Galvan Research and Trading has labelled Tullow Oil as a 'very strong buy' following last week's full-year results.Pre-tax profit for the 12 months ended December 31st surged by 499% from $179m to $1,073m on sales that jumped 111% from $1,090m to a record $2,304m. Working interest production increased by 35% during the year, from 58,100 barrels of oil equivalents per day (bopped) to 78,200, while the realised oil price was 38% higher at $108 per barrel, from $78 per barrel in 2010.Meanwhile, Tullow subsequently announced that the Enyenra-4A appraisal well, in the deep-water Tano licence offshore Ghana, has successfully encountered oil in very good quality sandstone reservoirs."Ongoing good news and fresh oil discoveries in Africa just keep rolling in at Tullow Oil, while the solid gold fundamentals are backed by a near 500% rise in profits last year. On this basis, the Galvan Research team view the shares as a very strong buy opportunity, and we tip the stock to head for 52-week highs in the coming weeks," said head of research Andrew Gibson.Gibson said he sees upside for the shares towards the late-2011 resistance line projection as high as 1,800p. BC