Unique flexibility in installation and workover reduces capex and opex
The HyFleX subsea tree system is based on existing qualified and field-proven conventional subsea tree components. However, in contrast to conventional subsea trees, the HyFleX subsea tree system is designed such that the tubing hanger and tree are completely independent of each other, providing unique flexibility in installation sequence and workover operations, resulting in lower capex and opex.
Conventional horizontal subsea trees are associated with lower capex due to the simple assembly in which the tubing hanger is installed on top of the tree. However, workover operational costs are typically higher as the tubing hanger needs to be recovered first to access the tree. Conversely, conventional vertical subsea trees are configured so that the tubing hanger is installed first, followed by the tree, leading to lower workover costs but higher capex due to the larger assembly. A compromise on capex versus opex is forced when choosing a conventional subsea tree system.
The HyFleX subsea tree system offers operators a unique economical alternative without the need for compromise. Because of the independent configuration of the tubing head spool, tree, and tubing hanger, the HyFleX subsea tree system components can be installed either like a conventional horizontal or vertical subsea tree. This independent design also supports the same flexibility for workover operations. The decreases capex and opex compared with conventional subsea tree systems due to the reduced overall weight and the accessibility to the tree without disturbing the tubing hanger.
The HyFleX subsea tree system comprises three main assemblies:
- The tubing head spool is standardized and robust, and consists of a wellhead connector and main valve body to isolate the well.
- The tubing hanger is a conventional horizontal tree tubing hanger and is installed in the tubing head spool.
- The tree module interfaces with and is landed around the tubing head spool, enabling the tree’s independence from the tubing hanger. The tree module can be configured to accommodate a project’s unique equipment requirements. It contains all hydraulically actuated valves, chokes, control systems, sensors, meters, and other instrumentation with the added benefit of enabling independent installation or retrieval of these items.
Features and benefits
Key advantages of the HyFleX subsea tree system that enable cost-efficiencies and significantly improve operational performance include
- mitigation of risk because the completion, tree installation, and workover are totally independent
- significant cost benefit during installation with ability to batch-set wells
- standardized tubing head spool with configurable tree functionality, enabling shorter time to well completion
- low overall lift weight due to the tubing head spool and tree module being independent of each other
- lowest tree workover costs due to the completion being unaffected by tree changeout and because the well may be isolated via the tubing head spool; no intervention package is required to work over the tree
- tree unit interchangeable throughout the life of the field
- based on qualified, field-proven conventional subsea tree and tooling technology.