Abstract
This work presents the first worldwide application of a new-generation, single-phase, low-viscosity retarded acid developed to effectively stimulate wells in High-Pressure, High-Temperature deep carbonate reservoirs. While single-phase retarded acid has shown success since implementation, the retardation performance is compromised at temperatures above 300°F, limiting acid concentrations to 20% HCl or lower depending on the bottomhole static temperature and well conditions. A new generation of single-phase retarded acid (Danican et al, 2024), capable of performing at temperatures up to 350°F was employed for the first time to stimulate deep and hot carbonate formations in Mexico.
The well selected for this first-time application is an openhole completed in a naturally fracture dolomitic reservoir with 905 meters openhole section and 367°F bottomhole static temperature. After dedicated laboratory test to qualify the fluid and complete placement computer modeling, we successfully executed a matrix stimulation treatment with the new single-phase retarded acid as main stimulation fluid. The initial production test, immediately after the stimulation, resulted in 3.6 production-fold increase; exceeding expectations and demonstrating that the acid system employed could create effective wormholes at this challenging conditions. This success has created opportunities to enhance stimulation outcomes in similar completions in this and other fields.
