Zonal Isolation in Horizontal Configurations: Dynamic Cement Placement Approach Applied in Argentina, a Case Study

Abstract

The increasing energy demand has led shale unconventional reservoirs to become a focal point for operators worldwide. Over the past decades, several technological advances were conveyed to drilling and completing horizontal geometry wells in which massive hydraulic fracture treatments are deployed to improve production of these reservoirs. Argentina has one of the largest shale-stored hydrocarbon reserves in the world and has become one of the leading countries in the exploration, appraisal, and development of unconventional reservoirs. The number of horizontal shale wells drilled in the country increased over the past decade, generating the need to find solutions to cement horizontal laterals and achieve the required zonal isolation for the normal completion and production of these wells, preserving well integrity. Based on the difficulties encountered to cement these horizontal wells, such as channeling and differential fluid velocities, among others, the need to implement casing rotation while cementing was considered. This mechanical method has remained locally as one of the least accepted solutions because of the fear that the high torques during the operations would cause casing failures. In a recent unconventional campaign, casing rotation was applied during well conditioning and along the cementing operation. A sensitivity study to rotational speed was performed, and the cementing design was optimized with a new 3D annular displacement simulator (3D-ADS) that predicts annular flow in complex geometries, accounting for pipe movement. The well was cemented successfully, obtaining congruent results from comparing bond logs and fluid placement simulations. This study defines some of the factors contributing to a successful cementing job in a horizontal geometry, the aspects to be analyzed from the cementing perspective when rotating casing to aid in mud displacement, and the evaluation of the wells cemented under these circumstances compared to the simulated results predicted during the design phase of the well.