Perforate or reperforate long intervals using controlled underbalance

CIRP completion insertion and removal under pressure equipment is used to insert and retrieve long gun strings under wellhead pressure when the surface pressure control equipment, or lubricator, is shorter than the gun string. With CIRP equipment, you can perforate a long interval under the optimal underbalance condition, and then retrieve the guns without exposing the formation to damaging kill fluids. You can also reperforate wells without killing them, minimizing production loss and formation damage. Multiple perforating runs can be completed without killing the well between runs.

In extended-reach wells, for example, the perforated interval may be longer than the maximum gun string that can be conveyed, mandating multiple runs. The length of the surface lubricator determines the length of the gun string interval between two connectors. the CIRP equipment is compatible with all Schlumberger hollow carrier perforating guns measuring 2 to 4 1/2 in.

Improve operations and reduce personnel exposure due to safer design

The CIRP equipment consists of three main components:

• connectors, which tie the gun sections together and provide sealed ballistic transfer
• deployment stack, which locks and unlocks connectors under pressure and supports the disconnected string
• two gate valves, which isolate the lubricator from well pressure to contain well pressure when short gun sections are being picked up or laid down.

The CIRP equipment comprises conventional lubricators, two or more gate valves, and a deployment stack with dual actuators. The lower actuator is a no-go ram with a lock to position the connector. The upper actuator is a guide ram with a rack to operate the locking mechanism on the connector. The system’s connector is the mechanical and ballistic link between the gun sections deployed in the lubricator. The lock and rack allow connection or disconnection of the connectors under pressure inside the lubricator assembly. Gun string segments matching the lubricator length can be installed or removed using the gate valve to close in the well before bleeding off and opening the lubricator during each step of the operation. Closing the gate valve allows the pressure in the lubricator to be bled off. It can then be disconnected for insertion or removal of gun sections. The sealed ballistic transfers seal the loaded guns before they are shot. 

The firing head is usually deployed separately, not attached to a gun, when pressure is equalized in the riser. Afterward, it is connected to the gun string with CIRP equipment. connector. The CIRP equipment allows completely remote operations, minimizing personnel exposure.