A Solution Model for Stuck-Pipe & Fishing Challenges in Geothermal Drilling- a Case of the Olkaria Geothermal Field

Abstract

Stuck pipe and fishing challenges occur while drilling a well. Stuck pipe presents an undesirable well condition when the drill string movement is deterred either in the vertical path or in rotation. Fishing operations, also being closely related and usually as a result of stuck pipe scenario, is yet another condition of dilemma when either part of the drill string, handling, accessory or well logging tools are lost in the well. Worldwide, it is estimated that stuck pipe and fishing operations contribute to 25% of the drilling cost. These two conditions are not only risky but equally consume the rig’s productive time. While a number of technologies, tools and expertise are available for stuck pipe and fishing challenges, statistics still indicate high failure rates leading to costly well abandonment or complex side-tracking efforts. Further, statistically documented literature on stuck pipe and fishing operations in geothermal drilling within Africa is also scanty. It is against this backdrop that this paper seeks to provide a systematic way of evaluating and overcoming various forms of stuck pipe and fishing challenges and further develop a solution model to be adopted by various drilling contractors and crews in geothermal drilling. The lessons leant while drilling wells in the Olkaria geothermal field shall form the basis of this investigation.