ANALYSIS OF STRESS SENSITIVITY FOR IRREDUCIBLE WATER OF GAS RESERVOIR

In the exploitation of gas reservoir, the pore pressure decreased with fluid issuing, and pressure between inside and outside of reservoir increased. The pressure has produced deformation of the reservoir rock. So pore volume and porosity of reservoir are reduced. And some free water is released from irreducible water going with fluid issuing. It shows that the irreducible water of pore reduced by the rock deformation, and phenomena of water produced in some gas wells by productivity increased are reasonable explained. At the same time, the irreducible water saturation is increased for capillary pressure increased by decrease of pore and throat's volume. So the stress sensitivity of the irreducible water is existed, and relationships between effective stress and the irreducible water or the irreducible water saturation are index relations.