Jeotermal kuyularda yaşanan buru ve kaçak problemlerinin sondaj sıvısı yönünden incelenmesi

Drilling in a lost circulation zone has long been a challenge in geothermal wells due to its strong potential for high torque and wellbore instability. Excessive torque and friction values cause overpull, pipe stuck and severe problems ending up with losing the well in some cases. High temperature-high pressure (HTHP) drilling fluids design; which minimize loss rates and friction values, is critical for the success of these challenging drilling practices. Known fact is that, oil/synthetic based drilling fluids have the best lubricity performance. However, application of these drilling fluid systems is limited because of high cost and environmental constraints. At this point, water-based drilling fluid compositions with high lubricity performance, HTHP resistance and high loss zone plugging performance, are investigated. In this study, HTHP drilling fluid system; frequently used in Turkey and worldwide, is selected for the experiments. Several chemical commercial lubricants are added in this fluid system to find the compositions for the highest lubricity performance closest to oil/synthetic based drilling fluid systems. Also, considering the formation characteristics and drilling limitations; best fluid compositions are formulated to plug the potential seepage and partial loss zones and reduce the differential-sticking tendency by using proper lost circulation materials. Results reveal that lubricity and pore plugging characteristics of the selected compositions are highly innovative and noteworthy to be used in field applications for geothermal drilling industry.