Well his father as PM a scant generation ago shut the door on Canadian crude exploration and expansion and is still bitterly remembered for it for this.
Pierre Trudeau poured massive amounts of taxpayer money into subsidising and expanding the oil industry. This included helping to bail out Syncrude and taking an equity stake in the company when the oil companies backing the proposal said that it was too big of a risk to privately finance. Syncrude were the ones who kicked off the oil sands industry on a big scale in Alberta, and it was their success which inspired other companies to follow (GCOS were there before, but were a small scale operation at the time). The province of Ontario also backed the venture financially with an equity stake.
Pierre Trudeau also started PetroCanada as a national state owned oil company, which was later privatised. It became Canada's largest oil company. It owned oil sands production, high Arctic oil exploration and production (another area which Trudeau subsidised), as well as refining and retail operations.
I'm not sure where you're getting your information about Pierre Trudeau "shutting the door on exploration and expansion" from, but it doesn't bear any resemblance to actual history. Conservatives didn't like it because they were against state involvement in business, but no other politician in Canadian history did more to subsidise and expand the oil industry as he did.