Schlumberger

Gun Swivel

Low-side shooting capability

Shooting only the low side of the hole is often preferred for sand control in highly deviated completions.

A gun swivel allows the gun string to rotate with respect to the tubing string. Asymmetrically loaded guns orient themselves because of the well deviation and their own weight (nonaxial center of gravity). Rotation is aided by roller adapters. The swivel is inserted either in the tubing string above the firing head or between guns. Axial and radial loads are supported by the use of both thrust and journal bearings.

Gun string positioning

To improve subsequent gravel packing in unconsolidated formations in deviated wells, the high side of the casing is not perforated. Therefore, guns are partially loaded to shoot only the lower 180 degrees of the casing.

The weight distribution caused by the missing charges on the upper side of the gun is usually sufficient to orient the guns downward, but a swivel is required to allow free rotation. The shooting ranges are aligned by placing orienting adapters between the guns.

Compatibility with other firing systems

A 3.06-in OD swivel is used with the hydraulic delay firing head HDF and the differential pressure firing head DPF because it allows a pressure path to the firing head with a debris deflection tube, preventing the accumulation of debris that can block the flow path. This model is used with gun diameters down to 2.875-in OD.

A 4.5-in OD fullbore swivel has a 2-in ID, which allows the use of the mechanical and trigger charge firing heads BHF and TCF.

Intragun swivel inserted between two guns

A 4.5-in intragun swivel, compatible with the ballistic transfers of the 4.5-in gun system, may be inserted between two guns anywhere in the gun string.