Since the 1870s, the onshore area of the Northeast Java Basin has been explored based on the traditional stratigraphic concept. Drilling near seepages were performed and finally discovered the Kuti-Gununganyar oil field (1888) and Lidah oil field (1889) near Surabaya, Ledok oil field (1893) and Kawangan oil field (1894) near Cepu. This was followed with discoveries and development more than 30 oil and gas fields within the basin.
In the 1970s, classic stratigraphic concept was introduced by several workers and lead Pertamina to conduct modern and intensive exploration in the proximity of Cepu. Several exploration wells such as Kujung-1, Durmawu-1, Purwodadi-11, Dander-1 and Jatirogo-1 have been drilled but failed to discover oil or gas in a commercial quantity.
In the 1980s, new classic and sequence stratigraphic concepts were applied in the Northeast Java Basin Based on this concept, Pertamina in Cepu area, JOB Stanvac in Gundih area and JOB Trend in Tuban area, ran some geological and geophysical surveys and drilled several exploration wells. However, once again, they failed to discover economical hydrocarbon reserves.
In the 1990s, modern sequence stratigraphic concept was widely applied in the petroleum industries in the world. Based on this modern concept Pertamina, Humpuss; JOB Santa Fe and JOB Huffco Brantas, started again to explore the onshore area of the Northeast Java Basin. Finally, JOB Santa Fe discovered oil in Tuban area, Pertamina found gas in Rembang area and JOB Huffco Brantas found gas in Porong area while Humpuss is still continuing their exploration effort in Cepu and the surrounding areas.
It is interesting to note that hydrocarbon play concept in the hydrocarbon exploration is very much influenced by the stratigraphic concept. The development of stratigraphic concept from traditional, classic to modern stratigraphy and their relationship to hydrocarbon play concepts applied to the Northeast Java Basin proved that they are important key factors in the hydrocarbon exploration.
Author : Sabardi Musliki