EXHIBIT  10.13

                     ROYALTY/REVENUE INTEREST SALE AGREEMENT
                        NIGERIAN OIL CONCESSION BLOCK 237

THIS  AGREEMENT  made  and  entered  into  this  31st  day  of  March,  1997:

BETWEEN:

     YINKA  FOLAWIYO  PETROLEUM  COMPANY  LIMITED,  a
     corporation  incorporated  pursuant  to  the  laws  of  Nigeria,
     (hereinafter  referred  to  as  "YFP")

                         and

     LIBERTY  TECHNICAL  SERVICES  LTD.  of  7th  Floor,  Folawiyo
     Plaza,  38  Warehouse  Road,  Lagos,  Nigeria,
     (hereinafter  referred  to  as  "Liberty")

RECITALS

WHEREAS:

1.   By virtue of a  Participation/Royalty  Agreement  dated  effective April 5,
     1995,  (the  "Participation/Royalty  Agreement") YFP acquired an overriding
     royalty (the "Overriding Royalty") consisting an entitlement to receive the
     proceeds of sale of 0.77379% of all Petroleum  Substances produced and sold
     from Nigerian oil Concession Block OPL 237 ("Concession  Block 237") before
     payout and  0.39393% of all  Petroleum  Substances  produced  and sold from
     Concession Block 237 after payout;

2.   Under the terms of the Participation/Royalty  Agreement, in addition to the
     Overriding   Royalty,   YFP  acquired  a  revenue  interest  (the  "Revenue
     Interest") on Concession Block 237 that provides YFP with an entitlement to
     receive the proceeds of sale of 1.707% of all Petroleum Substances produced
     and sold  from  Concession  Block  237  before  payout  and  0.869%  of all
     Petroleum  Substances  produced  and sold from  Concession  Block 237 after
     payout;

3.   YFP has agreed to sell, assign and convey to Liberty, all of its Overriding
     Royalty and a portion of its Revenue  Interest in the percentages set forth
     herein,  in  consideration  of  the  payment  of  U.S.$3,767,495.05  to  be
     satisfied  by the  issuance  of 482,239  common  shares of Abacan  Resource
     Corporation to YFP at a price of $7.8125 per common share;

NOW  THEREFORE  in  consideration  of the mutual covenants herein contained, the
Parties  hereto  agree  as  follows:

<PAGE>
1.   YFP shall and hereby does  irrevocably  sell,  convey,  assign and transfer
     unto  Liberty,  all  of  YFP's  right,  title  and  interest  to and in the
     Overriding  Royalty consisting of an entitlement to receive the proceeds of
     sale  of  0.7739%  of all  Petroleum  Substances  produced  and  sold  from
     Concession Block 237 before payout and 0.39393% of all Petroleum Substances
     produced  and sold  from  Concession  Block  237 after  payout  (the  "Sold
     Overriding Royalty Interest").

2.   YFP shall and hereby does  irrevocably  sell,  convey,  assign and transfer
     unto Liberty,  5.6% of YFP's right title and interest to and in the Revenue
     Interest  consisting of an  entitlement  to receive the proceeds of sale of
     0.09554% of all  Petroleum  Substances  produced  and sold from  Concession
     Block 237 before payout and 0.04863% of all Petroleum  Substances  produced
     and sold  from  Concession  Block  237  after  payout  (the  "Sold  Revenue
     Interest").

3.   Liberty hereby agrees to pay to YFP a purchase  price of  U.S.$3,767,495.05
     for the Sold  Overriding  Royalty  Interest and the Sold Revenue  Interest,
     which sums shall be satisfied by the delivery of 482,239  common  shares of
     Abacan Resource Corporation (the "Abacan Shares"). YFP agrees to accept the
     Abacan Shares  subject to any and all  restrictions  on trading  imposed by
     applicable regulatory authorities.

4.   YFP and  Liberty  hereby  acknowledge,  confirm  and  agree  that  upon the
     fulfilment of the  conditions set out in Paragraph 7 herein and the payment
     of the  consideration set out in Paragraph 3 above, the interests and right
     to the proceeds of sale of the Parties in the Overriding  Royalty Interest,
     expressed as a percentage  of all  Petroleum  Substances  produced and sold
     from  Concession  Block  237,  both  before  and after  payout  shall be as
     follows:


NAME OF PARTY                             BEFORE PAYOUT   AFTER PAYOUT
----------------------------------------  --------------  -------------
Yinka Folawiyo Petroleum Company Limited            0.0%           0.0%
----------------------------------------  --------------  -------------

Liberty Technical Services Ltd.                  0.7739%       0.39393%
----------------------------------------  --------------  -------------


5.   YFP and  Liberty  hereby  acknowledge,  confirm  and  agree  that  upon the
     fulfilment of the  conditions set out in Paragraph 7 herein and the payment
     of the  consideration  set out in Paragraph 3 above,  the interests and the
     right to the  proceeds  of sale of the  Parties  in the  Revenue  Interest,
     expressed as a percentage  of all  Petroleum  Substances  produced and sold
     from  Concession  Block  237,  both  before  and after  payout  shall be as
     follows:


NAME OF PARTY                             BEFORE PAYOUT   AFTER PAYOUT
----------------------------------------  --------------  -------------
Yinka Folawiyo Petroleum Company Limited        1.61146%       0.82037%
----------------------------------------  --------------  -------------

Liberty Technical Services Ltd.                 0.09554%       0.04863%
----------------------------------------  --------------  -------------


                                        2
<PAGE>
6.   YFP  represents  and warrants to Liberty that the Sold  Overriding  Royalty
     Interest  and the Sold  Revenue  Interest  are each  free and  clear of any
     charges,  liens or other encumbrances to any and all third parties and that
     any and all corporate steps,  consents,  resolutions or approvals necessary
     to give effect to the sale and  assignment of the Sold  Overriding  Royalty
     Interest and Sold Revenue Interest has been duly and fully obtained.

7.   The  completion of this  transaction  and the issuance of the Abacan Shares
     contemplated  herein  shall  be  subject  to  receipt  by  Abacan  Resource
     Corporation  of all necessary and  applicable  regulatory  approvals.  This
     condition  is for the sole  benefit of  Liberty  and may be waived by it in
     writing at its sole discretion.

8.   Each Party shall from time to time and at all  necessary  times do all such
     further acts and execute and deliver all further deeds and documents as may
     be reasonably  required in order to perform and carry out the terms of this
     Royalty/Revenue Interest Sale Agreement.

IN  WITNESS  WHEREOF  the  Parties  hereto have caused the within presents to be
executed  by  their  duly  authorized  representatives on the day and year first
above  written.

Liberty  Technical  Services  Ltd.          Yinka  Folawiyo  Petroleum  Company
Limited




Per:    /s/  Wade  Cherwayko     Per:   /s/  T.B.  Folawiyo
     -----------------------          ---------------------

                                        3
<PAGE>