Production Riser Insertion Using Protective Sleeve Removal
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Offshore hydrocarbon production risers face premature replacement due to changing fluid compositions and flow regimes over the life of an oil and gas field, leading to increased capital and operating expenses from frequent design and installation changes.
Innovation Solution
A production riser system that allows for diameter change by using a protective sleeve and temporary retaining ring, which can be removed and replaced with an insert riser, enabling adjustments without full replacement, utilizing intervention coiled tubing to expose a polished seal face for seal elements and locking ring installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a production riser is replaced with a different diameter or metallurgy to meet changing design requirements, then the riser can accommodate new flow regimes and fluid compositions, but capital and operating expenses increase due to offshore installation vessels and lengthy procurement processes
Solution Approach 1:
The patent employs a nested structure where an inner riser is inserted within an outer riser. The inner riser can be removed and replaced independently while the outer riser remains in place, enabling rapid diameter or metallurgy changes without complete riser replacement. This nested configuration allows the system to adapt to changing design requirements while minimizing installation time and cost.
Solution Approach 2:
The riser system is divided into separable segments - an outer riser and an inner riser - that can be independently handled. The inner riser is designed as a removable component that can be extracted and replaced through a access port, allowing modular updates to riser specifications without affecting the entire riser assembly or requiring lengthy offshore installation procedures.
2Adaptability or versatility
If additional riser slots are included to allow for future riser installation, then riser replacement becomes possible, but capital expense increases
Solution Approach 1:
The nested riser configuration eliminates the need for additional riser slots or parallel riser installations. The inner riser fits within the existing outer riser volume, allowing replacement capability without requiring extra space or additional capital-intensive installation infrastructure. The access port provides sufficient opening for inner riser manipulation while maintaining the original riser footprint.
3Reliability
If the production riser is designed for early life operations, then it meets initial production requirements, but it becomes unsuitable for late life operations when fluid velocities decrease and corrosivity increases
Solution Approach 1:
The riser system transitions from a static, fixed-specification design to a dynamic, upgradable configuration. The inner riser can be replaced with different materials or diameters based on evolving operational requirements - such as increased corrosion resistance for sour gas or different diameters for changed flow regimes - allowing the system to adapt dynamically throughout its operational lifecycle.
Solution Approach 2:
The patent enables parameter changes in the riser system by allowing replacement of the inner riser with versions having different metallurgy or dimensions. This facilitates adjustment of key parameters such as wall thickness for corrosion resistance, diameter for flow velocity, or material composition for chemical compatibility, ensuring the riser remains suitable for late-life operations with changed fluid characteristics.
Data Source
AI summary
An apparatus enables modifying a riser's operating parameters for transporting production fluids from a subsea well to an offshore production facility after an initial period of production to address changes over time in the conditions of the reservoir and/or the riser without removing the original riser. An insert riser having a smaller diameter is inserted into the riser after the initial period. The original riser has a recessed seal face for receiving seal element(s) and a recessed lock groove for receiving a locking ring. An intervention coiled tubing having a sleeve removal tool is inserted into the riser to engage a protective sleeve covering the recessed seal face. The tubing is pulled to the floating structure thereby removing the protective sleeve and the temporary retaining ring from the production riser, exposing the recessed seal face. The insert riser can then be inserted into the riser and locked into place.