UPDATE 1-Ensign Energy Q3 profit sinks 77 pct

* Q3 adj shr C$0.11 vs est C$0.16

* Rev falls 47 pct

Nov 9 (Reuters) - Ensign Energy Services Inc (ESI.TO) said on Monday its third-quarter profit fell 77 percent, hurt by reduced drilling activity levels and the weak global economy.

The company, Canada's biggest oilfield services firm by market value, reported net income of C$16.9 million ($15.88 million), or 11 Canadian cents a share, down from C$72.1 million, or 47 Canadian cents a share, in the third quarter of 2008.

Adjusted net income fell to C$16.4 million, or 11 Canadian cents a share, from C$61 million, or 39 Canadian cents a share, a year ago.

The adjusted result lagged analysts' average per-share profit forecast of 16 Canadian cents, according to Thomson Reuters I/B/E/S.

The company's quarterly revenue fell 47 percent to C$232.5 million.

Canada's oilfield services sector has struggled to boost profits as their customers pare back natural gas drilling to cope with low prices for the fuel.

Ensign Energy said it expects future activity levels to bump along at current historically low levels of activity.