Sand Filtration Fundamentals

Formation and fracturing sand moving at high pressure out of the wellbore pose intrinsic hazards. These include the immediate risk of failed/washed-out surface equipment. In an extreme case, sand can wash out an ESD valve, control valve, piping or elbow in under 1 minute. Sand can also clog or otherwise damage separators or control and measurement equipment.

The hazards posed by sand wash-out include fire, explosion, well blowout, equipment damage or even loss of life. Sand wash-outs are also expensive, requiring repair/replacement of the damaged equipment, at times even leading to a facility shut-down and/or pipeline pigging. In addition to the acute risks, chronic low sand volumes can gradually erode equipment, imposing additional maintenance and repair costs over the longer term.

Sand filtration is a critical performance item for any high-velocity well with entrained sand. The majority of natural gas and oil wells benefit from sand filtration during well testing, flowback/cleanup, flush production and, potentially, throughout the well’s producing life.

Sand filtration is especially important for liquids-rich gas wells stimulated through hydraulic fracturing. Long-leg horizontal wells may receive 1,000-3,000+ tonnes of fracturing sand, a portion of which flows back to surface. Certain unconventional reservoirs, such as the Montney, are heavy sand producers.

Traditional desanders – from every provider except Dynacorp – are pure velocity knock-outs. They are not filters. Desanders capture coarser material as the production stream enters the chamber and loses pressure and velocity. Fine material passes through, continuing into the producer’s infrastructure.

Desanders take care of the acute risks – equipment washout. But they do not address the long-term damage from gradual erosion caused by continual carry-over of fines. Once full, traditional desanders also allow carry-over of coarser material.

Nor can traditional desanders handle slugs of denser fluids. When slugs appear, the accompanying sand is passed through or the desander is clogged and the well needs to be shut-in.

Dynacorp provides genuine filtration. The two-stage system captures courser material and filters particles down to 50 microns in diameter.

This approach eliminates both the short-term/acute risks of washout and the longer-term risks of gradual erosion. It delivers industry-leading performance in wellhead sand filtration. It achieves production integrity, purifying your hydrocarbon stream and protecting your infrastructure.

Dynacorp’s in-house concept is an industry-wide innovation, with a patent-pending. It provides both knock-out and filtration. Larger/heavier particles fall out as the raw production enters the vessel and the velocity and pressure drop. Smaller/lighter particles are then physically screened.

This system is designed right from its conceptual stage to achieve sand retention. It has been proven to perform over hundreds of installations. Dynacorp provides several distinct configurations to suit well characteristics and the producer’s overall needs, with a number models in each configuration for varying well rates, fluid and sand volumes.