THE ROLE OF SECONDARY POROSITY IN THE COURSE OF SANDSTONE DIAGENESIS

1979 ◽  
pp. 175-207 ◽  
Author(s):  
VOLKMAR SCHMIDT ◽  
DAVID A. MCDONALD
Keyword(s):  
Secondary Porosity ◽  
Sandstone Diagenesis

scholarly journals The role of geological structures on groundwater occurrence and flow in crystalline basement aquifers: a status review

2018 ◽  
Vol 11 (1) ◽  
pp. 155-164
Author(s):  
M.A. Idris ◽  
M.L. Garba ◽  
S.A. Kasim ◽  
I.M. Madabo ◽  
K.A. Dandago
Keyword(s):  
Hydrological Cycle ◽  
Crystalline Basement ◽  
Geological Structures ◽  
Secondary Porosity ◽  
Groundwater Movement ◽  
Remote Sensing Technique ◽  
Basement Rocks ◽  
Groundwater Occurrence ◽  
Basement Aquifers

The paper is review on the role of geological structures on groundwater occurrence and flow in Crystalline Basement aquifers. The aim was to study the existing available literatures in order to evaluate structural/lineaments (faults, joints/fractures, folds, shear zone etc.) their influences and controls of groundwater occurrence and flow of bedrock of crystalline rocks of igneous and/or metamorphic origin. Groundwater in the basement aquifers resides/occurs within the weathered overburden and fractured bedrocks which originate from rainfall through the process of hydrological cycle. Remote sensing technique uses satellite imagery or aerial photograph to identify linear features on the ground and attempts to relate these lines to geologic structures capable of transmitting and storing large quantities of groundwater. Faults, joints/fractures and folds act as conduit and make rocks excellent aquifers. These features also, served as channels for groundwater movement which may results to an increased in secondary porosity, permeability and therefore, can results as a groundwater prospective/promising zones in crystalline basement rocks. Keywords: Basement Terrain, Groundwater, Lineament, Movement, Occurrence

scholarly journals GEOLOGICAL CONDITIONS OF SECONDARY POROSITY FORMATION AND ITS DISTRIBUTION IN ROCKS

2018 ◽  
pp. 37-41
Author(s):  
H. M. Bondar
Keyword(s):  
Oil And Gas ◽  
Pore Space ◽  
Effective Porosity ◽  
Gas Reservoirs ◽  
Secondary Porosity ◽  
Geological Conditions ◽  
Main Component ◽  
Filtration Properties ◽  
Sedimentation Processes

The paper presents the problem of collectors secondary porosity, which is the main component of the total effective porosity. Different aspects of this problem are considered: the origin and distribution of secondary porosity in the rock, the dependency between the structure of the pore space and its filtration properties, the formation of hydrocarbons deposits at great depths, the role of post-sedimentation processes in the formation of secondary porosity and fractures, as well as the issue of secondary porosity prediction and its role in prospecting secondary oil and gas reservoirs.

DIAGENESYS STAGE ANALYSIS OF SANDSTONE INTERVAL ON WELL DAR-24, GABUS FORMATION, ANOA FIELD, WEST NATUNA BASIN

KURVATEK ◽  
2018 ◽  
Vol 2 (2) ◽  
pp. 67-76
Author(s):  
Hanindya Ramadhani
Keyword(s):  
Secondary Porosity ◽  
Linear Distribution ◽  
Reservoir Rocks ◽  
Sandstone Diagenesis ◽  
Different Depths ◽  
Calcite Cement ◽  
Primary Porosity ◽  
Stage Analysis ◽  
Pore Lining

