Living in Oklahoma, I have become very familiar with earthquakes over the last few years. Right it wrong, we associated the earthquake increases with increased oilfield production. We were right.
[R]esearchers have found that the rate at which we dispose of … liquid may greatly impact the chance that [an earthquake] will occur. The faster we inject this water into the ground, the higher likelihood of induced Earth rumblings.
Why this happens has been known to geologists for a while.
Whenever fluid is added to or withdrawn from the ground, the state of stress on the crust changes. And if that fluid pressure changes inside a fault, friction can decrease, causing the two sides of the fault to push away from each other. Wastewater and fluid injection, dam and reservoir construction, mining, and hydraulic fracturing all contribute to these pressure changes
But this isn’t an all out nothing problem. Oil has been extracted from Oklahoma and Texas for a long time without increased seismic activity. What could be changing it now?
Weingarten and his research team catalogued the production rates of 180,000 injection wells located between Colorado and the East Coast. They found the wells that pumped more than 300,000 barrels of wastewater into the ground per month were statistically associated with earthquakes.
We seem to be closing in on the culprit responsible for the increase in earthquakes. This knowledge, along with future scientific research, should help us make a better decision regarding risk assessment with respect to increased oil production.