Effect of a Naturally Derived Deflocculant (Black Myrobalan) on Rheological Behavior of Heavy Drilling Fluids

Document Type : Original Article


1 Department of Petroleum Engineering, Ahwaz Faculty of Petroleum Engineering, Petroleum University of Technology, Ahwaz, Iran.

2 Department of Petroleum Engineering, Abadan Faculty of Petroleum Engineering, Petroleum University of Technology, Abadan, Iran.


Drilling process is the most important part of exploitation of hydrocarbon reservoirs and accomplishment of drilling a well is
determined by proper choice of the drilling fluid. The drilling fluid is related either directly or indirectly to almost every drilling
problem. Improvement of drilling fluid properties therefore would have direct impact on drilling process. Replacing common
additives by more efficient additives is an alternative to reach this goal. Plant based additives are suitable materials which have been
studying by researchers in recent years with aim of improving drilling fluid properties. In this study effect of Black Myrobalan (also
called Terminalia Chebula) extract on rheological behavior of a heavy weight mud were investigated experimentally. To do this
different concentrations of a Black Myrobalan solution (0.2, 0.6, 1.2, and 3 Vol %) were added to salt saturated mud and its
rheological properties, filtration volume along with density and pH were measured. Furthermore effect of time aging and hot rolling
at 200 °F was assessed. It was observed that Black Myrobalan decreases rheology of mud and increases filtration volume without
affecting mud weight at both after and before hot rolling. Among rheological parameters yield point decreased more than other
parameters. Moreover, hot rolling decreased the rheological parameters of mud while time aging increased them contrarily. The
optimum concentration of Black Myrobalan in order to decrease rheology of mud was 1.2 Vol %. It was also observed that pH of
mud decreased by increasing Black Myrobalan concentration. summarily Black Myrobalan acted as a deflocculant at concentrations
up to 1.2 Vol %.