** Halliburton shares HAL.N down 3.5% at $21.15 premarket
** Oilfield service provider posts lower Q1 profit due to slowdown in drilling activity in North America
** Revenue in North America fell 12% to $2.2 bln
** As of last close, shares are down 19.4% YTD
(Reporting by Katha Kalia in Bengaluru)
((Katha.Kalia@thomsonreuters.com))