EXHIBIT 10.18(A)

                               NOVATION AGREEMENT

This NOVATION  AGREEMENT is made the 4 day of Dec 1998
between:

(1)   THE EXPORT-IMPORT BANK OF KOREA (the Bank) whose principal office is at
      16-1, Yoidodong, Youngdungpo Gu, Seoul, Korea;

(2)   PETRODRILL OFFSHORE INC. (formerly Petrodrill Construction Inc.) (the
      BENEFICIARY) whose principal office is at Suite 205, Saffrey Square, PO
      Box N8188, Nassau, Bahamas; and

(3)   PETRODRILL SEVEN LIMITED (the NEW BENEFICIARY ), whose registered office
      is at Arias, Fabrega & Fabrega, Omar Hodge Building, 2nd Floor, Wickham's
      Cay 1, PO BOX 986, Road Town, Tortola, British Virgin Islands.

(together referred to as the PARTIES)

Whereas

      (A)   The Bank and the Beneficiary are parties to a Refund Guarantee dated
            16 April 1998 securing the obligations of Daewoo Corporation &
            Daewoo Heavy Industries Ltd. In respect of the construction and sale
            of a dynamic positioned semi-submersible drilling vessel with
            Builders Hull No. 3015 (including any amendments described in the
            associated memorandum, meeting minute and/or side letter made from
            time to time thereto) (the Guarantee).

      (B)   The Parties hereto have agreed to novate the Guarantee.

Now it is agreed that, with effect from the date of this Novation Agreement:

(1)   Terms and expressions defined in the Guarantee shall, unless the context
      otherwise requires, have the same meanings in this Novation Agreement.

(2)   The Beneficiary releases and discharges the Bank from the various
      covenants, undertakings, warranties and other obligations contained in the
      Guarantee which are enjoyed by the Beneficiary, and from all claims and
      demands whatsoever arising out of or in respect of the Guarantee whether
      prior to, on or subsequent to the date of this Novation Agreement.

(3)   The Bank agrees to perform all its duties and to discharge all its
      obligations under the Guarantee and to be bound by all the terms and
      conditions of the Guarantee in every way as if the New Beneficiary were
      named in the Guarantee as a party AB INITIO in place of the Beneficiary.
      Without limiting the generality of the foregoing, the Bank acknowledges
      and agrees that the New Beneficiary shall have the right to enforce the
      Guarantee and pursue all claims and demands (future or existing)
      whatsoever arising out of or in respect of the Guarantee whether arising
      prior to, on or subsequent to the date of this Novation Agreement.

                                      -1-

(4)   Each party shall take all steps, execute all documents and do everything
      reasonably required by any other Party to give effect to the transactions
      contemplated by this Novation Agreement.

(5)   This Novation Agreement is governed by and shall be construed in
      accordance with the laws of England and the Parties hereby submit to the
      exclusive jurisdiction of the courts of England.

      In witness whereof this Novation Agreement has been signed on behalf of
      the Parties the day and year first before written.


SIGNED on behalf of EXPORT-IMPORT
BANK OF KOREA in the presence of:                  )/s/ Illegible
                                                   )/s/ Illegible



SIGNED on behalf of PETRODRILL
OFFSHORE INC. in the presence of:                  )/s/ DEREK LEACH
                                                    D. Leach
                                                    Attorney
                                                   )/s/ H. STEPHEN ASSITER
                                                    H.S. Assiter Witness

SIGNED on behalf of PETRODRILL
SEVEN LIMITED in the presence of:                  )/s/ DEREK LEACH
                                                    D. Leach
                                                    Attorney
                                                   )/s/ H. STEPHEN ASSITER
                                                    H.S. Assiter Witness

                                      -2-