Reconstructing large‐scale karst paleogeomorphology at the top of the Ordovician in the Ordos Basin, China: Control on natural gas accumulation and paleogeographic implications

Xiao, Di; Tan, Xiucheng; Fan, Liyong; Zhang, Dao‐Feng; Nie, Wancai; Niu, Tong; Cao, Jian

doi:10.1002/ese3.494

Cited by 18 publications

(3 citation statements)

References 42 publications

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“…The best-known examples of hydrocarbon fields closely associated with karst reservoirs come from China. Reservoirs of this type have been identified there within a few large petroleum basins, including the Tarim Basin [6,7,30,[39][40][41][42][43], the Ordos Basin [44,45] or the Sichuan Basin [4,46], among others. The issue of identifying zones of paleokarst development in carbonate formations based on seismic and borehole data has been addressed by various authors, e.g., [8,10,12,47,48].…”

Section: Discussionmentioning

confidence: 99%

Examples of Paleokarst in Mesozoic Carbonate Formations in the Carpathian Foreland Area

Łaba-Biel,

Filipowska-Jeziorek,

Urbaniec

et al. 2024

Energies

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A paleokarst system developed in the Upper Jurassic–Lower Cretaceous carbonate complex has been recognized in the Carpathian Foreland area. Well logs testing and core data as well as an acoustic imager, a microresistivity scanner and six-arm dipmeter images were used to identify and analyze the character of the paleokarst features. A detailed interpretation of microresistivity and acoustic image logs allowed for the identification of different types of karst forms, such as caverns; multidirectional fractures, including fractures widened by dissolution; and the type of sediments filling them. The analysis of the seismic survey was conducted by linking the paleokarst characteristic features recognized in the seismic image to the karst intervals determined from borehole data. The set of seismic attributes calculated from the analyzed 3D seismic data, including the RMS amplitude, instantaneous frequency, consistent dip, variance, sweetness and relative acoustic impedance, helped to delineate the zones of the paleokarst distribution. Within the interpreted paleokarst surface developed in the carbonate formations in the study area, there are sinkholes, limestone pavements and valleys. Furthermore, in the northwestern part of the analyzed area, the development of paleokarst forms is related to the presence of a relatively deep branch of a paleovalley formed in the Paleogene, as well as to numerous discontinuities developed in carbonate formations. The development of this type of larger karst form was probably controlled primarily by tectonic faults. The research conducted by the authors of this paper showed the widespread presence of paleokarst features in Upper Jurassic–Lower Cretaceous carbonate formations in the study area. A good spatial identification of the paleokarst surface can be important in a regional context, since the highest part of the profile of carbonate formations is the most important reservoir for geothermal or hydrocarbon resources in this region.

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Section: Discussionmentioning

confidence: 99%

Examples of Paleokarst in Mesozoic Carbonate Formations in the Carpathian Foreland Area

Łaba-Biel,

Filipowska-Jeziorek,

Urbaniec

et al. 2024

Energies

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“…In addition, the sedimentary facies map can be drawn according to the ratio of sand stratum. Previous studies have shown that the Pre-Carboniferous period had been filled up by the end of the Taiyuan period, and there is a mirror-image relationship between the thickness of the Carboniferous strata and the paleogeomorphology of the Pre-Carboniferous period [19]. Therefore, the paleotopography map is roughly replaced by the thickness map of the Taiyuan Fm, so as to analyze the control of paleotopography on sedimentary facies and coal seams.…”

