关键词: 深度归位, 岩屑掉块, 元素数据, 定量荧光, 柴达木盆地

Abstract: The correct location of cuttings dropping depth is helpful to avoid sticking in drilling, and it is also an index to measure the stability of wellbore. However, conventional logging methods are difficult to accurately identify the depth of cuttings. In order to accurately determine the correct depth of cuttings and provide data support for optimizing drilling construction program, this paper puts forward five methods to judge the location of cuttings and blocks by using lithology contrast and homing method, the time of delay of tripping and tripping, Manhattan distance method of element data, adjacent well contrast method and quantitative fluorescence spectrum contrast method to comprehensively discriminate the cuttings dropping position and evaluate wellbore stability. This method has been successfully applied to CT 1 well of the No. 1 structure in the Qaidam Basin area, which provides a favorable basis for determining the drilling depth of the second opening and completion of the well, and avoids the occurrence of sticking and other complex engineering accidents, the drilling period is shortened by 33%, which indicates that this method has a certain value of popularization and application in drilling site.

Key words: depth homing, bits of rock fall off, element data, quantitative fluorescence, Qaidam Basin