Is Ophir Oil Field bigger than we think?

Have been researching Ophir oilfield after noticing different completion depths of the three horizontal production wells being installed at the moment. We haven't been told much about reserves, pay back time, contract duration etc so I thought i would look abit closer. Have found attached sectionals of Malay basin geology inc reference to Ophir.

We are just exploiting the J sands currently, there may be multiple oil sands below this which will affect the duration of Ophir production substantially. It always seemed strange to me that the only timeline I have seen on Ophir (3 years production) was so short. Interested to hear opinions.