卡瓦是钻井过程中经常使用的井口工具,目前国内各油田使用的卡瓦大多数是按照苏联四十年代和美国三十年代的老式卡瓦仿制的,结构笨重,容易损伤钻杆,甚至卡扁钻杆,一般仅用于浅井段的起下钻作业。对于中深井段的起下钻作业,如江汉油田规定,井深超过 Cava is a wellhead tool frequently used in the drilling process. At present, most of the kava used in various oil fields in China are imitated according to the old Soviet slips of the 1940s and the 1930s of the United States. The structure is bulky and easily damaged, and even the card Flat drill pipe, generally only used for shallow shaft drilling operation. For drilling operations in the deep section of deep wells, such as the provisions of Jianghan Oilfield, well depth exceeded