The International oil companies operating now in Sudan includes:
 
• Block  1,  2,  4,  Greater  Nile  Petroleum Operating Company (GNPOC). The  shareholders  are  CNPC  (40%), Petronas  (30%), (ONGC)  (25%)  and Sudapet (5%).
• Block  6,  China  National  Petroleum Company CNPC (95%) AND SUDAPET (5%).
• Block  5A,  the  shareholders  Petronas (68.876%),  OMV  AG  (26.125%)  and
Sudapet (5%).
• Block  3&7,  CNPC, 41%, PETRONAS 40%, THANI, 5%, GPC 6% and Sudapet 8%.
• Block  B,  Total  EXPLORATION  - Sudan, the shareholders are Total  Exploration  (32.5%),  Marathon
Petroleum  (32.5%),  Kuwait  Foreign Petroleum  Exploration  Co.  (25%)  and GPC (10%).
• Block  5B,  Petronas  (41%),  OMV (24.5%),  IPC  (24.5%)  and  Sudapet (10%).

The  Ministry  of  Energy  and  Mining  has adopted  the  block  system.  Since  1992, accordingly  the  Sudan  basins  were  divided into  a  number  of  blocks  based  on  the amount  of  geophysical,  geological  and drilling works done Fig (5) and table (2&3). Most of these blocks are free for contracting with any company or a group of companies, which are capable financially and technically to do the work. All data for the free blocks are available in the Sudan route.