What Is Radial Cement Bond Log?

The Radial Cement Bond Log is an advanced downhole logging tool, mainly used to evaluate the bonding quality of the cement ring between the casing and the formation after cementing operations in oil and gas wells. It combines two key technologies:

The Principle of Acoustic Logging - By emitting acoustic signals and receiving the acoustic waves returning from the casing, cement ring and formation to evaluate the cementation condition of cement.

Eight-Sector Measurement- The circumferential direction of the casing is divided into eight independent sectors (usually each sector covers a 45-degree angle), to provide circumferential non-uniform cementation information.

Memory Working Mode- It is equipped with a built-in battery and a large-capacity storage chip. During the logging process, data is recorded inside the instrument. After the instrument is removed from the well, the data is replayed and analyzed. This contrasts with the traditional "cable transmission" logging.

The core measurement contents include:

◆ Full-wave Acoustic Waveform

Records the complete sonic waveform, which is used to generate Variable Density Log (VDL) images and determine Cement Bond Log (CBL) amplitude, evaluating the bonding quality of the first interface (casing–cement) and the second interface (cement–formation).

◆ 8-Sector Amplitude

Measures sonic amplitude at eight equally spaced azimuths around the casing circumference to pinpoint the exact orientation of cement voids or poor bonding.

◆ Memory-Mode Operation

No Wireline Required– It can be run on drill pipe, tubing, or coiled tubing; ideal for highly-deviated, horizontal, and complex-geometry wells where wireline conveyance is problematic.

Saves Operation Time– logging is performed while tripping or during a conditioning run, improving operational efficiency.

◆ High-accuracy measurement
The tool carries eight piezo-ceramic transmitters and receivers, each covering a 45° sector, providing 360° evaluation of cement bond quality around the casing and displaying the results in an intuitive grayscale image.

◆Strong Interference Immunity
Unaffected by heavy mud, oil-based mud, or variations in casing thickness, ensuring reliable data in challenging well conditions.

◆Adaptability to High Temperature & High Pressure
Rated to 175 °C and 100 MPa, suitable for high-pressure, high-temperature wells.

 

Our Radial Cement Bond Log

 

◆ Advantage

Solving The Logging Problems of Complex Wells-It is a key technology for cement evaluation in high-angle, horizontal, and "three-high" (high-pressure, high-temperature, high-corrosion) environments.

Accurate Diagnosis-It can effectively identify local defects in the cement ring, providing precise basis for subsequent well repair operations such as cement extrusion and hole filling, and avoiding misjudgment.

Flexible Operation-The memory based design lowers demands on surface equipment and rig-up, making it especially suited for remote locations or offshore platforms.

High Safety-In wells with strict pressure control, the absence of a dynamic-seal wireline BOP stack reduces operational risk.

◆ Disadvantage

Non-Real-Time Data

As the tool operates in memory mode, data quality cannot be monitored in real time. If the tool malfunctions or is mis-configured, the problem will only be discovered after the tool is pulled out of the hole, potentially causing a failed run and the need for re-logging.

Cementing Quality Evaluation

Conduct hole and channel inspections on the first interface (casing-cement). The bonding degree assessment of the second interface (cement-formation) is often used for quality confirmation after the completion of oil and gas wells

Horizontal Wells & Inclined Wells

In highly deviated Wells and horizontal wells, cable-free logging is achieved by using the memory mode to ensure the integrity of logging data.

Deep Wells & High-Temperature Wells

It can withstand a pressure of 100 MPa and a temperature of 175 ℃, and is suitable for cementation detection in deep high-pressure and high-temperature oil and gas Wells.

Quality Evaluation of New Well Cementing

It is used to detect the cement bonding quality after well completion to ensure good sealing of the oil-water layer.

Secondary cementing evaluation of old Wells

It is applicable to the re-examination of cementing quality in old Wells and guides perforation and workover operations.

Evaluation of Staged Fracturing Wells

Evaluate the quality of the cement seal at the position of the bridge plug or sliding sleeve used for staged fracturing to ensure that there is no interlayer communication during fracturing.

A-One Oil Radial Cement Bond Log with the technical advantages such as all-round eight-sector acoustic imaging, double-layer CBL/VDL signals, and offline large-capacity storage, has become an important means of cementing quality evaluation, especially demonstrating significant adaptability and cost advantages in complex operating environments such as horizontal Wells, inclined Wells, and deep Wells. Its main disadvantages lie in its sensitivity to the acoustic impedance of well fluid, the size of the instrument and the requirements for post-treatment, which need to be supported by a corresponding software and maintenance system. Overall, with the improvement of domestic production and technological iteration, the application prospects of this tool in domestic and international oil and gas exploration and development are broad.

It is an important innovation in the traditional acoustic cement bonding logging technology. The memory design has solved the problem of instrument transportation in complex-structured Wells, and the eight-sector measurement has provided an unprecedented circumferential resolution capability. It is an important "quality inspection bridge" connecting drilling engineering and production testing.

Welcome to contact us to learn more about our tools via e-mail info@a-oneoil.com,A-One Oil provide customized Radial Cement Bond Log solutions for complex well conditions, to help ensure the safety, accuracy, and efficiency of your oilfield projects.