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In view of the complex geological conditions and high drilling risk of TN Oilfield, analysising the influence of oil source, unconformity surface, fault properties and sandstone by strengthening the study of oil-rich regularity. The oil field has the characteristics of “near source reservoir, fault controlled reservoir, and enrichment of domi-nant facies”. The rolling development model of oil reservoirs has been established, which involves tapping the potential of fault zones and evaluating new traps, finely delineating the main sandstone in lithological reservoirs, optimal selection of favorable areas by matching the main sandstone with favorable traps, and achieving good development results.

The Kerek Formation in Sojomerto, Kendal, Central Java is the westernmost part influenced by the Kendeng zone. The presence of sandstone lithofacies in the study area can be a useful tool for determining composition and the provenance. This study involved field observation and analysis of eight thin sections of sandstone from the field. There is no notable petrographic difference across the sandstone succession in the study. the sandstones are predominantly composed of lithic components (48%-63%), matrix (2%-16%), and quartz (1%-24%) thus classified as lithic arenite and lithic wacke. The combination of quartzfeldspar-lithic (QFL) diagram indicates that the sandstone in research area was the result of volcanic activity which is in the southern part of the study area.

The formation of iron- and/or manganese-rich dark patinas on sandstones is a common natural phenomenon that occurs also on building stones. Lunéville château, in eastern France, presents such patinas that developed either under natural conditions (rain and time) or after an accidental fire and exposure to significant amounts of water as part of attempts to extinguish the fire. The present study aimed at characterizing both types of patinas in an effort to determine their formation mechanisms and Mn sources. In both cases, Mn required for patina formation likely derives from the reductive dissolution of Mn-rich minerals present in pristine sandstones, as suggested by the contrasting mineralogy and chemistry of Mn-rich phases present in the bulk and in the patina of a given building block. Reduced Mn species then migrate to the exposed surface of building blocks where they are re-oxidized via undetermined processes. Patinas developing \"naturally\" over time result from the alternation of wetting-reducing and drying-oxidizing cycles and appear to be composed of birnessite. Patinas formed after the 2003 fire result from this single accidental event and form a much thinner, heterogeneous, and discontinuous layer of poorly crystalline lithiophorite at the sandstone surface (â¼ 0-150 µm compared to â¼ 300-600 µm for \"natural\" patinas). The lack of Mn-rich patinas on areas of Lunéville château is likely related to the lower Mn content of pristine sandstone blocks.

Calcium-containing sandstone layer is widely developed in the sandstone reservoir of D oilfield, accounting for 27.3% on average, with its cemented compaction, poor material property and poor oil content. The calcium-containing sandstone layer has been interpreted as a low hole and low permeability layer in the study area. According to the analysis of the closed core data, the medium and high permeability reservoir in the calcium content layer accounts for more than 60%, and the yield of oil immersion accounts for more than 50%, which is the reserve force for reserve replacement. Researchers from the origin of calcium layer, calcium layer core form, further study of calcium layer lithology, electrical, physical characteristics, the decomposition of calcium sandstone layer, by explaining the influence of calcium layer and calcium sandstone permeability on permeability, calcium permeability interpretation model, calcium layer permeability interpretation accuracy is greatly improved, explain the relative error from 898% to 50%, calcium layer between layers and layer differences get more accurate understanding, provide a more solid guarantee for reservoir fine development.

