Foamed drilling fluids, their process for preparation and the corresponding drilling method
First Claim
Patent Images
1. An aqueous foamed drilling fluid comprising water, at least one clay, at least one foaming agent, a foam generating gas or blend of such gases, and at least one additive component selected from aluminum hydroxide, magnesium hydroxide, mixed metal hydroxides, and blends thereof.
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Abstract
The present invention is directed to an aqueous foamed Drilling Fluid for drilling well bores into a subterranean formation, comprising water, at least one clay and at least one foaming agent. According to the invention, it further comprises at least one metal hydroxide. The invention further relates to a method for preparing said foamed drilling fluid.
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Citations
32 Claims
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1. An aqueous foamed drilling fluid comprising water, at least one clay, at least one foaming agent, a foam generating gas or blend of such gases, and at least one additive component selected from aluminum hydroxide, magnesium hydroxide, mixed metal hydroxides, and blends thereof.
- View Dependent Claims (2, 3, 4, 7, 8, 11, 12, 14, 17, 19, 21)
- 8. The aqueous foamed drilling fluid of claim 1 in which the additive component is a mixed metal hydroxide having the formula
- space="preserve" listing-type="equation">D.sub.d T(OH).sub.(2d+3+na) A.sub.a.sup.n
wherein D represents a divalent metal selected from Mg, Ca, Ba, Sr, Mn, Fe, Co, Ni, Cu, and Zn; d is a number from 1 to about 4; T is a trivalent metal; A is a mono or polyvalent anion, other than OH; a represents the number of A ions present; n is the valence of A; and (2d+3+na) is equal to or greater than 3.
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11. The aqueous foamed drilling fluid of claim 7 in which the divalent metal is Mg and the trivalent metal is Al.
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12. The aqueous foamed drilling fluid of claim 1 in which the additive component is a mixed metal hydroxide having the formula MgAl(OH)4.7 Cl0.3.
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14. The aqueous foamed drilling fluid of claim 1 containing a fluid loss control agent.
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17. The aqueous foamed drilling fluid of claim 1 in which the concentration of clay is from 8.56 to 57.11 g/l.
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19. The aqueous foamed drilling fluid of claim 17 in which the concentration of foaming agent is from 0.1 to 1.5 percent by volume.
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21. The aqueous foamed drilling fluid of claim 19 in which the foam generating gas is selected from air, CO2, N2, and mixtures thereof.
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5. An aqueous foamed drilling fluid formed by blending (1) at least one additive component selected from aluminum hydroxide, magnesium hydroxide, mixed metal hydroxides, and blends thereof;
- (2) clay;
(3) a pH modifying agent selected from caustic soda or similar alkali sufficient to provide an alkaline pH;
(4) and water; and
introducing an efficient quantity of foaming agent and an efficient quantity of foaming gas or gases. - View Dependent Claims (9, 10, 13, 15, 16, 18, 20, 22, 23)
- 10. The aqueous foamed drilling fluid of claim 5 in which the additive component is a mixed metal hydroxide having the formula
- space="preserve" listing-type="equation">D.sub.d T(OH).sub.(2d+3+na) A.sub.a.sup.n
wherein D represents a divalent metal selected from Mg, Ca, Ba, Sr, Mn, Fe, Co, Ni, Cu, and Zn; d is a number from 1 to about 4; T is a trivalent metal; A is a mono or polyvalent anion, other than OH; a represents the number of A ions present; n is the valence of A; and (2d+3+na) is equal to or greater than 3.
- (2) clay;
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13. The aqueous foamed drilling fluid of claim 5 in which the additive component is a mixed metal hydroxide having the formula MgAl(OH)4.7 Cl0.3.
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15. The aqueous foamed drilling fluid of claim 5 containing a fluid loss control agent.
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16. The aqueous foamed drilling fluid of claim 15 in which the fluid loss control agent is selected from carboxymethyl starch;
- crosslinked carboxymethyl starch; and
carboxymethyl cellulosic compounds having a low degree of substitution.
- crosslinked carboxymethyl starch; and
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18. The aqueous foamed drilling fluid of claim 5 in which the concentration of clay is from 8.56 to 57.11 g/l.
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20. The aqueous foamed drilling fluid of claim 18 in which the concentration of foaming agent is from 0.1 to 1.5 percent by volume.
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22. The aqueous foamed drilling fluid of claim 20 in which the foam generating gas is selected from air, CO2, N2, and mixtures thereof.
- 23. The aqueous foamed drilling fluid of claim 20 in which the additive component is a mixed metal hydroxide having the formula
- space="preserve" listing-type="equation">Li.sub.m D.sub.d T(OH).sub.(m+2d+3+na) A.sub.a.sup.n
wherein m represents the number of Li ions present;
including 0;D represents a divalent metal selected from Mg, Ca, Ba, Sr, Mn, Fe, Co, Ni, Cu, and Zn; d is a number from 1 to about 4; T is a trivalent metal; A is a mono or polyvalent anion, other than OH; a represents the number of A ions present; n is the valence of A; and (m+2d+3+na) is equal to or greater than 3.
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6. An aqueous foamed drilling fluid formed by blending (1) at least one additive selected from aluminum hydroxide, magnesium hydroxide, mixed metal hydroxides, and blends thereof;
- (2) clay;
(3) a pH modifying agent selected from alkali metal hydroxides and carbonates in a concentration sufficient to provide an alkaline pH;
(4) and water; and
introducing an efficient quantity of foaming agent and an efficient quantity of foaming gas or gases.
- (2) clay;
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24. A method for preparing an aqueous foamed drilling fluid comprising blending (1) an additive component selected from aluminum hydroxide, magnesium hydroxide, mixed metal hydroxides, and blends thereof;
- (2) clay;
(3) a pH modifying agent selected from caustic soda or similar alkali in a concentration sufficient to provide an alkaline pH;
(4) and water; and
introducing an efficient quantity of foaming agent and an efficient quantity of foaming gas or gases. - View Dependent Claims (25, 26)
- (2) clay;
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27. A method comprising blending (1) an additive component selected from aluminum hydroxide, magnesium hydroxide, mixed metal hydroxides, and blends thereof, (2) clay, (3) a pH modifying agent selected from caustic soda or similar alkali in a concentration sufficient to provide an alkaline pH;
- (4) and water; and
introducing an efficient quantity of foaming agent and an efficient quantity of foaming gas or gases to form an aqueous foamed drilling fluid;injecting said aqueous foamed drilling fluid into a wellbore and circulating said fluid downhole; returning the aqueous foamed drilling fluid to the earth'"'"'s surface and mechanically breaking the returned fluid. - View Dependent Claims (28, 32)
- (4) and water; and
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29. A method comprising injecting a fluid comprising water, at least one clay, at least one foaming agent and at least one an additive component selected from aluminum hydroxide, magnesium hydroxide, mixed metal hydroxides, and blends thereof, into a well bore;
- and introducing a foam generating gas into the wellbore and forming an aqueous foamed drilling fluid downhole.
- View Dependent Claims (30, 31)
Specification