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                                                                    EXHIBIT 4.12
 
                            FORM OF      % SERIES A
                     CUMULATIVE PREFERRED STOCK CERTIFICATE
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                            FORM OF      % SERIES A
                           CUMULATIVE PREFERRED STOCK
                                  CERTIFICATE
 
     This Preferred Security is a Global Certificate and is registered in the
name of The Depository Trust Company (55 Water Street, New York, New York) (the
"Depositary") or a nominee of the Depositary. This Preferred Security is
exchangeable for Preferred Security registered in the name of a person other
than the Depositary or its nominee only in limited circumstances and no transfer
of this Preferred Security (other than a transfer of this Preferred Security as
a whole by the Depositary to a nominee of the Depositary or by a nominee of the
Depositary to the Depositary or another nominee of the Depositary) may be
registered except in limited circumstances.
 
     Unless this Preferred Security is presented by an authorized representative
of the Depositary to the Company or its agent for registration of transfer,
exchange or payment, and any Preferred Security issued is registered in the name
of Cede & Co. or such other name as requested by an authorized representative of
the Depositary and any payment hereon is made to Cede & Co., ANY TRANSFER,
PLEDGE OR OTHER USE HEREOF FOR VALUE OR OTHERWISE BY A PERSON IS WRONGFUL
because the registered owner hereof, Cede & Co., has an interest herein.
 
Certificate Number
                  --------------------------------------------------------------
 
Number of Shares of Preferred Stock
                                   ---------------------------------------------
 
CUSIP NO.
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Certificate Evidencing Shares of Preferred Stock
 
of
 
UNION TEXAS PETROLEUM HOLDINGS, INC.
 
[          ]% Series A Cumulative Preferred Stock
 
(Par Value $.01 Per Share)
(Liquidation Preference Equivalent To $100.00 Per Share)
 
     UNION TEXAS PETROLEUM HOLDINGS, INC., a corporation formed under the laws
of the State of Delaware (the "Company"), hereby certifies that           (the
"Holder") is the registered owner of shares of preferred stock of the Company
representing undivided beneficial interests in the assets of the Company
designated the [     ]% Series A Cumulative Preferred Stock (par value $.01 per
share and liquidation preference equivalent to $100.00 per share) (the
"Shares"). The Shares are transferable on the books and records of the Company,
in person or by a duly authorized attorney, upon surrender of this certificate
duly endorsed and in proper form for transfer. The designation, rights,
privileges, restrictions, preferences and other terms and provisions of the
Shares represented hereby are issued and shall in all respects be subject to the
provisions of the Certificate of Designation filed with the Secretary of State
of Delaware on March   , 1998 (the "Designation"). Capitalized terms used herein
but not defined shall have the meaning given them in the Designation. The
Company will provide a copy of the Designation to a Holder without charge upon
written request to the Company at its principal place of business.
 
     IN WITNESS WHEREOF, the Company has executed this certificate this      day
of March 1998.
 
                                        UNION TEXAS PETROLEUM HOLDINGS, INC.
 
                                        By:
                                           -------------------------------------
                                        Name:
                                        Title:
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                          FORM OF REVERSE OF SECURITY
 
     Holders of Shares shall be entitled to receive, when, as and if declared by
the Board of Directors out of funds of the Company legally available therefor,
cumulative cash dividends at the rate of      % of the liquidation preference
per Share (equivalent to $          per annum per Share). Such dividends shall
accrue and be cumulative from the date of original issue and shall be payable
quarterly in arrears on the last day of each March, June, September and
December, or if such date is not a business day, the succeeding business day
(each, a "Dividend Payment Date"). The first dividend on the Shares, if
declared, will be paid on             , 1998. Any dividend payable on the Shares
for any partial dividend period will be computed on the basis of a 360-day year
consisting of twelve 30-day months. Dividends will be payable to holders of
record as they appear in the records of the Company at the close of business on
the applicable record date, which shall be the 15th day of the calender month in
which the applicable Dividend Payment Date falls or on such other date
designated by the Board of Directors of the Company for the payment of dividends
that is not more than 30 nor less than 10 days prior to such Dividend Payment
Date.
 
     The Shares will, with respect to dividend rights and rights upon
liquidation, dissolution or winding up of the affairs of the Company, rank (i)
senior to all classes or series of common stock of the Company, and to all
equity securities ranking junior to the Shares with respect to dividend rights
or rights upon liquidation, dissolution or winding up of the affairs of the
Company, (ii) on a parity with all equity securities issued by the Company the
terms of which specifically provide that such equity securities rank on a parity
with the Shares with respect to dividend rights or rights upon liquidation,
dissolution or winding up of the affairs of the Company, and (iii) junior to all
equity securities issued by the Company the terms of which specifically provide
that such equity securities rank senior to the Shares with respect to dividend
rights or rights upon liquidation, dissolution or winding up of the affairs of
the Company.
 
     The Shares have no stated maturity and will not be subject to any sinking
fund or mandatory redemption. The Shares shall be redeemable as provided in the
Designation.
 
ASSIGNMENT
 
FOR VALUE RECEIVED, the undersigned assigns and transfers this Certificate to:
 
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- --------------------------------------------------------------------------------
(Insert assignee's social security or tax identification number)
 
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(Insert address and zip code of assignee)
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and irrevocably appoints
 
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- --------------------------------------------------------------------------------
 
- ---------------------------------------------------------- agent to transfer
this Certificate on the books of the
Company. The agent may substitute another to act for him or her.
 
Date:
     -----------------------------------------------
 
Signature:
          ------------------------------------------
(Sign exactly as your name appears on the other side of this Certificate)
 
[Signature Guarantee*:
                      -------------------------------------------
 
* Signature must be guaranteed by an "eligible guarantor institution" that is a
  bank, stockbroker, savings and loan association or credit union meeting the
  requirements of the Registrar, which requirements include membership or
  participation in the Securities Transfer Agents Medallion Program ("STAMP") or
  such other "signature guarantee program" as may be determined by the Registrar
  in addition to, or in substitution for, STAMP, all in accordance with the
  Securities and Exchange Act of 1934, as amended.]