Shale inhibitor for drilling fluid based on microemulsion ionic liquid and preparation method thereof

Abstract

The invention relates to a shale inhibitor for a drilling fluid based on a microemulsion ionic liquid and a preparation method thereof. The shale inhibitor is prepared from the following components inpercent by mass: 35-45% of an ionic liquid, 10-15% of normal butanol, 3-6% of potassium chloride, 2-5% of nano calcium carbonate, 3-5% of polyoxyethylene sorbitan fatty acid ester, 1-3% of sorbitan aliphatic ester and the balance of water. By adopting an ionic liquid microemulsion synthesizing method, the shale inhibitor can exist in microemulsion cores stably. The coordinate repression of a system is further enhanced by adding KCl. The stability of the microemulsion in the drilling fluid is enhanced by using nano calcium carbonate. The nano calcium carbonate exists in form of double continuous microemulsion liquid drops in the drilling fluid, so that the shale inhibitor has certain slow release action after the drilling fluid to play a long-acting role. The relative expansion reduction rate of clay of the shale inhibitor for the drilling fluid based on the microemulsion ionic liquid exceeds 85%, and the triple shale rolling recovery rate exceeds 95%.

Description

technical field

[0001] The invention relates to a shale inhibitor for drilling fluid, in particular to a treatment agent for inhibiting accidents such as shale expansion and collapse when drilling a shale well section during drilling. Background technique

[0002] In the process of oil and gas drilling, complex formations are often encountered, such as shale formations. Most of the wellbore instability occurs in the shale section, and the loss caused by wellbore instability is as high as hundreds of millions of dollars every year. In terms of chemically stabilizing well walls, people have developed a variety of shale inhibitors, including inorganic salts, organic salts and synthetic inhibitors to inhibit mudstone expansion and shale collapse. For example, the use of potassium chloride, ammonium chloride, sodium chloride, silicate, etc. can effectively inhibit the expansion of clay, and the concentration is generally 5-37%. Inorganic salts mainly achieve the effect of inhibit...

Examples

preparation example Construction

[0025] The specific preparation method of the present invention comprises the following steps:

[0026] (1) Add 35~45g of ionic liquid into a 200mL three-necked flat-bottomed flask, heat to 50~70°C; slowly add 10~20g of water during stirring; add 3~6g of potassium chloride, and after the dissolution is complete, add 1 ~3g sorbitan fatty acid ester, stir again evenly, add in about 30 minutes;

[0027] (2) Slowly add 10~20g of water to the above reactor, the stirring speed is 750-850 r / min, after the addition is finished, add 3~5g of polyoxyethylene sorbitan fatty acid ester, the process The medium temperature is maintained at 50~70°C, and the stirring is continued for 30 minutes;

[0028] (3) Reduce the temperature of the reactor to 30~40°C, add 26~39g of water at one time, continue to stir for 20min, then slowly add 10~15g of n-butanol dropwise, increase the stirring speed to 2000 r / min, until a transparent phase appears After cooling to room temperature, add 2~5g of nano-ca...

Embodiment 1

[0030]Add 45g of 1-butyl-3-methylimidazolium hexafluorophosphate into a 200mL three-necked flat-bottomed flask, heat to 50°C; slowly add 10g of water while stirring; add 3g of potassium chloride, and after the dissolution is complete, add 1g of sorbitan fatty acid ester S-80, stirred evenly again, and finished adding in about 30 minutes; slowly added 10g of water to the above reactor at a stirring speed of 800 r / min, and after the addition was completed, added 3g of Polyoxyethylene sorbitan fatty acid ester T-80, maintain the temperature at 50°C during the process, continue to stir for 30 minutes; lower the temperature of the reactor to 30°C, add 13g of water at one time, continue to stir for 20min, then slowly add 10g of n-butyl Alcohol, increase the stirring speed to 2000 r / min until a transparent phase appears, cool to room temperature, add 5g of 601# nano-calcium carbonate, continue stirring for 30min, and discharge to obtain shale for drilling fluid based on microemulsion ...

