Two-Phase Flow in Tight Gas Sands. Annual Report April 1987-May 1988

摘要

Tight sandstones typically contain a pore geometry consisting of either grain-supported primary porosity with flowpaths restricted by authigenic minerals, or a highly altered pore system composed of secondary solution pores interconnected by narrow linear slot pores between quartz overgrowths. Gas movement through these restrictive pores is quite sensitive to net confining stress and partial water saturation. Movement of gas and liquid phases simultaneously in tight gas sand occurs with difficulty because of the tendency for the liquid to block narrow flow-paths. Investigation of the Travis Peak Sandstone of eastern Texas revealed that deeper parts of the formation have many of the highly altered pore morphologies and petrophysical properties observed in tight gas sands of the Rocky Mountains, while shallower portions contain less altered pore geometries and correspondingly different petrophysical properties. The purpose of the study is to systematically identify the relationships between pore morphology, reservoir properties and fluid flow through the matrix of low permeability sandstones to better assess reservoir quality.