Development and scaling relationships of a stylolite population

The frequencies, amplitudes and insoluble residue thicknesses of 4639 stylolites have been measured from ∼674.3 m of core from four vertical wells in the Khuff Formation, a Permo-Triassic carbonate reservoir, offshore Abu Dhabi. Although there are similar numbers of stylolites per metre of core in dolomites and limestones, the stylolites in the limestones have approximately double the cumulative amplitudes and insoluble residue thicknesses than the stylolites in dolomites. This indicates that stylolites in the limestones have grown at approximately twice the speed or for twice as long as the stylolites in the dolomites. Stylolite amplitudes in dolomites and limestones together appear to obey a power-law scaling relationship over about one order of magnitude (∼20–150 mm). Stylolite amplitudes in dolomites, however, have a higher power-law exponent than those in the limestones, and appear to obey a power-law down to ∼10 mm. This indicates that stylolites in the limestones have merged more than the stylolites in the dolomites. The amount of pressure solution, and possibly the scaling of a population of stylolites, may also be controlled by location within the fold, with less pressure solution in the hinge region, into which hydrocarbons migrated earlier than in the limbs.