Water-wettable drilling mud additives containing uintaite

Abstract

A water-based drilling mud additive comprising a preblended combination of about 2 parts of high softening point uintaite, about 1 part of a lower softening point uintaite, about 1 part of causticized lignite, and a strongly lipophilic, non-ionic surfactant is disclosed. This composition decreases shale sloughing and bore-hole instability during drilling of wells.

What is claimed is: 
     
       1. A method of preparing a water-wettable drilling mud additive comprising the steps of: mixing together about 2 parts of a high softening point uintaite solid having a softening point of at least 360° F., and about 1 part a low softening point uintaite solid having a softening point of about 330° F. or lower; adding causticized lignite and a strongly lipophilic surfactant.   
     
     
       2. A method as described in claim .[.11.]. .Iadd.1.Iaddend., wherein said lignite is added while pulverizing the uintaite solids and wherein said surfactant is added by spraying. 
     
     
       3. A water-wettable drilling mud additive that stabilizes a borehole during well drilling, comprising a preblended stabilizing combination of about 2 parts of a high softening point uintaite to about 1 part of a low softening point uintaite, combined with causticized lignite and a strongly lipophilic non-ionic surfactant which provides a rewetting index of less than about 4 to the uintaites, wherein the softening point of said uintaites are about 40° F. apart or greater. 
     
     
       4. A water-wettable drilling mud additive comprising a mixture of: (a) 45 to 55 percent of a high softening point uintaite having a softening .[.pint.]. .Iadd.point .Iaddend.above about 375° F.;   (b) 20 to 30 percent a low softening point uintaite having a softening point below about 330° F.;   (c) 20 to 30 percent of causticized lignite; and   (d) 2 to 4 percent a strongly lipophilic non-ionic surfactant which provides a rewetting index of less than about 4 to the uintaites.   
     
     
       5. A drilling mud additive as described in claim 4, wherein said lipophilic surfactant comprises a block copolymer of ethylene oxide and propylene oxide, and provides a rewetting index of less than about 2 to the uintaites. 
     
     
       6. A drilling mud additive .Iadd.for stabilizing boreholes during well drilling.Iaddend., comprising: a pre-blended, borehole stabilizing mixture of a high softening point uintaite having a softening point of at least 360° F., a low softening point uintaite having a softening point of about 330° F. or lower, causticized lignite, and a surfactant that provides the uintaites with a rewetting index of less than about 4, wherein the ratio of said high softening point uintaite to said low softening point uintaite is about 2 to 1.   
     
     
       7. A drilling mud additive as described in claim 6, wherein said surfactant provides the uintaites with a rewetting index of less than about 2. 
     
     
       8. A drilling mud additive as described in claim 6, wherein said surfactant is a highly lipophilic non-ionic surfactant comprising a block copolymer of ethylene oxide and propylene oxide. 
     
     
       9. A drilling mud additive as described in claim 6, wherein the weight ratio of said high softening point uintaite to said low softening point uintaite to said causticized lignite is about 2 to about 1 to about 1. 
     
     
       10. A drilling mud additive as described in claim 6, wherein said high softening point uintaite has a softening point above about 375° F. 
     
     
       11. A drilling mud additive as described in claim 10, wherein the softening points of the two uintaites are at least 40° F. apart. 
     
     
       12. A drilling mud additive as described in claim 6, wherein said low softening point uintaite has a softening point of from 290 to 330° F.[.and said additive is storage stable.].. 
     
     
       13. A drilling mud additive as described in claim 12, wherein said high softening point uintaite has a softening point above about 375° F. 
     
     
       14. A water-wettable drilling mud additive that stabilizes a borehole during well drilling, comprising a preblended stabilizing combination of a high softening point uintaite, having a softening point of at least 360° F., a low softening point uintaite having a softening point of about 330° F. or lower, causticized lignite, and a strongly lipophilic non-ionic surfactant which provides a rewetting index of less than about 4 to the uintaites, wherein the ratio of said high softening point uintaite to said low softening point uintaite is about 2 to 1. 
     
     
       15. A water-wettable drilling mud additive as described in claim 14 comprising about 2 parts by weight of said high softening point uintaite, about 1 part by weight of said low softening point uintaite, and about 1 part by weight of said causticized lignite. 
     
     
       16. A drilling mud additive as described in claim 14, wherein said non-ionic surfactant comprises a block copolymer of ethylene oxide and propylene oxide, and provides a rewetting index of less than about 2 to the uintaites. 
     
     
       17. A drilling mud additive as described in claim 14, wherein the amount of said non-ionic surfactant is 1 to 5 wt. % of said additive. 
     
     
       18. A drilling mud additive .[.ass.]. .Iadd.as .Iaddend.described in .[.claimed.]. .Iadd.claim .Iaddend.14.[.;.]. wherein said high softening point uintaite has a softening point above about 375° F. 
     
