the field became progressively sour gen.

[Marina Khabibullina]

Как перевести sour в следующем контексте:

A Texas-based oil and gas company operated nine producing and five saltwater disposal
wells in eastern Utah. Over time, the field became progressively sour as a result of
contaminated water used in completion and workover fluids.

[hsakira1]

http://www.multitran.ru/c/M.exe?l1=1&l2=2&s=acidification of soil