Higher prices, corporate tax cuts and increased production of oil and natural gas helped boost quarterly earnings at three members of Canada's oilpatch Suncor, Shell Canada and Imperial Oil.

Suncor (SU), which is in the process of expanding its oilsands operations in Alberta, posted a second-quarter profit of $164 million, up from $111 million in the same period of last year. The most recent quarterly result includes a $49-million gain from reduced income tax rates, compared with a $7-million gain last year.

Suncor's cash flow moved up $2 million to $246 million.

The company said its oilsands expansion is about 95 per cent, but added that the project's final cost estimate has shot up to $3.25 billion, roughly 16 per cent higher than previously estimated.

At Shell Canada (SHC), profits almost doubled to $314 million. On a per-share basis, the company's earnings were $1.14, up from 59 cents a share a year earlier.

Revenues hit $2.04 billion, up from $1.8 billion.

"Market conditions and good operating performance enabled us to achieve strong first-half results," company president Tim Faithfull said in a release, adding that second-half results may be weaker due to falling natural gas prices and margins.

Imperial Oil (IMO)said net earnings hit $414 million, or $1.04 a share, up from $285 million, or 67 cents a share.

Revenues at the subsidiary of Exxon Mobil were $4.8 billion, up 13 per cent from $4.2 billion a year earlier.