Buoyancy Technology Used to Successfully Install Casing in Argentina's Longest Extended Reach Slim Well Pad

Abstract

The main objective of this paper is to summarize and present the results of extended reach casing installations in the Vaca Muerta basin in Argentina. The wellbores used as case studies in this paper had lateral lengths up to 4250m and includes the longest lateral cased in the Vaca Muerta region. A discussion of the operational parameters, placement philosophies and a risk assessment will be covered. A glass disc flotation collar was installed as part of the casing string. This device traps air between it and the float equipment, reducing the frictional forces acting on the casing through the buoyancy effect. At the target depth, a pre-determined pressure is applied to the glass disc, rupturing the disc and allowing circulation in preparation for the cementing operation to follow. Previous papers such as Rastegar et al. (2018), introduced the concept of placing the flotation collar at an "optimal" location. These previous attempts all assumed that the optimal position was the location that yielded the maximum hookload possible at target depth. While this is often the case, an alternative approach was taken in this case study whereby the flotation collar was placed to maximum the hookload at the build and curve section of the wellbore where frictional forces are often of highest concern. Operation decisions that impact flotation collar effectiveness are also discussed in this paper. The primary discussion point is centered around the mud filling strategy used and improvements implemented at the rig. A discussion of the early filling strategy used, and the improvements made for the case study will be covered in detail. The results of the case study project determined that there was a 28% reduction in the run-in-hole time when using the new deployment strategies. These strategies also reduced the need for string rotation, ultimately reducing casing wear and fatigue.