Tight Gas Sandstone Reservoirs , Part 1 : Overview and Lithofacies 14

Although shale gas plays have been in the spotlight recently, natural gas in tight sandstones is actually also an important hydrocarbon resource. In many cases, tight gas sandstone resources can be developed more easily than shale gas reservoirs as the rocks generally have higher quartz content, and are more brittle and easier to complete for production. This chapter first gives an overview of evaluating tight gas sandstone reservoirs, including their depositional environments, and other reservoir characteristics. Then, it presents an integrated methodology for lithofacies analysis and modeling. Because identification of lithofacies and rock typing is a key to characterizing these types of reservoirs (Rushing et al., 2008), we discuss lithofacies classification using wireline logs. We present methods on how to populate the lithofacies data from wells to a three-dimensional (3D) model while discussing the advantages and disadvantages of each method for modeling tight gas formations. The next chapter is the second part of tight gas sandstone reservoirs, in which petrophysical analysis, formation evaluation, and 3D modeling of petrophysical properties are presented.