A temperature-sensitive acidic completion fluid technology

A temperature-sensitive mud cake remover (G315) was developed using ethyl lactate as the primary component. Based on this, a temperature-sensitive acidic completion fluid (CF-G315) was formulated. Core evaluation tests, mud cake dissolution tests and corrosion tests were conducted to analyze the mud cake removal performance of G315, the removal efficiency of CF-G315, and its ability to modify the near-wellbore reservoirs, corrosion to casing and hydrolysis performance. Results indicate that ethyl lactate in G315 exhibits weak acidity at room temperature and decomposes into lactic acid under high temperatures. The lactic acid reacts with the calcium carbonate in the mud cake, generating bubbles that dislodge the mud cake and form soluble salts that are subsequently removed by fluid flow, thereby ensuring effective mud cake clearance. CF-G315 removes mud cake efficiently and enhances near-wellbore reservoir permeability. It demonstrates low corrosivity and environmental compatibility, contributing to equipment safety, simplified operational procedures and reduced operational risks. CF-G315 is promising for application in scenarios such as horizontal wells, open-hole completions and gravel pack completions.