Exxon is now circling the same distressed prize Chevron has been eyeing: chunks of Lukoil’s global portfolio, suddenly up for grabs after Washington loosened the legal chokehold on the sanctioned Russian major. Multiple sources say Exxon is actively weighing options to acquire Lukoil assets in Kazakhstan, where both companies already sit alongside the Russian firm in the Karachaganak and Tengiz projects. Chevron, a partner in both fields, has been running its own valuation process since last week’s Treasury move cracked the door open.…