Differential Sticking Control Methods


During construction of directional wells with horizontal wellbore drilling companies face almost all kinds of complications. The most frequent complication is sticking. Historically, sticking effects are divided into mechanical and differential sticking. According to a modern terminology, mechanical sticking can be classified under two separate categories: sticking caused by drilled cuttings or cavings and jamming at intervals with a complex wellbore geometry. Differential sticking proportion is 80%, proportion of mechanical sticking and sticking caused by equipment failure is 20%.

Most often sticking is caused by drilling cuttings or cavings. Usually it happens during tripping up, but also fixed drill string can stick when circulation is stopped for a long period. Sometimes this sticking occurs during tripping down into the well. Sticking caused by drilling cuttings or cavings is the most dangerous. Generally, it is harder to release drill string which was stuck due to cuttings or cavings than drill string which was jammed at intervals with a complex wellbore geometry or stuck due to a differential pressure. Often, most of drilling equipment is lost during recovering of stuck pipes that forces drilling company to drill a side track. The most of sticking issues caused by drilling cuttings or cavings occur during tripping up. The reason of this type of sticking is an incorrect cleanout operation or poor wellbore stability.


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