Situated at tropical latitudes with a humid paleoclimate, the area of the present-day Indonesian archipelago was very suitable for production and accumulation of carbonate sediment during much of the Cenozoic. Following early Paleogene rifting that resulted in development of horst and graben structures, the peak of carbonate production occurred from the late Oligocene to Mio–Pliocene. This paper summarizes several Indonesian isolated carbonate platforms that formed on marine horsts. Of these examples, Banyu Urip in Java, Kerendan in Kalimantan, and Arun Field in Sumatra have provided important contributions to Indonesian oil and gas production for the last few decades, whereas Natuna D-Alpha in the Natuna Sea will become a giant gas field in the future. To achieve the objective of characterizing Cenozoic carbonate platform reservoirs of Indonesia, this study reviews the Cenozoic carbonates in the East Java Basin, Kutei Basin, North Sumatra Basin, and Natuna area and places them in the context of the regional geology of Sundaland. Insights from previously published work are supplemented by new descriptions of cores, well-log analyses, and interpretations of two- and three-dimensional seismic facies analysis, well-log correlation, and sequence stratigraphy. These geological and geophysical data have been integrated with dynamic reservoir data to validate the geological and geophysical interpretations. The results reveal that the Indonesian carbonates of Banyu Urip, Kerendan, Arun, and Natuna D-Alpha are classic isolated carbonate platforms and can serve as examples to recognize reservoir character. Those platforms developed in the same general regional geologic setting relative to the Sundaland continent and share certain similarities, but local geologic variations and distinct processes gave each platform particular characteristics. Reservoir quality of the carbonate platforms is influenced by relative changes in sea level, the position relative to the shoreline or fully open-marine settings, and the influences of both regional and local tectonic events. The fields thus illustrate several conceptual models of carbonate reservoirs in isolated platforms. Understanding the character and variety of Indonesian reservoirs as related to their depositional processes and regional position provides insights for exploration and reservoir management of analogs elsewhere.

Abstract This chapter presents a collection of first-generation Swiss geologists, who, around 1900, went abroad in order to work for oil organizations, both public and private. With the rise of oil exploration after 1900, the demand for experienced oil geologists grew rapidly. Oil companies started hiring trained geologists from different parts of the world, which led to an increasing number of Swiss geologists finding employment abroad. One of the first to start his career abroad was Carl Schmidt (1862–1923) from Basel, highly esteemed and later renowned for his achievements as a teacher of younger oil geologists. Another was Josef Erb (1874–1934), who accomplished an unparalleled career at Royal Dutch Shell. Other examples include Hans Hirschi (1876–1964), who worked for the Union des Pétroles d’Oklahoma for a few years, and Arnold Heim (1882–1965), working nearly 50 years for major oil companies. Many more followed over the decades to come, so that virtual successions took place between them: specific territories and specific companies were ‘handed down’ between geologists of the same nationality. Where once the Swiss were employed, others took over; the pioneers acted as door-openers for future generations.