"어디에 기름이 있습니까?"
Translation:Where is the oil?
Its right. Here's the official dictionary: https://krdict.korean.go.kr/eng/mainAction?nation=eng
Technically, it is "어디" that means "where". However, it is often used with the location markers "에/에서" depending on the context. While it is possible to make sentences without location-marking particles, you can make your message very clear by using the right location marker.