Michigan Region

The Michigan region accounts for 5% of total proved reserves and approximately 7% of the Company's year-end 2005 production. We drilled or participated in the drilling of 39 Michigan wells during 2005, 37 of which were completed as producers. On a net basis, 9.6 wells were productive out of a total of 10.7 wells drilled for a success rate of 90%. We hold approximately 74,000 net acres in Michigan.

Antrim Shale Play

In northern Michigan, Whiting owns an interest in more than 50 multi-well Antrim Shale natural gas projects, all of which contain proved reserves as well as additional probable and possible reserve potential. Approximately 10 of these Antrim Shale projects have significant remaining development potential. In 2005, Whiting participated in the drilling and completion of 20 Antrim Shale wells. In 2006, we plan to continue to pursue development drilling opportunities and will evaluate the potential upside of utilizing horizontal drilling in this unconventional formation.

Other Michigan Production

Whiting also produces gas and oil from the Prairie du Chien, Glenwood and Trenton Black River formations located in central Michigan. Whiting operates seven fields and owns an interest in another 13 fields in this area. The Prairie du Chien fields produce natural gas and condensate from various intervals within a 500-foot to 800-foot sequence of sandstones and dolomitic sandstones at depths of between 10,500 feet and 11,200 feet. The low permeability and heterogeneous character of the Prairie du Chien reservoirs has resulted in low historical recovery of the original reserves in place from existing wells, providing the Company with significant opportunities for increased recovery through infill drilling. During 2005, we drilled two Prairie du Chien wells in Clayton field, both of which encountered hydrocarbons in a middle interval that has not previously produced in the area. We have been encouraged by these results and are in the process of working with a drilling contractor to move a rig into the area for additional drilling in 2006.