Saint-Petersburg Mining University, Oil and Gas Department, Saint Petersburg, Russia
Filtration of the drilling mud is one of it's most important parameters, especially when drilling-in producing formation. Decrease of filtration characteristics allows reducing both solid and liquid phases's penetration zone into the formation. The study of the effect of the weighting-bridging agent's fractional composition on the filtration rate allows selecting of optimal composition of the solid phase in the the drilling mud. This paper presents studies of the static filtration rate of drilling mud with addition of various weighting-bridging agents. The obtained result indicates that an intensive decrease in the filtration rate is observed at calcium carbonate's introduction into the solution with an average particle size of up to 50 μm. Further studies should be directed to investigate the dynamic filtration rate, the possibility of "mixing" of various fractions in the composition of one solution and the evaluation of their influence on the filtration rate.