Experimental and Computational Study on Conductors Bearing Capacity in Offshore Drilling

Area of Science:

• Geotechnical Engineering
• Offshore Drilling Technology
• Wellhead Stability

Background:

• Conductor height is critical for offshore wellhead stability.
• Insufficient cement slurry return height can compromise conductor mechanical behavior.

Purpose of the Study:

• Analyze the impact of limited cement slurry return height on conductor axial load distribution and bearing capacity.
• Develop a model to predict conductor axial bearing capacity considering conductor size and cement return height.
• Investigate the influence of cement return height on ultimate bearing capacity and interface strength over time.

Main Methods:

• Analysis of axial load distribution and bearing capacity mechanisms.
• Development of a calculation model for axial bearing capacity.
• Field experiments to study cement return height effects and interface strength evolution.

Main Results:

• Established a calculation model for conductor axial bearing capacity.
• Field experiments revealed the influence of cement return height on ultimate bearing capacity.
• Identified time-dependent strength differences between conductor-cement and cement-soil interfaces.

Conclusions:

• Friction between the cement sheath and the seabed soil layer is the dominant factor in conductor load-bearing capacity.
• Cement sheath height and integrity are crucial for ensuring wellhead stability in offshore drilling.