MOSCOW — As the gusher of oil money that underpinned the rise of President Vladimir V. Putin has dwindled in the price slump, the Kremlin has found ways to keep the economy chugging along, albeit at a reduced rate, spending down rainy day funds and cutting wages and pensions.

But the budget strains are worsening as the price decline grinds along, forcing the Kremlin to look for new sources of money — freezing pensions, withholding wages, raising some taxes, selling off chunks of state-owned companies, even reportedly trimming military outlays.

Things have become so tight, insiders say, that the Kremlin is considering cracking open the one piggy bank that was always considered sacrosanct, one that carries long-term consequences for the Russian economy: taxing the funds that oil companies need to invest to ensure future oil production.

That move would be the oil industry equivalent of eating the seed corn. The longer the government keeps extracting cash from the crucial oil sector, the greater the damage to the country’s future economic prospects, even if oil prices rebound.