Innovative forging process produces seamless landing strings

HOUSTON -- Vallourec has developed an innovative forging process to produce seamless forged landing strings. The technology involves a hot forming process using a four-hammer forging machine on a cylindrical mandrel.

Traditionally, thick-walled drill pipe was used as landing string in order to perform completion and intervention operations in shallow waters. In deeper waters however, these conventional landing strings cannot withstand higher hook loads due to a phenomenon called “slip crushing”. This phenomenon is a major problem which needs to be addressed when designing landing strings and slips. As a result of biaxial loads, stress concentrations may damage, and in some cases even crush, pipe, hence reducing the axial load rating of the
landing string.

One of the current operational challenges with existing friction welded landing strings is linked to the
positioning of the slips sufficiently far from both the weld area and the Heat Affected Zone. The limited length
available for setting the slips requires additional time for proper positioning and set up. This is particularly
problematic when using extended slip designs, newly introduced to the industry.

The main advantage of this technology is to achieve outstanding dimensional tolerances, shaped tubes, and excellent metallurgical properties. This new friction-weld free construction has no heat affected zone which could potentially pose a risk hazard to drillers and operators.