US 11,952,531 B1
Compound grease coating for controlled dissolution of a dissolvable component of a downhole tool
Lei Zhao, Houston, TX (US); Jiaxiang Ren, Houston, TX (US); Tim Dunne, Pearland, TX (US); Peng Cheng, Houston, TX (US); and Huailiang Liu, Beijing (CN)
Assigned to CNPC USA Corporation, Houston, TX (US); Beijing Huamel, Inc., Beijing (CN); and China National Petroleum Corporation, Beijing (CN)
Filed by CNPC USA Corporation, Houston, TX (US); BEIJING HUAMEI, INC., Beijing (CN); and CHINA NATIONAL PETROLEUM CORPORATION, Beijing (CN)
Filed on Oct. 11, 2022, as Appl. No. 18/045,769.
Int. Cl. E21B 33/12 (2006.01); C09K 8/40 (2006.01); C10M 101/00 (2006.01); C10M 105/76 (2006.01); C10M 107/00 (2006.01); E21B 33/134 (2006.01)
CPC C09K 8/40 (2013.01) [C10M 101/00 (2013.01); C10M 105/76 (2013.01); C10M 107/00 (2013.01); E21B 33/12 (2013.01); E21B 33/134 (2013.01)] 5 Claims
OG exemplary drawing
 
1. A method for removing a downhole tool from a wellbore, the method comprising the steps of:
spraying an activation layer on a component substrate of the downhole tool onsite at a wellbore location, said activation layer being comprised of an activation compound and having an activation layer thickness with an activation layer thickness range of 10-500 μm,
wherein said activation compound comprises silicones, epoxy or acrylic;
applying a first grease layer over said activation layer onsite at said wellbore, said first grease layer having a first grease layer consistency range of NLGI 200-270 and a first grease layer thickness with a first grease layer thickness range of 100-1000 μm, said first grease layer being bonded non-uniformly to said activation layer;
applying a second grease layer over said first grease layer onsite at said wellbore location, said second grease layer having a second grease layer consistency range of NLGI 280-320 and a second grease layer thickness with a second grease layer thickness range that is 500-2000 μm, said second grease layer being bonded non-uniformly to said first grease layer, so as to form a compound coating on said component substrate;
forming a transition zone with said first grease layer and said second grease layer;
deploying said component substrate with said compound coating to a downhole location;
protecting said component substrate from dissolution with said compound coating on said component substrate for 6-24 hours; and
dissolving said component substrate so as to remove the downhole tool from the wellbore.