Hollow Carrier Gun Survival

All hollow carrier gun systems swell when being initiated and must survive the forces of the shaped charge detonations without cracking, splitting or swelling too much. This will ensure the user is able to retrieve the spent gun system safely and without getting stuck after initiation.

There are two major groups of hollow carrier guns, liquid guns and gas guns that can be used in gas and/or in liquid. The liquid gun can only be shot in a fluid with the density of water (1.0g/cc or greater) in the casing around the gun. The gas gun, on the other hand, is qualified to survive in air. Engineering testing with the gun carrier has been conducted in air at ambient pressure resulting in the gun surviving in both fluid and gas. Shooting a liquid only gun in gas will result in major problems and can lead to the loss of the well, therefore always follow the recommendations provided by the manufacturers.

The following pictures are provided as references and show catastrophic hollow carrier gun body failure:

All carrier guns swell when initiated. However, the amount of swell can vary depending on the following factors:

?       Gun diameter

?       Gun wall thickness & material grade

?       Charge size & Shot density (amount of explosives)

?       Shot phasing

?       Well bore pressure

?       Well bore fluid/ gas type and density

The gun swell can range from approximately 10% in small guns shot in low-pressure wells to less than 1% in larger guns shot at high pressure. The guns are designed for maximum performance and survivability; therefore hollow carrier guns should not split, crack or exhibit any major deformity after initiation. The charge and gun must be designed and tested as a system to ensure optimal performance and gun survivability.

Many parameters and factors affect the maximum swell and survivability of a hollow carrier gun system. There is no hard and fast rule of which gun size can be safely deployed into any giving well bore as it depends on the customers personal preference, well bore environment, fishing contingencies, well bore ID (drift ID + Casing Burr)or profiles to name a few. Always consider the maximum swell when planning a job and its contingencies.

The API 19b Section 6 will serve as a guide to gun survivability, swell and gun bending.

For more information, visit DynaEnergetics.com.