WINNIPEG, Manitoba, Aug 31 (Reuters) - Canada's conventional natural gas and oil producers cut greenhouse gas emissions by 24% while increasing output 21% from 2012 to 2021, an oil industry group said on Thursday, although its analysis covers only a small portion of its related emissions.

Conventional production, which uses vertical wells, does not include the oil sands that account for the vast majority of Canada's crude output. Oil sands emissions were flat in 2022 even as output grew, a separate independent analysis showed this month.

Prime Minister Justin Trudeau's Liberal government plans to cap Canada's oil and gas emissions, angering Alberta's government that says those plans amount to a limit on production, which is a provincial responsibility.

Emissions from conventional oil and gas production declined from 100 million metric tons of carbon dioxide equivalent in 2012 to 76 million tons in 2021, according to the Canadian Association of Petroleum Producers (CAPP) analysis, which it based on Canadian government emissions and production data.

The reduction reflects in part regulations from Alberta, Canada's main fossil fuel producing province, and other oil and gas producing provinces for companies to lower methane emissions, which happen from flaring and leaky equipment.

CAPP's analysis only includes emissions from oil and gas production, not indirect emissions from energy that a company purchases or from combustion of gas and oil such as through driving - which accounts for the majority of emissions associated with oil and gas.

"This research obscures the fact that the bulk of emissions that the oil and gas sector is responsible for occurs when these fuels are burned," said Caroline Brouillette, executive director of Climate Action Network Canada. "Ongoing production expansion is incompatible with a safe climate."

The oil and gas sector was Canada's biggest emissions source in 2021, accounting for 28% of total national emissions.

"Canada’s conventional producers are demonstrating we can grow energy production to address energy security while also lowering emissions," CAPP CEO Lisa Baiton said.

(Reporting by Rod Nickel in Winnipeg, Manitoba; Editing by Josie Kao)