Cased hole logging is an important part of oil and gas well analysis, but it can also seem complicated if you’re new to the industry. Don’t worry – this FAQ guide will walk you through the basics so you understand this key well-logging technique. Would you be ready to learn more? Let’s get started!
What Is Cased Hole Logging?
Cased hole logging refers to well logging operations that are conducted after the drilling and casing of a well. Unlike open-hole logging, which occurs during drilling before the casing is installed, cased-hole logging allows you to evaluate the subsurface through the steel casing.
Why Is Cased Hole Logging Important?
There are a few key reasons why cased hole logging is so vital:
- It provides critical information about your well’s performance and production capacity.
- You can identify problems or issues that may need to be addressed.
- It enables you to make informed decisions about current and future operations.
- Regulatory agencies often require periodic case hole logs.
So, this type of well logging gives you the data you need to keep your wells producing optimally.
What Tools Are Used?
Cased hole logging utilizes specialized instruments that are designed to evaluate well conditions and formation properties through steel casing. Some common cased hole tools include:
- Cement bond tools to analyze cement integrity
- Neutron porosity tools to measure formation porosity
- Gamma ray tools to characterize formation lithology
- Resistivity and micro resistivity devices to determine water saturation
The specific tools used depend on your well objectives and the casing’s thickness and composition.
How Is the Data Analyzed?
The data from case hole logging tools is recorded digitally and is then analyzed by specialized software and experienced log analysts. Key things they evaluate include:
- Cement bond quality and channels
- Formation porosity, permeability, and fluid saturation
- Reservoir boundaries and oil/gas/water contacts
- Production zones and hard spots
- Corrosion and casing integrity
By combining various case hole data sets, analysts can provide a comprehensive assessment of well conditions.
What Are the Limitations?
While cased hole logging is extremely useful, it does have some limitations:
- Resolution is lower compared to open-hole logging.
- Not all parameters can be measured directly through casing.
- Cement and casing quality impact results.
- Specialized tools are required that may have accessibility limitations.
- Uncertainty is greater vs. open-hole data.
Even with these limitations, though, cased hole logging remains an indispensable well-analysis technique.
Now you have a solid understanding of cased hole logging and why it’s so important for well management. With this FAQ knowledge guide under your belt, you’ll be able to talk about logging operations with confidence. Ready to put your new skills into action? Get out there and start casing those holes!