Methods for wellbore strengthening

Patent metadata

Field	Value
Publication number	US-11535786-B2
Application number	US-201917309267-A
Country	US
Kind code	B2
Filing date	Nov 12, 2019
Priority date	Nov 14, 2018
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

A wellbore fluid may include an oleaginous fluid forming a continuous phase; a non-oleaginous fluid forming a discontinuous phase; at least one emulsifier stabilizing an emulsion of the non-oleaginous continuous phase within the oleaginous continuous phase; and at least one viscosifier dispersed into the oleaginous continuous phase in a concentration of at least 4 ppb; wherein upon subjecting the wellbore fluid to shear rate of at least 10,000 s −1 , the emulsion is disrupted and the non-oleaginous fluid contacts the at least one viscosifier, thereby solidifying the wellbore fluid.

First claim

What is claimed:

1. A wellbore fluid comprising:
an oleaginous fluid forming a continuous phase;
a non-oleaginous fluid forming a discontinuous phase;
at least one emulsifier stabilizing an emulsion of the non-oleaginous continuous phase within the oleaginous continuous phase;
at least one viscosifier dispersed into the oleaginous continuous phase in a concentration of at least 4 ppb; and
at least one crosslinker selected from the group consisting of a zirconium salt or an iron salt to crosslink the viscosifier dispersed in the oleaginous continuous phase,
wherein upon subjecting the wellbore fluid to shear rate of at least 10,000 s −1 , the emulsion is disrupted and the non-oleaginous fluid contacts the at least one viscosifier, thereby solidifying the wellbore fluid; wherein the wellbore fluid comprises at least one hydratable non-organophillic clay present in a concentration that ranges from 10 pp to 20 ppb.

2. The wellbore fluid of claim 1 , wherein the oleaginous continuous phase is present in at least 20% by volume of the wellbore fluid.

3. The wellbore fluid of claim 1 , wherein the non-oleaginous discontinuous phase is present in at least 70% by volume of the wellbore fluid.

4. The wellbore fluid of claim 1 , wherein the at least one viscosifier is selected from the group of polysaccharides.

5. The wellbore fluid of claim 1 , wherein the at least one crosslinker is present in an amount less than 1 ppb.

6. The wellbore fluid of claim 1 , wherein the hydratable clay is dispersed in the oleaginous continuous phase.

7. The wellbore fluid of claim 1 , wherein the emulsifier is an imidazoline-derivative.

8. The wellbore fluid of claim 7 , wherein the emulsifier is selected from the group of hydroxyethyl imidazolines, aminoethyl imidazolines, amidoethyl imidazolines, alkylamphodiacetates, alkyliminipropionates, or alkylamphopropionates.

9. A method of reducing loss of a wellbore fluid in a wellbore to a formation, the method comprising:
pumping a wellbore fluid into the wellbore, the wellbore fluid comprising:
an oleaginous fluid forming a continuous phase;
a non-oleaginous fluid forming a discontinuous phase;
at least one emulsifier stabilizing an emulsion of the non-oleaginous continuous phase within the oleaginous continuous phase; and
at least one viscosifier dispersed into the oleaginous continuous phase in a concentration of at least 4 ppb;

subjecting the wellbore fluid to shear forces generated by pumping the wellbore fluid into the formation through a nozzle in a drill bit, thereby exposing the at least one viscosifier to the non-oleaginous fluid, wherein the wellbore near the drill bit is at a temperature of at least 65.6° C.; and
allowing the wellbore fluid to solidify; wherein the wellbore fluid comprises at least one hydratable non-organophillic clay present in a concentration that ranges from 10 pp to 20 ppb.

10. The method of claim 9 , further comprising pumping the wellbore fluid into a circulation zone, wherein the wellbore fluid solidifies to form a seal or a plug at an entrance of a fracture, fissure or vug or inside a fracture, fissure or vug, thereby reducing a loss circulation.

11. The method of claim 9 , wherein the at least one viscosifier is selected from the group of polysaccharides.

12. The method of claim 9 , wherein the at least one hydratable clay is dispersed in the oleaginous continuous phase.

13. The method of claim 9 , wherein the wellbore fluid further comprises at least one crosslinker to crosslink the at least one viscosifier dispersed in the oleaginous continuous phase.

14. The method of claim 13 , wherein the at least one crosslinker is selected from the group consisting of a zirconium salt and an iron salt.

15. The method of claim 13 , wherein the at least one crosslinker is present in an amount less than 1 ppb.

16. The method of claim 9 , wherein the at least one emulsifier is an imidazoline-derivative.

Assignees

• Schlumberger Technology Corp

Inventors

• Young Steven
• Blue Aaron
• Sheldon Josh

Classifications

• C09K8/36 Primary

  Water-in-oil emulsions · CPC title

• C09K8/502 Primary

  Oil-based compositions · CPC title

• E21B10/60

  characterised by conduits or nozzles for drilling fluids (for roller bits E21B10/18; for percussion drill bits E21B10/38) · CPC title

• E21B21/003

  Means for stopping loss of drilling fluid (plastering the borehole wall E21B33/138) · CPC title