Abstract
There are a significant number of extended reach wells that cannot be effectively intervened to total depth due to tubing string lock-up. If the horizontal section of the wellbore is sufficiently long, the axial compressive load conveying the tubing into the wellbore will cause the tubing to buckle. Buckling initiates in a sinusoidal mode and progresses to a helical mode. Once the tubing buckles helically, the string quickly locks-up due to increased normal forces and frictional interaction with the wellbore.
Several commercial vibration devices attempt to extend intervention depths in extended reach wells. One of the primary modes of vibration employed in these devices is axial. We have developed a simulation tool to enhance understanding of how axial vibration devices extend reach. In the first section, we introduce a 1D finite rigid body dynamic model. This computational tool models the propagation of axial excitation in the presence of borehole frictional contact. In the second section, we demonstrate that the reach extension of axial vibration tools can be represented by an effective tractoring force, which is dependent upon vibration amplitude and injection speed. In the third section, we present field trial results of an axial vibration tool currently under development. Using tool output measured via a downhole force gauge, we compare reach extension seen in the field trials with modeling predictions.
