An Innovative Device to Enhance Conductor Bearing Capacity in Deepwater Drilling Operations

Abstract

Deepwater environments raise higher demand on the bearing capacity of the drilling conductor below the mudline. To deal with this problem, a conductor bearing capacity enhancement device was designed. The setting capability of this device and its axial bearing capacity were analyzed with soil mechanics and pile theory. Furthermore, a calculation model was developed, and a numerical method was used to solve for the lateral capacity, coupled with drilling platform, riser, conductor, seabed soft soil, and the device. The result shows that proper setting depth of the device is primarily determined by the property of the soil, rather than the conductor jetting operation. Additionally, appropriate determination of the diameter and wall thickness (WT) of this device can greatly improve the lateral bearing capacity of the conductor.

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“…The large diameter of the device increases the contact area of the string with the soft soil, thus increasing the conductor axial load carrying capacity. In addition, the unit shares the moment of the riser, thereby increasing the lateral load-carrying capacity of the conductors (see Figure 12) [163,164]. Kan Changbin et al designed a new duct assembly structure to improve the vertical and lateral bearing capacity of the duct and anchor the barrel-shaped foundation to the seabed mudline to increase the frictional contact area to maintain the vertical bearing capacity.…”