The interpretation of depositional environment and diagenesis controls on petroleum reservoirs are a major challenge that has an impact on the petroleum system of hydrocarbon reservoirs. For the evaluation of hydrocarbon exploration and development, detailed depositional facies and reservoir characteristics are needed. However, some oil fields worldwide lack core samples, which are needed for accurate research. This research aims to analyze the consequences of integrating gamma-ray log patterns with petrographic analysis to describe the depositional setting in the Baba sandstone hydrocarbon reservoir within the Badri field in Egypt's south-central Gulf of Suez. The effect of diagenesis on the reservoir pore system network was also investigated. For this study, the available dataset includes wireline logs dataset and ditch cutting analysis to provide rock mineralogy, grain size, texture, sorting, cementation, accessory minerals, and lithology. Petrographic analysis reveals that Baba sandstone is dominated by medium-grained, moderately to poorly sorted, and arkose. Based on petrographic analysis data, the Baba sandstone provenance is constrained to the adjacent Precambrian Basement units of the Sinai peninsula. Thin section analysis and the point count method identify primary intergranular macroporosity, secondary intragranular macropores, and intercrystalline micropores within the studied sandstone. Based on petrographic analysis, grain–grain relationships, and framework grain–cement relationships of thin sections, the Baba sandstone has most likely been subjected to significant physical and chemical diagenetic processes, resulting in a decrease in primary porosity. The diagenetic analysis suggests that the sandstone has undergone significant alteration such as compaction, cementation, dissolution, and clay minerals alteration. Based on gamma-ray log investigation, the cylindrical gamma-ray pattern is the sole electrofacies that characterized the Baba sandstone. The tidal sand bar is the most likely depositional environment based on log pattern, petrographic analysis, and elongated depositional direction. The present study provides insights into how to solve the lack of core samples in petroleum reservoirs and it can be applied elsewhere to better interpretation of depositional settings, and diagenesis control on the reservoir pore system network.

In this paper, the synchronous squeezing wavelet transform (SSWT) is used to process the conventional logging curve, and the spectral characteristics of logging signal are obtained. The results show that the spectral characteristics of SSWT logging in tight sandstone reservoir are more obvious than that in depth domain, and have different characteristics for different reservoir fluid properties, which is helpful to identify the fluid properties of complex reservoirs.

The fluvial-aeolian Upper Rotliegend sandstones from the Bebertal outcrop (Flechtingen High, Germany) are the famous reservoir analog for the deeply buried Upper Rotliegend gas reservoirs of the Southern Permian Basin. While most diagenetic and reservoir quality investigations are conducted on a meter scale, there is an emerging consensus that significant reservoir heterogeneity is inherited from diagenetic complexity at smaller scales. In this study, we utilize information about diagenetic products and processes at the pore- and plug-scale and analyze their impact on the heterogeneity of porosity, permeability, and cement patterns. Eodiagenetic poikilitic calcite cements, illite/iron oxide grain coatings, and the amount of infiltrated clay are responsible for mm- to cm-scale reservoir heterogeneities in the Parchim formation of the Upper Rotliegend sandstones. Using the Petrel E&P software platform, spatial fluctuations and spatial variations of permeability, porosity, and calcite cements are modeled and compared, offering opportunities for predicting small-scale reservoir rock properties based on diagenetic constraints.

Under the action of a load, internal pores and cracks expand, and irreversible plastic deformations occur. Compared with conventional rock mechanics tests, nuclear magnetic resonance (NMR) can characterize the size and distribution of pores at the microscopic scale. In this study, a series of low-confining-stress triaxial compression tests were performed on different types of sandstone samples using real-time T2-weighted NMR spectra and imaging. It was found that the area of macropores in sandstone significantly increased only during the initial loading stage, but played an opposite role in the damage evolution process. This phenomenon is contrary to our expectations and provides a new basis for understanding the evolution of damage in rocks. Furthermore, during the linear deformation stage, the number of pores and mesopores increased, whereas the number of macropores decreased. A damage model based on the NMR results is proposed. The value of Dn sharply increases during the initial stage due to the expansion of pores, then decreases, and finally begins to increase again before the failure stage and until the sample fractures owing to the development of macroscopic cracks. In conclusion, the structure of micropores has a significant influence on the failure mode of sandstone rocks in low-confining-pressure triaxial compression tests.HighlightsThe area of macropores in sandstone significantly increased only during the initial loading stage and played an opposite role in the damage evolution process.During the linear deformation stage, the number of pores and mesopores increased, whereas the number of macropores decreased.The structure of micropores has a significant influence on the failure mode exhibited by sandstone during low-confining-pressure triaxial compression tests.