Research on Bearing Capacity of Conductor Anchor Node Wellhead in Deepwater——A Case Study of Conductor Anchor Node Wellhead of the Horizontal Well in Wisting Oilfield, Norway

In recent years, with the development of shallow oil & gas reservoirs in deepwater, the conductor anchor nodes are used abroad as wellhead support devices instead of conventional conduits. For example, In Norway Wisting Field, conductor anchor nodes had been used to drill extremely shallow horizontal wells. The conductor anchor wellheads are seldom used as the subsea wellheads for deepwater drilling in China. In order to ensure operation safety, it is necessary to study the bearing capacity of conductor anchor wellhead. In this paper, according to the API conductor ultimate bearing capacity calculating model and single pile axial ultimate bearing capacity empirical formula, combined with the negative pressure loading of conductor anchor node, the instantaneous bearing capacity and the real time bearing capacity of suction anchor in the process of placement are studied. A coupling calculation model of conductor anchor node bearing capacity, soil restoration coefficient and soil strength is established. As an example, taking the design parameters of conductor anchor node and the undrained shear strength of regional soil in Wisting Oilfield, Norway, the calculated results are in good agreement with the engineering practice.