Downhole Capsule With Bulkhead For Dual ESP Modules
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Solution Overview
Problem
The existing electrical submersible pump (ESP) systems require frequent retrieval for maintenance or repair, which is time-consuming, especially for offshore installations, due to the need to pull the entire tubing assembly, and there is a lack of efficient solutions for simultaneous operation or redundancy of pump assemblies.
Innovation Solution
A downhole capsule design that houses two ESP modules with a bulkhead dividing the capsule into upstream and downstream chambers, allowing for simultaneous operation or selective activation of each pump, and includes a power lead and sensor lines that can be sealed within the capsule to reduce the need for dedicated communication lines and facilitate easier maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single ESP assembly is used, then the device complexity is low, but the reliability is reduced due to lack of backup and frequent maintenance requirements
Solution Approach 1:
The pump system is segmented into two independent ESP modules housed within a single capsule, allowing each module to function autonomously. This segmentation enables redundancy (improving reliability) while containing complexity within a unified structural envelope (the capsule), thus resolving the contradiction between reliability and device complexity.
Solution Approach 2:
Two complete ESP assemblies are nested within a single capsule structure, with each ESP module containing its own motor and pump components. This nesting approach allows the system to achieve higher reliability through redundancy while managing device complexity by organizing multiple independent systems within a unified outer structure.
2Ease of repair
If the entire tubing assembly is pulled for maintenance, then the pump can be repaired or replaced, but the loss of time is significant especially for offshore installations
Solution Approach 1:
The ESP system is segmented into modular units housed within a capsule that can be independently retrieved from the tubing string. This segmentation allows maintenance crews to retrieve only the capsule containing the failed ESP module rather than pulling the entire tubing assembly, significantly reducing maintenance time while maintaining ease of repair.
Solution Approach 2:
The ESP module requiring maintenance is extracted from the capsule, which itself can be extracted from the tubing string without pulling the entire tubing assembly. This two-stage extraction process isolates the maintenance task to a specific module, reducing the time loss associated with retrieving and replacing entire tubing strings.
3Measurement precision
If a dedicated sensor line is used for reservoir sensing, then the measurement precision is high, but the device complexity increases due to additional communication lines
Solution Approach 1:
The sensor line for reservoir sensing is merged with the power cable that already exists in the system. This combining approach maintains measurement precision by providing dedicated sensing capability while reducing device complexity by eliminating the need for separate communication lines, as the sensor signals are superimposed on the existing power cable infrastructure.
Solution Approach 2:
The power cable serves multiple functions: it provides electrical power to the ESP motor and simultaneously carries sensor signals for reservoir monitoring. This multi-functionality maintains measurement precision through dedicated sensing while reducing device complexity by eliminating the need for separate dedicated communication lines.
Data Source
AI summary
Upstream and downstream pump assemblies are mounted in a capsule having a bulkhead between the upstream and downstream pump assemblies, dividing the capsule into upstream and downstream chambers sealed from each other. In a dual operation mode, well fluid flows through the inlet of the capsule into the upstream chamber, where it is pumped to a first pressure level by the upstream pump assembly and discharged into the downstream chamber. The downstream pump assembly then pumps the well fluid to a second pressure level and discharges the well fluid out the outlet of the capsule. The assembly has also an upstream pump assembly only operational mode and a downstream pump assembly only operational mode.