**EXHIBIT 4.2****SUPPLEMENTAL INDENTURE**     SUPPLEMENTAL INDENTURE (this “SupplementalIndenture”), dated as of September13, 2007, but effective as of August 29, 2007, among Advanced Oilwell Services, Inc. (the“GuaranteeingSubsidiary”), a subsidiary of SESI, L.L.C., a Delaware limitedliability company (the “Company”), the Company, the other Guarantors (as defined in theIndenture referred to herein) and The Bank of New York Trust Company, N.A., as trustee under theIndenture referred to below (the “Trustee”).WITNESSETH     WHEREAS, the Company has heretofore executed and delivered to the Trustee an Indenture, datedas of December 12, 2006 (the “Indenture”), providing for the issuance of 1.50% SeniorExchangeable Notes due 2026 (the “Securities”);     WHEREAS, the Indenture provides that under certain circumstances the Guaranteeing Subsidiaryshall execute and deliver to the Trustee a supplemental indenture pursuant to which theGuaranteeing Subsidiary shall unconditionally guarantee all of the Company’s Obligations under theSecurities and the Indenture on the terms and conditions set forth herein (the“Guarantee”); and     WHEREAS, pursuant to Section 3.09 of the Indenture, the Trustee is authorized to execute anddeliver this Supplemental Indenture.     NOW THEREFORE, in consideration of the foregoing and for other good and valuableconsideration, the receipt of which is hereby acknowledged, the Guaranteeing Subsidiary and theTrustee mutually covenant and agree for the equal and ratable benefit of the Holders of theSecurities as follows:     1. *Capitalized Terms*. Capitalized terms used herein without definition shall have themeanings assigned to them in the Indenture.     2. *Agreement to Guarantee*. The Guaranteeing Subsidiary hereby agrees to provide anunconditional Guarantee on the terms and subject to the conditions set forth in the Guarantee andin the Indenture including but not limited to Article 13 thereof.     3. *No Recourse Against Others*. No past, present or future director, officer, employee,incorporator, stockholder or agent of the Guaranteeing Subsidiary (other than the Company or aGuarantor in its capacity as a stockholder of a Subsidiary), as such, shall have any liability forany obligations of the Company or any Guaranteeing Subsidiary under the Securities, any Guarantees,the Indenture or this Supplemental Indenture or for any claim based on, in respect of or by reasonof, such obligations or their creation. Each Holder of the Securities by accepting a Securitywaives and releases all such liability. The waiver and release are part of the consideration forissuance of the Notes. Such waiver may not be effective to waive liabilities under the federalsecurities laws and it is the view of the SEC that such a waiver is against public policy.
 

 
     4. *New York Law to Govern*. THE INTERNAL LAW OF THE STATE OF NEW YORK SHALL GOVERN AND BE USEDTO CONSTRUE THIS SUPPLEMENTAL INDENTURE.     5. *Counterparts.*The parties may sign any number of copies of this Supplemental Indenture.Each signed copy shall be an original, but all of them together represent the same agreement.     6. *Effect of Headings*. The Section headings herein are for convenience only and shall notaffect the construction hereof.     7. *The Trustee*. The Trustee shall not be responsible in any manner whatsoever for or inrespect of the validity or sufficiency of this Supplemental Indenture or for or in respect of therecitals contained herein, all of which recitals are made solely by the Guaranteeing Subsidiary andthe Company.*[Signature pages follow.]*
 

 
     IN WITNESS WHEREOF, the parties hereto have caused this Supplemental Indenture to be dulyexecuted and attested, all as of the date first above written.      ADVANCED OILWELL SERVICES, INC.