Abstract A novel composition and method is provided for temporarily plugging wellbores for extended periods of time, e.g., up to 10 years and more. The composition comprises a thickened aqueous based mixture containing water-swellable clay and inorganic, acid soluble particles, such as minerals, e.g., CaCO3, as solid constituents. The method comprises introducing said novel composition into a well to be plugged followed by a sufficient amount of an aqueous medium to provide a hydrostatic head over and in contact with said composition which exerts a pressure on said mixture which is greater than the formation pressure at the point of application. The plugging composition can be removed from the well when desired by contacting it with acidic solutions.
Inventors
👤 Caleb M Stout
👤 Charles F Smith
👤 Thomas J Nolan
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-23 11:09
CPC Classifications
C; C09; C09K; C09K8/00; C09K8/50
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
15 words
The method as defined in claim 1 wherein said permeable formation is a producing formation.
Claim 2
Dependent Claim
36 words
The method as defined in claim 1 wherein said thickening agent comprises two materials comprising a quickly hydrating-type thickening agent and a thickening agent stable at elevated temperatures of about 150* F. to about 250* F.
Claim 3
Dependent Claim
91 words
The method as defined in claim 3 wherein said mixture comprises: a. water swellable clay particles from about 15 to about 20 percent; b. water insoluble, acid soluble particulate mineral from about 40 to about 50 percent; c. thickening agent from about 15 to about 30 percent; and d. an effective amount of a crosslinking agent for said thickening agent; and e. an aqueous carrier liquid for said mixture in an amount such that said mixture ranges from about 0.5 to about 65 pounds per barrel of said aqueous carrier liquid.
Claim 4
Dependent Claim
14 words
The method as defined in claim 4 wherein said carrier liquid is a brine.
Claim 5
Dependent Claim
17 words
The method as defined in claim 5 including in said mixture an effEctive amount of a bactericide.
Claim 6
Dependent Claim
36 words
The method as defined in claim 4 wherein said aqueous carrier liquid is provided in an amount such that said mixture ranges from about 25 to about 60 pounds per barrel of said aqueous carrier liquid.
Claim 7
Dependent Claim
15 words
The method as defined in claim 7 wherein said aqueous carrier liquid is a brine.
Claim 8
Dependent Claim
34 words
The method as defined in claim 7 including in addition in said mixture a sufficient amount of a basic material to provide a pH ranging from about 8.6 to 13.5 in said carrier liquid.
Claim 9
Dependent Claim
25 words
The method as defined in claim 1 wherein said pressure exerted by said hydrostatic head is at least 100 p.s.i. greater than said formation pressure.
Claim 10
Dependent Claim
24 words
The method as defined in claim 1 wherein said pressure exerted by said hydrostatic head is about 1,500 p.s.i. greater than said formation pressure.