1 Exhibit B SECOND AMENDMENT TO SHAREHOLDERS' AGREEMENT This Second Amendment to Shareholders' Agreement (this "Second Amendment") is made as of September 30, 1997 by and among Somerset Drilling Associates, L.L.C., a Delaware limited liability company...

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                                                                       Exhibit B



                  SECOND AMENDMENT TO SHAREHOLDERS' AGREEMENT

    This Second Amendment to Shareholders' Agreement (this "Second Amendment")
is made as of September 30, 1997 by and among Somerset Drilling Associates,
L.L.C., a Delaware limited liability company ("Somerset"), Somerset Capital
Partners, a New York general partnership and the Managing Member of Somerset
("SCP"), Xxx X. Xxxxxx, Xx., a natural person ("Xxxxxx"), U.S. Rig and
Equipment, Inc., an Oklahoma corporation ("USRE"), Xxxx Xxxxxx Energy Equipment
Resource, Inc., a Texas corporation ("EER"), GCT Investments, Inc., a Texas
corporation ("GCT"), Xxxx X. Xxxxxx, a natural person ("Xxxxxx"), Norex
Drilling Ltd., a Bermuda corporation ("Norex Drilling"), and Pronor Holdings
Ltd., a British Virgin Islands corporation ("Pronor").

    WHEREAS, Somerset, SCP, Xxxxxx, USRE, EER, GCT, Xxxxxx, Norex Drilling and
Pronor (collectively, the "Shareholders") are parties to the Shareholders'
Agreement (the "Agreement") dated as of May 7, 1996, as amended by the
Amendment to Shareholders' Agreement dated as of June 11, 1996; and

    WHEREAS, the Shareholders desire to terminate the provisions of the
Agreement.

    NOW, THEREFORE, each of the Shareholders hereby agrees and amends the
Agreement such that all agreements, obligations, rights, representations,
warranties, covenants and other provisions of the Shareholders' Agreement are
terminated in their entirety and henceforth shall be of no force and effect.

    EXECUTED to be effective as of the date set forth above.

                                       SOMERSET DRILLING ASSOCIATES, L.L.C.
                                       
                                       By:     /s/ Xxxxxxx X. Xxxxxxx          
                                            -----------------------------------
                                       Name:   Xxxxxxx X. Xxxxxxx
                                       Title: Partner of SCP, Managing Member
                                       
                                       SOMERSET CAPITAL PARTNERS ("SCP")
                                       
                                       By:     /s/ Xxxxxxx X. Xxxxxxx          
                                            -----------------------------------
                                       Name:   Xxxxxxx X. Xxxxxxx
                                       Title: Partner


                    (SIGNATURES CONTINUED ON FOLLOWING PAGE)





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                                       XXX X. XXXXXX
                                       
                                       By:     /s/ Xxx X. Xxxxxx
                                            -----------------------------------
                                       Name:   Xxx X. Xxxxxx
                                       
                                       U.S. RIG AND EQUIPMENT, INC.
                                       
                                       By:     /s/ Xxx X. Xxxxxx
                                            -----------------------------------
                                       Name:   Xxx X. Xxxxxx
                                       Title: President
                                       
                                       XXXX XXXXXX ENERGY EQUIPMENT
                                       RESOURCE, INC.
                                       
                                       By:     /s/ Xxxx Xxxxxx
                                            -----------------------------------
                                       Name:   Xxxx Xxxxxx
                                       Title: President
                                       
                                       GCT INVESTMENTS, INC.
                                       
                                       By:     /s/ Xxxx Xxxxxx
                                            -----------------------------------
                                       Name:   Xxxx Xxxxxx
                                       Title: President
                                       
                                       Xxxx X. Xxxxxx
                                       
                                       By:     /s/ Xxxx X. Xxxxxx
                                            -----------------------------------
                                       Name:   Xxxx X. Xxxxxx
                                       
                                       NOREX DRILLING LTD.
                                       
                                       By:     /s/ Xxxxx Xxxxxxxx
                                            -----------------------------------
                                       Name:   Xxxxx Xxxxxxxx
                                       Title: President
                                       
                                       PRONOR HOLDINGS LTD.
                                       
                                       By:     /s/ Xxxxx Xxxxxxxx
                                            -----------------------------------
                                       Name:   Xxxxx Xxxxxxxx
                                       Title: President





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