Open-system chemical behaviour of Wilcox Group mudstones. How is large scale mass transfer at great burial depth in sedimentary basins possible? A discussion

Bjørlykke, Knut

doi:10.1016/j.marpetgeo.2011.01.009

Cited by 41 publications

(21 citation statements)

References 10 publications

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“…This phenomenon is consistent with clay minerals dominated by mixed layers C/S in E 3 d 1+2 (Figure 8), which can be interpreted as strong hydration and hydrolysis of tuff and eruptive rock detritus precipitated voluminous authigenic smectite at an early diagenesis stage [46][47][48]. Smectite can easily transform to mixed-layer I/S or discrete illite with increasing temperature where a potassium source exist ( [49][50][51][52]; Cama et al 2000). Meanwhile, the conversion of smectite to mixed-layer C/S occurred where aqueous medium environments were enriched in magnesium.…”

Section: Ferromagnesian Aqueous Medium Environmentsupporting

confidence: 64%

Pore Fluid Evolution Influenced by Volcanic Activities and Related Diagenetic Processes in a Rift Basin: Evidence from the Paleogene Medium-Deep Reservoirs of Huanghekou Sag, Bohai Bay Basin, China

Sun

Zhu

et al. 2017

Geofluids

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Volcanic activities exert a significant influence on pore fluid property and related diagenetic processes that substantially controlled reservoirs quality. Analysis of Paleogene medium-deep sandstones on the Huanghekou Sag provides insight into relating the diagenetic processes to pore fluid property evolution influenced by volcanic activities. Three distinct types of pore fluids were identified on the basis of an integrated and systematic analysis including core and thin section observation, XRD, SEM, CL, and trace element. Alkaline aqueous medium environment occurred in E2s1+2 where volcanic activities have insignificant influence on pore fluids, evidenced by typical alkaline diagenetic events such as K-feldspar albitization, quartz dissolution, feldspar dissolution, and carbonate cementation. During the deposition of E3d3, influx of terrestrial freshwater and alteration of ferromagnesian-rich pore water result in the formation of mixing aqueous medium environment through volcanic eruption dormancy causing zeolite dissolution, clay mineral transformation, and K-feldspar albitization. Ferromagnesian-rich aqueous medium environment developed resulting from the intensive hydrolysis of the unstable ferromagnesian minerals formed due to intense volcanic activities during E3d1+2 and corresponding predominant diagenetic processes were characterized by the precipitation and dissolution of low-silica zeolites. Therefore, the differential properties of pore fluids caused various diagenetic processes controlling reservoir quality.

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Section: Ferromagnesian Aqueous Medium Environmentsupporting

confidence: 64%

Pore Fluid Evolution Influenced by Volcanic Activities and Related Diagenetic Processes in a Rift Basin: Evidence from the Paleogene Medium-Deep Reservoirs of Huanghekou Sag, Bohai Bay Basin, China

Sun

Zhu

et al. 2017

Geofluids

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“…The homogenization temperatures (Th) were measured for the aqueous inclusions that were trapped during quartz cementation and range from 70-120°C ( Figure 13). Moreover, the temperatures calculated fromδ 18 O in carbonate cements (Ca-II, ferroan calcite and ankerite)range from-21.07‰ to -16.58‰, thus yield Th ranges from 90-123°C ( Table 2). The results suggest that precipitation of Ca-II, ferroan calcite, ankerite and quartz cementation mainly occurred in the mesodiagenetic stages, which is consistent with the thin section observations.…”

Section: Fluid Inclusions Analysismentioning

confidence: 99%

“…The dissolution of detrital anorthite and carbonate grains is not obvious in the Lulehe sandstone, and the distribution pattern and occurrence form of the carbonate cements (Figure 8) suggests that external or mixed sources may be the main sources for these cements, which is consistent with the estimation scatter diagram of the material source based on the δ 13 C PDB and δ 18 O PDB isotopic values (Figure12a). The integration of the δ 13 C and δ 18 O isotopic values of carbonate cements and the burial and thermal history can effectively elucidate the origin of the potential source material and precipitation temperature involved in the cementation process. Generally, the δ 13 C isotopic value distribution in carbonates is mainly related to carbon sources.…”

Section: Origin and Sources Of Carbonate Cementsmentioning

confidence: 99%

“…Diagenesis, including physical processes of mechanical compaction and chemical action of mineral dissolution and precipitation, has a great influence on subsequent evolution paths of porosity and permeability [15][16][17]. According to burial history and depositional composition, the porosity of shallow sandstone with little cementation can be accurately predicted [18,19]. However, under a deeper burial environment, porosity is much more difficult to predict because of the import and export of materials related to dissolution and precipitation of minerals involved in chemical diagenesis [18,20].…”

Section: Introductionmentioning

confidence: 99%

“…According to burial history and depositional composition, the porosity of shallow sandstone with little cementation can be accurately predicted [18,19]. However, under a deeper burial environment, porosity is much more difficult to predict because of the import and export of materials related to dissolution and precipitation of minerals involved in chemical diagenesis [18,20]. Therefore, a comprehensive understanding of the diagenesis process of dissolution and precipitation of cements and the origin and sources of minerals are the key to predicting the quality of deeply buried sandstone.…”

