Inflatable gas bag for use as a borehole plug

A chemically inflatable gas bag for use as a borehole plug, comprising:

• acetic acid;
• sodium bicarbonate;
• an HDPE bag, wherein said acetic acid is releasably contained within said HDPE bag;
• and
• a substantially gas-impermeable inflatable outer bag comprising at least one layer of nylon and at least one layer of PE, wherein said sodium bicarbonate and said HDPE bag are contained within said outer bag,
• wherein said outer bag has a first side, a second side, a top side, a bottom side, a first side edge, a second side edge, and two bottom corners, and wherein (a) the bottom corner of said first side is folded diagonally inward and the bottom corner of said second side is folded diagonally outward, (b) said first side edge is folded inwardly along a first line substantially parallel to said first side edge of said gas bag and said second side edge is folded outwardly along a second line substantially parallel to the first line, and (c) said first side is folded inwardly along a third line substantially parallel to said first line and between said first line and said second line and said second side is folded outwardly along a fourth line substantially parallel to said second line and between said second line and said third line, wherein none of said lines intersect said HDPE bag.