependent Claim 143 words

The method of claim 28 wherein the cement has a density greater than the mud and the spacer is prepared from components including water and: anhydrous sodium metasilicate, about 0.1-5 percent, BWOW; calcium chloride in an amount sufficient to provide from about 0.3 to about 1.3 moles Ca ++ per mole of sodium metasilicate; carboxymethyl cellulose, about 0.5-1.5 percent, BWOW; silica flour having a particle size diameter of from about 1 micron to about 100 microns, about 1-100 percent, BWOW; a weak chelating agent selected from the group consisting of citric acid, alkali metal citrates, alkali metal hexametaphosphates, alkali metal tetraphosphates, alkali metal bicarbonates, and sodium acid pyrophosphate, in an amount up to about 2 percent BWOW; and a weighting agent effective to adjust the density of the spacer to greater than that of the mud but less than that of the cement.

Claim 38

Dependent Claim 67 words

The method of claim 34 wherein the following amounts of the respective components are employed in the preparation of the spacer: anhydrous sodium metasilicate, about 0.5-3 percent BWOW; calcium chloride in an amount sufficient to provide from about 0.7-1 mole Ca ++ per mole of sodium metasilicate; carboxymethyl cellulose, about 0.75-1.25 percent, BWOW; silica flour, about 5-15 percent BWOW; and sodium citrate dihydrate, about 1 percent BWOW.

Claim 39

Dependent Claim 39 words

The method of claim 35 wherein a volume of spacer is employed sufficient to separate the mud from the cement by at least about 500 feet, calculated on the basis of the average cross sectional area of the annulus.

Claim 40

Dependent Claim 18 words

The method of claim 28 wherein the mud is of the water based type or oil-in-water emulsion type.

Claim 41

Dependent Claim 164 words

In a method for acidizing or fracturing a formation penetrated by a borehole initially containing a drilling mud, wherein a casing is cemented into position within said borehole prior to said acidizing or fracturing step, the improvement which comprises: (a) temporarily positioning said casing in said mud-containing borehole; (b) providing a spacer comprised of water, a water soluble alkali metal silicate, and a water soluble metal compound capable of releasing a multivalent metal cation to react with the water soluble silicate, said spacer components being provided in amounts effective to form a pumpable gel; (c) displacing at least a portion of said mud from said borehole with said spacer; (d) injecting a cement slurry into said borehole immediately following said spacer and circulating said slurry into position; (e) permitting said slurry to set, thereby permanently cementing said casing into position; and (f) thereafter carrying out said acidizing or fracturing step; the quantity of spacer employed being sufficient to separate said mud from said cement.

Claim 42

Dependent Claim 164 words

In a method for acidizing or fracturing a formation penetrated by a borehole initially containing a drilling mud, wherein a casing is cemented into position within said borehole prior to said acidizing or fracturing step, the improvement which comprises: (a) temporarily positioning said casing in said mud-containing borehole; (b) providing a spacer comprised of water, a water soluble alkali metal silicate, and a water soluble metal compound capable of releasing a multivalent metal cation to react with the water soluble silicate, said spacer components being provided in amounts effective to form a pumpable gel; (c) displacing at least a portion of said mud from said borehole with said spacer; (d) injecting a cement slurry into said borehole immediately following said spacer and circulating said slurry into position; (e) permitting said slurry to set, thereby permanently cementing said casing into position; and (f) thereafter carrying out said acidizing or fracturing step; the quantity of spacer employed being sufficient to separate said mud from said cement.

Claim 43

Dependent Claim 20 words

The method of claim 38 wherein the mud is of the water based type, or of the oil-in-water emulsion type.

Claim 44

Dependent Claim 23 words

The method of claim 38 containing a weak chelating agent for polyvalent metal cations in an amount up to about 2 percent, BWOW.

Claim 45

Dependent Claim 27 words

The method of claim 38 wherein the spacer includes a water dispersible cellulose compound and an inert particulate which together impart fluid loss control to said spacer.

Claim 46

Dependent Claim 38 words

The method of claim 38 wherein a volume of spacer is employed sufficient to separate the mud from the cement by at least 500 feet, calculated on the basis of the average cross sectional area of the annulus.

Claim 47

Dependent Claim 72 words

The method of claim 38 wherein the spacer contains: alkali metal silicate, about 0.1-5 percent, BWOW; metal compound, an amount sufficient to release from about 30 to about 130 percent of the molar equivalents of the polyvalent metal cation stoichiometrically required to react with the alkali metal silicate; cellulose compound, about 0.5-1.5 percent BWOW; and an inert particulate having a particle size diameter ranging from 1 to 100 microns, 1-100 percent BWOW.

Claim 48

Dependent Claim 47 words

The method of claim 43 wherein the cement slurry has a density greater than that of the mud and the spacer contains a weighting material to adjust the density of the spacer to greater than that of the mud but less than that of the cement slurry.

Claim 49

Dependent Claim 74 words

The method of claim 44 wherein the spacer contains: sodium metasilicate, about 0.5-3 percent, BWOW; calcium chloride, about 0.7-1 mole per mole of sodium metasilicate; carboxymethyl cellulose, about 0.75-1.25 percent, BWOW; silica flour as the inert particulate, about 5-15 percent BWOW; and wherein sufficient spacer is employed to separate the cement slurry from the mud by at least about 500 feet, calculated on the basis of the average cross sectional area of the annulus.