Section: Introductionmentioning

confidence: 99%

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Origin and Sources of Minerals and Their Impact on the Hydrocarbon Reservoir Quality of the PaleogeneLulehe Formation in the Eboliang Area, Northern Qaidam Basin, China

et al. 2019

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The Lulehe sandstone in the Eboliang area is a major target for hydrocarbon exploration in the northern Qaidam Basin. Based on an integrated analysis including thin section analysis, scanning electron microscopy, X-ray diffraction, cathodoluminescence investigation, backscattered electron images, carbon and oxygen stable isotope analysis and fluid inclusion analysis, the diagenetic processes mainly include compaction, cementation by carbonate and quartz, formation of authigenic clay minerals (i.e., chlorite, kaolinite, illite-smectite and illite) and dissolution of unstable materials. Compaction is the main factor for the deterioration of reservoir quality; in addition, calcitecement and clay minerals are present, including kaolinite, pore-filling chlorite, illite-smectite and illite, which also account for reservoir quality reduction. Integration of petrographic studies and isotope geochemistry reveals the carbonate cements might have originated from mixed sources of bioclast- and organic-derived CO2 during burial. The quartz cement probably formed by feldspar dissolution, illitization of smectite and kaolinite, as well as pressure solution of quartz grains. Smectite, commonly derived from alteration of volcanic rock fragments, may have been the primary clay mineral precursor of chlorite. In addition, authigenic kaolinite is closely associated with feldspar dissolution, suggesting that alteration of detrital feldspar grains was the most probable source for authigenic kaolinite. With the increase in temperature and consumption of organic acids, the ratio of K+/H+ increases and the stability field of kaolinite is greatly reduced, thereby transforming kaolinite into mixed layer illite/smectite and illite. Within the study area, porosity increases with chlorite content up to approximately 3% volume and then decreases slightly, indicating that chlorite coatings are beneficial at an optimum volume of 3%. A benefit of the dissolution of unstable minerals and feldspar grains is the occurrence of secondary porosity, which may enhance porosity to some extent. However, the solutes cannot be transported over a large scale in the deep burial environment, and simultaneous precipitation of byproducts of feldspar dissolution such as authigenic kaolinite and quartz cement will occur in situ or in adjacent pores, resulting in heterogeneity of the reservoirs.

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Diagenesis and reservoir quality of the second member of the Upper Triassic Xujiahe Formation tight gas sandstones in the Western Sichuan Depression, southwest China

et al. 2021

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The tight sandstones reservoir of the second member of the Xujiahe Formation (Xu2 member) is gradually becoming the main reservoir for natural gas exploration and exploitation in the Western Sichuan Basin. The tight sandstone is normally deeply buried, where it is controlled by complex diagenetic processes. To gain insights into reservoir exploration of the Xu2 member, the diagenetic history and the impacts of diagenesis on reservoir quality were established using several experimental methods.The sandstones were found to be mainly litharenite, sublitharenite, and feldspathic litharenite. The reservoir quality was characterized by low porosity (3.4% on average), low permeability (0.17 mD on average), low pore throat radius, and high displacement pressure. The tight sandstones experienced a series of significant diagenetic processes, including mechanical compaction, early dissolution, and precipitation of carbonate and siliceous cements during eodiagenesis. They also underwent chemical compaction, late dissolution, and transformation of clay minerals during mesodiagenesis. The silica cementation mainly resulted from chemical compaction, feldspar dissolution, and the transformation of clay minerals. A higher degree of compaction has a vital role in destroying most of the primary pores. Cementation had a significant impact on reducing the porosity and permeability, although chlorite preserved primary pores by slowing the compaction. This study aimed to provide a comprehensive insight into diagenesis and its impact on the reservoir quality of deeply buried sandstone, and provide insights into reservoir exploration and development in deeply buried tight sandstones.

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Open-system chemical behaviour of Wilcox Group mudstones. How is large scale mass transfer at great burial depth in sedimentary basins possible? A discussion

Cited by 41 publications

References 10 publications

Pore Fluid Evolution Influenced by Volcanic Activities and Related Diagenetic Processes in a Rift Basin: Evidence from the Paleogene Medium-Deep Reservoirs of Huanghekou Sag, Bohai Bay Basin, China

Pore Fluid Evolution Influenced by Volcanic Activities and Related Diagenetic Processes in a Rift Basin: Evidence from the Paleogene Medium-Deep Reservoirs of Huanghekou Sag, Bohai Bay Basin, China

Origin and Sources of Minerals and Their Impact on the Hydrocarbon Reservoir Quality of the PaleogeneLulehe Formation in the Eboliang Area, Northern Qaidam Basin, China

Diagenesis and reservoir quality of the second member of the Upper Triassic Xujiahe Formation tight gas sandstones in the Western Sichuan Depression, southwest China

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