In the pilot, it is shown that guests to the Getty Estate were directed to make calls using the payphone. This incident may have painted him as a miser, but there was a practical reason for doing so. Before the installation of the payphone, there was major hike in his communications cost, due to guests taking advantage of many phones throughout the house that had direct access to outside lines (long-distance, or placing drawn-out local calls). In addition to the payphone, the other phones had dial-locks placed on top of it.
The names of his exploratory wells: Hamish, Rob Roy, and Ivanhoe, are all characters from the books of Sir Walter Scott. Rob Roy was based on the exploits of an historical figure of that name.
This is not the first time Donald Sutherland played a billionaire. In Dirty Sexy Money (2007), his character was the polar opposite of JP Getty, in that he was more thoughtful and introspective, he tried to rectify the wrongs his family committed in the past and tried to guide the family on the right path into the future. JP Getty, on the other hand, seemed rather callous and indifferent to the needs of his family, and he only cared if they reflected poorly on him.