Willbros Completes Public Offering

Willbros Group has closed a public offering of its common shares at $34.00 per share. The Company sold a total of 7,906,250 shares including shares to cover the full exercise of the over-allotment option. Approximately 37,038,000 shares are outstanding after the offering. UBS Investment Bank and Credit Suisse Securities (USA) LLC were the joint book-running managers for the offering. Calyon Securities (USA) Inc., Bear, Stearns & Co. Inc., D. A. Davidson & Co. and Natixis Bleichroeder Inc. were co-managers. Net proceeds received by the Company, approximately $255.4 million, will be used to fund the cash portion of the acquisition of InServ (approximately $208.9 million including working capital and other closing adjustments), capital expenditures, working capital and additional possible acquisitions of assets and businesses, which would complement the Company's capabilities.

Willbros also reported that it has completed the transaction to acquire all the shares of Integrated Service Company, a Tulsa, Oklahoma based company. The Company previously had announced on October 31, 2007 a definitive agreement to acquire InServ.

Willbros also announced that it has entered into a new credit agreement with a bank group led by Calyon for a $150 million three-year senior secured revolving credit facility. The Company may elect to increase the total capacity under the facility to $200 million, with consent from Calyon. The facility, which includes a $50 million component for cash borrowing, will be used primarily for commercial letters of credit to support projects and for general corporate purposes. This facility replaces the Company's existing three-year $100 million synthetic credit facility.