Claim 50

Dependent Claim 72 words

An aqueous fluid composition suitable for use as a spacer in treating wells comprising: (a) water, and effective amounts of (b) a water soluble alkali metal silicate, (c) a water soluble metal compound capable of releasing a multivalent metal cation to react with the water soluble silicate to form a pumpable gel, and (d) a water dispersible cellulose compound and an inert particulate which together impart fluid loss control to said composition.

Claim 51

Dependent Claim 72 words

An aqueous fluid composition suitable for use as a spacer in treating wells comprising: (a) water, and effective amounts of (b) a water soluble alkali metal silicate, (c) a water soluble metal compound capable of releasing a multivalent metal cation to react with the water soluble silicate to form a pumpable gel, and (d) a water dispersible cellulose compound and an inert particulate which together impart fluid loss control to said composition.

Claim 52

Dependent Claim 14 words

The fluid of claim 46 containing a weighting material to increase the density thereof.

Claim 53

Dependent Claim 23 words

The fluid of claim 46 containing a weak chelating agent for polyvalent metal cations, in an amount up to about 2 percent, BWOW.

Claim 54

Dependent Claim 76 words

The fluid of claim 46 comprising an alkali metal silicate, about 0.1-5 percent, BWOW; a metal compound in an amount sufficient to release from about 30 to about 130 percent of the molar equivalents of the polyvalent metal cation stoichiometrically required to react with the alkali metal silicate; a water dispersible cellulose compound, about 0.5-1.5 percent, BWOW; and an inert particulate having a particle size ranging from about 1 to 100 microns, about 1-100 percent, BWOW.

Claim 55

Dependent Claim 23 words

The fluid of claim 49 containing a weighting agent selected from the group consisting of fly ash, barium sulfate, pozzolan, hematite, and ilmenite.

Claim 56

Dependent Claim 18 words

The fluid of claim 50 wherein the silicate is sodium metasilicate and the metal compound is calcium chloride.

Claim 57

Dependent Claim 46 words

The fluid of claim 51 containing: sodium metasilicate, about 0.5-3 percent BWOW; calcium chloride, about 0.7-1 mole per mole of sodium metasilicate; carboxymethyl cellulose, about 0.75-1.25 percent, BWOW; silica flour as the inert particulate, about 5-15 percent BWOW; and sodium citrate dihydrate, about 1 percent BWOW.

Claim 58

Dependent Claim 27 words

The fluid of claim 52 containing, BWOW, about 1 percent carboxymethyl cellulose and about 10 percent silica flour which passes a 200 mesh screen, U.S. Sieve Series.

Claim 59

Dependent Claim 142 words

A blend of solids suitable for use as an additive to water to form an aqueous spacer for treating wells, said blend comprising: (a) from about 0.1 to about 5 parts by weight a water soluble alkali metal silicate; (b) a water soluble metal compound capable of releasing a multivalent metal cation to react with the water soluble silicate, in an amount sufficient to release from about 30 to about 130 percent of the molar equivalents of the polyvalent metal cation stoichiometrically required to react with the alkali metal silicate; (c) from about 0.5 to about 1.5 parts by weight a water dispersible cellulose compound; and (d) from about 1 to about 100 parts an inert particulate which, when said blend is added to water in an effective amount, cooperates with said cellulose compound to impart fluid loss control to said spacer.

Claim 60

Dependent Claim 142 words

A blend of solids suitable for use as an additive to water to form an aqueous spacer for treating wells, said blend comprising: (a) from about 0.1 to about 5 parts by weight a water soluble alkali metal silicate; (b) a water soluble metal compound capable of releasing a multivalent metal cation to react with the water soluble silicate, in an amount sufficient to release from about 30 to about 130 percent of the molar equivalents of the polyvalent metal cation stoichiometrically required to react with the alkali metal silicate; (c) from about 0.5 to about 1.5 parts by weight a water dispersible cellulose compound; and (d) from about 1 to about 100 parts an inert particulate which, when said blend is added to water in an effective amount, cooperates with said cellulose compound to impart fluid loss control to said spacer.

Claim 61

Dependent Claim 48 words

The blend of claim 54 including a weak chelating agent for polyvalent metal cations, in an amount up to about 2 parts by weight, selected from the group consisting of citric acid, alkali metal citrates, alkali metal hexametaphosphates, alkali metal tetraphosphates, alkali metal bicarbonates, and sodium acid pyrophosphate.

Claim 62

Dependent Claim 58 words

The blend of claim 55 consisting essentially of, by weight: about 13.2 percent anhydrous sodium metasilicate; about 14.4 percent calcium chloride flake containing 77-80 weight percent active CaCl 2 ; about 6.6% percent carboxymethyl cellulose; about 60 percent ground silica having an average particle size of less than about 200 mesh; and about 6.6 percent sodium citrate dihydrate.

Claim 63

Dependent Claim 23 words

The blend of claim 54 including a weighting material selected from the group consisting of fly ash, barium sulfate, pozzolan, hematite, and ilmenite.

Claim 64

Dependent Claim 54 words

The blend of claim 54 including anhydrous sodium metasilicate, about 0.5-3 parts; calcium chloride, about 0.7-1 mole per mole of sodium metasilicate; silica flour having an average particle size of less than about 200 mesh as the inert particulate, about 5-15 parts; carboxymethyl cellulose, about 0.75-1.25 parts; and sodium citrate dihydrate, about 1 part.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1981-04-10	1981-10-10	1982-04-11	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1985-04-10	1985-10-10	1986-04-11	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1989-04-10	1989-10-10	1990-04-11	$7700.00	Window Closed / Lapsed

Spacer composition and method of use

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