WDC Series Wellhead Desanding Cyclone
Overview
Cyclotech has developed a new generation of desanding systems specifically to separate solids from multi-phase well streams. The Cyclotech WDC Series Wellhead Desanding Cyclone can be applied at all wellhead gas: liquid ratios ranging from 100% liquid (0% gas) to 100% gas (0% liquid). This technology allows the separation of sand upstream of the production chokes, manifolds and separators which can have the following benefits:
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Protection of chokes, flow-lines and manifolds from erosion;
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Protection of downstream equipment from erosion / corrosion and blockage;
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Reduced Production Separator sand-jetting requirements;
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Increased production above limiting sand-free rates.
Applications for this technology lie in both permanent production systems (such as unconsolidated reservoirs or proppant flowbacks) and temporary service systems (such as well workover services, start up and underbalanced drilling operations).
Principle of Operation
A Wellhead Desanding Cyclone has no moving parts and achieves solids separation from a multiphase well stream by virtue of a pressure drop across the cyclone. A solids laden multiphase flow is forced under pressure into the inlet section of the cyclone via a tangential inlet port. This, together with the presence of a gas phase, causes the fluid to spin at a very high velocity, which creates a high g radial acceleration field. The solid particles, being the densest phase, are forced outwards to the hydrocyclone inner wall. Here, through internal hydrodynamic forces, the solids are ejected from the apex of the cyclone while the rest of the multiphase flow exits counter currently via an axial port adjacent to the inlet. The separated solids are collected in a separate solids accumulator, which can be periodically purged, on line without interruption to the Wellhead Desanding Cyclone operation. This negates the requirement for duty/standby operation.which respresents a significant advantage over conventional filter pot equipment.
Selection
The Cyclotech WDC Series Wellhead Desanding Cyclones are bespoke designed for each application. Key to the design is the accommodation of the gas phase to ensure that the presence of gas improves, rather than depresses, the separation performance. It is for this reason that a standard solid/liquid cyclone should NOT be used for multiphase desanding applications. The WDC Series cyclones are provided in the form of a single or, in certain cases, multiplicity of cyclone inserts housed inside a vessel designed to suit the application.
System Design
Given the difficulty with many applications in predicting with any accuracy the range actual wellhead flowing conditions, the key technical challenges that Cyclotech have overcome in developing this new generation of WDC technology are:
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To design a cyclone geometry which accommodates the gas phase while maximizing the operational envelope to variations in the inlet gas liquid ratio
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To accurately model operational pressure drop and solids separation performance. This enables correct sizing which is critical to the successful design and implementation of the technology to a given application.
Standard Wellhead Desanding Cyclones are available for operation upstream or down stream of the choke with pressure ratings of up to 15,000 psi. Above pressure ratings of ANSI class #1500, our WDC vessels are API 6A coded bespoke units, manufactured from machined forgings. Systems can be manual or fully automated for operation on Normally Unmanned Installations (NUIs).
Materials of construction for WDC Series Cyclone Inserts are typically Duplex Stainless Steels, which are either surfaced hardened or tiled with Reaction Bonded Silicon Carbide, an extremely hard wearing advanced ceramic. Vessels, pipework and valving materials can be upgraded for applications with high H2S and/or CO2 levels.
Separated Sand Handling
The handling of the sand separated in the Wellhead Desanding Cyclone is often a major challenge especially for high-pressure systems. Cyclotech can offer solutions incorporating:
These solutions will involve the use of our proprietary sand transport technologies which include the
SANDSCAPE® (solids fluidization and eduction) and the
PLD (slurry Pressure Let Down) devices.
Leased Equipment
Cyclotech own fleet of flexible, production scale (up to 100,000 MMSCFD) skid mounted Wellhead Desanding packages available on long or short term lease contracts. The equipment is available globally but supported at a local level which allows Cyclotech to assist the customer in the design, integration, operation and manning of these temporary systems. A
5k psi Wellhead Desanding system will be available for rental from February 2009.
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You have sand erosion and/or blockage problems;
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You have wells that can only operate at low sand free rates;
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You have gas wells fractured with proppant systems;
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You have an onerous well service programme;
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You have a requirement to lease a Wellhead Desanding Cyclone system.
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