Rheological and Filtration Performances of Rhizophora mucronata Tannin Water-Based Drilling Fluid

Abstract Rheological and filtration performances of water-based drilling fluid (WBDF) with tannin as deflocculant and fluid loss additive were conducted at high pressure and high temperature (HPHT). Different masses of tannin (0, 2, 4, 6 and 8 g) were added into WBDF and the prepared samples were tested at 3 different temperatures namely 250, 300 and 350 °F. Rheological properties including plastic viscosity (PV), yield point (YP), and gel strength (GS) were evaluated for pre and post aging processes. Filtration properties were measured based on the filtrate volume and mud cake thickness using low pressure low temperature (LPLT) and HPHT filter press. The rheological properties for post-aging process seem to be lower than the pre-aging except for 8 g tannin. The viscosity decreased by compensating attractive charges among the clay particles to flocculate. At higher temperature, tannin tends to absorb the extra heat and prevents water molecules from forming hydrogen. The filtration properties were also improved with low filtrate volume and thin mud cake. The optimum mass was achieved at 6 g of tannin. The rheological and filtration properties values of tannin were compared with commercial deflocculant (CD) and the differences were in range of 5-14 %.