U.S. natural gas inventories likely saw their smallest weekly build so far of the current injection season as hot weather kept up power-sector demand, offset in part by strong production and limited LNG exports.

Natural gas in underground storage facilities is expected to have increased by 31 billion cubic feet to 3,115 Bcf in the week ended July 31, according to the average estimate in a Wall Street Journal survey of 10 analysts, brokers and traders. Estimates range from an injection of 22 Bcf to an injection of 37 Bcf.

It would be the smallest storage build so far in the injection season, which typically runs from the end of March through October, but bigger than the five-year average increase for the week of 23 Bcf. It would expand the surplus over the five-year average to 193 Bcf from 185 Bcf the week before, while shrinking the deficit against the year-earlier level to 14 Bcf from 32 Bcf.

The U.S. Energy Information Administration is scheduled to release the storage data on Thursday at 10:30 a.m. EDT.