Exxon Mobil’s chief, Rex Tillerson, might want to encase the company’s third-quarter earnings release in Lucite — because it’s unlikely to be repeated. While the oil giant raked in a $14.8 billion profit, a new record for a United States corporation, it must now consider buying a rival at home to protect itself from a worsening environment toward Big Oil abroad.

The days of $145 a barrel are over, at least for the foreseeable future. With oil now trading at around $65 a barrel, it will become harder to obscure the industry’s biggest challenge: declining reserves and increasingly inhospitable host nations.

To wit, Exxon produced 8 percent less oil and gas equivalent last quarter than it did a year earlier. That’s not good when one considers that sky-high prices last quarter should have naturally motivated the company to ramp up production.

Some of the decline had to do with events like hurricanes. But lower entitlement volumes — industry parlance for the amount of oil host nations let their private drilling partners skim off — also played a big factor.

Exxon faces a further challenge to its profits as falling prices pressure oil-producing nations to keep more of the spoils for themselves. When oil was strong, Venezuela, Russia, Iran and others ramped up their budget spending. As oil prices slide, their budgets risk fall into deficit. Some are already there. Iran, according to Deutsche Bank, needs some $95 a barrel to balance its budget.

As a result, governments will try to keep more of their oil to themselves. Brazil, which has offshore fields with enormous reserves, is contemplating the creation of a new state-owned entity to manage them. Earlier this week, Mexico failed to loosen oil and gas rules that might have opened the doors to foreign companies.

Add that to a 26 percent quarterly jump in Exxon’s capital spending, which reflects the difficulty the industry faces in obtaining and exploiting the few new energy reserves it manages to get its drills into, and it’s clear Exxon will need to put some new options on the table.

With headwinds like these, it won’t be long before Exxon breaks down and uses its $37 billion cash pile to buy a weaker rival, preferably one with energy assets in the United States, which — at least for now — hasn’t begun to arbitrarily claw back profits from private oil producers.