Essex lost their first wicket in the third over when Varun Chopra edged a Matthew Nicholson out-swinger but Pettini and the in-form Bopara took advantage of some wayward bowling to seize control.
BBC: Pettini puts Surrey to the sword
2.
Sidebottom also removed Jim Troughton and Tim Ambrose lbw in an opening spell of three for 11 from nine overs, while Shreck's out-swinger was too good for Trott, who edged low to Adam Voges at second slip.