SINGAPORE, Aug 16 (Reuters) - Middle East crude values jumped on Tuesday as strong appetite from refiners for October cargoes shifted sentiment, setting the stage for a swift comeback from what most traders said would be a sluggish trading month. Among the reasons for the rebound, there was speculation that Taiwan's Formosa Petrochemical Corp. 540,000-barrel-per-day (bpd) refinery would resume operations this month. Other plants were expected to end maintenance and process crude at full capacity to benefit from attractive gas oil margins. At the same time, high prices in Europe and West Africa restricted export flows to Asia, tightening supplies in a market that until a week ago seemed oversupplied. Oman crude cargoes for loading in October were heard offered at a premium as high as 30 cents to Dubai quotes, up 50 cents from a discount of about 20 cents at the end of last week. U.S. major Exxon Mobil and Korea's GS Caltex were heard to have bought Oman lots at premiums of about 10 cents. Abu Dhabi Murban crude was valued at a premium of more than 20 cents to the ADNOC official selling price. * TENDERS - The strength in the market permeated to heavy sour Qatari al-Shaheen crude, as discussion revolved around Tasweeq's tender to sell nine 600,000-barrel cargoes for October. - Traders expected al-Shaheen to trade at premiums as high as 5 or 10 cents to Dubai quotes, almost in line with Oman values, after Danish producer Maersk last week sold cargoes at discounts as deep as 40 cents. - The tender was expected to be awarded by the end of the trading day on Tuesday, with results becoming known on Wednesday. * EAST/WEST - The Brent/Dubai Exchange of Futures for Swaps (EFS) for September fell 25 cents to $5.10 a barrel at 0830 GMT, Reuters data showed. The front-month EFS on June 15 touched $9.20, the highest intraday value since the spread reached a record of almost $12 in October 2004. * DME OMAN - September Oman traded on the DME jumped 44 cents to a premium of 41 cents to Dubai swap quotes at 0830 GMT, using the settlement price for DME futures, the ICE one-minute marker for Singapore and the Brent-Dubai EFS as calculated by Reuters. * MARKET NEWS - PetroChina's Dalian refinery may need another 10 days to restart its 200,000-barrel-per-day crude unit after being hit by a fire one month ago, said a company source on Tuesday, prolonging the shutdown and possibly cutting further into this month's production. - The outage at the crude unit, nearly half of the plant's total nameplate refining capacity of 410,000 bpd, forced the refinery, PetroChina's largest, to cut back crude throughput last month to below 1.2 million tonnes (283,000 bpd), or a third less than its peak rates. - China is accelerating the construction of eight crude oil reserve sites in the second-phase of its strategic plan and aims to complete them before the end of 2012, the official China Securities Journal said on Tuesday. - Chinese maritime authorities are considering demanding more than 100 million yuan ($15.6 million) in compensation from CNOOC Ltd and ConocoPhillips following a spill at a Bohai Bay oilfield jointly owned by the firms, a Chinese newspaper reported on Tuesday. - Japanese refiner Nansei Sekiyu KK said it resumed refining operations at its sole 100,000 barrels per day Nishihara plant in Okinawa, southwestern Japan, from 9 a.m. (0000 GMT) on Tuesday, following repairs to damage from a strong typhoon earlier this month. * CRACK SPREADS - Gas oil's September crack lost 65 cents to a premium of $18.08, while the October crack was 66 cents lower at a premium of $17.96 a barrel to Dubai crude because of higher crude benchmarks. - Fuel oil's September crack widened a slight 4 cents to a discount of $5.49 a barrel. - Naphtha's September crack was 11 cents wider at a discount of $5.29 a barrel, while the October contract was also 28 cents weaker at minus $5.32. * OUTRIGHT PRICES - September ICE Brent LCOc1 rose to $108.70 a barrel at 0830 GMT, up 33 cents from the same time on Monday.

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