Solo Oil said chief executive Dan Maling had stood down with immediate effect, following the completion of a strategic review.
Chairman Alastair Ferguson had taken on the role of executive chairman.
'These changes are a continuation of the board restructuring that started in 2018,' the company said.
Douglas Rycroft and John Daniel had been appointed to the roles of operations manager and technical advisor, respectively.
'The board has undertaken a full review of all internal business systems, including joint venture management, finance and communications and has taken the appropriate actions to reduce the overall cost structure of the business,' Solo said.
The company's core focus would be on monetisation of existing assets, rigorous cost control, balance sheet stabilisation and, in time, expected distributions to shareholders, it added.
At 8:07am: (LON:SOLO) Solo Oil PLC share price was 0p at 1.68p