PORT OF SPAIN, Dec 28 (Reuters) - Trinidad and Tobago is preparing to reject four offshore exploration bids by BP Plc (BP.L) and Shell Plc (SHEL.L), according to people familiar with the matter, because they failed to meet the government’s minimum requirements.Trinidad and Tobago’s deep-water bid round closed in early June with offers received only from a BP-Shell consortium on four of the 17 blocks.The Caribbean country urgently needs new gas supplies to boost its liquefied natural gas (LNG) production.A BP spokesperson said this month that the company was "looking forward to progressing talks on deepwater blocks," but declined to comment on the timing of any talks, saying the detail should come from the government in Port of Spain.BP’s president for Trinidad and Tobago operations, David Campbell, had urged movement on the bids saying BP needs to access deepwater fields for future output."