Complex sentence: Trinidad and Tobago has been involved in the petroleum sector for over one hundred years undertaking considerable oil and gas exploration activity on land and in shallow water with cumulative production totaling over three (3) billion barrels of oil.
Split into simpler sentences: Trinidad and Tobago has been involved in the petroleum sector for over one hundred years. There been considerable oil and gas production on land and in shallow water, with cumulative production totaling over three billion barrels of oil.