Innovative Technology Designed to Secure the Wellbore Stability Resulted in the Elimination of a Casing Section, Significantly Improvement of Rop and Drilling Fluid Saving, Avoiding Side-Track
Authors: Pedrote Alberto Rivera , Ramirez Walter , Valdivieso Alex Mauricio Pupiales , la Fuente Carlos de , Hernandez Armando , Maldonado Reinaldo 
Published: October 2024

This paper documents best practices and lessons learned from drilling Tertiary formations in one the field located onshore southeast Mexico, primarily in the Oligocene, Eocene, and Paleocene formations with extensive sandstone bodies interbedded with shales. These formations exhibit high permeability and potential for losses, compounded by overpressured sand bodies with high pressure and a significant risk of influx, adding complexity beyond initial expectations. This field, affected by compressive stresses and salt tectonics, consists of an anticline with its major axis trending NW-SE in the north and S-SW in the central and southern portions. Its NE end is bounded by a major NW-SE trending reverse fault, with a smaller reverse fault in the central and SE parts of the eastern flank.

To the west, the reservoir shows natural closure dipping downward, delimited by the 7720 mvbnm contour, marking its conventional boundary.

Inappropriately increasing density causes well issues, so reinforcing the wellbore wall is crucial to mitigate losses and create a "shielding" that allows the formation to withstand additional pressures, thereby increasing its operational window. The use of Wellbore Shielding technology (Ultra-Low Invasion) in the new field extension has proven ultra-resistant and flexible for real-time borehole reinforcement during drilling, enabling operations without compromising well integrity. Continuous Sand Bed Test (SBT) monitoring allows timely detection of unfavorable conditions and immediate response, as shown in the upcoming case study.

The increase in the operating window has been made possible by Wellbore Shielding Technology, enabling necessary density steps without compromising drilling conditions despite high circulation loss rates. Real-time monitoring is essential for timely decision-making and optimal practices in response to well behavior. Accurate data on pore and fracture sizes is crucial for addressing initial problems directly, while materials for broad-spectrum mixtures at low and medium concentrations are key to successful hole reinforcement. Constant real-time monitoring of SBT tests ensures proper techniques for maintaining reinforcement systems. The inclusion of Wellbore Shielding Technology in well drilling has been driven by synergy, teamwork, lessons learned, and good practices.

Unlike other materials, particles from Wellbore Shielding technology do not penetrate the formation, maintaining their size despite drilling forces. This minimizes the material needed for maintenance. Wellbore Shielding additives form flexible "shields" in the fluid system, creating an extremely low permeability barrier in the wellbore. Unlike conventional techniques, this barrier remains stable under high cutting forces and temperatures, resulting in ultra-low invasion across various permeabilities and microfractures up to 3,000 μm. Developed as an alternative to conventional techniques, WST technology creates an impermeable "shield" around mechanically weak, depleted, and fragile formations during drilling. The non-damaging shield is strong and flexible enough to withstand large pressure differentials, increasing the operational window and minimizing fluid losses.