Folawiyo Aje Services Limited (FASL), Subsea Well Completion Design, Nigeria
OML 113 is an offshore oil concession block located in the Nigerian sector of the Benin Embayment. The block contains the Aje field, which was discovered in 1996 and declared commercial in 2009. The field is located approximately 24km offshore in a water depth of ~295m.
FASL required subsea oil production well completion design for the first phase of their Aje field development, which involved the drilling and completion of a new well (Aje-5) and the re-entry and completion of the existing Aje-4 well. The reservoir has two main productive intervals and the key drivers in the completion design were simplicity and operational effectiveness.
FASL procured surplus subsea trees (SST) from another operator and had a production manifold, flowlines and jumpers manufactured. NauticAWT also oversaw the stack-up and integration testing of the subsea trees.
The completion design selected used a conventional simple packer/locator seal combination with tubing conveyed perforating (TCP) guns run on the production packer. This simplified the completion installation, allowing correct location of the perforating guns when setting the packer. Artificial lift is provided by gas lift and each well included two pre-sheared shear orifice gas lift valves. Benefits of the selected design are:
- Well completed and SST installed prior to perforating with underbalance – no well control issues.
- Pre-sheared gas lift valves allows commencement of gas lift as soon as compression facilities are available, potentially providing production acceleration.
- Simplicity of well design reduced capital expenditure on downhole equipment, which was tried and tested and readily available.
- Underbalance perforating using high shot density TCP provides excellent connectivity to the reservoir.