Study: Lat­est ev­i­dence links quakes to oil wells

The Arizona Republic - - News 2 -

wells or re­duce the vol­ume of wa­ter they in­ject.

In the Raton Basin of north­ern New Mex­ico and southern Colorado, earth­quakes be­gan to in­crease in 2001, about two years af­ter large-scale waste­water in­jec­tion be­gan, the U.S. Ge­o­log­i­cal Ser­vice said. The waste­water comes from wells that ex­tract nat­u­ral gas from un­der­ground coal beds.

The big­gest quake in the basin since 2001 was mag­ni­tude 5.3 in 2011. It caused mi­nor dam­age to build­ings in Trinidad, Colorado, about 15 miles from the epi­cen­ter.

A 2014 pa­per by the Ge­o­log­i­cal Ser­vice blamed in­jec­tion wells for the area’s quakes.

The new Univer­sity of Colorado study went fur­ther, us­ing com­puter mod­els and records of waste­water in­jec­tion to con­clude that enough pres­sure built up to cause the quakes.

Justin Ru­bin­stein, a geo­physi­cist with the Ge­o­log­i­cal Ser­vice who was the lead au­thor of the 2014 pa­per, said the com­puter mod­els have been used in other lo­ca­tions but not in the Raton Basin be­fore now.

Ru­bin­stein was not in­volved in the Univer­sity of Colorado study and said he was not fa­mil­iar with all its de­tails but that the gen­eral con­clu­sions made sense. “It’s con­sis­tent with what my re­search has shown,” he said.

The Univer­sity of Colorado study also found that the Raton Basin earth­quakes were more wide­spread than pre­vi­ously thought, said Nakai.

DAN EL­LIOTT

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