Study on Selection Strategy of Dry and Wet Christmas Trees for Deepwater Oil and Gas Development

This study addresses key technical challenges encountered in the selection of Christmas trees for deepwater oil and gas field development. A comparison is conducted between dry trees and wet trees, focusing on their technical characteristics and engineering adaptability. A theoretical basis is established for the selection of technical solutions in specific deepwater projects. The technical differences between the two tree types are systematically analyzed, with particular emphasis placed on their relationship with platform development models, including TLP and SPAR. The Gulf of Mexico is utilized as a case study, where historical data on actual operating water depths are incorporated. The adaptability of different technical solutions is thoroughly assessed through this approach. Subsea trees are characterized by their compact structure and standardized modular design. Their technology is considered increasingly mature, with applications demonstrated across most current water depths in the Gulf of Mexico. In contrast, dry trees are designed to allow direct operation and maintenance under atmospheric conditions. However, more complex interfaces are required with traditional riser systems, thereby limiting their applicability in deepwater fields. The selection of Christmas trees is regarded as a critical technical decision in deepwater development. Decisions should be grounded in integrated engineering analysis, where reservoir development plans, subsea layout, and full lifecycle operational strategies are all taken into account. A technical comparison framework is developed in this study, which can be directly referenced for engineering design and equipment selection in similar deepwater projects.