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Abstrak :
Penelitian ini merupakan langkah awal yang terbilang baru di Formasi Jatiluhur, Sungai Cibeet untuk menganalisis proses diagenesis, mengidentifikasi fitur diagenesis dan sejarahnya. Daerah penelitian tersusun oleh batuan silisiklastik berupa batupasir, batulanau, batulempung, terdapat pula batuan bersifat karbonatan. Sebanyak sepuluh sampel dilakukan analisis petrografi untuk menentukan karakterisasi tekstur dan mineralogi batuan. Selain analisis petrografi, analisis SEM dan XRD sebanyak masing-masing tiga sampel dapat digunakan untuk studi diagenesis. Beberapa proses diagenesis seperti kompaksi, sementasi, disolusi, dan penggantian mineral dapat memengaruhi keterbentukan batuan Formasi Jatiluhur. Proses kompaksi menghasilkan kontak antarbutir berupa point, long, concavo-convex, dan sutured serta semen yang ditemukan berupa semen kalsit dan mineral lempung seperti albit, ilit, kaolinit, dan smektit. Mineral kuarsa, mika, dan feldspar mengalami penggantian. Proses-proses diagenesis tersebut mengakibatkan perubahan porositas dari batuan. Tipe-tipe porositas didominasi oleh tipe intergranular dan intrapartikel dengan persentase antara 5-30%. Sejarah diagenesis pada daerah penelitian diawali oleh tahap eogenesis, mesogenesis, dan telogenesis. Dengan adanya pelaksanakan studi diagenesis, maka kualitas reservoar (misalnya) dapat ditentukan. Penelitian ini menunjukan bahwa proses diagenesis mengakibatkan adanya heterogenitas batuan Formasi Jatiluhur di sekitar aliran Sungai Cibeet. ......This research is a relatively new to conduct in the Jatiluhur Formation, especially Cibeet River that aimed to analyse the diagenesis process and identify diagenesis features and its history. The research area is composed of siliciclastic rocks in the form of sandstone, siltstone, and claystone but there are also carbonate rocks. A total of ten samples were subjected to petrographic analysis to determine the characterisation of rock textures and mineralogy. In addition to petrographic analysis, SEM and XRD analysis of three samples each are used for diagenesis studies. Several diagenesis processes such as compaction, cementation, dissolution, and mineral replacement affected the rock formation of the Jatiluhur Formation. The compaction process produced contact between grains in the form of point, long, concavo-convex, and sutured contacts as well as cement found in the form of calcite cement and clay minerals such as albite, illite, kaolinite, and smectite. Quartz, mica, and feldspar minerals underwent mineral replacement. These diagenesis processes resulted in changes in the rock porosity. The types of porosity are dominated by intergranular and intraparticle types with the percentage between 5-30%. The history of diagenesis in the research area began with the stages of eogenesis, mesogenesis, and telogenesis. With the implementation of a diagenesis study, the quality of the reservoir (for example) can be defined. This study shows that the diagenesis process resulted in the heterogeneity of the Jatiluhur Formation rocks around the Cibeet River streams.

Abstrak :
ABSTRAK
Batugamping Formasi Kais merupakan reservoar utama penghasil hidrokarbondilapangan Asmorom yang berumur Miosen Tengah. Lapangan ini berada diCekungan Bintuni Papua Barat dan merupakan bekas peninggalan Belanda.Penelitian ini bertujuan untuk melakukan detail fasies pengendapan dan prosesdiagenesis serta rock typing diharapkan dapat memberikan hasil yang lebih baikuntuk melihat karakteristik reservoar karbonat dan potensinya. Batugamping Kaisdiidentifikasi menjadi tiga unit yaitu lapisan Kais Atas, Kais Tengah, dan Kais Bawah yang berasosiasi menjadi lima fasies yaitu fasies shelf, front reef, interreef, back reef, dan core reef. Asosiasi fasies ini diinterpretasikan sebagai fasieskarbonat platform. Kualitas reservoar ini direview dari asosiasi fasies, analisispetrografi dan biostratigrafi, memperlihatkan bahwa lapisan atas dan bawahdikontol oleh proses diagenesis kompaksi dan porositas rekahan sedangkanlapisan bawah dikontrol oleh proses diagenesis dolomitisasi, pelarutan, danporositas rekahan.

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ABSTRACT
Kais Formation limestone is the main reservoar that produce hydrocarbon inAsmorom field in Middle Miocene. This field is located at Bintuni Basin WestPapua and used to run by Ducth company. The researchs proposed to do detaildepositional facies and diagenesis process with rock typing to characterize thepotential of carbonate reservoir. Kais Limestone can be identified in to threemembers namely Upper Kais, Middle Kais, and Lower Kais which are associatedin five different faciesnamely shelf, front reef, inter reef, back reef, and core reeffacies. The facies associations are interpreted as reefal platform carbonate. Thereservoir quality, which is reviewed from facies association, petrography andbiostratigraphy analysis shows that the Upper and Middle kais are controlled bycompaction diagenesis and fractures porosity, in another hand the Lower Kais iscontrolled by dolomitization diagenesis, dissolution, and fractures porosity.

Abstrak :
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. ......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.

Abstrak :
ABSTRAK
Pada kebutuhan industri, terutama di bidang eksplorasi migas dan hidrogeologi, nilai porositas pada batuan dianggap sangat penting. Porositas pada umumnya terdapat di batuan sedimen, khususnya batupasir yang terdapat Formasi Cipacar. Penelitian ini bertujuan untuk mengetahui karakteristik batupasir, nilai porositas, proses diagenesis, dan hubungan antar porositas dan diagenesis. Data penelitian ini didapat dari singkapan permukaan dan dilakukan analisis petrografi. Hasil penelitian ini menunjukkan bahwa batupasir Formasi Cipacar memiliki nilai porositas antara 8-14% dan telah mengalami proses diagenesis berupa kompaksi, sementasi, dan pelarutan yang termasuk dalam rezim mesogenesis.

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ABSTRACT
On industrial needs, especially in oil & gas and hydrogeology exploration porosity in rock isconsidered valuable. Porosity in rock basically available in sedimentary rock, particulary sandstone in Cipacar Formation. The aims of this research are to examine sandstone characteristic, porosity value, diagenesis process, and implication between porosity and diagenesis. The data of this study were obtained from surface outcrops and petrographic analysis. Results of this research show that sandstones in Cipacar Formation have porosity value between 8-14%, and have undergone diagenesis process such as compaction, cementation, and dissolution which classified in mesogenesis regime.