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UNITED STATES SECURITIES AND EXCHANGE COMMISSION
 Washington, D.C. 20549
 FORM 10-Q/A
 Amendment No. 1
  þ
    
    QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
EXCHANGE ACT OF 1934 FOR THE QUARTERLY PERIOD ENDED SEPTEMBER 30, 2006 OR
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    TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE
ACT OF 1934 FOR THE TRANSITION PERIOD FROM ____________ TO ____________
 Commission file number 1-2199
 ALLIS-CHALMERS ENERGY INC.
  DELAWARE
    
    39-0126090(State or other jurisdiction of 
incorporation or organization)
    
    (I.R.S. Employer
Identification No.)
 5075 WESTHEIMER, SUITE 890, HOUSTON, TEXAS 77056
 (713) 369-0550
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TABLE OF CONTENTS  EXPLANATORY NOTEITEM 6. EXHIBITSSIGNATURESEXHIBIT INDEXStrategic AgreementAmendment No.1 to Strategic AgreementAmendment No.2 to Strategic AgreementCertification of CEO Pursuant to Section 302Certification of CFO Pursuant to Section 302    Table of Contents  
 EXPLANATORY NOTE
   
 ITEM 6. EXHIBITS
  
 SIGNATURES
  Allis-Chalmers Energy Inc.
 (Registrant)
 /s/ Munawar H. HidayatallahMunawar H. HidayatallahChief Executive Officer and
Chairman




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EXHIBIT INDEX
 1.1
    
    Underwriting Agreement dated as of August 8, 2006 by and between the Registrant and the
underwriters listed on Schedule A thereto (incorporated by reference to Exhibit 1.1 to the
Registrants Form 8-K filed on August 9, 2006).4.1
    
    First Supplemental Indenture dated as of August 11, 2006 by and among Allis-Chalmers GP, LLC,
Allis-Chalmers LP, LLC, Allis-Chalmers Management, LP, Rogers Oil Tool Services, Inc., the
Registrant, the other Guarantors (as defined in the Indenture referred to therein) and Wells
Fargo Bank, N.A (incorporated by reference to Exhibit 4.2 to the Registrants Form 8-K filed
on August 14, 2006).10.1
    
    Purchase Agreement dated as of August 8, 2006 by and between the Registrant, the guarantors
listed on Schedule B thereto and RBC Capital Markets Corporation (incorporated by reference to
Exhibit 10.4 to the Registrants Form 8-K filed on August 14, 2006).10.2
    
    Registration Rights Agreement dated as of August 14, 2006 by and among the Registrant, the
guarantors listed on Schedule A thereto and RBC Capital Markets Corporation (incorporated by
reference to Exhibit 10.1 to the Registrants Form 8-K filed on August 14, 2006).10.3
    
    Investors Rights Agreement dated as of August 18, 2006 by and among the Registrant and the
investors named on Exhibit A thereto (incorporated by reference to Exhibit 10.1 to the
Registrants Form 8-K filed on August 14, 2006).10.4
    
    First Amendment to Amended and Restated Credit Agreement dated as of August 8, 2006, by and
among the Registrant, the guarantors named thereto and Royal Bank of Canada (incorporated by
reference to Exhibit 10.3 to the Registrants Form 8-K filed on August 14, 2006).10.5
    
    2006 Incentive Plan (incorporated by reference to Exhibit 10.1 to the Registrants Form 8-K
filed on September 18, 2006).10.6
    
    Form of Employee Restricted Stock Agreement (incorporated by reference to Exhibit 10.2 to the
Registrants Form 8-K filed on September 18, 2006).10.7
    
    Form of Employee Nonqualified Stock Option Agreement (incorporated by reference to Exhibit
10.3 to the Registrants Form 8-K filed on September 18, 2006).10.8
    
    Form of Employee Incentive Stock Option Agreement (incorporated by reference to Exhibit 10.4
to the Registrants Form 8-K filed on September 18, 2006).10.9
    
    Form of Non-Employee Director Restricted Stock Agreement (incorporated by reference to
Exhibit 10.5 to the Registrants Form 8-K filed on September 18, 2006).10.10
    
    Form of Non-Employee Director Nonqualified Stock Option Agreement (incorporated by reference
to Exhibit 10.6 to the Registrants Form 8-K filed on September 18, 2006).10.11
    
    Stock Purchase Agreement dated October 17, 2006 by and between Allis-Chalmers Production
Services, Inc. and Randolph J. Hebert (incorporated by reference to Exhibit 10.1 to the
Registrants Form 8-K filed on October 19, 2006).10.12
    
    Asset Purchase Agreement dated October 25, 2006 by and between the Registrant and Oil & Gas
Rental Services, Inc. (incorporated by reference to Exhibit 10.1 to the Registrants Form 8-K
filed on October 26, 2006).10.13*
    
    Strategic Agreement dated July 1, 2003 between Pan American Energy LLC Sucursal Argentina
and DLS Argentina Limited Sucursal Argentina.10.14*
    
    Amendment No. 1 dated May 18, 2005 to Strategic Agreement between Pan American Energy LLC
Sucursal Argentina and DLS Argentina Limited Sucursal Argentina.




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10.15*
    
    Amendment No. 2 dated January 1, 2006 between Pan American Energy LLC Sucursal Argentina and
DLS Argentina Limited Sucursal Argentina.31.1*
    
    Certification of Chief Executive Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.31.2*
    
    Certification of Chief Financial Officer pursuant to Section 302 of the Sarbanes-Oxley Act of 2002.
 
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    Filed herewith.