Willbros Canada Announces Purchase of Amec Canadian Pipeline Contractor Midwest Management (1987) Limited

Willbros Group, Inc. (NYSE: WG) announced today that one of its subsidiary companies has entered into a Share Purchase Agreement with AMEC to acquire all of the shares of Midwest Management (1987) Limited (“Midwest”), a Canadian pipeline and facilities construction company, for approximately $17.5 million (C$18.5 million) plus working capital of approximately $3.3 million (C$3.5 million). Midwest, together with its wholly owned subsidiaries, Midwest Pipeline Rental Inc. and Midwest General Contractors Ltd., offers a complete range of services, including cross country pipeline construction, rehabilitation and maintenance, water crossings installation and replacement, and facilities fabrication. Closing of this transaction, which is subject to regulatory approval pursuant to the Competition Act (Canada) and other typical closing conditions, is expected to take place in the late second quarter or early third quarter of 2007.

Randy Harl, President and Chief Executive Officer of Willbros, commented, “This acquisition provides substantial opportunities for Willbros to participate in large diameter pipeline projects related to the development of the Canadian oil sands and natural gas reserves expected during the next several years. The additional capabilities of a mainline pipeline construction entity in Canada will complement Willbros’ traditional Canadian activities which include providing maintenance, capital projects and modular fabrication services to the oil sands developments. With the addition of Midwest, we will now have in WILLBROS GROUP, INC. NEWS RELEASE FOR IMMEDIATE RELEASE 2 Canada a cross-country pipeline construction company with experience, systems, equipment and corporate identity bolstered by the global resume of Willbros. The resultant organization can offer pipeline construction and project logistics experience unmatched by any competitor in Canada.”

Crown Capital Partners Inc. acted as financial advisor to Willbros in this transaction.

Willbros Group, Inc. is an independent contractor serving the oil, gas and power industries,
providing engineering and construction services to industry and government entities
worldwide. For more information on Willbros, please visit our web site at www.willbros.com.

AMEC is an international project management and services company that designs, delivers
and supports client assets for customers across the public and private sectors. AMEC
employs more than 20,000 people working from a network of offices throughout the U.K.,
U.S. and Canada, as well as regional offices and projects worldwide. AMEC shares are
traded on the London Stock Exchange where the company is listed in the Support Services
Sector (LSE: AMEC:L).

This announcement contains forward-looking statements. All statements, other than statements of historical facts, which address activities, events or developments the Company expects or anticipates will or may occur in the future, are forward-looking statements. A number of risks and uncertainties could cause actual results to differ materially from these statements, including those discussed above and such things as the possible losses arising from the discontinuation of operations and the sale of the Nigeria assets; fines and penalties by government agencies; the outcome of the current Securities and Exchange Commission, Office of Foreign Assets Control and Department of Justice investigations; the potential for additional investigations; the identification of one or more other issues that require restatement of one or more prior period financial statements; the existence of material weaknesses in internal controls over financial reporting; availability of quality management; availability and terms of capital; changes in, or the failure to comply with, government regulations; ability to remain in compliance with, or obtain waivers under, the Company's loan agreements and indentures; the promulgation, application, and interpretation of environmental laws and regulations; future E&P capital expenditures; oil, gas, gas liquids and power prices and demand; the amount and location of planned pipelines; the effective tax rates of the different countries where the work is being conducted; development trends of the oil, gas and power industries; changes in the political and economic environment of the countries in which the Company has operations; as well as other risk factors described from time to time in the Company's documents and reports filed with the SEC. The Company assumes no obligation to update publicly such forward-looking statements, whether as a result of new information, future events or otherwise.