US 11,987,743 B2
Compositions and methods for well cementing
Bipin Jain, Clamart (FR); and Shameed Ashraf, Kuala Lumpur (MY)
Assigned to Schlumberger Technology Corporation, Sugar Land, TX (US)
Filed by Schlumberger Technology Corporation, Sugar Land, TX (US)
Filed on Dec. 10, 2021, as Appl. No. 17/643,701.
Prior Publication US 2023/0183544 A1, Jun. 15, 2023
Int. Cl. C09K 8/467 (2006.01); C09K 8/36 (2006.01); C09K 8/40 (2006.01); C09K 8/42 (2006.01)
CPC C09K 8/40 (2013.01) [C09K 8/36 (2013.01); C09K 8/424 (2013.01); C09K 8/467 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method, comprising:
preparing a drilling fluid comprising a non-aqueous fluid and a first expanding agent comprising calcium oxide or calcined magnesium oxide or both, wherein the first expanding agent is present in the drilling fluid at a concentration between 0.1 wt % and 20 wt %;
during a cementing operation in a well, placing the drilling fluid in the well and then placing a cement slurry in the well, such that the drilling fluid flows ahead of the cement slurry, the cement slurry comprising a non-aqueous additive, the non-aqueous additive comprising a second expanding agent comprising a mixture of calcium oxide and calcined magnesium oxide, the second expanding agent being present in the non-aqueous additive at a concentration between 0.1 wt % and 20 wt %, and wherein the drilling fluid and the cement slurry are placed in the well at a volume ratio of about 80:20;
causing the drilling fluid to commingle with the cement slurry, thereby forming an interface; and
curing the cement slurry and the interface, wherein the interface expands or does not shrink upon the curing.