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This paper describes drilling operations in two rank wildcats drilled by Mobil in the karst region of Irian Jaya. Exploration interest in this area was sparked by Chevron - BP discoveries in Papua New Guinea. In 1988, Mobil was awarded two PSCs in Irian Jaya, in partnership with BHP Petroleum. These blocks are about 500 miles West of the Chevron - BP discoveries. Later, Mobil and BHPP were awarded a third block West of the original two (Figure 1).Two rank wildcats have been drilled so far in a difficult operating environment. Major factors discussed in this paper, include the remoteness of the area, helicopter lift, the 2,000 mile barge trip to the main supply point, drilling with foam, and massive lost circulation. Mobil intends t,o drill one or two more wells in Irian Jaya within 12 months.Operations in the karst area of Irian Jaya are remarkably different from operations in the rest of Indonesia. Resupply is a 3 week barge trip from a major supply point. Conventional seismic tools cannot be employed due to energy absorption by the overlying vuggy carbonate. ConventionalSoft Rock considerations featuring high thermal and pore pressure gradients, the importance of casing seat integrity, etc. fall by the wayside here. These items, as well as the importance of logistics (2/3 of well costs), helicopter services, marine supply, and preplanning are all addressed in this paper.