Experimental investigation of drilling problems of clay content formations

The Southeastern Anatolia Region of Turkey possesses the country's largest oil reserves and is also the area where the highest oil production takes place. Particularly, the Batman and Diyarbakır regions in these areas contain dense clay minerals in terms of formation characteristics. Consequently, stability issues in oil drilling occur in these regions, leading to well problems. Each problem encountered results in both financial and spiritual losses. The increase in data from activities in oil wells has contributed to more efficient drilling operations by rehabilitating these formations with different drilling fluids. In this study, wells A-1 and B-1 located in A and B oil fields in the Batman and Diyarbakır regions were selected as the study area. The drilling problems experienced with the dense clay formations in these areas were addressed, and step-by-step rehabilitation methods were conducted through experimental studies under dynamic conditions. The stability problem in the selected A and B oil fields was attempted to be minimized by applying KCl polymer mud against it. The KCl polymer mud used during the drilling contained specific features, especially potassium with ionic inhibition, and polymers for controlling fluid loss and rheological properties were kept under control. The ongoing rehabilitation methods during drilling ensured the smooth continuation of the operations. In this thesis, daily laboratory experiments on the drilling of Germav-Kastel formations rich in clay content, causing stability problems in A-1 and B-1 wells, were conducted using KCl polymer mud in accordance with API standards and reported. Rehabilitation procedures were determined based on the analyses of the experiments. The effectiveness of KCl polymer mud on clay formations under dynamic conditions is demonstrated in this study. In the A-1 well where these formations are present, results indicate that KCl polymer mud provides effective and safe drilling when correct rehabilitation methods are applied, taking the mud properties pilot experiment results as a reference. However, due to logistical issues in the B-1 well and its nature as an exploration well, the effectiveness of KCl polymer mud could not be achieved, leading to drilling problems such as wellbore collapses and mud losses. Both wells and pilot experiment results addressed in this study have shown that the correct use of KCl polymer mud prevents financial and spiritual losses.