Analytical solution for stuck pipe problems based on worldwide company practices
Research output: Research › Master's Thesis
Demands for natural resources, primarily for oil and gas in the world, are not decreasing. But on the other hand, in order to fulfil the requirements of the market, drilling limits are being pushed, resulting in problems becoming more frequent. One of the most frequent and widespread problems in the oil industry is a stuck pipe, which requires a lot of time and effort to release the stuck pipe string, with an outcome which is always uncertain. The appropriate response to the actual stuck pipe condition is sometimes the key to defining the success of further stuck pipe releasing activities. Keeping in the mind that the chances of releasing a stuck pipe string decreases over time, misjudging the stuck pipe mechanism and applying an inappropriate freeing procedure can further complicate the situation and make releasing the drill string uncertain. At the beginning of this work an overview of all the stuck pipe mechanisms is given, as well as the deviation in the operational parameters in regard to the stuck pipe mechanisms before and at the moment of the stuck pipe condition. Subsequently, all of the selected companies’ freeing procedures will be presented. This thesis continues with an analytical model whose purpose is deriving general freeing procedures with the sequence of operations for the group of the three main types of stuck pipe mechanisms: mechanical sticking and wellbore geometry, differential sticking and the solid induced pack-off. The quality of the derived general freeing procedures is directly related to the amount of available freeing procedures for each stuck pipe mechanism, individually, which belongs to the aforementioned group. In order to be able to use the model, a coding system is introduced, then, based on the amount of collected freeing procedures, the threshold values are estimated. After this the function average and standard deviation will be introduced and the final result will be the general freeing procedure. When the freeing procedure is finally obtained, each code is replaced with the certain operation, which should be performed when a stuck pipe occurs. Finally, the presented model results in obtaining the general freeing procedures, from which one of these should be chosen according to the particular stuck pipe mechanism, which has been tested on an artificial data set created by the author, where its validity should be confirmed.
|Award date||30 Jun 2017|
|State||Published - 2017|