The exploitation of natural resources by man would be at the origin of the climate change in the world. Moreover, recent studies suggest that oil and gas operations in the USA cause earthquakes in southwestern Texas and New Mexico. Since 2009, the number of earthquakes keeps increasing in this area known as Delaware Basin. Researchers at the University of Texas at Austin associate the majority of them with oil and gas sites In the region.
They claim that 68% of earthquakes with a magnitude greater than 1.5 would be closely linked to the Hydraulic fracking. This technique which consists of break the stone thanks to a liquid injected at very high pressure to access gas or oil reserves trapped inside a rock formation would be dangerous for the environment.
Moreover, the soil pollution and the evacuation of formation water out of shallow geological formations also seems increase seismicity in the region.
Release of formation water increases pore pressure
Geologists have studied seismicity and oil and gas production in the region between 2017 and 2020. As all tanks underground passages in the area include training waterthis last one is evacuated at the same time than oil and gas. Unfortunately, companies that operate oil or gas wells pollute the surrounding geological formations with this hydrocarbon-rich water.
Alexandros Savvaidis, co-author of the study and researcher at the Office of Economic Geology at the University of Texas, particularly points the finger at the many oil fields of the Delaware basin. In particular, he stated that these large-scale drilling and mining activities raised the subsurface pore pressurea free area that sits just above the reservoirs.
New modeling techniques to reduce drilling risks
High pore pressure of the subsurface promotes the spread seismic waves in the ground. This is why the researchers claimed that increased seismicity of the region is directly linked to these mass oil and gas operations. Besides, statistical analyzes and modelization based on physics have confirmed this hypothesis.
These works are interesting insofar as these new modeling techniques could allow producers and regulators anticipate potential risks related to hydrocarbon drilling. The latter will thus be able adjust their activities to reduce the negative effects of oil and gas development on the environment.