Further research on chlorite rims in sandstones: evidence from the Triassic Yanchang Formation in the Ordos basin, China

Fang, Xiang-Min; Yuwan, Wang; Feng, Qiming; Zhang, Deyan; Zhao, Jian‐xin

doi:10.1007/s12517-016-2518-3

Cited by 10 publications

(4 citation statements)

References 4 publications

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“…5) shows that the correlation between chlorite content to surface porosity and sample porosity is very poor, while the correlation with primary intergranular porosity is positive, and the correlation with solution porosity is negative. The results of this study indicate authigenic graincoating chlorite has a good positive correlation with primary intergranular porosity, a conclusion shared with the studies by Sun et al (2012Sun et al ( , 2014 and Xiang et al (2016). Many researchers thought grain-coating chlorite was beneficial to reservoir porosity preservation, especially for primary intergranular pores.…”

Section: Relationship Of Grain-coating Chlorite and Reservoir Porositysupporting

confidence: 88%

“…Many researchers thought grain-coating chlorite was beneficial to reservoir porosity preservation, especially for primary intergranular pores. However, some researchers believed good-quality reservoirs develop as a result of good primary intergranular porosity, and the existence of grain-coating chlorite is only indicative of primary intergranular porosity (Xiang et al 2016). Based on the correlation of chlorite content with surface porosity and sample porosity in this study, it was concluded that the development of chlorite did not play a positive role in the reservoir porosity preservation and it may have influenced dissolution, to a certain extent.…”

Section: Relationship Of Grain-coating Chlorite and Reservoir Porositymentioning

confidence: 65%

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Formation mechanisms and sequence response of authigenic grain-coating chlorite: evidence from the Upper Triassic Xujiahe Formation in the southern Sichuan Basin, China

Lin

Gao

2016

Pet. Sci.

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Authigenic grain-coating chlorite is widely distributed in the clastic rocks of many sedimentary basins around the world. These iron minerals were mainly derived from flocculent precipitates formed when rivers flow into the ocean, especially in deltaic environments with high hydrodynamic conditions. At the same time, sandstone sequences with grain-coating chlorites also tend to have relatively high glauconite and pyrite content. EPMA composition analysis shows that glauconites with ''high Al and low Fe'' content indicate slightly to semi-saline marine environments with weak alkaline and weakly reducing conditions. By analyzing the chlorite-containing sandstone bodies of the southern Sichuan Xujiahe Formation, this study found that chlorite was mainly distributed in sedimentary microfacies, including underwater distributary channels, distributary channels, shallow lake sandstone dams, and mouth bars. Chlorite had a tendency to form in the upper parts of sandstone bodies with signs of increased base level, representing the influence of marine (lacustrine) transgression. This is believed to be influenced by megamonsoons in the Middle and Upper Yangtze Region during the Late Triassic Epoch. During periods of abundant precipitation, river discharges increased and more Fe particulates flowed into the ocean (lake). In the meantime, increases or decreases in lake level were only affected by precipitation for short periods of time. The sedimentary environment shifted from weakly oxidizing to weak alkaline, weakly reducing conditions as sea level increased, and Fe-rich minerals as authigenic chlorite and glauconite began to form and deposit.

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Section: Relationship Of Grain-coating Chlorite and Reservoir Porositysupporting

confidence: 88%

Section: Relationship Of Grain-coating Chlorite and Reservoir Porositymentioning

confidence: 65%

Formation mechanisms and sequence response of authigenic grain-coating chlorite: evidence from the Upper Triassic Xujiahe Formation in the southern Sichuan Basin, China

Lin

Gao

2016

Pet. Sci.

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“…Small amounts of grain-coating chlorite have been found in the Xujiahe sandstone, showing a positive relationship with porosity and a slight relationship with permeability (Figure 14(e) and (f)). Previous studies have focused on the relationship of authigenic grain-coating chlorite with reservoir porosity preservation (Bloch et al., 2002; Ehrenberg, 1993; Huang et al., 2004; Xiang et al., 2016; Yu et al., 2016). They reported that grain-coating chlorite is beneficial to reservoir porosity preservation by enhancing resistance of compaction and inhibit growth of quartz cement, especially in deeply buried sandstone reservoirs (Bloch et al., 2002; Ehrenberg, 1993; Huang et al., 2004).…”

Section: Discussionmentioning

confidence: 99%

“…It therefore played no role in inhibiting quartz cementation. Xiang et al (2016) believed that grain-coating chlorite has no obvious effect on porosity preservation. Further studies are required to understand the effect of grain-coating chlorite on reservoir quality.…”

Section: Diagenetic Controls On Quality Of Reservoirmentioning

confidence: 99%

Diagenesis and reservoir characteristics analysis of the Late Triassic Xujiahe Formation tight gas sandstone in the northern Sichuan Basin, China

Lin

Zhai

et al. 2017

Energy Exploration & Exploitation

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The Late Triassic Xujiahe Formation is a key target for tight gas in the northern Sichuan Basin. Thin section, scanning electron microscopy, X-ray diffraction, porosity and permeability analyses have been performed to delineate the diagenesis and reservoir characteristics of Xujiahe sandstone. The results show that the Xujiahe Formation contains feldspathic litharenite, litharenite, sublitharenite and quartzarenite sandstone. Sandstones of the Xujiahe Formation are characterized by low feldspar content and both secondary and micro-fracture porosity. Porosity and permeability analyses of 185 core samples show a broad but low porosity range from 0.79 to 10.43% (average 4.55%) and wide but low permeability range (0.0021-26.001 mD, average 0.449 mD). The higher permeabilities result from micro-fracturing. Strong mechanical compaction plays a more important role in reducing primary porosity of sandstone than cementation during eodiagenesis. Carbonate cement is detrimental to reservoir porosity. Early carbonate cement precipitated from depositional water during eodiagenesis can block primary pores while late carbonate cement formed during mesodiagenesis can fill secondary pores. Quartz cement shows a slight relationship with porosity and permeability. There is a positive relationship between grain-coating chlorite and porosity and permeability. The effect of diagenesis on the reservoir quality of Xujiahe tight gas sandstone is greater that depositional environment during deep burial.

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Fast Equivalent Micro-Scale Pipe Network Representation of Rock Fractures Obtained by Computed Tomography for Fluid Flow Simulations

Feng

Jiang

2020

Rock Mech Rock Eng

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Further research on chlorite rims in sandstones: evidence from the Triassic Yanchang Formation in the Ordos basin, China

Cited by 10 publications

References 4 publications

Formation mechanisms and sequence response of authigenic grain-coating chlorite: evidence from the Upper Triassic Xujiahe Formation in the southern Sichuan Basin, China

Formation mechanisms and sequence response of authigenic grain-coating chlorite: evidence from the Upper Triassic Xujiahe Formation in the southern Sichuan Basin, China

Diagenesis and reservoir characteristics analysis of the Late Triassic Xujiahe Formation tight gas sandstone in the northern Sichuan Basin, China

Fast Equivalent Micro-Scale Pipe Network Representation of Rock Fractures Obtained by Computed Tomography for Fluid Flow Simulations

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