Clive Mather, president and chief executive of Shell Canada, talks about his time running the Canadian company in Calgary May 31, 2007. He will step down on June 7 when Royal Dutch Shell assumes full ownership of Shell Canada. REUTERS/Todd Korol (CANADA) 

Clive Mather, president and chief executive officer of Shell Canada, reflects on his time running the Canadian company in Calgary May 31, 2007. He will step down on June 7, 2007 when Royal Dutch Shell assumes full ownership of Shell Canada. REUTERS/Todd Korol (CANADA) 

Clive Mather, president and chief executive officer of Shell Canada, reflects on his time running the Canadian company in Calgary May 31, 2007. He will step down on June 7, 2007 when Royal Dutch Shell assumes full ownership of Shell Canada. REUTERS/Todd Korol (CANADA) 

Clive Mather, president and chief executive officer of Shell Canada poses in Calgary May 31, 2007. He will step down on June 7, 2007 when Royal Dutch Shell assumes full ownership of Shell Canada. REUTERS/Todd Korol (CANADA) 

Clive Mather, President and CEO of Shell Canada, talks to a student at the University of Calgary in Calgary, Alberta, February 26, 2007. REUTERS/Todd Korol (CANADA) 

Clive Mather, President and CEO of Shell Canada, talks to students at the University of Calgary in Calgary, Alberta, February 26, 2007. REUTERS/Todd Korol (CANADA) 

Clive Mather, President and CEO of Shell Canada, talks to reporters at the University of Calgary in Calgary, Alberta, February 26, 2007. REUTERS/Todd Korol (CANADA) 

Clive Mather, President and CEO of Shell Canada, talks to students at the University of Calgary in Calgary, Alberta, February 26, 2007. REUTERS/Todd Korol (CANADA) 

Clive Mather, President and CEO of Shell Canada, talks to students at the University of Calgary, in front of the Shell Ferrari Formula One race car in Calgary, Alberta, February 26, 2007. REUTERS/Todd Korol (CANADA) 

President and CEO of Shell Canada Clive Mather (L) looks at a solar powered car next to Adam Berti, a student at the University of Calgary, in Calgary, Alberta, February 26, 2007. REUTERS/Todd Korol (CANADA) 

Clive Mather, CEO of Shell Canada Ltd., speaks at the Reuters Global Energy Summit in New York, May 23, 2006. 

Clive Mather, CEO of Shell Canada Ltd., speaks at the Reuters Global Energy Summit in New York, May 23, 2006. REUTERS/Brendan McDermid 

Clive Mather, CEO of Shell Canada Ltd., speaks at the Reuters Global Energy Summit in New York, May 23, 2006. REUTERS/Brendan McDermid 

Clive Mather, CEO of Shell Canada Ltd., speaks at the Reuters Global Energy Summit in New York, May 23, 2006. REUTERS/Brendan McDermid 

Clive Mather, president of Shell Canada, talks to reporters at a news conference after the company's annual meeting in Calgary, Canada, April 28, 2006. REUTERS/Todd Korol 

Clive Mather, president of Shell Canada, shows his company's profit growth at the company's annual meeting in Calgary, Canada, April 28, 2006. REUTERS/Todd Korol 

Clive Mather, president of Shell Canada, talks to reporters at a news conference after the company's annual meeting in Calgary, Canada, April 28, 2006. REUTERS/Todd Korol 

Clive Mather, president of Shell Canada, addresses shareholders at the company's annual meeting in Calgary, Canada, April 28, 2006. REUTERS/Todd Korol 

Clive Mather, CEO of Shell Canada, speaks at the Reuters Energy Summit in New York, June 22, 2005. 

Clive Mather, CEO of Shell Canada, speaks at the Reuters Energy Summit in New York, June 22, 2005. REUTERS/Chip East CME/LA 

Clive Mather, CEO of Shell Canada, speaks at the Reuters Energy Summit in New York, June 22, 2005. REUTERS/Chip East CME/LA 

Shell Canada's President and Chief Executive Officer Clive Mather answers questions with the media after Shell's Annual General Meeting, in Calgary, April 29, 2005. REUTERS/Patrick Price PP 

Shell Canada's President and Chief Executive Officer Clive Mather answers questions with the media after Shell's Annual General Meeting, in Calgary, April 29, 2005. REUTERS/Patrick Price PP 

Shell Canada's President and Chief Executive Officer Clive Mather gestures while talking in Shell Canada's head office in Calgary, November 19, 2004. Mather assumed the head job in August, 2004. 

Shell Canada's President and Chief Executive Officer Clive Mather gestures while talking in Shell Canada's head office in Calgary, November 19, 2004. Mather assumed the head job in August, 2004. REUTERS/Patrick Price/FEATURE/ENERGY-SHELLCANADA PP/HB