Tullow Oil today swung back into profit for the first half of the year and upped its production targets as it looked to get back on a surer footing after several challenging years. The firm booked a profit of $93m for the first six months, having posted a whopping $1.3bn loss in the same period last year due to impairment charges. Revenue year-on-year was flat at $737m. For the full year, the FTSE 250 oil explorer said that production would come in at 58,000-61,000 barrels per day after an increase in output at one of its fields in Gabon. Last…