Further compounding the challenge of solids recovery is the ever-decreasing size of sand particles now widely used in frac operations; smaller particles are harder to separate from the flowstream but are just as damaging to downstream equipment – in many cases smaller particles can be more invasive and destructive.
Even before sand nudged out the more costly ceramic and resin-coated materials as the preferred proppant in frac operations, cyclonic traps have been the most common method of sand management. Most of these cyclonic traps, however, are unable to generate the requisite level of centrifugal force to separate the finer particles.
To redress the problem of fine particle removal has often meant adding filtration systems to compensate for inefficient cyclonic traps. But filter systems introduce unwanted pressure differentials that inhibit flow and production levels. Moreover, their screens must be constantly removed and cleaned out or replaced, and the denser the screen – to capture finer particles – the greater the pressure differential.
Another common method of sand management is the static, gravity-based sand separator, which functions much like similar devices for separating oil, gas and water. Unfortunately, it too is inefficient, especially when the flowback contains oil emulsion. Achieving the necessary degree of sand recovery and flowstream purity often entails staging multiple sand separators and even pairing them with a filtration system. All this adds up to more equipment, more personnel, expanded logistics, a bigger footprint and higher costs.
Developing a new system
A new development in hydrocyclones is the TETRA SandStormTM advanced cyclone technology, which is engineered to generate calculated centrifugal forces that separate the targeted particle sizes from the flowstream.
The cyclone uses a proprietary design that maximises centrifugal forces, capturing the smallest of particles while remaining below the excessive velocities that can damage equipment. It has no moving parts, imposes no flow restrictions on the flowstream, has a smaller footprint than competing systems and is more efficient than conventional sand separators and other cyclonic traps, achieving up to 99% sand recovery.
This is an abridged version of an article originally published in Issue 1 2021 of Oilfield Technology magazine. To read the full article, follow the link to the issue and turn to page 39: https://bit.ly/3cAmyDU. And to sign up to receive a free regular digital copy of the magazine, follow this link: https://www.oilfieldtechnology.com/magazine/oilfield-technology/register/
Read the article online at: https://www.oilfieldtechnology.com/special-reports/05042021/innovating-against-the-grain/
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