Initial Research on the Effect of Inorganic Salt on Rate of Penetration (ROP) in Drilling Fluids

Abstract

The authors attempt to investigate the interaction between inorganic components of drilling fluids and sandstones as well as the influence on the rate of penetration (ROP) imposed by inorganic components. With the analysis of Zeta potential of cuttings solution, the mechanism of the experiment is initially achieved. The results show that the ROP will be enhanced by 33.7% when AlCl 3 concentration is up to 0.01 mol/L, and therefore AlCl 3 and Al 2 (SO 4 ) 3 possess a tendency to enhance ROP. In addition, Al 3C enables Zeta potential of the solution containing cuttings shifted from negative value to zero, and finally to positive value by means of analyzing Zeta potential, which contributes to the significant improvement of ROP when Zeta potential is greater than 10 mV. Higher surface free energy created by the close-to-zero Zeta potential is conducive to crushing rocks, which in turn increases the ROP and meanwhile reduces drilling costs.

Laboratory investigations on the effects of surfactants on rate of penetration in rotary diamond drilling

“…The other mechanism is that during the rock-breaking process the ζ value influences the specific surface free energy of the rock. In accordance with the opinions reported by Engelmann et al (1988) and Zhao and Gao (2013), when drilling is regarded as activated cracking Fig. 13.…”

“…This effect has been confirmed on different rocks such as Sioux quartzite Rao and Misra, 1998), Minnesota taconite and marble (Bhatnagar et al, 2011). Zhao and Gao (2013) discussed the effects of different inorganic salts on the ROP in rotary diamond drilling and the relevant mechanism.…”