Why were the earliest oil companies unable to drill in Indian Territory?

They did not have the equipment.

They did not have government approval.

The Native Americans refused their offers.

The workers were not available.

The natives refused their offers

The earliest oil companies were unable to drill in the Indian territory because the Native Americans refused their offers.

Explanation:

The Native Americans, in the first place, were reluctant towards the establishment of colonies by the Spanish, French, English and the Dutch. They had already started looking at it as infiltration of the outsiders into their homeland.

Wherever the settlers tried to use force to pursue the Native Americans to allow them to mine and drill, there were conflicts and casualties were caused on both sides.

The colonists soon overpowered the Native Americans as they brought modern weapons like guns in use. It was only after the Native Americans came to know that they cannot win against the colonists in war, they backed up and allowed oil companies to drill in their territories.