Tullow Oil, a London-listed firm focused on oil and gas developments in Africa, has extended debt maturities by two and a half years in a major refinancing agreement with the holders of two-thirds of senior notes and with mining and commodity giant Glencore. Tullow Oil on Friday said it had entered into a binding Lock-Up Agreement to implement a refinancing transaction with holders of about 66% of its $1.28 billion in senior secured notes due May 2026, as well as with Glencore. The refinancing transaction releases its Senior…