Stage of diagenesis of a rock will effect the quality of the rock as a reservoir. Hence, it is a necessary to analyze the diagenesis stage of sandstone at Anoa Field, West Natuna Basin, since the diagenesis stage has not been identified properly. The analysis is carried out using thin section method in five different depths. The product of diagenesis is observed for its cementation level, compaction, recrystallization, dissolution, replacement, and type of porosity wich developed in the rock. The appearance of quartz overgrowth cement and pore filling and pore lining calcite cement show a diagenesis stage which are recrystallization and cementation. The appearance of bent mica mineral and suture grain contact can be a sign of late stage compaction. Dissolution of matrix, cement and grain in the sample show that the rock has come to mesodiagenesis stage. As a result of the observation, the conclusion can be made that the rock has passed the eodiagenesis and mesodigenesis phase. Porosity of the section is both primary porosity (interparticle) and secondary porosity (dissolved) with a range 15%-20% (medium to good). Crossplot depth vs porosity show a linear distribution, which when the depth is increase the porosity will decrease. So it can be concluded that the process of diagenesis is very influential on the quality of reservoir rocks in the study area.Keyword: Gabus Formation, sandstone diagenesis, stage of diagenesis.

scholarly journals Analysing the influencing factors of a postgenetic subsidence doline’s development using model experiments

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Szilárd Vetési-Foith
Keyword(s):  
Grain Size ◽  
Influencing Factors ◽  
Model Experiment ◽  
Final Solution ◽  
Secondary Porosity ◽  
Model Experiments ◽  
Cover Thickness

The subsidence dolines are the most common surface forms of the concealed karsts. One type of these dolines is the suffosion doline. In this model experiment the influential role of these kind of dolines’ development factors were analyzed. The aim of the study was to determine the significance of the parameters (cover thickness, secondary porosity of the bedrock, chimney diameter, grain size) that influence the development of a suffosion doline. To study the influencing factors numerous (162) experiments were made with different parameters, in a manner that during the experiments we changed only one parameter, so the effects of it would be detectable from the final solution. These measurements were made with the use of a special tool, designed and built for this purpose. According to the data we gained from the model experiments, the development of a suffosion doline is influenced by many parameters. If these parameters are in an optimal connection to each other, a suffosion doline may appear on the surface. Knowing these parameters of the covered karstic depressions lets us estimate other parameters that may influence the development of the subsidence dolines.

Diagenetic complexities of iron oxide cements in Mesozoic sandstones of Utah, U.S.A.

2021 ◽  
Author(s):  
Sally Potter-McIntyre ◽  
Marjorie Chan
Keyword(s):  
Iron Oxide ◽  
Multiple Scales ◽  
Age Dating ◽  
Fluid Composition ◽  
Navajo Sandstone ◽  
Sandstone Diagenesis ◽  
Porosity And Permeability ◽  
Complex Relationships ◽  
Diagenetic History

<p>Stratigraphic units of the Colorado Plateau comprise a remarkable Mesozoic section in Utah. Thse units are ideal for studying sandstone diagenesis where there is established basinal context of depositional facies and tectonics, as well as continuity of exposure. To untangle the complex relationships and diagenetic histories, it is crucial to understand host rock properities (porosity and permeability), authigenic mineralogies (that give clues to fluid composition), diagenetic textures, and age dating. This study is a review and synthesis of previous work that has contributed to the understanding of the diagenetic history recorded in authigenic iron oxide precipitates. We discuss cement generations and mineralogies, fluid chemistries, origins and mobilization of iron, and timing of precipitation. Spheroidal cemented mineral masses (concretions) are common within many Mesozoic units of Utah – most notably the Jurassic Navajo Sandstone.  However, formation of these concretions is still not completely understood. Spheroidal concretions are currently a “hot topic”, especially since the discovery of similar “blueberry” features on Mars with their implications for habitability, and the potential for these nodules to host biosignatures. Several models for spheroidal concretion formation are evaluated. Understanding how iron is mobilized and precipitated and how spheroidal concretions form have implications for similar geometries and mineralogies in many terrestrial regions, but will require continued integrated studies across multiple scales (see Baker and Potter-McIntyre, this session). These scales include the submicroscopic levels of understanding and detecting the potential role of microbes in mineral precipitation, to the larger scale mapping of regional diagenetic coloration and mineral patterns that could represent records of basinal fluids and the response to climate, tectonics, and regional hydrology.</p>

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