Mechanical Response Study of Stability Analysis of Conductor Pipe in Shallow-Water Field

Summary Maintaining a vertical position of conductor pipe during drilling and non-drilling operations remains a challenge in shallow-water fields. In Tianjin shallow-water field, a conductor pipe left for evacuation was found displaced on resumption for drilling operation. This prompts the need to address the problem by investigating the stability of the conductor pipe and to prevent its future occurrence. In this work, a governing equation is presented to study the mechanical behavior of conductor pipe in a shallow-water field under combined effect of soil, waves, current, and wind. The displacement response equation of the conductor pipe was solved numerically from which other responses were obtained. Various influencing factors such as internal fluid, top-weight, and wall thickness are analyzed for the conductor pipe. Modal analysis carried out shows that the part of the conductor pipe in the soil tends to vibrate for higher modes which thus threatens the stability of the conductor. Results show that significant displacement occurs for the conductor part in water which indicates that combination of waves and current on the conductor prevails over the top free-boundary condition effect. Analysis results also show that drilling mud of higher density in conductor with applied top-weight on it improves the stability of conductor. The results have been validated using Abaqus simulation.