RIASSUNTO
Abstract
The complexity of petroleum wells has increased significantly during the past decade. Both inclination and horizontal departure are greater than before, leading to additional demands on well operations. Buckling of drillpipe and completion string is seen as a critical parameter. In this paper we review available buckling models and show applicable theory for practical well operations.
Introduction
During the last few years, well lengths are more than doubled. The consequence is often that offshore oil and gas fields can be drained from a small number of platforms. This demonstrates the significance directional drilling has on the recovery of hydrocarbons.
To reach the desired targets, well friction is an important parameter to control. This has several practical consequences, such as the maximum wellbore inclination for drilling and completing a well and maximum bit force to avoid buckling of a slender bottomhole assembly.
The extended use of coiled tubing in drilling, completion and well intervention, has led to the conclusion that pipe buckling is a critical parameter. The presented paper aims at addressing aspects of this.
Reachable depth, force and torque are controlled by buoyed weight, curved-well effects and corkscrewing of the pipe. Helical buckling of drillpipe or workstring may eventually lead to lockup or excessive pipe stresses. Theory is presented that describe wellbore friction caused by helical buckling, pipe weight and wellbore curvature. An example well is analyzed.