The Oseberg ship was not actually used as a burial site itself. The ship was found in a burial site in 1904. Located within the burial mound, archaeologists found the Oseberg ship (named after the farm site it was discovered upon), the skeletons of two women, and multiple objects typically found within a burial mound. The ship has renown as the most spectacular Viking ship from history.
Given the moisture content of the haugr (or burial mound), the contents found in the burial mound were very well preserved.
The skeletons of the women were placed in a wooden tent in a central location of the mound. Research states that one woman was around eighty (and she suffered from arthritis) and the other woman around fifty. Nothing has been found to suggest the relationship between the two at all. Some have suggested that the older of the two women may have been the grandmother of Norway's first king, Queen Asa.
Therefore, since nothing solid has ever been found to suggest that the body is actually that of Asa, the conclusion has to be that the Oseberg ship's use to accompany two women to their deaths didn't imply more than that bear fact. The kind of person buried with the Oseberg ship is known only to be female (given that no other research or findings suggest anything different).