Characteristics of Pressure Relief Gas Extraction in the Protected Layer by Surface Drilling in Huainan

Figure 3

Diagram illustrating gas concentration and flow rate in gas extraction and pressure relief for typical single surface wells: (a) protective layer working face 2662(1), (b) protective layer working face 2371(1), and (c) protective layer working face 2371(1) rising period.

(a)

(b)

(c)