Perforation Depth Control Log (PDC Log) in Drilling & Well Completion

A Perforation Depth Control Log (PDC Log) is a critical tool used in well completion operations to accurately determine the depth of perforation charges placed within the casing string. This log provides vital information for:

1. Ensuring Proper Perforation Depth:

• The PDC log allows engineers to verify that perforation charges are placed at the intended depth within the casing, optimizing well stimulation and production.
• This ensures the charges are positioned effectively to create holes in the casing and the formation beyond it, enabling well production.

2. Avoiding Damage to Equipment and Formation:

• Accurate depth control prevents perforation charges from being placed in unintended zones, like within the casing or in a different formation layer.
• This protects equipment from damage and avoids unnecessary perforation of formations that are not meant to be accessed.

3. Optimizing Production:

• Correct perforation depth is crucial for maximizing production.
• If charges are placed too shallow, the well may not be effectively stimulated.
• Conversely, if they are too deep, they may damage the formation or create a larger fracture than necessary, leading to potential instability and reduced production.

How the PDC Log Works:

The PDC log is typically generated using a specialized tool called a "depth control tool" which is run downhole alongside the perforation charges. This tool:

• Measures the depth of the charges relative to the casing
• Records the information electronically
• Provides real-time feedback to operators during the perforation process

Types of PDC Logs:

Several types of PDC logs are available, including:

• Mechanical PDC logs: Rely on mechanical sensors to measure the depth.
• Electronic PDC logs: Use electronic sensors for depth measurement and provide more accurate and detailed information.

Importance in Well Completion:

The PDC log is a vital component of well completion operations. It ensures that perforation charges are placed precisely where they are needed, maximizing production and minimizing risks. The information provided by the log allows for optimized well stimulation and production, contributing to a safer and more efficient well completion process.