This study was conducted to obtain the characteristics of the source rock through organic geochemical analysis in Central Deep, NE Java Basin, in the field off the north coast of Madura. Three samples of Cassiopeia-1, Pollen-1, and Alpha-1 wells were analyzed using organic geochemical methods including Total Organic Carbon analysis, Maturity using vitrinite reflectance, Tmax, and Production Index data, and then analysis of the kerogen type, isoprenoid, sterane, and carbon isotope. Based on those data, an analysis was carried out to determine the origin of the material and the depositional environment. The rock samples in the three wells showed characteristics in TOC, maturity, kerogen type and source of organic material have a similarity. The source rock characteristics have a medium to a good category as source rock and tend to generate gas and a little oil from kerogen types II and III. This source rock is included in the category of immature to mature, deposited in delta until terrestrial depositional environment and contains sources terrestrial and marine organic material.Keywords: Madura, North East Java Basin, organic geochemical, source rock.

The results of this study identified two potential source rock intervals of Permian age in the North Arafura Shelf area of Papua, Indonesia. The first potential source rock interval (SR-1) was identified at 3834.9 m to 3838.6 m depth within the Kola-1 well, which is believed to be good to very good potential source rock with TOC in the range of 2.94 to 3.4 wt %, S1 0.78 to 0.97 mg HC/g, and S2 5.63 to 9.5 mg HC/g. The source rock is composed of type II and III kerogens with HI in the range of 164 to 275 mg HC/gTOC and reached the maturation stage with Ro of 0.83 -0.86%, Tmax of 442 -444 o C, and Production Index (PI) of 0.09 -0.12. The second potential source rock interval (SR-2) is at 3060.1 -3136.3 m depth in the ASM-1X well and has fair potential to be source rock with TOC of 0.95 wt %, S1 of 1.01 mg HC/g, and S2 of 3.39 mg HC/g. This source rock has type II kerogen with a HI value of 357 mg HC/g TOC and has reached maturation as indicated by a Ro value of 0.63%, Tmax of 430 o C, and PI of 0.23. Biomarker analysis revealed SR-1 is type III kerogen with terrigenous input and was deposited in an estuarine environment.

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