Shun Chiyonobu

The Jurassic Period was a significant phase of variable organic matter accumulation in paleo-shelf areas of the southern Tethys (Egypt). Reconstructing the paleoredox conditions, paleoclimate, and weathering intensity, along with the role of terrigenous sediment flux and mineralogical maturity, is important for understanding basin infill history and prevalent paleoenvironmental conditions. Here, inorganic geochemical data are presented from the Middle Jurassic Khatatba Formation and two samples from the underlying Ras Qattara and the overlying Masajid formations in the Jana-1x well, Shushan Basin, Western Desert. Twenty-four (24) whole-rock samples were analyzed for their major and trace element composition and carbonate content. The Khatatba Formation represents one of the major hydrocarbon source rocks in the North Western Desert, Egypt. Redox conditions were assessed based on enrichment factors of redox-sensitive elements Mo, V, U, and Co. Results revealed that the Khatatba Formation was deposited under predominant anoxic bottom and pore water conditions, in contrast to the oxic settings that were prevalent during the deposition of the Ras Qattara and Masajid formations. Continental weathering intensity and paleoclimate were reconstructed based on several proxies, such as the chemical index of alteration (CIA), K₂O/Rb, Rb/Sr, Ln(Al₂O₃/Na₂O), and Al/K ratios, indicating that the studied succession was deposited during alternating phases between weak and moderate weathering intensity under arid and warm-humid climates, respectively. Periods of enhanced continental weathering were associated with high values of clastic ratios such as Si/Al, Ti/Al, and Zr/Al, suggesting increased terrigenous sediment supply during intensified hydrological cycling. These ratios further provided inferences about the changes in sediment grain size, such as a change from shale to coarse silt- and sand-size fractions.

In northern Afghanistan, the Kashkari oil field’s first production well was drilled in 1976, and by 1979, there were a total of ten wells drilled in the area. According to the results of surveys and calculations conducted by research institutions, the total amount of original oil in place (OOIP) in the Kashkari oil site was around 140 million barrels (MMbbls). Therefore, a method to increase the total amount of recoverable oil in the Kashkari oil field by low-salinity water flooding is presented in this study. First, the oil extraction method by low-salinity water injected into the underlying petroleum storage tank was examined by both a laboratory core flooding test and a numerical simulation model. Laboratory conditions (temperature, pressure, rock properties, and oil properties) were designed to mimic those of the Kashkari oil field. Additionally, different injection (Inj) and production patterns were considered to achieve the best results. Next, results obtained from the laboratory and computer simulations were compared. Then, the total amount of recoverable oil was calculated using the low-salinity water flooding method. Based on the findings, details of the simulated model were applied to the Kashkari reservoir model for extracting oil by injecting low-salinity water in the oil field. As a result, an amount of 10.3 MMbbls, which is about 7.5% of the field, was produced.

Classification, segmentation, and recognition techniques based on deep-learning algorithms are used for smart farming. It is an important and challenging task to reduce the time, burden, and cost of annotation procedures for collected datasets from fields and crops that are changing in a wide variety of ways according to growing, weather patterns, and seasons. This study was conducted to generate crop image datasets for semantic segmentation based on an image style transfer using generative adversarial networks (GANs). To assess data-augmented performance and calculation burdens, our proposed framework comprises contrastive unpaired translation (CUT) for a conditional GAN, pix2pixHD for an unconditional GAN, and DeepLabV3+ for semantic segmentation. Using these networks, the proposed framework provides not only image generation for data augmentation, but also automatic labeling based on distinctive feature learning among domains. The Fréchet inception distance (FID) and mean intersection over union (mIoU) were used, respectively, as evaluation metrics for GANs and semantic segmentation. We used a public benchmark dataset and two original benchmark datasets to evaluate our framework of four image-augmentation types compared with the baseline without using GANs. The experimentally obtained results showed the efficacy of using augmented images, which we evaluated using FID and mIoU. The mIoU scores for the public benchmark dataset improved by 0.03 for the training subset, while remaining similar on the test subset. For the first original benchmark dataset, the mIoU scores improved by 0.01 for the test subset, while they dropped by 0.03 for the training subset. Finally, the mIoU scores for the second original benchmark dataset improved by 0.18 for the training subset and 0.03 for the test subset.

