Freshfields Bruckhaus Deringer, Paul Hastings, Memery Crystal and Akin Gump Strauss Hauer & Feld have all won roles on the restructuring and possible sale of troubled oil explorer Gulf Keystone.

Gulf Keystone has undergone a turbulent few years, with its share price tumbling from a high of £4.11 in 2012 to 4.3p today.

The oil explorer, which has holdings in Iraqi Kurdistan, was approached on Friday (29 July) by Norwegian-listed oil explorer DNO, which offered $300m (£228m) for its full share capital.

The offer is contingent on a successful conclusion to Gulf Keystone's ongoing financial restructuring.

Freshfields is advising DNO on its offer with a team led by corporate partner Christopher Mort.

DNO is also being advised by Norwegian firm Advokatfirmaet Thommessen and Bermudan firm Conyers Dill & Pearman.

Memery Crystal, Gulf Keystone's long-term adviser, is acting for the oil explorer on corporate matters with a team led by corporate partners Nick Davis and Kieran Stone.

Paul Hastings restructuring partner David Ereira is leading on the debt restructuring of the company. Ereira joined Paul Hastings in late 2015 from Linklaters, where he had been a partner since 2007.

Akin Gump is representing the ad hoc committee of bond holders on the debt restructuring with a team led by London restructuring partner James Terry, Frankfurt restructuring partner Christian Halasz and London corporate partner Vance Chapman.

Memery Crystal is a longstanding adviser to Gulf Keystone. The firm has acted for Gulf Keystone since its 2004 initial public offering on the AIM market.

The firm also acted for Gulf Keystone in a long-running court battle, which concluded in 2013, with investor Excalibur Ventures for control of Gulf Keystone's oil fields in Iraq.

Clifford Chance acted for Excalibur on that matter while Jones Day acted for the other defendant, Texas Keystone.