AMENDMENT TO

                                PROMISSORY NOTES

         THIS AMENDMENT (the "Amendment") is entered into as of this 20th day of
January, 2000 by and between Greka Energy Corporation f/k/a Horizontal Ventures,
Inc., a Colorado  corporation  ("Maker") and International  Publishing  Holding,
Inc., a Cayman Islands corporation and the assignee of International  Publishing
Holding, s.a. of Luxembourg, or its designee ("Holder") based upon the following
terms and conditions.

         WHEREAS, Maker promised to pay to the order of Holder the principal sum
of five hundred thousand dollars ($500,000),  without interest,  on December 31,
1998  pursuant to that certain  Promissory  Note  executed  October 6, 1998,  as
amended,  (the "First Note") and that certain Pledge  Agreement dated October 6,
1998; and

         WHEREAS, Maker promised to pay to the order of Holder the principal sum
of one million five hundred thousand dollars ($1,500,000),  with interest at the
rate of 6% per annum,  on December 31, 1998 pursuant to that certain  Promissory
Note executed November 4, 1998, as amended, (the "Second Note") and that certain
Pledge Agreement dated November 2, 1998; and

         WHEREAS,  Maker and Holder desire to further amend and modify the First
and Second Notes as set forth below.

         NOW, THEREFORE,  for good and valuable  consideration,  the receipt and
sufficiency of which are hereby acknowledged, the parties agree as follows:

1.   Parties.  The  parties  agree that all  references  in the First and Second
     Notes  to  Maker  and  Holder  shall be  deemed  to  refer to Greka  Energy
     Corporation and International Publishing Holding, Inc., respectively.

2.   Consolidation.  Effective as of January 1, 2000, the terms of the First and
     Second Notes are consolidated,  providing for anaggregate  principal amount
     of two million dollars ($2,000,000) owed by Maker to Holder  (collectively,
     the "Consolidated Note").

3.   Maturity Date. The Maturity Date of the Consolidated Note shall be extended
     to June 30,  2000  whereupon  the entire  unpaidprincipal  and  accrued but
     unpaid interest shall be paid in full.

4.   Interest.  The unpaid principal shall accrue simple interest at the rate of
     nine percent (9%) per annum commencing January 1,2000 payable quarterly, on
     March 31, 2000 and June 30, 2000.

5.   Installment Payments. Commencing on February 25, 2000 and continuing on the
     25th day of each month thereafter through theMaturity Date, Maker shall pay
     Holder as a reduction in principal one hundred thousand dollars ($100,000).

6.   Additional  Consideration.  Interest  accrued on the  unpaid  balance up to
     January 1, 2000 is  cancelled.  Upon the  parties'  full  execution of this
     Amendment,  Maker  shall pay to Holder  the  amount of one  hundred  eighty
     thousand dollars  ($180,000) as a restructuring fee, and such payment shall
     not be deemed to be a payable under any other provision of this Amendment.

                                                           _/s/_____  /s/______
                                                           (initials) (initials)

<PAGE>

7.   Prepayment.  Maker  may  prepay  any or all of the  amounts  due  under the
     Consolidated Note at any time, and from time to time, without penalty.

8.   Security.  The obligations of Maker under the Consolidated Note are secured
     pursuant to the provisions of the Pledge  Agreements  dated October 6, 1998
     and  November  2,  1998  between   Maker  and  Holder.   The  reference  to
     "obligations"  in those Pledge  Agreements  shall be deemed to refer to the
     obligations of Maker under the Consolidated Note.

9.   Default.  If the entire unpaid principal and/or accrued but unpaid interest
     is not paid in full on June 30, 2000, then:

     a.   on July 1, 2000,  the amount of principal owed by Maker shall increase
          by fifteen percent (15%) of the unpaid  principal  outstanding on June
          30, 2000, and

     b.   the  accrued  but unpaid  interest as of July 1, 2000 will be added to
          the amount of the unpaid principal; and

     c.   the interest accruing on the unpaid principal as of July 1, 2000 shall
          increase  to the rate of fifteen  percent  (15%) per annum  commencing
          July 1, 2000; however, in no event shall Holder be entitled to collect
          any interest in excess of the maximum interest permitted by applicable
          law.

10.  Place of Payments.  All payments by Maker to Holder under the  Consolidated
     Notes shall be made by wire transfer to:


     Bank:        United Bank of Switzerland
                  677 Washington  Blvd.,  Stanford,  CT 06901 USA

     A/C no:      101WA003611000
     ABA #:       026007993
     SWIFT code:  SBCO US33
     For further credit to:  VP Bank Luxembourg, Grand Duchy of Luxembourg
     Beneficiary:            International Publishing Holding Inc. A/C No. 69270

11.  Miscellaneous.  This Agreement,  once executed by a party, may be delivered
     to the other  party  hereto  by  facsimile  transmission  of a copy of this
     Agreement  bearing the signature of the party so delivering this Agreement.
     This  Amendment  supersedes  all prior  amendments  to the First and Second
     Notes.  All other  terms and  conditions  of the First and Second  Notes as
     originally stated therein remain in full force and effect.

     IN WITNESS WHEREOF,  the parties have executed this Amendment  effective as
of the day first written above.

Greka Energy Corporation                  International Publishing Holding, Inc.

By:  /s/__________________________        By:  /s/__________________________