Mass of the earth:5.9742 × 10^24 kilograms or 5974200000000000000000000 kg.

Mass of one barrel of oil:138.8 kg (avg) 276000000 Kg of oil have leaked so far, given an avg of 40K bbl/day


4.6198654213116400522245656322185 x10-17% (read, a really tiny, infinitesimal fraction) of the earth's mass is involved.

I wouldn't worry about it.

Not even close to the mass % you lose if you pop a zit.