L02-FA

Location

The L02-FA oil project is located in the Niger Delta, specifically within the Field L02 reservoir streams. The Niger Delta is a major geological feature known for significant petroleum exploration and production in Nigeria, extending in an east-west direction from southwest Cameroon to the Okitipupa Ridge.

Geological Setting

The Niger Delta, where Field L02 is situated, is characterized by an arc-shaped, high-energy constructive delta. The delta is framed by older mega tectonic elements such as the Calabar Flank, the Benin Flank, and the Abakaliki anticlinorium. This region is a leading oil province in Africa.

Field Description

Field L02 has four drilling platforms, each producing from relatively different reservoirs within the same field. There are a total of 39 oil-producing wells across these platforms.

Production Characteristics

• Crude Oil and Produced Water: Crude oil samples and produced water samples from Field L02 were analyzed. The crude oil samples showed high acidic composition, indicative of naphthenic acid content.
• pH and Metal Ions: The pH of the produced water samples ranged from 6.9 to 8.9, which is above the threshold value of 6.0. High concentrations of metal ions, particularly Ca++ and Na+, were observed, which can aid in the formation of metal-naphthenate deposits.

Operational Challenges

• Naphthenate Deposition: The high pH and metal ion concentrations in the produced water create conditions favorable for metal-naphthenate precipitation. This can impede crude oil production in the field. The study indicates that Field L02 is at high risk of organic deposition due to these conditions.
• Mitigation Measures: Acetic acid treatment was found to be effective in lowering the pH of the produced water, thereby inhibiting metal-naphthenate deposition. For example, at well E in Field L02, the pH was reduced from 8.2 to 7.40 after acetic acid treatment.

Production Status

The field is currently operational, but there are indications of slight naphthenate deposition, which has the potential to grow into bulk deposition if not properly addressed. The study suggests ongoing monitoring and mitigation strategies to manage this issue.

Conclusion

The L02-FA oil project in the Niger Delta is a significant oil production field facing specific operational challenges related to naphthenate deposition. Understanding the geological setting, production characteristics, and implementing effective mitigation measures such as acetic acid treatment are crucial for maintaining optimal production levels.