Gretchen Watkins, former CEO of Maersk Oil, will officially join Shell on 1 May and be appointed EVP Unconventionals effective 1 July. She succeeds EVP Unconventionals Greg Guidry, who is leaving his role on 31 June after a 36-year career with the company. After more than 37 years of Shell service, Shell Oil Company President and US Country Chair Bruce Culpepper has c…