Research status and development trend of acid-fracturing technologies

Acid-fracturing technologies have become conventional measures to increase production in the field of petroleum engineering， and they are widely used in carbonate rock， tight sandstone， and volcanic rock reservoirs. However， relevant research mainly focuses on specific blocks， and there is a lack of a systematic and comprehensive summary of relevant research progress. This paper comprehensively investigated the latest progress of acid-fracturing technologies in China and abroad， systematically concluded the research achievements including the hot acid-fracturing technologies， difficulties and measures of acid-fracturing simulation in different reservoirs， acid-fracturing mechanism， and factors affecting acid-fracturing， and pointed out the development trend and existing problems of acid-fracturing technologies. Differentiated multi-staged acid-fracturing technology， volume acid-fracturing technology， and fracture height control acid-fracturing technology are hot acid-fracturing technologies in recent years. There are certain differences in the difficulties of acid-fracturing simulation in different reservoirs. Therefore， it is necessary to formulate corresponding acid-fracturing technology policies according to reservoir characteristics. The acid-fracturing mechanism can be analyzed through theoretical calculation and experiments. Theoretical calculation is the basis of acid-fracturing technology research，and experiments can provide important guidance for the research on acid-fracturing mechanisms and the determination of process parameters. Acid-fracturing technologies are affected by both geological and engineering factors. Geological factors are the basis of acid-fracturing technology policies， and engineering factors are the key to improving acid-fracturing effects. At present， acid-fracturing technologies are developing in four directions： deep and ultra-deep acid-fracturing layers， accurate acid-fracturing objects， expanded acid-fracturing scope， and controllable acid-fracturing technologies. It is suggested to strengthen the research on acid-fracturing theories， continuously improve the process and equipment， and establish the implementation template of typical acid-fracturing technologies， so as to guide the implementation of acid-fracturing technologies.