Abraham was from Urkesh not Sumeria.

It's a pretty controversial position to take, that the Ur Kassadim "Ur of the Chaldeans" Abraham came from wasn't Ur in Southern Mesopotamia, but a city in modern Turkey.
UrKesh
First I'll copy this information from the Urkesh Wikipedia Talk page.

The gratuitous polemic "There seems to be a need to prove that Urkesh was not Ur of the Chaldees" has no place in this article, since no such link can be proven or disproven. While there may indeed be no link between Urkesh and the Biblical "Ur Kasdim", the obsessive and repeated attempts by archeologists, historians, and scholars to force an identification of Ur Kasdim with Sumerian "Ur" have proven groundless, and none of the aforementioned seems to have the courage to simply admit that the link is tenuous at best. The following are worth bearing in mind: 1. Sumerian "Ur" is a pure misnomer. In Sumerian cuneiform, it is called "Urima", and in Accadian "Uriwa", and the root of both names URI, is demonstrably of different form from the Hebraic name Ur. 2. The "Chaldees" is not the name of a country in the Bible, but of a tribe, Chaldeans. They are depicted in later books of the Bible as conquerors from outside Mesopotamia who conquered the area and took control of Babylon. However, there is no mention of the Chaldeans as a tribe anywhere in the Pentateuch, only the refererence to "Ur Kasdim". The name Kasdim may be ethymologically related to a relative of Abraham, Kesed, who, together with Aram, are descendants of Abraham's brother Nahor based in the vicinity of Harran, in Upper Mesopotamia. This region, known in Genesis as Aram Naharaim, is very clearly and repeatedly referred to as the place of origin of the Hebrew patriarchs, NOT Sumeria (which is referred to in Genesis as the 'Plain of Shinar'). There is no mention of Chaldeans active in this region until the late Israelite monarchy, more than 1000 years later, and their is no precedent in the Pentateuch for an anachronism on a scale of this magnitude. After the Exodus from Egypt, in Deuteronomy 26, the Hebrews are asked to recite a passage to recall their patrimony: "A wandering Aramean was my ancestor; he went down into Egypt and lived there as an alien, few in number, and there he became a great nation, mighty and populous." It is clear that the association of their patrimony was with rustic pastoralism, and not with the settled urbanised city life characteristic of the bustling urban metropolis and port city of Sumerian "Ur". The lifestyles of the early patriarchs simply cannot be tallied with those of the cityfolk of the Sumerian metropoli. It is evident from the Biblical narratives that the patrimony of the Hebrews is placed in the vicinity of Harran. I do not believe that Urkesh was Ur Kasdim, and in my opinion, a far more likely candidate for it is Urfa, AKA Edessa, which is regarded in Islamic tradition as the birthplace of Abraham. Such a tradition is not a recent invention, but stemmed from ancient Syriac Christian tradition linked to the city, which in turn must have come from the very ancient Jewish community there (one of the ancient Greek names for the town was reputedly Αντιόχεια της Ιουδαίας , i.e. Antioch of the Jews.) In fact, one of the earliest known Hellenistic Greek names of the city, was Ορρα (ORRA, Romanized form Orrha). Such a link cannot be made with certainty, but it is the certainty with which sholars identify Sumerian "Ur" with Ur of the Chaldees when not a shred of evidence exists to justify such a link that ought to raise eyebrows. --Jacob Davidson

Urkesh also had a King named  Te'irru . He's probably not the same person as Terah the Father of Abraham, but often people are named after Kings, or Kings are named after famous people.

I agree with the Specialtyinterests site's argument for the Kassites and the Kassadim/Chaldeans being the same people.  They connect the etymology very well.  But I'm not sure I agree with moving down the Kassite period.
www.specialtyinterests.net/the_grand_vizier
The point is that identification verifies that the Kassadim where NOT in Mesopotamia until well after the time of Abraham, at the soonest the Kassites came to Shinar at the start of the Hycsos/Judges period.  They originally migrated from a mountain region in modern Turkey, which one is uncertain, the Zargos mountains are popular , but the Taurus mountains where Urkesh is are also possible.  They may have inhabited more then one range.

I enjoy Velikovsky's article on Hammurabi.
http://www.varchive.org/ce/hammurabi.html