     
       19. A drilling mud additive as described in claim 14, wherein the softening points of the uintaites are about 50° F. apart, or greater. 
     
     
       20. A drilling mud additive as described in claim 14, wherein said low softening point uintaite has a softening point of from 290° to 330° F.[.and said additive is storage stable.].. 
     
     
       21. A drilling mud additive as described in claim 20, wherein said high softening point uintaite has a softening point above about 375° F. 
     
     
       22. A water based drilling fluid containing the additive of claim 14 or 4 or 6 or 3. 
     
     
       23. A method of decreasing shale sloughing and borehole instability, comprising the step of: incorporating the additive of claim 14 or 4 or .[.5.]. .Iadd.6 .Iaddend.into a water-based drilling fluid at a rate of about 2 .[.roo.]. .Iadd.to .Iaddend.6 lbs. of additive per barrel of drilling fluid.   
     
     
       24. A method of drilling a well, comprising the steps of inserting a drill bit into the well and circulating a drilling mud comprising the additive of claim 14 or 4 or 6. 
     
     
       25. A method of drilling a well .[.las.]. .Iadd.as .Iaddend.described in claim 24, wherein the bottom hole temperature of said well ranges from ambient up to 400° F. 
     
     
       26. A method of drilling a well as described in claim 24, wherein the bottom hole temperature of said well ranges from ambient to about 300° F. .Iadd. 
     
     
       27.  A method of preparing a water-wettable drilling mud additive comprising the steps of: mixing together a high softening point uintaite solid having a softening point of at least 360° F., and a low softening point uintaite solid having a softening point of about 330° F. or lower; and adding causticized lignite and a surfactant effective to decrease the rewetting index of the uintaites, wherein the weight ratio of said uintaites to said causticized lignite is between about 3:1 to about 4:1..Iaddend..Iadd.28. A method as described in claim 27, wherein said lignite and surfactant are added concurrently while pulverizing said uintaite solids..Iaddend..Iadd.29. A method as described in claim 27, wherein said lignite is added while pulverizing the uintaite solids and prior to the addition of the surfactant..Iaddend..Iadd.30. A method as described in claim 27, wherein said surfactant is added prior to the addition of said lignite..Iaddend..Iadd.31. A method as described in claim 27, wherein said solids are pulverized such that no more than about 20% of said solids are greater than about 200 mesh..Iaddend..Iadd.32. A water-wettable drilling mud additive that stabilizes a borehole during well drilling, comprising a preblended stabilizing combination of a high softening point uintaite and a low softening point uintaite, combined with a causticized lignite and a surfactant effective to decrease the rewetting index of the uintaites, wherein the softening point of said uintaites are about 40° F. apart or greater and wherein the weight ratio of uintaites to said causticized lignite is about between about 3:1 to about 4:1. .Iaddend..Iadd.33. An additive as described in claim 32, wherein the additive stabilizes boreholes over a temperature range of at least   
     
     
        125° F to 250° F..Iaddend..Iadd.34.  A drilling mud additive as described in claim 32, wherein said surfactant comprises a block copolymer of ethylene oxide and propylene oxide..Iaddend..Iadd.35. The drilling mud additive of claim 32, wherein said surfactant provides the uintaites a rewetting index of less than about 4..Iaddend..Iadd.36. The drilling mud additive of claim 35, wherein said surfactant provides the uintaites with a rewetting index of less than about 2..Iaddend..Iadd.37. A drilling mud additive for stabilizing boreholes during well drilling, comprising: a pre-blended, borehole stabilizing mixture of a high softening point uintaite having a softening point of at least 360° F., a low softening point uintaite having a softening point of about 330° F. or lower, causticized lignite, and a surfactant effective to decrease the rewetting index of the uintaites, wherein the weight ratio of uintaites to said causticized lignite is between about 3:1 to about 4:1..Iaddend..Iadd.38. A drilling mud additive as described in claim 37, wherein said surfactant provides the uintaites with a rewetting index of less than about 4..Iaddend..Iadd.39. A drilling mud additive as described in claim 38, wherein said surfactant provides the uintaites with a rewetting index of less than about 2. .Iaddend..Iadd.40. A drilling mud additive as described in claim 37, wherein said surfactant is a strongly lipophilic non-ionic surfactant comprising a block copolymer of ethylene oxide and propylene oxide..Iaddend..Iadd.41. A drilling mud additive as described in claim 37, wherein said low softening point uintaite has   
     
