Light crude oil from the Bakken and Eagle Ford shales as well as the Permian Basin is making its presence felt in Energy Information Administration (EIA) data on the character of U.S crude production.

New data from EIA show that for the first nine months of 2015, the majority of crude oil produced in the Lower 48 states was light oil. As categorized by API (American Petroleum Institute) gravity, a measure of the density of oil, the largest share of production was in the 40.1 to 45 degree API gravity range.

The data comes from the recently expanded EIA-914 survey, which tabulates production from oil and natural gas well operators. EIA surveys operators for their production in 15 individual states and the federal offshore Gulf of Mexico. Production from the remaining producing states is collected in an “other states” category.The results are published monthly.

Slightly more than half of Lower 48 production during the first nine months of 2015 had an API gravity above 40 degrees. Production increases over the past several years in the Bakken Shale, Permian Basin, and Eagle Ford Shale formations accounted for almost all of crude oil production growth in the United States, and consist of light crude oil from low-permeability formations.

Crude oil streams vary throughout the Lower 48. Production in California, North Dakota and Texas has significantly different characteristics. Most of California’s oil is heavy, with more than 90% having an API gravity of 30 degrees or less. Oil produced in North Dakota tends to be light — more than 90% of production has an API gravity of 40.1 to 50 degrees. Texas has a broader distribution of crude oil quality, with most production ranging from medium gravity oils to light oils, EIA said.

The lighter crude slate being produced from some of the shale plays has presented a challenge to domestic refineries, which generally have been designed to process heavier crudes, such as those that are imported. Some refineries have undergone modifications in order to be able to handle lighter crudes. Additionally more robust crude blending capabilities have been proposed for the Gulf Coast region in order to provide refiners with crudes tailored to their requirements (see Shale Daily, Oct. 6).

Aggregated crude production volumes for the Lower 48 states are reported to EIA for 10 API gravity categories that range from less than 20 degrees, to more than 55 degrees along with an “unknown” or “not reported” category. For individual states, four category breakouts of production by API gravity are provided: less than or equal to 30 degrees, 30.1-40 degrees, 40.1-50 degrees, and greater than 50 degrees.

“These new data on API gravity will give energy analysts a better handle on a variety of issues related to U.S. crude oil production, such as refinery inputs and utilization, crude oil trade, and regional crude oil pricing, said EIA Administrator Adam Sieminski. “Knowing more about the quality of domestic crude oil production can help oil markets operate more efficiently.”