Royal Dutch Shell PLC has reported lower profits for the first quarter, as a decline in oil prices offset improved earnings from its refining arm.

The company reported net profit Thursday of $8.18 billion, down from $8.74 billion in the first quarter of 2012. Revenues fell 5.1 percent to $112 billion.

Stripping out the impact of oil price fluctuations and asset sales, underlying earnings grew 2 percent.

Shell produced 3.56 million barrels of oil per day, fractionally higher than 3.55 million a year ago. Shell said core production is growing, but some of its capacity in Nigeria is closed due to security threats.

Production earnings fell 10 percent to $5.65 billion due to lower oil prices. The company's refining arm profits rose 28 percent to $1.69 billion amid better margins.