Experimental Evaluation of Authigenic Acid Suitable for Acidification of Deep Oil and Gas Reservoirs at High Temperatures

Abstract

During the acid pressure conversion process in high-temperature, deep oil and gas reservoirs, a number of challenges are encountered that hinder the effectiveness of acid fracturing. These obstacles include significant corrosion of acidized pipe strings, rapid reaction rates of acid with rock, limited reach of acid liquids, and shallow penetration depth of active acids. Additionally, the transportation of highly corrosive acids presents safety risks, necessitating surface conditions that are free of acidity. However, underground conditions require strongly acidic liquids to meet enhanced ecological and environmental protection requirements. To address these limitations, experimental investigations have been conducted to examine the reaction rates of low-corrosive and low-acid rocks in alkaline systems involving halides and carbonyl compounds. Through meticulous assessments of reaction rates and dissociation effects in acid rocks, parameters have been successfully optimized to incorporate erythropoiesis and other compounding agents into acid-pressing designs. The experimental findings indicate that the concentration of released H⁺ ions after 60 min exceeded that of the conventional acid solution processed for 15 min. Enhanced dissolution was observed when erythropoietin content was increased to 20%. Furthermore, combining 10% acetic acid with 20% caustic acid resulted in a significant increase of 6.08% in the dissolution rate from 10 to 120 min, while exhibiting lower dissolution values compared with other types of acids. The development of naturally occurring acids with reduced rates of dissolution and acid–rock reaction holds significant potential for enhancing the efficacy of high-temperature, deep oil and gas reservoirs through acid fracturing stimulation.