1997
Trefoil was incorporated on 13 November 1997 as Norbay Oil International Limited.

1999
On the 13 December 1999, the Company’s strategy was redefined and under a new management changed its name to Trefoil Limited.

2001
On 29 June, 2001 Trefoil, through its subsidiary PETSA, entered into the JV agreement with Chañares for the development and exploitation of the Chañares Herrados and Puesto Pozo Cercado fields which are located in the Province of Mendoza, Argentina.

2002
Trefoil divested its assets in the United States and Mozambique in order to focus in the southern cone of South America.

2005
A share issue raised USD 90 million in equity and on 20. December Trefoil Limited was listed at Oslo Stock Exchange.

2006
On February 8th Petrolera El Trebol took over and started operations of the Puesto Rojas and Cerro Mollar Oeste fields in the Province of Mendoza.In August, Petrolera El Trebol acquired the two licenses, Atamisqui and Refugio Tupungato, located in Mendoza. The operations were taken over in October.In October, Petrolera El Trebol acquired 33% of the license Atuel Norte from Techpetrol (operator) and Petrobras.

2008
In December Petrolera El Trebol was granted a 33% share in Exploration block Rio Atuel, with joint venture partners Tecpetrol and Petrobras. Delta Hydrocarbons (www.deltahydrocarbons.com) made a public offer in April 2008 to acquire the outstanding shares of the company and Petrolera El Trebol was de-listed in August 2008.