Water shut-off method for porous formations

Patent metadata

Field	Value
Publication number	US-10351756-B2
Application number	US-201815918540-A
Country	US
Kind code	B2
Filing date	Mar 12, 2018
Priority date	Apr 22, 2014
Publication date	Jul 16, 2019
Grant date	Jul 16, 2019

Abstract

Organoclay is used as an alternative emulsifier and reinforcing agent to enhance the strength of emulsified polymeric gel aqueous solutions and form water in oil emulsions. The stability of the emulsion can be controlled by controlling salinity and the intensity of initial mixing. The new system can be used for water shut-off treatments as well as a relative permeability modifier in high water permeability zones. In addition, the system can tolerate salts much better than classical surfactants. This system will be appropriate for wellbores having high temperature (>85° C.) with harsh environmental conditions.

First claim

The invention claimed is:

1. A method for water shut-off in a porous formation surrounding a wellbore, comprising:
forming an aqueous gel solution comprising a polyacrylamide and a polyethyleneimine crosslinker,
dissolving an organoclay emulsifier in an oil to form an oil matrix,
mixing the oil matrix with the aqueous gel solution to form an encapsulated aqueous gel solution as aqueous phase droplets in the oil matrix, and form an emulsion,
injecting the emulsion into said porous formation at a temperature at which the emulsion separates into a water phase and an oil phase in the porous formation,
crosslinking the polyacrylamide with the polyethyleneimine crosslinker in the porous formation to form a gelled water phase and a mobile oil phase,
wherein the organoclay consists essentially of at least one ditallow-dimethyl-ammonium salt and at least one phyllosilicate.

2. The method of claim 1 , wherein the porous formation has a temperature greater than 85° C.

3. The method of claim 1 , wherein the organoclay is present in the emulsion an amount range from 300 to 1,000 ppm and wherein the aqueous phase droplets in the oil matrix have a droplet size ranging from 15 to 20 μm.

4. The method of claim 1 , wherein the at least one phyllosilicate is bentonite.

5. The method of claim 1 , wherein the oil is diesel oil.

6. The method of claim 1 , wherein the aqueous gel solution is formed from is sea water or brine.

7. The method of claim 1 , wherein the organoclay emulsifier is the only emulsifier present in the emulsion.

8. The method of claim 1 , wherein the oil comprises a tallowamine acetate salt surfactant.

9. The method of claim 1 , wherein the emulsion comprises a tallowamine acetate salt.

Assignees

• Univ King Fahd Pet & Minerals
• King Abdulaziz City Of Science And Tech
• King Abdulaziz City Sci & Tech

Inventors

• Hussein Ibnelwaleed Ali
• Adewunmi Ahmad Akanbi
• Sultan Abdullah Saad
• Elkarsani Khalid Saad
• Al-Muntasheri Ghaithan A

Classifications

• C09K8/512 Primary

  containing cross-linking agents · CPC title

• E21B33/138

  Plastering the borehole wall; Injecting into the formation · CPC title

• C09K8/516

  characterised by their form or by the form of their components, e.g. encapsulated material · CPC title