The Determination of Ultimate Releasable Hook Load in Casing Running Through an Air-filled Wellbore

Abstract

The pipe is frequently stuck in casing running through the wellbore drilled by air hammer, and releasing part of suspending weight is commonly practiced to solve this problem, which would engender the strong axial vibration of casing string and make the operation in high risk when wellbore is filled with air or gas. In this paper, the propagation mode of the stress wave has been distinguished based on explicit dynamic finite analysis, where various length of string and released load have been considered. The influence of damping to the fluctuation characteristics of hook load has been discussed, and Rayleigh damping has been applied. With the investigation of the stress wave characteristics in the vibration of casing string, a new method to determine the ultimate releasable hook load in casing running through an air-filled wellbore has been proposed. The results have been validated in an oilfield of western China. The methodology and approach presented in this paper can be used to guide operation in casing running practices by engineers.