Batupasir Formasi Jatiluhur merupakan lapisan yang merupakan analogi singkapan yang baik dari salah satu lapangan migas di Cekungan Jawa Barat Utara. Aktivitas tektonik sejak Miosen Tengah telah menyebabkan lapisan ini pecah, terlipat, dan terpapar ke permukaan, yang menyebabkan lapisan ini mengalami proses diagenesis secara bertahap. Penelitian ini dilakukan untuk mengetahui tahapan dan proses diagenesis yang terjadi serta pengaruhnya terhadap porositas batuan. Data dalam penelitian ini berasal dari pengukuran potongan stratigrafi yang kemudian dimasukkan ke dalam laboratorium petrografi dan SEM. Hasil analisis petrografi menunjukkan bahwa batupasir Formasi Jatiluhur telah mengalami proses diagenesis berupa pemadatan, pelarutan, dan sementasi. Pemadatan meliputi penataan kembali butiran sedimen dan rekahan dalam sampel batuan. Sementasi terlihat pada analisis SEM yang menunjukkan bahwa semen pada batupasir adalah kalsit, ilit, smektit, dan pirit mineral autigenik. Pelarutan sampel batuan membentuk porositas sekunder, sehingga meningkatkan bilangan porositas. Porositas berkisar antara 1-20%. Variasi nilai porositas ini disebabkan oleh proses sementasi dan pelarutan yang intensif. Dari hasil integrasi analisis petrografi dan SEM, disimpulkan bahwa batupasir Formasi Jatiluhur telah mengalami regim mesogenesis diagenesis.

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The Jatiluhur Formation Sandstone is a layer which is an analogy of a good outcrop from one of the oil and gas fields in the North West Java Basin. Tectonic activity since the Middle Miocene has caused this layer to break, fold, and be exposed to the surface, which causes this layer to undergo a gradual diagenetic process. This research was conducted to determine the stages and processes of diagenesis that occur and their effect on rock porosity. The data in this study came from measurements of stratigraphic pieces which were then entered into the petrographic laboratory and SEM. The results of petrographic analysis show that the sandstones of the Jatiluhur Formation have undergone diagenetic processes in the form of compaction, dissolving, and cementation. Compaction includes the rearrangement of sediment grains and fractures in rock samples. Sementation can be seen in SEM analysis which shows that the cement in the sandstones is calcite, illite, smectite, and autigenic mineral pyrite. The dissolving of rock samples forms secondary porosity, thereby increasing the porosity number. The porosity ranges from 1-20%. This variation in the porosity value is caused by the intensive cementation and dissolving processes. From the results of the integration of petrographic and SEM analysis, it is concluded that the sandstones of the Jatiluhur Formation have undergone a mesogenesis diagenesis regime.