Basra Heavy crude fell to $67.70 per barrel on Tuesday morning, down $2.38, or 3.40%.
Basra Medium crude also declined, dropping $1.38, or 1.89%, to $71.70 per barrel.
Global oil prices moved in the opposite direction. US West Texas Intermediate (WTI) crude rose by $0.12, or 0.12%, to $98.65 per barrel, while Brent crude increased by $0.24, or 0.22%, to $109.79.
Meanwhile, UAE Murban crude fell $2.26, or 1.99%, to $111.10 per barrel.
The OPEC basket of crude oils also declined, losing $3.60, or 3.23%, to reach $108 per barrel, according to Oil price.com data.