Advance and Prospect of Acid Fracturing in Deep Carbonate Reservoirs
Acid fracturing is a valuable tool for effective development and exploitation of deep carbonate reser-voirs.As exploration and development move towards ultra-deep formation,it is crucial to elucidate the current sta-tus and trends in acid-fracturing.This study elaborates on acid-fracturing mechanism from three aspects:the initia-tion and propagation of acid-fractures,the formation of acid-etched hydraulic fractures and conductivity,and acid-fracturing modeling and numerical simulation technology.Then four types of high-temperature-resistant retarded acid systems are analyzed,including viscosity-controlled,acid generation time control,H+ shielding adsorption,and non-hydrochloric based acid systems.The four stages of the development of acid fracturing technology in deep carbonate reservoirs in China are systematically reviewed,and the four challenges currently faced by acid fractu-ring in ultra-deep carbonate rocks at 9,000 m are analyzed:the ability to fracturing the reservoir,reservoir temper-atures exceeding the temperature limits of acid systems,lack of high-temperature and high-pressure testing meth-ods,and difficulty in targeted communication with natural fractures and caves.Based on this,five prospects are proposed for acid-fracturing research:precise prediction of fracturing pressure in ultra-deep wells,development of a multifunctional acid system resistant to 220℃,construction of a extra high-temperature and high-pressure exper-imental platform,fully online acid-fracturing technology,and exploration of supercritical CO2 acid-fracturing tech-nology,aiming to achieve high-efficiency three-dimensional exploitation of ultra-deep carbonate reservoirs.
NETL
NSTL
万方数据
维普
