Advanced Carbonate Acidizing with Optimized Retarded Acid to Reduce Matrix Acidizing Carbon Footprint

Abstract

Abstract In pursuit of the 1.5°C climate threshold set by the Paris agreement above pre-industrial levels, achieving net-zero CO2 emissions by 2050 is identified as crucial. This necessitates leadership from the energy industries in formulating and executing sustainability development goals. Addressing all emissions sources is imperative for the success of this ambitious endeavor. The study investigates the application of an optimized dosage of a novel single-phase retarded acid (SPRA) fluid system to reduce the carbon footprint in stimulating horizontal extended reach wells targeting lower-permeability reservoirs in Middle East. Hydrochloric acid (HCl), which is commonly employed in matrix acidizing for creating wormholes in carbonate reservoirs, faces challenges in achieving the desired productivity index due to rapid reactions at high bottomhole static temperatures. The development of SPRA, an HCl-based fluid with enhanced retardation factor, demonstrated superior wormhole penetration depth through the synergistic action of two retarding agents. Employing stimulation modeling analysis, this work investigated optimized SPRA dosage and demonstrated its superior performance over regular HCl acid in post-stimulation skin reduction and wormhole generation. In most of the SPRA applications, the performance of the stimulation treatment is still higher compared to the straight acid, even at reduced volume. Subsequent history matching exercises confirmed the generation of longer wormholes and the effective reduction of skin across the entire lateral section of the well. Validation of simulation findings was achieved through flowback and production data collected after stimulation. The presented case studies demonstrate the implementation of the innovative SPRA fluid system, resulting in a significant reduction of up to 51%, equivalent to 274 metric tons of CO2 emissions throughout the entire value chain. This includes a 50% reduction in total acid volume and a substantial 67% decrease in flowback time. These findings underscore the considerable environmental and operational benefits of the SPRA fluid system in advanced carbonate acidizing of extended reach wells.