from the time of the flood receding to Abraham was 344 years. Noah lived another 350 years, so he died when Abraham was 6. During this 344 year period, the world population seemingly exploded from nowhere. Noah had 16 grandson's : Japeth 7 sons, Shem 5 sons, and Ham 4 sons. mathematically it is improbable that this small family could have been alone in re-populating the earth. During this time period the tower of babel was built and the languages confused, and many nations were established.
soon after, war broke out; 5 kings allied against 4, during which Abraham's kinsmen, Lot, is captured. Abraham mobilizes his 318 trained men (presumably there were some untrained), and effects a rescue.
Eventually at 84 and then at 100 Abraham has Ishmael and Isaac. The covenenat is made and the family flourishes.
Again his kinsman Lot seems to be at the center of trouble, as he is dwelling in the wicked city of Sodom. Sodom was one of the nations at war earlier mentioned. There population would have been at 1000 people (minimally), as they had an army, slaves, women and a government system.
My point is this: in 344+100=444 years. when disease, infant mortality rates, famine and war are considered, the population density is far too high. Up to around the time of Abraham, the history is not plausible or feasable.