SINGAPORE, Aug 22 (Reuters) - The Asian naphtha price was at a four-session low on Wednesday at $954.50 a tonne while margins slipped to a three-session low of $97.55 a tonne, weighed down by ample supplies.      Yemen's Aden Refinery has sold about 60,000-80,000 tonnes of naphtha to Glencore for second-half August and first-half September lifting, its first spot sales in at least nine months, traders said.  
  ID:nL4E8JM3PH
       The volumes were broken down into two shipments, each of which comprised heavy and light naphtha grades.      This came at a time when there were an estimated 900,000 tonnes of Western naphtha hitting Asian shores next month.      "It is mainly a supply issue. Formosa having not bought any spot cargoes have also impacted the market," said a Singapore-based trader, who was convinced that the Taiwanese refiner will skip October spot purchase.      Formosa is Asia's top naphtha buyer and it has already skipped buying spot naphtha for a few months due to cracker outages and maintenance.      Its last purchase of open-spec naphtha was for May delivery.     Formosa on Aug. 15 shut a 1.03 million tonnes per year (tpy) No. 2 cracker for a 30-day inspection.      Japan's Mitsui Chemicals on the other hand had shut a 612,000 tpy cracker following problems with an electrical system on Tuesday.      It was unclear when the unit can resume operations.  
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            GASOLINE CRACKS AT 3-WEEK LOW     Asia's gasoline cracks slipped 3 percent to reach a three-week low of $10.99 a barrel on reduced demand as seasonal peak demand in Indonesia tapered off.      Indonesia is Asia's top gasoline importer while Vietnam is the second largest importer. But demand from Vietnam is expected to be lower as operating rates at its only refinery has reached full capacity.     The 135,000 barrels per day (bpd) plant resumed operations last week following an unplanned shutdown recently.      It remained to be seen if the U.S. would pull in more gasoline cargoes from North Asia as Chevron has yet to restart its crude distillation unit (CDU) at its 245,000 bpd plant in Richmond, California following a fire on Aug. 6.      So far, one cargo has already been lifted this month from North Asia to fill the supply gap because of the shutdown.  
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            * SINGAPORE CASH DEALS: Shell bought a 95-octane gasoline cargo for Sept. 8-12 loading at $128.60 a barrel from Vitol, making this the only cash deal for the day.        LIGHT DISTILLATES                                                                 CASH ($/T)                     ASIA CLOSE  Chang  %       Prev    RIC                                                    Change  Close     OSN Naphtha CFR Japan M1           954.50  -2.50   -0.26  957.00   
  NAF-1H-TYO
    OSN Naphtha CFR Japan M2           951.00  -3.00   -0.31  954.00   
  NAF-2H-TYO
    OSN Naphtha Diff                     3.50   0.50   16.67    3.00   
  NAF-TYO-DIF
    Naphtha Netback FOB Sing           103.86  -0.27   -0.26  104.13   
  NAF-SIN
    Naphtha Diff FOB Sing                0.31   0.03   10.71    0.28   
  NAF-SIN-DIF
    Naphtha-Brent  Crack                97.55  -0.48   -0.49   98.03   
  NAF-SIN-CRK
    Gasoline 97                        132.35  -2.70   -2.00  135.05   
  GL97-SIN
    Gasoline 95                        128.60  -0.55   -0.43  129.15   
  GL95-SIN
    Gasoline 92                        125.25  -0.61   -0.48  125.86   
  GL92-SIN
    Gasoline crack                      10.99  -0.34   -3.00   11.33   
  GL92-SIN-CRK
                                                                                      SWAPS  ($/T)                   ASIA CLOSE  Chang  %       Prev    RIC                                 (0830 GMT)         Change  Close     Brent M1                           114.26  -0.27   -0.24  114.53   
  BRENTSGMc1
    Naphtha CFR Japan M1               949.00  -2.00   -0.21  951.00   
  NACFRJPSWMc1
    Naphtha CFR Japan M1/M2              2.38  -0.37  -13.45    2.75   
  NACFRJPSDMc1
    Naphtha CFR Japan M2               946.62  -1.63   -0.17  948.25   
  NACFRJPSWMc2
    Naphtha Japan-Sing Netback M1       17.05   1.15    7.23   15.90   
  NAPTC4SPDMc1
    Naphtha Japan-Sing Netback M2       18.27   1.07    6.22   17.20   
  NAPTC4SPDMc2
    Naphtha FOB Sing M1                103.55  -0.35   -0.34  103.90   
  NAFOBSGSWMc1
    Naphtha FOB Sing M1/M2               0.40  -0.05  -11.11    0.45   
  NAFOBSGSDMc1
    Naphtha FOB Sing M2                103.15  -0.30   -0.29  103.45   
  NAFOBSGSWMc2
    Naphtha Cracks M1                   -9.08   0.09   -0.98   -9.17   
  NACFRJPCKMc1
    East-West Naphtha M1                 5.25   0.12    2.34    5.13   
  NAPJPEWMc1
    East-West Naphtha M2                 8.50   0.00    0.00    8.50   
  NAPJPEWMc2
    NWE Naphtha M1                     943.75  -2.12   -0.22  945.87   
  NAPCNWEAMc1
    NWE Naphtha M1/M2                    5.63  -0.49   -8.01    6.12   
  NAPCNWEASMc1
    NWE Naphtha M2                     938.12  -1.63   -0.17  939.75   
  NAPCNWEAMc2
    Crack NWE Naphtha-Brent M1         -10.02   0.09   -0.89  -10.11   
  NAPCNWEACMc1
    Crack NWE Naphtha-Brent M2         -10.09  -0.05    0.50  -10.04   
  NAPCNWEACMc2
    *Sing refers to Singapore                                                           (Reporting by Seng Li Peng; editing by James Jukwey)  ((lipeng.seng@thomsonreuters.com)(+65 6870 3086)(Reuters Messaging: lipeng.seng.reuters.com@reuters.net))  Keywords: MARKETS ASIA/NAPHTHA GASOLINE