The Strategic Petroleum Reserve (SPR) contains a number of domestic and foreign crude oils.  For the most part, these are of light gravity (30 to 40° API) and contain less than 2.0 mass percent total sulfur.  These crude oils are not segregated in storage but are commingled according to their sulfur content into two categories - one sweet and the other sour.  For the purposes of the SPR, sweet crude oils are defined as containing a maximum of 0.50 mass percent total sulfur, while sour crude oils can contain up to a maximum of 1.99 mass percent total sulfur.  Only similar quality crude oils are commingled in storage, with no mixing of sweet and sour streams being practiced.

The crude oil inventory comprising each of the eight SPR streams is stored in from two to 13 caverns, depending on the site.  The attached assays for these eight streams is a volumetric average of the assays for the individual caverns comprising each stream.

Any questions regarding the assays or the analytical methods used in obtaining these should be addressed to Jeremy J. Cusimano, Economist, Petroleum Reserves, US Department of Energy, RM: 3G-052, 1000 Independence Ave. SW, Washington, DC 20585, tel: 202-586-6244, fax: 202-586-0835.