Abstract:

It is traditionally considered that sutures in the carbonates were formed under the pressure solution caused by rock load or tectonic stress, which is a result of chemical compaction. Here we demonstrate that sutures are characterized by integrality, hydrophilicity, antihole， and burst and concourse. Sutures are a kind of sawtooth cracks caused by the rock bursting due to hydrocarbons (or mud) under the rock load or tectonic stress, which are hydrocarbon (mud)expulsion passages. The contribution of pressure solution is not clear. Compared with carbonates, mudstone has few sutures. This is because the mudstones have relatively larger pore radius, and hydrocarbons can be expelled through micropore permeation. on the basis of  the studies of formation mechanism of sutures, we investigated the difference of hydrocarbon expulsion between carbonates and mudstones, and compared their sealing capabilities.

Key words: suture, pressolution, burst, concourse； integrality, hydrophilicity, antihole