The influence of pore fluids on seismic wave velocities under high temperature and high pressure conditions: Development of a new technique with gas apparatus at AIST, Japan

In order to study the effects of different pore fluids on elastic-wave velocities, we developed a new system for measuring elastic wave velocities (V_p and V_s) under high-pressure conditions up to 200 MPa and high-temperature conditions up to 200°C using a gas-medium high-pressure and high-temperature apparatus. During the V_p and V_s measurements, we can also control the pore pressures from outside the rock samples. We measured V_p and V_s of the Berea sandstone samples under three different pore-fluid conditions including dry (without pore-fluids), in the presence of pore water, and in the presence of pore gas. Here we describe our new measurement technique and establish the capacity of the gas apparatus and measurement technique and their potentialities for the solution of geological problems.