CLAY MINERALS IN ATOKAN DEEP-WATER SANDSTONE FACIES, ARKOMA BASIN: ORIGINS AND INFLUENCE ON DIAGENESIS AND RESERVOIR QUALITY

Author(s):  
DAVID W. HOUSEKNECHT ◽  
LOUIS M. ROSS
2021 ◽  
Vol 13 (2) ◽  
pp. 601-610
Author(s):  
K. Itiowe ◽  
R. Oghonyon ◽  
B. K. Kurah

The sediment of #3 Well of the Greater Ughelli Depobelt are represented by sand and shale intercalation. In this study, lithofacies analysis and X-ray diffraction technique were used to characterize the sediments from the well. The lithofacies analysis was based on the physical properties of the sediments encountered from the ditch cuttings.  Five lithofacies types of mainly sandstone, clayey sandstone, shaly sandstone, sandy shale and shale and 53 lithofacies zones were identified from 15 ft to 11295 ft. The result of the X-ray diffraction analysis identified that the following clay minerals – kaolinite, illite/muscovite, sepiolite, chlorite, calcite, dolomite; with kaolinite in greater percentage. The non-clay minerals include quartz, pyrite, anatase, gypsum, plagioclase, microcline, jarosite, barite and fluorite; with quartz having the highest percentage. Therefore, due to the high percentage of kaolinite in #3 well, the pore filing kaolinite may have more effect on the reservoir quality than illite/muscovite, chlorite and sepiolite. By considering the physical properties, homogenous and heterogeneous nature of the #3 Well, it would be concluded that #3 Well has some prospect for petroleum and gas exploration.


Clay Minerals ◽  
1982 ◽  
Vol 17 (1) ◽  
pp. 55-67 ◽  
Author(s):  
U. Seemann

AbstractThe Southern Permian Basin of the North Sea represents an elongate E-W oriented depo-centre along the northern margin of the Variscan Mountains. During Rotliegend times, three roughly parallel facies belts of a Permian desert developed, these following the outline of the Variscan Mountains. These belts were, from south to north, the wadi facies, the dune and interdune facies, and the sabkha and desert lake facies. The bulk of the gas reservoirs of the Rotliegend occur in the aeolian dune sands. Their recognition, and the study of their geometry, is therefore important in hydrocarbon exploration. Equally important is the understanding of diagenesis, particularly of the diageneticaily-formed clay minerals, because they have an important influence on the reservoir quality of these sands. Clay minerals were introduced to the aeolian sands during or shortly after their deposition in the form of air-borne dust, which later formed thin clay films around the grains. During burial diagenesis, these clay films may have acted as crystallization nuclei for new clay minerals or for the transformation of existing ones. Depending on their crystallographic habit, the clay minerals can seriously affect the effective porosity and permeability of the sands.


Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Meng Xiao ◽  
Xuanjun Yuan ◽  
Dawei Cheng ◽  
Songtao Wu ◽  
Zhenglin Cao ◽  
...  

Feldspar dissolution is a common feature in clastic rock reservoirs of petroliferous basins and has an important influence on reservoir quality. However, the effect of feldspar dissolution on reservoir quality varies under different depositional environments and diagenetic systems. The study area in this paper is located in the Baikouquan Formation in the northwestern margin of the Junggar Basin, which is significantly influenced by feldspar dissolution. Based on the analyses of core and thin section observations, QEMSEM, XRD, SEM, CL, fluorescence, and image analysis software combined with logging and physical property data, this study shows that feldspar dissolution in the subaqueous distributary channel of a fan delta plain, which has good original physical properties and low mud contents, significantly improves the properties of the reservoir. The main reasons for this are as follows: (1) the sedimentary facies with good original properties and low mud content is a relatively open system in the burial stage. The acidic fluids needed for feldspar dissolution are mostly derived from organic acids associated with the source rocks and migrate to the good-permeability area of the reservoir; (2) the by-products of feldspar dissolution, such as authigenic clay minerals and authigenic quartz, are transported by pore water in a relatively open diagenetic system and then precipitated in a relatively closed diagenetic system; and (3) the clay minerals produced by feldspar dissolution in different diagenetic environments and diagenetic stages have different effects on the reservoir. When the kaolinite content is less than 3%, the illite content is less than 4%, and the chlorite content is less than 12%, the clay minerals have a positive effect on the porosity. These clay minerals can reduce porosity and block pore throats when their contents are larger than these values.


2021 ◽  
Author(s):  
Anton Khitrenko ◽  
Adelia Minkhatova ◽  
Vladimir Orlov ◽  
Dmitriy Kotunov ◽  
Salavat Khalilov

Abstract Western Siberia is a unique petroleum basin with exclusive geological objects. Those objects allow us to test various methods of sequence stratigraphy, systematization and evaluation approaches for reservoir characterization of deep-water sediments. Different methods have potential to decrease geological uncertainty and predict distribution and architecture of deep-water sandstone reservoir. There are many different parameters that could be achieved through analysis of clinoform complex. Trajectories of shelf break, volume of sediment supply and topography of basin influence on architecture of deep-water reservoir. Based on general principles of sequence stratigraphy, three main trajectories changes shelf break might be identified: transgression, normal regression and forced regression. And each of them has its own distinctive characteristics of deepwater reservoir. However, to properly assess the architecture of deepwater reservoir and potential of it, numerical characteristics are necessary. In our paper, previously described parameters were analyzed for identification perspective areas of Achimov formation in Western Siberia and estimation of geological uncertainty for unexplored areas. In 1996 Helland-Hansen W., Martinsen O.J. [5] described different types of shoreline trajectory. In 2002 Steel R.J., Olsen T. [11] adopted types of shoreline trajectory for identification of truncation termination. O. Catuneanu (2009) [1] summarize all information with implementation basis of sequence stratigraphy. Over the past decade, many geoscientists have used previously published researches to determine relationship between geometric structures of clinoforms and architecture of deep-water sediments and its reservoir quality. Significant amount of publications has allowed to form theoretical framework for the undersanding sedimentation process and geometrical configuration of clinoforms. However, there is still no relationship between sequence stratigraphy framework of clinoroms and reservoir quality and its uncertainty, which is necessary for new area evaluation.


2020 ◽  
Vol 1 (1-2) ◽  
pp. 8-19
Author(s):  
Dongdong Hong ◽  
Jian Cao ◽  
Tao Wu ◽  
Sisi Dang ◽  
Wenxuan Hu ◽  
...  

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