Offshore Gravity-Based LNG Storage and Offloading Facility Design
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Solution Overview
Problem
The cost of LNG storage and offloading facilities has increased significantly, and existing designs focus mainly on storage tank size optimization and berth utilization, necessitating the exploration of alternative designs for more economical and efficient solutions.
Innovation Solution
An integrated storage/offloading facility that includes a gas processing facility, liquefaction facility, and a subsea or trestle-based cryogenic pipeline system, allowing for transportable and modular construction, with a boil-off gas reliquefaction unit and ballast system for stable positioning, enabling efficient LNG transfer and storage at a selected water depth, and accommodating multiple LNG carriers with a multilateral footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional onshore LNG storage and offloading facilities are used with elevated supporting trestle structures, then LNG transfer reliability is maintained, but facility cost increases significantly
Solution Approach 1:
The patent inverts the traditional approach by moving the storage facility from onshore to offshore location. Instead of bringing the jetty and storage tanks to the gas field, the facility is positioned on the seabed near the gas field, with LNG carriers berthing alongside the submerged storage facility. This inversion eliminates the need for expensive elevated trestle structures while maintaining reliable LNG transfer operations.
Solution Approach 2:
The patent transitions from a two-dimensional onshore layout to a three-dimensional offshore configuration. The storage facility is positioned on the seabed (vertical dimension), with LNG carriers berthing at various positions around the facility. This spatial reconfiguration allows direct subsea pipeline connections without requiring elevated structures, reducing construction costs while maintaining transfer reliability.
2Productivity
If storage tank size is increased to leverage economies of scale, then berth utilization improves, but facility complexity and cost increase
Solution Approach 1:
The patent divides the storage facility into multiple modular tank units that can be independently configured. Instead of one large complex tank, multiple smaller tanks are arranged around the central platform, allowing flexible berth utilization while maintaining manageable facility complexity. Each tank can be independently maintained or upgraded without shutting down the entire facility.
Solution Approach 2:
The offshore storage facility is designed to serve multiple functions: LNG storage, LNG loading to carriers, boil-off gas processing, and potential relocation to different gas fields. This multi-functionality improves berth utilization across different operational scenarios while avoiding the complexity of separate dedicated facilities for each function.
3Stability of the object's composition
If fixed onshore LNG production plants are used, then operational stability is maintained, but adaptability to different locations and market demands decreases
Solution Approach 1:
The patent creates a dynamic facility that can be relocated from one gas field to another. The modular construction and standardized components allow the entire offshore storage and offloading facility to be dismantled, transported, and reassembled at different locations. This provides location adaptability while maintaining operational stability through proven design and procedures.
Solution Approach 2:
The facility is designed with pre-engineered modular components that can be assembled in a standardized sequence. Ballast tanks are pre-configured for stable positioning, and the modular tank modules are pre-fabricated with standardized connections. This preliminary design work enables rapid deployment at new locations while ensuring operational stability from the outset.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces the overall cost of LNG projects by optimizing facility design, enhancing stability and flexibility, and minimizing boil-off gas losses through reliquefaction, while allowing for relocation and efficient berthing of LNG carriers.
Implementation Method 1
a cryogenic pipeline (subsea or on a trestle) to a storage facility for receiving the product stream of LNG from the liquefaction facility
Implementation Method 2
the integrated storage/offloading facility includes a ballast storage compartment, and the integrated storage/offloading facility is settled into the selected location by way of addition of a ballasting material to the ballast storage compartment
Data Source
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AI summary
An LNG production plant positioned at a production location adjacent to a body of water is described. The LNG production plant comprises a plurality of spaced-apart facilities including a first facility and a second facility, each facility provided with plant equipment related to a pre-determined function associated with the production of LNG, wherein the first facility is an onshore facility and the second facility is an integrated storage/offloading facility arranged on a gravity-based structure having a base that rests on the seabed at a selected location within the body of water.