BROOKLYN UNION <BU> TO BUY GAS FROM SHELL OIL Brooklyn Union Gas Co said it has contracted to purchase up to 60 mln cubic feet of natural gas per day from Shell Oil Co, a Royal Dutch/Shell Group <RD> <SC> subsidiary. Brooklyn Union said the long-term contract will cover about 15 pct of its total supplies. A spokesman said Shell and the utility agreed to not disclose the length of the contract or the price of the gas, which he described as competitive with a market sensitive escalation formula. Brooklyn Union said the gas from Shell Oil will replace about 25 pct of the gas previously supplied by Transco Energy Inc's <E> Transcontinental Gas Pipe Line Corp subsidiary. The utility said Transcontinental will transport the gas being purchased from Shell Oil, possibly beginning as soon as November 1.