Down-dipHi, The statement of not encountering "down-dip water contact" needs to be parsed. Sedimentary rock units consist of many roughly parallel layers, each with small or large differences in properties. Because thay are typically tilted or folded over time, they are said to dip, ie get deeper from the surface in a certain direction. Dip angle is the slope of the unit or bed. Due to their different densities, in a typical unit gas will be at the upper part of the slope, then oil, and finally water at the lowest part, "down-dip." In a BCGA, the generation of gas at depth, in a tight (very little permeability, or ability of a fluid to pass between grains or through cracks), the gas manages to push the water upward. The lower or lowest, or down-dip, portion of the units contain gas, with water above them. This is a reversal of the normal conditions.
So, no "down-dip water contact" means there was no indication that a unit has continuous water below the gas. That statement is consistent with what is expected in a BCGA. There can be isolated pockets of water in a BCGA, but not a down-dip water contact.
The more wells that show no ddw contact, the more certain one is of the BCGA and the better the extent of the BCGA is delineated. Note also that geophysical measurements and nearby well data also assist in defining the BCGA and its extent.