Gulf Keystone Petroleum said in a letter to shareholders on Friday that its chief operating officer will helm the Kurdistan-focused company on an interim basis following the retirement of its chief executive earlier this week.
John Gerstenlauer will take over for Todd Kozel until a permanent replacement is found, the company said.
Financial controller Mary Hood will assume the role of acting chief financial officer, replacing Ewen Ainsworth, who resigned recently.
A search to find permanent replacements for both positions is already under way, the company said.
London-listed shares of Gulf Keystone have risen around 40% since Kozel announced his retirement on Wednesday, effective 17 July. They closed the week at 109.25 pence. Non-executive directors Jeremy Asher and John Bell will also step down as directors.
Takeover rumours have supported the stock as has a ruling from the Supreme Court in Iraq that rejected a request from Baghdad to prevent the Kurdistan Regional Government from independently exporting oil.
Analysts at energy investment bank Tudor Pickering Holt said the ruling "opens the floodgates for a potential ramp in production... assuming the violence in Iraq doesn't spread".
Tudor Pickering said exports could rise from around 125,000 barrels per day of oil to 400,000 bpd by the end of the year.
Gulf Keystone has said plans to double output from its Shaikan oilfield to 40,000 bpd by the end of this year.