Innovative Technology to Release Stuck Pipe Problems in Gas Wells of Tripura, India - Case Histories

Stuck pipe incidents are the most troublesome and costliest drilling problem worldwide. in terms of time and financial cost. It's also a major contributor to non-productive time (NPT), which continues to comprise 20-25% of annual rig operating time. This may be due to differential sticking forces, inadequate hole cleaning and the consequent formation of cuttings beds in high angle wells, chemically active formations and inadequate mud weight leading to wellbore instability, fractured/faulted formations, and over-pressured formations. Sticking can occur while drilling, making a connection, logging, testing, or during any kind of operation which may involve leaving the equipment in the hole. When a pipe sticks the driller usually tries to free it by mechanical movement e.g.by pulling, jarring or, if the pipe was moving immediately prior to sticking, trying to move it in the opposite direction. Frequently this fails to release the pipe as there is a limit to the force which can be applied, since too much force could fracture the pipe and make the situation worse. If the pipe remains stuck then the practice is to apply a Stuck pipe release agent/pill. It is observed that there are many such pipe release agents/pills known in the industry but these are time-consuming and costly. In those cases where environmental concerns do not permit or discourage their use, diesel oil has been used with a fair amount of success but there are cases where asphalt, diesel oil, mineral oil or other oil-based spotting fluids cannot or should not be used. Many other commercially available, environmentally-friendly spotting fluids have been used in an attempt to free stuck pipe, but with limited success. It is therefore the primary object to present this paper to provide new and environmentally-friendly more reliable materials which can be used to free stuck pipe. The paper further discusses the current testing and evaluation methods used for screening, testing, and evaluating spotting fluids to select the superior and reject the inferior along with their advantages and disadvantages with existing Mud Systems. Finally, a recommendation is made to improve the testing and evaluation method and overcome the limitations of conventional methods and apparatus.