Inventor

CHAPMAN WILLIAM D

US3 patents

⚠️ This page may combine multiple inventors who share the name “CHAPMAN WILLIAM D”. Patents are grouped by organization below to help distinguish them — per-person disambiguation is on the roadmap.

DU MICHAEL H

1 patent

US8496064B2Jul 30, 2013

System and method for engaging completions in a wellbore

DU MICHAEL H12 citations81

DUHN OIL TOOL INC

1 patent

US4974676ADec 4, 1990

Ground subsiding wellhead

DUHN OIL TOOL INC8 citations68

DUHN IND

1 patent

US5611398AMar 18, 1997

Two-piece drilling flange

DUHN IND16 citations66