Changes

| II || Scattered || Abundant to common || Needle probe can only occasionally dislodge a grain from rock surface || ± 0.5–1.0 md (depending on particle size, sorting, and clay mineral content)

| II || Scattered || Abundant to common || Needle probe can only occasionally dislodge a grain from rock surface || ± 0.5–1.0 md (depending on particle size, sorting, and clay mineral content)

|-

|-

| style=white-space:nowrap | III || None to very isolated || None to a few pores || Usually very well consolidated and/or pores filled with clays or other pore-filling material || Too tight to produce gas at commercial rates even when fractured or interbedded with type I rocks

| III || None to very isolated || None to a few pores || Usually very well consolidated and/or pores filled with clays or other pore-filling material || Too tight to produce gas at commercial rates even when fractured or interbedded with type I rocks

|}

|}