The kinetics of dolomite dissolution have been investigated in experiments conducted at conditions characteristic of the Rotliegend gas fields in the northeast of the Netherlands (Temperature 100 oC, Brine ionic strength I>6.4M, pH=2-5). Experiments were performed in closed, stirred, batch reactors at far from equilibrium conditions, with dolomite powders of different diameter fractions: 20-25 microns, 75-100 microns, and 300-350 microns, with respective geometric surface areas: 935cm2/g, 225 cm2/g and 65 cm2/g. Dissolution experiments were also conducted in deionized water for the largest grain size to determine the effect of solution composition on dolomite kinetics. The rates were deduced from the change in the amount of Mg2+ released in brine with time and were normalized by the surface area of the minerals at each time interval. Dolomite dissolution rates were faster in brine than in deionized water by almost a factor of 2, which was not anticipated in such high salinity brine. Ionic strength and ion pairing overshadow the common ion effect, thus enhancing dissolution. In this work, smaller grains exhibited faster rates after normalization for surface area.