Claims
- 1. A method of inhibiting the swelling of shale in a modified non-polluting liquid phase drilling fluid, comprising the steps of:
- (1) preparing a non-polluting modified liquid phase drilling fluid consisting essentially of:
- (a) a water phase comprising fresh water, sea water, brine, simulated brine, or mixtures thereof;
- (b) a water soluble component selected from the class consisting of glycol ethers, polypropylene glycols, polyethylene glycols, ethylene oxide-propylene oxide copolymers, alcohol-initiated ethylene oxide-propylene oxide copolymers and/or mixtures thereof, the ratio of said water-soluble component to the total liquid phase being from between at least about 20% to about 50% by volume;
- (c) a viscosifier for a suspension of solids in said liquid phase; and
- (d) a filtration control agent, the linear swelling of said drilling fluid on a reconstituted "gumbo" shale inserted for about 60 minutes in said drilling fluid being lower than that for substantially the same fluid without the water soluble component, as measured by the "Swelling Test", "Rigsite Shale Evaluation Techniques for Control of Shale-Related Wellbore Instability Problems", SPE/IADE Paper No. 16054, Pages 52-53 (1987); and
- (2) circulating said drilling fluid into, through and out of said subterranean well whereby said drilling fluid contacts formation particulate matter in the bore of said well.
- 2. A method of inhibiting the swelling of shale in a modified non-polluting liquid phase drilling fluid, comprising the steps of:
- (1) preparing a non-polluting modified liquid phase drilling fluid consisting essentially of:
- (a) a water phase comprising fresh water, sea water, brine, simulated brine, or mixtures thereof;
- (b) a water soluble component selected from the class consisting of glycol ethers, polypropylene glycols, polyethylene glycols, ethylene oxide-propylene oxide copolymers, alcohol-initiated ethylene oxide-propylene oxide copolymers and/or mixtures thereof, the ratio of said water-soluble component to the total liquid phase being from between at least about 20% to about 50% by volume;
- (c) a viscosifier for suspension of solids in said liquid phase; and
- (d) a filtration control agent, the linear swelling of said drilling fluid on a reconstituted "gumbo" shale inserted for about 60 minutes in said drilling fluid being lower than that for substantially the same fluid without the water soluble component, as measured by the "Swelling Test", Rigsite Shale Evaluation Techniques for Control of Shale-Related Wellbore Instability Problems", SPE/IADC Paper No. 16054, Pages 52-53 (1987), said drilling fluid being less toxic to mysid shrimp than an 80:20 oil based drilling fluid containing a mineral seal oil as the oil phase following toxicity test procedures as set forth in "Acute Toxicity of Eight Laboratory Prepared Generic Drilling Fluids to Mysids (Mysidopsis Bahia)", 1984 EPA-600/3-84-067; and
- (2) circulating said drilling fluid into, through and out of said subterranean well whereby said drilling fluid contacts formation particulate matter in the bore of said well.
Parent Case Info
This is a continuation of application Ser. No. 128,798 filed Dec. 4, 1987 now U.S. Pat. No. 4,830,765.
US Referenced Citations (9)
Continuations (1)
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Number |
Date |
Country |
Parent |
128798 |
Dec 1987 |
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