Unocal Corp. said development work is going faster than expected on the Muni field in the Gulf of Mexico where appraisal drilling found additional secondary natural gas pay zones. Production from the field on Ship Shoal Block 295 is now expected late this year at an initial sustained rate of 100 million cubic feet of gas and 2,000 barrels of condensate per day, the company said in a report on exploration drilling to date this year prior to Monday's annual meeting in Brea, Calif. Unocal said the first Muni appraisal well penetrated two additional secondary gas pay zones and estimated reserves for the 100 percent owned field offshore Louisiana at 100 to 130 billion cubic feet.