Gravity Desanding Vessel With Filter Polishing for Multiphase Sand Separation
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Solution Overview
Problem
Current desanding apparatuses for oil and gas wells face challenges such as equipment abrasion, temporary solutions, difficulty in separating sand from multiphase effluents, and high maintenance costs, particularly in handling high-pressure and toxic environments, with existing systems either being inefficient or hazardous for workers.
Innovation Solution
A desanding apparatus that utilizes a cylindrical, pressurized vessel with a baffle to separate sand from a fluid stream through gravity, allowing sand to fall out of the fluid stream and accumulate in a lower section, enabling easy removal and minimizing downtime, while also incorporating a filter for polishing the liquid portion to ensure continuous operation and reduced maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a P-Tank is used for desanding, then sand can be removed from the fluid stream, but the large size of the P-Tank restricts the maximum operating pressure to 1,000-2,100 kPa
Solution Approach 1:
The desanding process is divided into multiple stages: a first desanding stage using a separator and a second desanding stage using a cyclone device. This segmentation allows each stage to be optimized for different pressure ranges, with the cyclone operating at higher pressures while the separator handles lower pressure stages, thereby resolving the contradiction between effective sand removal and pressure limitations.
Solution Approach 2:
A multi-phase pump is introduced as an intermediary device between the separator and the cyclone device. This pump acts as a mediator that transfers the fluid stream from the lower pressure separator environment to the higher pressure cyclone environment, enabling the system to achieve both effective sand removal across different pressure stages and high operating pressures.
2Stress or pressure
If pressure control is placed on the well to protect the P-Tank, then the P-Tank is protected from overpressure, but pressure reduction increases gas velocity which makes sand-laden effluent more abrasive
Solution Approach 1:
The pressure control function is segmented between two devices: the separator operates at lower pressures to protect equipment, while the cyclone device operates at higher pressures to reduce gas velocity and minimize abrasion. This segmentation allows pressure control to be optimized for different stages of the desanding process, resolving the contradiction between protecting equipment and reducing abrasion.
3Reliability
If hydrocyclone devices are used for separating particles, then separation can be achieved by centripetal force, but they have difficulty separating sand from effluents with more than two phases and have pressure drop issues
Solution Approach 1:
The separation process is segmented into two distinct stages: a first desanding stage using a separator that handles multiphase effluents (gas, liquid, and sand) and a second desanding stage using a cyclone device that further separates particles. This segmentation allows each device to be optimized for its specific function, with the separator handling the complexity of multiphase flow and the cyclone providing enhanced particle separation, thereby resolving the contradiction between separation capability and adaptability to multiphase effluents.
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 separates sand from multiphase fluid streams, reduces operational space requirements, and allows for easy cleaning and maintenance, enhancing separation efficiency and safety by enabling on-the-fly sand purging and backflushing, thus addressing the limitations of existing technologies.
Implementation Method 1
directs the fluid stream along an annular path, allowing sand to fall out under gravity
Implementation Method 2
incorporating a filter stage for polishing the liquid
Data Source
AI summary
Apparatus and method disclosed herein related to first stage gravity separation of liquid and sand from a gaseous fluid stream in an upper portion of a desanding vessel, sand separating from gas along an annular path about a shell, the sand-free gas directed back down into the shell to a fluid outlet for removal as a product stream. A second stage gravity separation of sand from accumulated liquid occurs in a lower section of the vessel. An optional final or polishing stage of the liquid is conduct using a filter. A stacked-plate filter can extend an intake opening of the fluid outlet into the accumulated liquid. Further, the filter plates can be configured with parallel filtering of gas/liquid separation for gas intake above, and with liquid/sand separation below including pressure management of the filter operation.