UBS has upgraded its rating on oil and gas stocks Caltex (CTX) and Tap Oil (TAP) from Neutral to Buy. The broker adjusted down the long-term Brent crude price forecast to US$92/bbl as well as the AUD to US92c. For CTX, the outlook for refining in the near-term is positive and expected to benefit from a lower AUD. Target price for CTX is $20.35 (currently:$18.33) with an 11% expected return. TAP has been upgraded based on potential exploration upside of its recently spudded, albeit risky, Starfish well in Ghana. Target price is $0.67 (currently:$0.52) with an expected return of 29%.