Working Out of a Tight Spot
The art and science of jarring operations
Stuck pipe has long been the bane of drillers worldwide. The inability to move drillpipe upward or downward or to rotate it while drilling costs operators millions of dollars per year in nonproductive time, lost downhole equipment, and sidetrack operations. For decades, the last line of defense against the harsh consequences of stuck pipe has been jars: tools designed to deliver a significant upward or downward force to the drillpipe in an effort to hammer it free of whatever force is holding it in place.
Today, advances in hardware technology have delivered new methods and tools with which to maximize the impact of this longtime drilling tool. At the same time, engineers have increased their understanding of the dynamics of jarring operations and have used this knowledge to develop software that helps them place jars within the drillstring where they will be the most effective based on specific drilling environments and parameters. Additionally engineers are using these new tools to meet unique jarring requirements encountered in highly deviated and horizontal wells.
Adding a robust hydraulic jar to the drillstring on a wellsite in Canada allowed engineers to free stuck pipe in seven hours because they were able to fire and reset the jars more than 200 times without failure. In Oman, the inclusion of a jar accelerator tool allowed drillers to extricate themselves from a stuck pipe incident within hours. In the US, jar placement and equipment preplanning allowed engineers to free stuck pipe in 45 minutes while damping vibrations that might otherwise have damaged surface equipment.
A recent article in Oilfield Review describes how operators are using new tools and software specifically designed for jar placement to minimize the effects of stuck pipe.
Read the full article at the Oilfield Review Web site.
Costo B, Cunningham LW, Martin GJ, Mercado J, Mohon B and Xie L: “Working Out of a Tight Spot,” Oilfield Review 24, no. 1 (Spring 2012): 16–23.
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