Abstract: Gas Blocking in Gas Storages at Simultaneous Gas and Water Flow

CZOLBE, PETER; HANS-JURGEN KRETZSCHMAR

Laboratory measurements, theoretical investigations and field experience illustrate a reducing phase conductivity during the repeated gas-water displacement. The cyclic displacement leads to an increased dispersion of gas and water in the pore space mainly behind pore constrictions. Gas and water are forming a "mechanical" mixture during the flow process. The media are transfered more and more from the continuous state in the discontinuous. The change of flow directions during the storage operations causes a reduction of gas mobility. The result of the intensive gas sorption in the pores and the phase dispersion is the formation of dead gas. The dead gas and the blocked residual water reduce the "active" pore space. These phenomena can exercise a significant influence on the effective regime of operation of aquifer gas storages or natural gas deposits.

The multicyclic laboratory gas-water flow tests show this shift and change of the relative permeabilities curves, the lowering of phase mobilities and the reduction of the utilizable pore space in dependence on displacement velocity or pressure gradient. So it is possible to select the mode of the storage operations according to the results of laboratory measurements of the relative permeabilities for several storage cycles that the dead gas formation is reduced.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria