We carried out a screening study for an exploration license in a deep water section of Tonga’s territorial waters. A range of potential prospective oil field sizes were evaluated ranging from 30-150 million barrels recoverable. A database of onshore well logs was used to develop potential properties for the offshore prospects. The study’s key objective was to establish if economic solutions could be established for development of these relatively small prospective fields. In addition, detailed planning and cost assessments were carried out on the planned exploration drilling. Exploration, appraisal, development and operating cost estimates were generated using our NETCO$TER cost Evaluation Software.