Impact Of Diagenetic Processes Research Articles

Correction to: Impact of diagenetic processes on the petrophysical properties and quality of the Miocene “Reefal limestone” reservoir in Al-Hamd field, Gulf of Suez, Egypt

Correction to: Impact of diagenetic processes on the petrophysical properties and quality of the Miocene “Reefal limestone” reservoir in Al-Hamd field, Gulf of Suez, Egypt

Impact of diagenetic processes on the petrophysical properties and quality of the Miocene “Reefal limestone” reservoir in Al-Hamd field, Gulf of Suez, Egypt

Unconventional reservoirs have burst with a great force in the oil and gas worldwide production. Reefal limestone reservoir is one of them. The present study deals with the reefal carbonate Hammam Faraun Member in Al-Hamd oil field. This study focus on the interpretation of sedimentological and petrophysical data to show the effect of diagenetic processes on middle and lower Miocene reefal carbonate reservoirs in Al-Hamd oil field. Comprehensive petrophysical analysis for Hammam Faraun Member was performed using wireline logs and core data to determine the proper petrophysical parameters. Of the reservoir intervals. The analytical reservoir rock achieving the main reservoir parameters as shale content (Vsh), effective porosity (Oeff), water and hydrocarbon saturation (SW and Shr) as well as the net-pay thickness. The Formation Micro Imager (FMI) was also applied to detect the variation, types, and directions of the fracture systems that present in the lower and middle Miocene reefal limestone reservoir. Petrographic analysis was done, indicating the presence of a clear effect of diagenetic factors on the quality, productivity, and efficiency of the reefal limestone reservoirs behavior. The diagenetic factors include dolomitization, slicification, recrystallization, and solution process which affect greatly the petrophysical characteristics of the reefal carbonate Hammam Faraun reservoir in the study area. The core analyses were also used to detect the paleo environment, associated textural/ lithological and sedimentological characteristics to gain and understand the factors responsible for the productivity behavior of the reservoir in the Al-Hamd oil field. Rock facies have been divided as specific characteristics and were further described considering their color, texture, grain-size characteristics, and the depositional and biogenic sedimentary structures.

Pore network properties of sandstones in a fault damage zone

The understanding of fluid flow in faulted sandstones is based on a wide range of techniques. These depend on the multi-method determination of petrological and structural features, porous network properties and both spatial and temporal variations and interactions of these features. The question of the multi-parameter analysis on fluid flow controlling properties is addressed for an outcrop damage zone in the hanging wall of a normal fault zone on the western border of the Upper Rhine Graben, affecting the Buntsandstein Group (Early Triassic). Diagenetic processes may alter the original pore type and geometry in fractured and faulted sandstones. Therefore, these may control the ultimate porosity and permeability of the damage zone. The classical model of evolution of hydraulic properties with distance from the major fault core is nuanced here. The hydraulic behavior of the rock media is better described by a pluri-scale model including: 1) The grain scale, where the hydraulic properties are controlled by sedimentary features, the distance from the fracture, and the impact of diagenetic processes. These result in the ultimate porous network characteristics observed. 2) A larger scale, where the structural position and characteristics (density, connectivity) of the fracture corridors are strongly correlated with both geo-mechanical and hydraulic properties within the damage zone.

Earth's energy “Golden Zone”: a synthesis from mineralogical research

AbstractThe impact of diagenetic processes on petroleum entrapment and recovery efficiency has focused the vast majority of the world's conventional oil and gas resources into relatively narrow thermal intervals, which we call Earth's energy “Golden Zone”. Two key mineralogical research breakthroughs, mainly from the North Sea, underpinned this discovery. The first is the fundamental particle theory of clay mineralogy, which showed the importance of dissolution/precipitation mechanisms in the formation of diagenetic illitic clays with increasing depth and temperature. The second is the surface area precipitation-rate-controlled models for the formation of diagenetic cements, primarily quartz, in reservoirs. Understanding the impacts of these geological processes on permeability evolution, porosity loss, overpressure development, and fluid migration in the subsurface, lead to the realization that exploration and production risks are exponential functions of reservoir temperature. Global compilations of oil/gas reserves relative to reservoir temperature, including the US Gulf Coast, have verified the “Golden Zone” concept, as well as stimulated further research to determine in greater detail the geological/mineralogical controls on petroleum migration and entrapment efficiency within the Earth's sedimentary basins.

Re-examination of the temperature-dependent relationship between δ18Odiatoms and δ18Olake water and implications for paleoclimate inferences

The oxygen isotope composition (δ18O) of diatoms is commonly used for paleoclimate reconstruction. There is, however, no consensus regarding the equilibrium isotopic fractionation factor between diatom silica and the water in which it is precipitated. We re-examined the temperature-dependent relationship between δ18Odiatoms and δ18Olake water from Lake Annecy (France). A temperature coefficient of −0.16‰/°C (R 2 = 0.51) was determined, supporting findings from previous calibration studies. However, regression lines obtained from different calibration studies, though displaying similar slopes, were shifted. In this manuscript, we propose that several factors, including selected variables (temperature, δ18Olake water), analytical techniques, the impact of diagenetic processes and biological effects, may influence the silica-water fractionation factor for diatom silica. The similar magnitude of the diatom-temperature coefficients determined across studies is promising, supporting its use as a valuable tool for interpreting variations in δ18O values from fossil lacustrine diatoms in temperate lakes. With respect to paleoclimatic applications, the temperature-dependent relationship yielded uncertainties of ±3°C on reconstructed temperatures and ±0.5‰ on δ18Olake water.

Abstract: Impact of Diagenetic Processes on Sandstone Reservoir Quality: Controls, Effects, and Predictive Evaluation Using Data from Natural and Experimental Systems 

Abstract: Impact of Diagenetic Processes on Sandstone Reservoir Quality: Controls, Effects, and Predictive Evaluation Using Data from Natural and Experimental Systems 

Possible effects of chemical heterogeneity in higher land plant cuticles on the preservation of its ultrastructure upon fossilization

Morphologically well preserved fossilized cuticles of Symplocos hallensis of Eocene age from Geiseltal (Germany) and isolated cuticles from its “extant relative” Symplocos paniculata have been studied in order to determine the possible impact of diagenetic processes on the structure and chemical composition of higher plant cuticles. Both samples were studied by means of transmission electron microscopy, ultrahistochemical staining reactions, and extraction, and chemical degradation methods in combination with gas chromatography-mass spectrometry and Curie-point pyrolysis-gas chromatography/mass spectrometry. Diagenesis apparently induced several significant changes in the cuticle of S. hallensis. There were considerable differences in leaf anatomy and fine structure between the two species. A cuticle proper could not be detected in S. hallensis but ultrastructural observations permit the inference that it could have disintegrated as first part of the cuticular membrane during diagenesis. Furthermore, the fossil species S. hallensis contained, apart from the resistant biopolymer cutan, “cutin-derived” material with non-saponifiable intermolecular linkages instead of the saponifiable biopolyester cutin present in S. paniculata. The “cutin-derived” material could either have been biosynthesized by the plant itself or be the result of diagenetically induced reactions of reactive groups, such as epoxide, originally present in the cutin. It is speculated that the absence the cuticle proper in S. hallensis is related to its very specific chemical composition which is different from that of the cuticular layer.