This is an important question. Let me name three factors.
First, Chevron is a profitable oil company. So, from a social responsibility point of view, it would do a world of good for them to take part is anything that helps the environment. Helping other charities can be helpful as well, such as education. All companies try to give back; large oil companies should do the same.
Second, in view of the BP spill in the gulf, any more oil spills will get negative press. In light of this fact, it would be wise for Chevron to put a top priority on safety. The public and the media may not put up with another disaster. It could be the end of a company, if the lack of safety caused more environmental damage.
Third, Chevron and other oil companies may also want to benefit the nations and places where this oil is pumped. There is always the perception that western companies take from resource wealthy nations without benefiting them properly.