Exploration and practice of air drilling technology in Karst area

With the deep exploration and exploitation of petroleum and natural gas,the ancient Karst was found to be a good storage structure for oil and gas.However,the drilling engineering in karst area had to face tremendous challenges due to unique geological characteristics.Based on geological features of Karst,the formation principle of Karst was briefly introduced,the drilling difficulties and risks were analyzed,and then measurements for coping with caves and underground river were proposed.The greatest advantage of air drilling technology was applied to deal with the malignant cave leakage in Karst area,which achieved faster and safer drilling.Anye 1 was a parameter well located in the typical Karst area.The application of air drilling was successfully solved the challenges caused by underground river.At the same time,it obtained high ROP and shortened the drilling cycle in Anye 1.The results indicated that the air drilling technology provided good guidance for drilling in Karst area.