OFFER TO PURCHASE FOR CASH
ALL OUTSTANDING SHARES OF COMMON STOCK
SUPERIOR WELL SERVICES, INC.
DIAMOND ACQUISITION CORP.
A WHOLLY OWNED SUBSIDIARY
NABORS INDUSTRIES LTD.
$22.12 NET PER SHARE
To Our Clients:
Enclosed for your consideration is an Offer to Purchase, dated August 11, 2010 (the “ Offer to
Purchase ”), and the related Letter of Transmittal, relating to an offer by Diamond Acquisition
Corp., a Delaware corporation (“ Offeror ”) and a wholly owned subsidiary of Nabors Industries
Ltd., a Bermuda exempt company (“ Nabors ”), to purchase for cash all the outstanding shares of
common stock, par value $0.01 per share (the “ Shares ”), of Superior Well Services, Inc., a
Delaware corporation (“ Superior ”), at a purchase price of $22.12 per Share, net to sellers in
cash, (such amount per Share paid pursuant to the Offer, the “ Offer Price ”), upon the terms and
subject to the conditions set forth in the Offer to Purchase, and in the related Letter of Transmittal
(which, together with the Offer to Purchase and any amendments or supplements to the Offer to
Purchase or to the Letter of Transmittal, collectively constitute the “ Offer ”) enclosed herewith.
Holders of Shares whose certificates for such Shares (the ‘‘ Share Certificates ”) are not
immediately available or who cannot deliver their Share Certificates and all other required
documents to the Depositary (as defined in the Offer to Purchase) on or prior to the Expiration
Date (as defined in the Offer to Purchase), or who cannot complete the procedure for book-entry
transfer on a timely basis, must tender their Shares according to the guaranteed delivery
procedures set forth in Section 3 — “Procedures for Accepting the Offer and Tendering Shares”
of the Offer to Purchase.
We are the holder of record of Shares held by us for your account. A tender of such
Shares can be made only by us as the holder of record and pursuant to your instructions.
The Letter of Transmittal is fu