     
        softening point of from 290° to 330° F..Iaddend..Iadd.42.  A drilling mud additive as described in claim 41, wherein said high softening point uintaite has a softening point above about 375° F..Iaddend..Iadd.43. A drilling mud additive as described in claim 41, wherein the amount of said surfactant is 1 to 5 wt. % of said additive..Iaddend..Iadd.44. A drilling mud additive as described in claim 37, wherein said high softening point uintaite has a softening point above about 375° F..Iaddend..Iadd.45. An additive as described in claim 37, wherein the additive stabilizes boreholes over a temperature range of at least 125° F to 250° F..Iaddend..Iadd.46. A method of preparing a water-wettable drilling mud additive comprising the steps of: a) mixing together about a high softening point uintaite solid having a softening point of at least 360° F., a low softening point uintaite solid having a softening point of about 330° F. or lower;   b) melting the mixture of step a;   c) dissolving or trapping a surfactant effective to decrease the rewetting index of the uintaites in the molten mixture of step b;   d) solidifying the mixture of step c;   e) pulverizing the mixture of step d; and   f) adding causticized lignite, wherein the weight ratio or uintaites to said causticized lignite is between about 3:1 to about 4:1..Iaddend..Iadd.47. A water-wettable additive for water-based drilling fluids that stabilizes a borehole during well drilling, comprising a pre-blended stabilizing combination including causticized lignite, a high softening point uintaite, an amount of low softening point uintaite effective to stabilize boreholes over a temperature range of between about 125° F to about 250° F, and a surfactant effective to   
     
     
        decrease the rewetting index of the uintaites..Iaddend..Iadd.48.  The additive of claim 47, further including an intermediate softening point uintaite..Iaddend..Iadd.49. The additive of claim 47, wherein said surfactant provides said uintaites a rewetting index of less than about 4..Iaddend..Iadd.50. The additive of claim 47, wherein the weight ratio of said high softening point uintaite to said low softening point uintaite is between about 1:1 and about 4:1..Iaddend..Iadd.51. The additive of claim 50, wherein said weight ratio is between about 3:1 and about 4:1..Iaddend..Iadd.52. The additive of claim 47, wherein said temperature range is between about 125° F and 450° F..Iaddend..Iadd.53. The additive of claim 47, wherein said surfactant is strongly lipophilic..Iaddend..Iadd.54. A drilling mud additive for stabilizing boreholes during well drilling, comprising a pre-blended borehole stabilizing mixture of causticized lignite, a high softening point uintaite, an amount of low softening point uintaite effective to stabilize boreholes over a temperature range of between about 125° F, and about 250° F, and a surfactant which is effective to decrease the rewetting index of the uintaites..Iaddend..Iadd.55. The additive of claim 54, wherein said surfactant is strongly lipophilic..Iaddend..Iadd.56. The additive of claim 54, wherein said temperature range is between about 125° F and 450° F..Iaddend..Iadd.57. A method of preparing a water-wettable drilling mud additive for stabilizing boreholes during well drilling, comprising the steps of mixing a high softening point uintaite with an amount of low softening point uintaite effective to stabilize boreholes over a temperature range of between about 125° F and 250° F, and adding causticized lignite and a surfactant effective to decrease the rewetting index of the uintaites..Iaddend..Iadd.58. The method of claim 57, wherein said surfactant is a strongly lipophilic non-ionic surfactant..Iaddend..Iadd.59. The method of claim 57, wherein said temperature range is between about 125° F and 450° F..Iaddend..Iadd.60. A water-based drilling fluid containing the additive of claim 32, or 37, or 47, or 54..Iaddend..Iadd.61. A method of decreasing shale sloughing and borehole instability, comprising the step of: incorporating the additive of claim 32, or 37, or 47, or 54 into a water-based drilling fluid at a rate of about 2 to 6 lbs of additive per barrel of drilling fluid..Iaddend..Iadd.62. A method of drilling a well, comprising the steps of inserting a drill bit into the well and circulating a drilling mud comprising the additive of claim 32, or 37, or 47 or 54..Iaddend..Iadd.63. A method of drilling a well, comprising the steps of inserting a drill bit into the well to form a bore-hole and circulating a drilling mud into said bore-hole and through said well during said drilling, said drilling mud containing a water-wettable additive for water-based drilling fluids that stabilizes a borehole during well drilling, said additive including a pre-blended stabilizing combination including a high softening point uintaite, an amount of low softening point uintaite effective to stabilize boreholes at a temperature above about 125° F, and a surfactant effective to decrease the rewetting index of the uintaites, said additive being effective to substantially reduce sloughing shales and bore-hole erosion to thereby reduce bore-hole collapse, while increasing bore-hole   
     
     
        lubrication..Iaddend..Iadd.64.  The method of claims 57 or 63, wherein the softening points of said high softening point uintaite and said low softening point uintaite are at least about 40° F apart..Iaddend..Iadd.65. The method of claims 57 or 63, wherein said high softening point uintaite has a softening point of at least 360° F and said low softening point uintaite has s softening point of about 330° F or lower..Iaddend..Iadd.66. The method of claims 57 or 63, wherein said low softening point uintaite has a softening point of between about 290° F and about 330° F..Iaddend.