Subsea Tree Bidirectional Flow Choke Block
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Solution Overview
Problem
Subsea trees face challenges in efficiently controlling and regulating fluid flow in both injection and production wells, particularly in deepwater environments, where existing solutions are complex and costly, and require frequent maintenance due to the need for reconfiguration and downtime during repairs.
Innovation Solution
A subsea tree configuration with a master block, swab valve, master valve, and choke block that allows for fluid redirection and flow reversal without reconfiguring the choke, enabling efficient operation in both injection and production modes, and incorporating retrievable choke inserts to minimize downtime during maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a subsea tree is configured for injection well operations, then it can effectively manage fluid injection into the reservoir, but it cannot be used for production well operations without reconfiguration
Solution Approach 1:
The subsea tree is designed with a universal configuration that can perform both injection and production functions. The master block includes a flow bore that can handle bidirectional fluid flow, and the choke block with retractable choke insert can regulate flow in both directions. The swab valve and master valve are positioned to control flow whether it is being injected into or produced from the well, eliminating the need for separate trees for injection and production operations.
Solution Approach 2:
The choke insert is designed to be retractable within the choke block, allowing dynamic adjustment of the flow path. During injection operations, the choke can be positioned to regulate downward flow; during production operations, the same choke mechanism can be adjusted to regulate upward flow. This dynamic repositioning capability enables the subsea tree to adapt to different operational modes without physical reconfiguration.
2Ease of operation
If the choke is fixed in position for production operations, then flow control is simple, but the subsea tree cannot efficiently handle injection operations requiring flow reversal
Solution Approach 1:
The choke insert is designed to be movable within the choke block, capable of being repositioned between different locations. For production operations, the choke can be positioned in a first location optimized for upward flow control. For injection operations, the same choke can be moved to a second location that optimizes downward flow regulation. This dynamic repositioning maintains operational simplicity while providing the flexibility needed for bidirectional flow management.
3Reliability
If the subsea tree requires reconfiguration when switching between injection and production modes, then specialized optimization is possible, but operational downtime increases
Solution Approach 1:
The subsea tree employs a universal design where the same structural components serve both injection and production functions. The master block with its centrally located flow bore, the swab valve positioned to control flow from the wellbore, and the master valve configured to regulate flow to the surface can handle both upward production flow and downward injection flow. This eliminates the need for physical reconfiguration when switching between well types, thereby minimizing downtime and maintaining operational efficiency.
Solution Approach 2:
The subsea tree is pre-configured with bidirectional flow capability from the outset. The choke block is designed with the capacity to accommodate and regulate flow in either direction, and the valve positions are selected to be effective for both injection and production modes. This preliminary design consideration ensures that when operational mode needs to change, no time-consuming reconfiguration is required, as the system is already prepared to handle either flow direction.
4Reliability
If maintenance requires removing and replacing the entire subsea tree, then component reliability is maintained, but operational downtime and costs increase
Solution Approach 1:
The subsea tree is divided into modular segments, with the choke insert being a distinct, removable component housed within the choke block. During maintenance operations, only the choke insert needs to be removed and replaced, rather than the entire subsea tree. This segmentation allows for quick replacement of the specific component requiring maintenance while leaving the rest of the subsea tree in place, thereby maintaining reliability through component replacement while minimizing operational downtime and associated costs.
Data Source
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AI summary
A subsea tree for use with a well includes a master block that has a flow hub located at the top of the subsea tree, a flow bore in fluid communication with the well, a swab valve, and a master valve. A choke block is coupled to a side of the subsea tree and includes a choke in a flow passage of the choke block. The swab valve is selectively closed so that fluid flowing through the master block is directed through the choke in the choke block. A method for operating the subsea tree, includes directing flow of a first fluid into the flow bore of the subsea tree, through the choke of the choke block, and then into the flow bore of the subsea tree. The method includes reversing flow of a direction of a second fluid through the subsea tree.