Embodiment 2

[0032] Add 40g of 1-butyl-3-methylimidazolium tetrafluoroborate into a 200mL three-necked flat-bottomed flask, heat to 60°C; slowly add 12g of water while stirring; add 5g of potassium chloride, and after the dissolution is complete, Add 2g of sorbitan fatty acid ester S-60, stir evenly again, and finish adding in about 30 minutes; slowly add 13g of water to the above reactor at a stirring speed of 800 r / min, after the addition is completed, add 4g The polyoxyethylene sorbitan fatty acid ester T-60, the temperature during the process was maintained at 60°C, and continued to stir for 30 minutes; the temperature of the reactor was lowered to 35°C, 8g of water was added at one time, and 12g of normal For butanol, increase the stirring speed to 2000 r / min until a transparent phase appears, cool to room temperature, add 4g of 602# nano-calcium carbonate, continue stirring for 30min, and discharge to obtain a microemulsion ionic liquid-based drilling fluid. rock inhibitors.

technical field

[0001] The invention relates to a shale inhibitor for drilling fluid, in particular to a treatment agent for inhibiting accidents such as shale expansion and collapse when drilling a shale well section during drilling. Background technique

[0002] In the process of oil and gas drilling, complex formations are often encountered, such as shale formations. Most of the wellbore instability occurs in the shale section, and the loss caused by wellbore instability is as high as hundreds of millions of dollars every year. In terms of chemically stabilizing well walls, people have developed a variety of shale inhibitors, including inorganic salts, organic salts and synthetic inhibitors to inhibit mudstone expansion and shale collapse. For example, the use of potassium chloride, ammonium chloride, sodium chloride, silicate, etc. can effectively inhibit the expansion of clay, and the concentration is generally 5-37%. Inorganic salts mainly achieve the effect of inhibit...

Examples

preparation example Construction

[0025] The specific preparation method of the present invention comprises the following steps:

[0026] (1) Add 35~45g of ionic liquid into a 200mL three-necked flat-bottomed flask, heat to 50~70°C; slowly add 10~20g of water during stirring; add 3~6g of potassium chloride, and after the dissolution is complete, add 1 ~3g sorbitan fatty acid ester, stir again evenly, add in about 30 minutes;

[0027] (2) Slowly add 10~20g of water to the above reactor, the stirring speed is 750-850 r / min, after the addition is finished, add 3~5g of polyoxyethylene sorbitan fatty acid ester, the process The medium temperature is maintained at 50~70°C, and the stirring is continued for 30 minutes;

[0028] (3) Reduce the temperature of the reactor to 30~40°C, add 26~39g of water at one time, continue to stir for 20min, then slowly add 10~15g of n-butanol dropwise, increase the stirring speed to 2000 r / min, until a transparent phase appears After cooling to room temperature, add 2~5g of nano-ca...

Embodiment 1

[0030]Add 45g of 1-butyl-3-methylimidazolium hexafluorophosphate into a 200mL three-necked flat-bottomed flask, heat to 50°C; slowly add 10g of water while stirring; add 3g of potassium chloride, and after the dissolution is complete, add 1g of sorbitan fatty acid ester S-80, stirred evenly again, and finished adding in about 30 minutes; slowly added 10g of water to the above reactor at a stirring speed of 800 r / min, and after the addition was completed, added 3g of Polyoxyethylene sorbitan fatty acid ester T-80, maintain the temperature at 50°C during the process, continue to stir for 30 minutes; lower the temperature of the reactor to 30°C, add 13g of water at one time, continue to stir for 20min, then slowly add 10g of n-butyl Alcohol, increase the stirring speed to 2000 r / min until a transparent phase appears, cool to room temperature, add 5g of 601# nano-calcium carbonate, continue stirring for 30min, and discharge to obtain shale for drilling fluid based on microemulsion ...

Embodiment 2

[0032] Add 40g of 1-butyl-3-methylimidazolium tetrafluoroborate into a 200mL three-necked flat-bottomed flask, heat to 60°C; slowly add 12g of water while stirring; add 5g of potassium chloride, and after the dissolution is complete, Add 2g of sorbitan fatty acid ester S-60, stir evenly again, and finish adding in about 30 minutes; slowly add 13g of water to the above reactor at a stirring speed of 800 r / min, after the addition is completed, add 4g The polyoxyethylene sorbitan fatty acid ester T-60, the temperature during the process was maintained at 60°C, and continued to stir for 30 minutes; the temperature of the reactor was lowered to 35°C, 8g of water was added at one time, and 12g of normal For butanol, increase the stirring speed to 2000 r / min until a transparent phase appears, cool to room temperature, add 4g of 602# nano-calcium carbonate, continue stirring for 30min, and discharge to obtain a microemulsion ionic liquid-based drilling fluid. rock inhibitors.

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