Sand-Jet Perforating with Annular Fracs

The NCS Mongoose Frac® system is the simplest multistage completion technology in the field. It requires no sliding sleeves, no perforating guns, and no pumpdown plugs or sand plugs. It uses our exclusive resettable frac plug to isolate stages and high-velocity abrasive slurry to cut perforations. Fracs are pumped down the coiled-tubing/casing annulus. The Mongoose Frac system is typically used with cemented completions. Although it requires more time per stage than our Multistage Unlimited sliding-sleeve system, it is a practical option when wells are already cased or when completion economics and design dictate.

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Sand-friendly, resettable frac plug

The unique Multistage Unlimited resettable frac plug isolates the frac zone from the hole below and anchors the isolation assembly during sand-jet perforating and frac pumping.

Sand-jet perforating sub

Sand-jet perforating subs are heavy-wall components with engineered tungsten-carbide nozzles. The number, spacing, and phasing of nozzles is matched to each job. To cut perforations, sand-laden fluid is pumped down the coiled tubing and through the nozzles. The high-velocity slurry cuts through the casing and cement and into the formation in about 8 minutes. The resulting perforations serve as excellent initiation points for fracturing.

Typical completion sequence

Perforating

 

 

The completion begins at the toe of the well, with the frac-isolation assembly positioned at the lowest planned stage. Depth correlation is aided by the mechanical casing collar locator. The resettable frac plug isolates the zone from the well bore below and anchors the assembly. Abrasive slurry is pumped through the perforating sub nozzles. High-velocity jets cut through the casing and cement and into the formation. To accelerate the frac process and to conserve water and frac fluids, the pad and frac can be circulated down the annulus to the frac zone before jet perforating begins.

Annular frac

 

 

When the perforations are complete, frac pressure is applied down the annulus to peform the frac. The coiled tubing serves as a deadleg for monitoring actual pressure at the frac point to assist in adjusting pad size, sand concentration and ramp, fluid viscosity and pump pressure in real time. With planning and coordination, stages can be completed quickly and smoothly at a rate of more than one per hour. After the last stage, the isolation assembly is retrieved, and the full-open wellbore is ready for production.

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