A PVT chamber for observing the time-lapse seismic response to pressure

Abstract

As oil fields produce liquids (oil or gas/condensate), they undergo pressure change, with the pressure reducing as a function of production rates. Equally, the high production of water from a reservoir can cause major reduction in pressures of gas fields resulting in an increase in the gas cap size and a potential loss of gas through spillage to the surrounding formations. The injection of water or CO2 into reservoirs or underground storage areas causes an increase in local pressure which in turn, has the potential to cause local increases in permeability in the reservoir or at the storage site. Time-lapse three dimensional (3-D) seismic methods are used to monitor the fluid movement during both fluid extraction in producing fields and injection of water or CO2 for EOR or storage purposes. Little is understood about the seismic effects caused by variations in both pore pressure or rock matrix stress as a result of these operations. During 2003, a pressure/volume/temperature (PVT) chamber was built at Curtin University to simulate such effects, and to establish the seismic reflection response under these variations. This paper discusses the development of this facility and the applications of this unique PVT chamber.