Actuatable Flow Conditioner for Multiphase Pumping
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Solution Overview
Problem
Multiphase mixers designed for long-term subsea deployment face challenges such as hydrodynamic slugging, sand and debris accumulation, and difficulty in starting up dead fields due to gas presence in flow lines, which compromise performance and efficiency.
Innovation Solution
An actuatable apparatus with a movable inner vessel within an outer vessel allows for adjustable annulus size, enabling improved handling of multiphase fluids, debris flushing, and liquid recirculation to enhance operating envelopes and startup capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the mixer is designed larger to handle hydrodynamic slugging, then the ability to handle variable flow rates improves, but the annulus clearance must be reduced which compromises performance at higher GVF levels
Solution Approach 1:
The patent applies the dynamics principle by making the inner vessel movable rather than fixed. The inner vessel can be actuated to change its position relative to the outer vessel, thereby dynamically adjusting the annulus clearance size. This allows the mixer to adapt to different operating conditions - larger clearance for low GVF operations and smaller clearance for high GVF operations, resolving the contradiction between handling variable flow rates and maintaining performance at higher GVF levels
2Duration of action of stationary object
If the mixer is designed for long-term deployment, then durability improves, but sand and solid debris accumulate within the volume blocking the mixer
Solution Approach 1:
The movable inner vessel enables the mixer to be actuated for debris flushing operations. By moving the inner vessel, the system can change flow paths and clear accumulated sand and solid debris from the mixer volume, preventing blockages during long-term deployment while maintaining durability
Solution Approach 2:
The system uses its own multiphase fluid flow to flush debris from the mixer volume when the inner vessel is actuated. The fluid itself serves the dual purpose of both mixing and cleaning accumulated debris, eliminating the need for external cleaning systems during long-term operation
3Productivity
If the flow splitter is self-draining into the bypass header, then liquid removal capability improves, but the pump station can be quickly emptied of liquid when starting up dead fields with gas in the flow line
Solution Approach 1:
The movable inner vessel in the flow splitter allows dynamic control of the liquid flow path. During normal operation, the inner vessel maintains the self-draining configuration for efficient liquid removal. During startup of dead fields, the inner vessel can be actuated to redirect liquid flow back into the pump station, preventing complete emptying and enabling successful startup
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
The apparatus effectively manages varying flow rates and gas volume fractions, prevents clogging by flushing debris, and ensures liquid recirculation to initiate flow from non-producing wells, thereby improving system reliability and efficiency.
Implementation Method 1
a lower annulus is formed between an outer lower portion of the inner vessel and an inner lower portion of the outer vessel. Actuating the inner vessel in the vertical direction can alter the size of the lower annulus, thereby altering an operating envelope of the apparatus.
Implementation Method 2
The multiphase mixer utilizes a large volume tank and it is advantageous to design the mixer for long-term installation on the sea floor. Because the multiphase mixer is often intended to be deployed for long periods of time, up to the lifetime of the field, it should be designed to deal with a relatively wide operating envelope in terms of both flow rate and gas volume fraction (GVF).
Data Source
AI summary
An actuatable apparatus, such as a mixer or flow splitter, is described that forms part of a multiphase pumping station. An outer tank has an upper inlet and an actuatable inner vessel disposed within the outer vessel. Multiphase fluid can pass from the outer vessel into the inner vessel though large upper openings. The inner vessel is configured to be actuatable such that the inner vessel moves in a vertical direction, thereby altering the size of an annular opening between the bottom of the inner vessel and the outer vessel. In some cases, the annular opening is adjusted to alter the operating envelope of a mixer. In other cases, the annular opening is opened to allow for sand cleaning. In yet other cases the apparatus is a downstream flow splitter, and the annulus is shut off to prevent loss of liquid phase during the startup of a dead field.