The Sensex opened with a positive gap of 87 points at 19,941, and breached the 20,000-mark in early deals.A minor bout of profit-taking saw the index drop to a low of 19,897, but renewed buying in heavyweights like Reliance, SBI and L&T saw the index zoom to a high of 20,211.The Sensex finally closed with a gain of 338 points (1.70%) at 20,192.The BSE Oil & Gas Index moved up 3% to 13115. The BSE Smallcap Index was also up 3% at 12,342.The market breadth was extremely bullish - out of 2,945 scrips traded, 2,278 scrips logged gains today.INDEX GAINERS....Reliance led the rally with a gain of nearly 4% (Rs 109) at Rs 2,897.SBI moved up 3% (Rs 69) to Rs 2,399.L&T gained 2.6% (Rs 105) to Rs 4,194.DLF moved up 4% to Rs 1,014.Hindalco, Tata Steel, Tata Motors, BHEL and Reliance Energy also finished with gains of over 3% each today.....AND LOSERSBajaj declined 1% to Rs 2,682. ONGC was also down 1% at Rs 1,236.MOST ACTIVE COUNTERSReliance Petroleum was the most active counter with a turnover of Rs 241 crore followed by Essar Oil (Rs 219 crore), NDTV (Rs 213 crore), Reliance Energy (Rs 199 crore) and Reliance (Rs 173 crore).