The Gas Well Trail in Penn Hills Community Park, Verona, PA, is a moderate 1.3 mile hike.
The trail starts along Plum creek and follows the creek for about 0.5 mile or so, before shooting up a large hill. You hike up the hill for about 0.2 miles before the trail starts to level out a bit more. On top of the hill, you'll find at least 2 gas wells, currently active. In the fall, there are some areas with nice views of the surrounding hills from breaks within the trees.
The trail finally descends back into Penn Hills Community Park near the baseball field. You'll have to walk an extra 0.2 miles to complete the loop for 1.5 miles or so.