Figure 4.
The panel a graph plots elapsed time from about 5180 to 5225 days. The left vertical axis gives S T P flow rate in cubic metres per second and the right vertical axis gives gas pressure in kilopascal. Gas pressure increases from about 4200 kilopascal to about 5350 kilopascal by Event 2, decreases to about 5200 kilopascal after Event 2, then gradually increases to about 5350 kilopascal before a slight decrease near Events 4 and 5. Predicted pressure follows the gas pressure trend. Flow into the system remains nearly constant at about 2.0 times 10 to the negative 8 cubic metres per second to 3.0 times 10 to the negative 8 cubic metres per second. Flow into the buffer remains near zero before Event 2, then rises sharply to about 3.7 times 10 to the negative 7 cubic metres per second and subsequently declines with smaller peaks near Events 3 and 5. Dashed vertical lines mark Events 1 to 5. Panel b plots pore pressure against elapsed time over the same period. Multiple sensors record pressure changes, with several traces increasing sharply after Event 2, followed by gradual increases or decreases until Events 4 and 5. The highest values remain below 300 kilopascal. Panel c plots radial stress against elapsed time over the same period. Most sensor traces increase markedly after Event 2, several continue increasing until about Event 4, then decrease slightly after Events 4 and 5. Radial stress values range from near 0 kilopascal to more than 700 kilopascal. Dashed vertical lines mark Events 1 to 5.Gas Test 5. (a) Flow of gas into the system and the buffer; (b) pore pressure at the deposition wall around the time of peak gas pressure; (c) radial stress on the deposition wall around the time of peak gas pressure. Note: For display purposes in (b) and (c) each sensor has undergone translation along the y-axis