Section: Geophysical Response Characteristics Of Coal Seamsmentioning

confidence: 99%

Distribution of Upper Paleozoic Coal Seams in the Southeastern Ordos Basin

Guan

Guo

et al. 2022

Energies

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The Ordos Basin contains abundant coal resources in the Upper Paleozoic strata. They are shallowly buried or exposed in the periphery of the basin, forming recoverable coal mines and coalbed methane resources. For the deeply buried coal seams of the basin, however, due to complex changes and difficult mining, less attention was paid before. In recent years, with the exploitation of tight gas related to coal source rocks, a large amount of drilling and seismic data has been accumulated in the southeastern Ordos Basin, which makes it possible to study the distribution change and factors controlling Upper Paleozoic coal seams. Delineation of deep coal development and distribution is an important basis for coal, coalbed methane and related tight gas resources in the Upper Paleozoic. We use core, logging and seismic data to analyze the coal geophysics, thickness variation, paleotopography and sedimentary facies in the southeastern Ordos Basin. The lower part of the Shanxi Formation (Fm.) and the upper part of the Taiyuan Fm. in the southeastern part of the basin are characterized by low natural gamma ray, low density, high resistivity and high sonic logging values. As the coal velocity is very low and alternates with the high-velocity Taiyuan Fm. and Ordovician limestones, the two sets of coals below and above the Taiyuan limestones form an extremely strong-amplitude reflection in the seismic profile. The two sets of coals are cumulatively 1–10 m thick, averaging 2.4 m, and 4 m is the maximum induvial thickness. The individual coal seams thicker than 2 m cover an area of approximately 2500 km2, and the burial depths of the coal seam range from 2500 to 3000 m. The thick coal seams of the Taiyuan Fm. are mainly distributed proximally in the Ordovician paleokarst depression, while the Ordovician paleokarst depression without incised origin was deposited by distal coeval limestone rocks. There is a complementary relationship between the coal seams and the thickened zone of distributary channel sandstone in the Shanxi Fm.

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“…For example, gypsum (i.e. anhydrite) is dissolved leaving residual marl due to the action of near-surface meteoric waters (Adams and Diamond, 2017; Xiao et al, 2019a; Zhao et al, 2014). Anaerobic activity of microorganisms means that early low-temperature degradation of such rocks is caused by nitrate reduction, and secondary dissolution is induced by pyrolysis-generated CO 2 gas and organic acids during burial (Druckman and Moore, 1985; Hu et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Genesis and pore evolution of dolomite reservoir in the Majiagou Formation, Ordos Basin, China

Wang

Tan

et al. 2021

Energy Exploration & Exploitation

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In gypsum–carbonate rock assemblages, multistage and complex fluids control the formation of dolomite reservoirs that are a focus of hydrocarbon exploration. It is difficult to determine the types of dolomite reservoirs and their formation mechanisms due to the diverse rock assemblages and multiple stages of diagenesis. In this study, we investigated the petrology, reservoir physical properties, and geochemistry of the 6th sub-member of member five of the Majiagou Formation (i.e. Ma56) in the Ordos Basin, China. These data were used to determine the nature and types of gypsum–carbonate rocks, and constrain their reservoir characteristics and diagenetic history, and fluid-related mechanisms that led to dolomite reservoir development and preservation. The Ma56 was deposited on a restricted evaporatic platform in the North China Craton, and contains three main types of dolomite reservoirs with variable types of reservoir space. Dolomite reservoir formation was closely related to penecontemporaneous dolomitization, karstification, and differential cementation. Early large-scale dolomitization produced dolomitized carbonate sediments that were resistant to compaction and dissolution, which was conducive to the preservation of primary and secondary pores. The intermittent exposure and dissolution of mound–shoal facies sediments, due to high-frequency sea-level fluctuations, was the dominant mechanism for formation of secondary dissolved pores and high-quality reservoirs. During burial, differential cementation occurred due to interaction between fluids and pore size, which determined the extent of reservoir preservation. In general, the studied dolomite reservoirs have undergone multistage diagenesis and alteration, which led to complex and multistage development of the reservoir porosity. However, the reservoir lithology and pore space developed mostly in the depositional to penecontemporaneous stages. Our results provide new insights into the origins of deeply buried dolomite reservoirs in carbonate–evaporite successions.

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Reconstructing large‐scale karst paleogeomorphology at the top of the Ordovician in the Ordos Basin, China: Control on natural gas accumulation and paleogeographic implications

Cited by 18 publications

References 42 publications

Examples of Paleokarst in Mesozoic Carbonate Formations in the Carpathian Foreland Area

Examples of Paleokarst in Mesozoic Carbonate Formations in the Carpathian Foreland Area

Distribution of Upper Paleozoic Coal Seams in the Southeastern Ordos Basin

Genesis and pore evolution of dolomite reservoir in the Majiagou Formation, Ordos Basin, China

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