Improving rheological and filtration properties of drilling muds with addition of greek ligniteImproving rheological and filtration properties of drilling muds with addition of greek lignite Δημοσίευση σε Συνέδριο Conference Publication 2015-11-112004enThe suitability of some Greek lignites as additives to control rheology and filtration characteristics of drilling fluids has been studied. Various types of lignites and peats from different parts of Macedonia, Thrace and Thessaly have been provided by the Institute of Geology and Mineral Exploration (IGME). They have been activated with ΝαΟΗ (caustisized), and added at different concentrations to fresh water muds, containing a drilling fluid quality Naactivated bentonite from Milos, and an appropriate amount of NaOH to adjust the pH of the fluid around 10. The drilling fluids were then aged statically at 177 °C for 16 hours. The rheological properties were measured in a six speed rotational viscometer, (Fann 35S) while the filtration characteristics were measured in a low pressure low temperature API filter press. The results were then compared to the values taken before aging, without the addition of lignite and with the addition of commercial lignite product used by the drilling industry for the same purpose. It was observed that addition of lignite improves the stability of the drilling fluid. A major improvement is observed when 3% lignite is used as additive. The performance of Greek lignite was comparable to the performance of the commercially available lignite product. An attempt is made to quantify the positive effects in terms of the type of lignite added.http://creativecommons.org/licenses/by/4.0/7th National Congress on Mechanics Mihalakis S. Makri Pagona Μακρη Παγωνα Kelesidis Vasilis Κελεσιδης Βασιλειος Christidis Georgios Χρηστιδης Γεωργιος Foskolos Antonis Φωσκολος Αντωνης Papanikolaou C.E. Biological rheology Biorheology rheology biology biological rheology biorheology