The Onnagawa shale is a middle Miocene deposit that extends along the Akita coastal area. This formation contains organic carbon enriched siliceous mudstones deposited in the basins during the early stages of the Japanese sea opening. Some researchers in petroleum geochemistry have demonstrated that these organically enriched rocks possess attributes common to oil source rocks. JOGMEC has previously perfomed shale oil reservoir characterization of the Onnagawa shale, pilot hydraulic fracturing tests, and coring through the Onngawa shales sequence. The main goal of this paper is to use methods to estimate rock properties characterized by porosity and permeability to develop an understanding of fraccability based on lithofacies and mineral composition and their distribution in the Onnagawa Formation. Core sample from the Onnagawa shale were drilled at the Unosaki coast in the Oga peninsula. Rock property, mineral composition, and lithofacies were analyzed by CMS-300, QEMSCAN, and FIB-SEM in JOGMEC-TRC. The study results identify successes or fail parts of hydraulic fracturing depending on lithofacies and mineral compositions and indicate that 1）the lihofacies of the Onnagawa shale are dark gray to light gray colored massive, bedded, and laminated. 2）the porosity and permeability values in the light gray colored facies are relatively higher than dark gray colored facies. 3）the QEMSCAN shows the Onnagawa Formation is characterized by layered carbonate concretions with dolomite and calcite and consists chiefly of quartz with clay minerals and framboidal pyrite. 4）hydraulic fracturing tests succeeded in dolomite and calcite composed carbonate concretion layers.

Sedimentological, geochemical, and chronological analyses were carried out on 18 carbonate rock samples collected at depths of 938, 1085, and 3354 m on the western slope of Minamitorishima (Marcus Island), which is located near the western margin of the Pacific Plate. Four groups of carbonate rocks were distinguished: a mollusk‐rich limestone, a coral‐rich dolomite, a foraminiferal‐nannofossil packstone, and a phosphatized mudstone/wackestone. The mollusk‐rich limestone is characterized by the dominance of bivalves (including rudists) and gastropod shells. Strontium isotope ratios (⁸⁷Sr/⁸⁶Sr) and Mesorbitolina ex gr. texana (a large benthic foraminifer) indicate that the shallow‐water carbonates were deposited during the late Aptian–early Albian (ca. 123–111 Ma). The coral‐rich dolomite is characterized by abundant scleractinian corals and nongeniculate coralline algae associated with encrusting acervulinid foraminifers. The biotic composition is similar to that of the Oligocene–Pleistocene carbonates reported from other seamounts in the northwestern Pacific. Geochemical data show that the coral‐rich carbonates were dolomitized at 9.5–6.8 Ma (Tortonian–Messinian) and that normal seawater was the most likely parent fluid. The foraminiferal‐nannofossil packstone is a semi‐consolidated foraminiferal‐nannofossil ooze and was deposited during the Pleistocene (0.99–0.45 Ma). The phosphatized mudstone/wackestone is marked by the absence of macrofossils and the presence of traces of planktic foraminifers. Although its depositional age is not constrained, the Sr isotope ratios indicate that the phosphatization occurred at 33.2–28.9 Ma. After the deposition of the Cretaceous shallow‐water carbonates, including the mollusk‐rich limestone, Minamitorishima was drowned and its top was covered with a pelagic cap, represented by the mudstone/wackestone. The late Eocene–early Oligocene volcanism (40.2–33.2 Ma) caused episodic uplift and returned the top of Minamitorishima to a shallow‐water environment. After the early Oligocene phosphatization of the pelagic cap, coral reefs flourished on the top of this island. The reef limestone was dolomitized during the Tortonian–Messinian.