Enrichment and distribution of shale oil in the Cretaceous Qingshankou Formation, Songliao Basin, Northeast China

Liu, Cheng‐Lin; Wang, Ziling; Guo, Zeqing; Weiyu, Hong; Dun, Chao; Zhang, Xu; Li, Bing; Wu, Linqiang

doi:10.1016/j.marpetgeo.2017.06.034

Cited by 58 publications

(29 citation statements)

References 23 publications

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“…e UCQ formation has a maximum depth of about 2500 m, while the UCN formation is 0-1900 m deep [21,22]. e UCQ and UCN formations both contain Type I kerogen and are mainly within the oil window with vitrinite reflectance (R o ) values in the basin center exceeding 1.1%, decreasing below 0.5% near the basin margins [12,19]. As a result, in the Songliao basin, UCQ and UCN formations are the vital source rocks for conventional petroleum development, as well as the primary target for shale oil exploration.…”

Section: Geological Backgroundmentioning

confidence: 99%

“…Sequence stratigraphy and geochemistry indicated the UCQ formation has a better hydrocarbon source rock potential and slightly higher oil yield during pyrolysis than UCN formation [11]. For UCQ formation, its clay content averages 55% [12], raising concerns that it might not be amenable to effective hydraulic fracturing. Although UCQ and UCN shales are mentioned a lot, the characterization of their pore structure is rarely presented in recent research.…”

Section: Introductionmentioning

confidence: 99%

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Pore Structure Petrophysical Characterization of the Upper Cretaceous Oil Shale from the Songliao Basin (NE China) Using Low-Field NMR

Liu

Zhang

Bai

et al. 2020

Journal of Spectroscopy

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Low-field NMR theory was employed to study the pore structure of the upper cretaceous oil shale, on the basis of fourteen core samples collected from Qingshankou (UCQ) and Nenjiang (UCN) formations in the Songliao basin. Results indicated that the T 2 spectra from NMR measurements for collected samples contain a dominant peak at T 2 � 1∼10 ms and are able to be categorized as three types-unimodal, bimodal, and trimodal distributions. e various morphologies of T 2 spectra indicate the different pore type and variable connection relationship among pores in shale. By contrast, UCN shale has more single pore type and adsorption pores than UCQ shale. Besides, NMR-based measurements provide reliable characterization on shale porosity, which is verified by the gravimetric approach. Porosities in both UCN and UCQ shales have a wide range (2.3%∼12.5%) and suggest the strong heterogeneity, which partly makes the challenge in selection of the favorable area for shale oil exploration in the Songliao basin. In addition, the pore size of the collected sample has two distribution types, namely, peaked at ∼10 nm and peaked at ∼100 nm. Similarly, two distribution patterns emerge to the specific surface area of the study shale-peaked at ∼2 nm − 1 and peaked at ∼20 nm − 1 . Here, more investigations are needed to clarify this polarization phenomenon. Basically, this study not only exhibits a preliminary understanding on the pore structure of the upper cretaceous oil shale, but also shows the reliability and pertinency of the low-field NMR technique in the petrophysical characterization of the shale oil reservoir. It is expected that this work is helpful to guide the investigation on the pore structure of oil shale from the Songliao basin in theory.

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Section: Geological Backgroundmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pore Structure Petrophysical Characterization of the Upper Cretaceous Oil Shale from the Songliao Basin (NE China) Using Low-Field NMR

Liu

Zhang

Bai

et al. 2020

Journal of Spectroscopy

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“…For instance, the average clay mineral contents of both the Triassic Chang-7 lacustrine organic-rich shales and Upper Paleozoic paludal organic-rich mudstones (carbonaceous shales) in the Ordos Basin are commonly higher than 45%, while the brittle mineral contents are relatively low (Zhao et al 2016b;Jiang et al 2016). The lacustrine-deposited Cretaceous Qingshankou Formation shales in the Songliao Basin may also be clay rich, with an average content of clay minerals of 55.1% at well ZK-01 (Liu et al 2017). Nonetheless, the lacustrine shales of the upper Es 4 and lower Es 3 of the Eocene Shahejie Formation in the Dongying Depression, Bohai Bay Basin, are carbonate rich and clay poor, with an average content of authigenic carbonate of 37%, clay 25%, quartz 29%, and feldspar 5% (Li 2013), which is probably one of the crucial factors accountable to the breakthrough of oil production in this shale play.…”

Section: A Hydrocarbon-generating Conditionmentioning

confidence: 99%

The petroleum system: a new classification scheme based on reservoir qualities

Zhao

et al. 2018

Pet. Sci.

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A new classification of petroleum systems (PSs) based on reservoir qualities is proposed. We classify PSs into the following three basic types: (1) source-rock petroleum system (SPS); (2) tight-reservoir or tight petroleum system (TPS); and (3) conventional-reservoir or conventional petroleum system (CPS). The CPS is a PS in which hydrocarbons accumulate in conventional reservoirs, and all the essential elements and processes are significant and indispensable. Oil and gas accumulations are geographically discrete and therefore exist as discontinuous accumulations. The TPS is a PS where hydrocarbons accumulate in tight reservoirs and the source rock, reservoir, seal, migration, and trap are also indispensable, but the traps are mostly non-anticlinal and the accumulations are primarily quasi-continuous and secondarily discontinuous. The SPS is a PS where both hydrocarbon generation and accumulation occurred in source rocks and traps and migration are unnecessary or inconsequential; the hydrocarbon distribution is extensive and continuous and has no distinct boundaries. The aforementioned three PSs can be derived from a common hydrocarbon source kitchen and are closely linked in terms of their formation and distribution. Therefore, to maximize the exploration efficiency, a comprehensive study and different strategies are needed by considering the SPS, TPS, and CPS as parts of a greater whole.

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“…The vitrinite reflectance (R o ) is between 0.5% and 1.1%, and the peak temperature of pyrolysis (T max ) ranges from 430 • C to 450 • C. These parameters indicate that the shale formations in K 2 qn 1 are in low-mature to mature stage and are currently generating a large quantity of oil. 17 Core observations showed that there are widely developed silty beds/laminae in the Qingshankou shale formations. Most of these silty Fractal Characterization of Silty Beds/Laminae beds/laminae are less than 1 cm.…”

Section: Introductionmentioning

confidence: 99%

“…Studies indicated that the shale systems of the Cretaceous Qingshankou Formation (K 2 qn) in Songliao Basin have favorable geological conditions for the formation of shale oil. 17 The first member of the Cretaceous Qingshankou Formation (K 2 qn 1 ) has the highest organic matter content in Songliao Basin. The average total organic carbon (TOC) content is over 2%.…”

Section: Introductionmentioning

confidence: 99%

Fractal Characterization of Silty Beds/Laminae and Its Implications for the Prediction of Shale Oil Reservoirs in Qingshankou Formation of Northern Songliao Basin, Northeast China

Liu

Jin

2019

Fractals

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Cretaceous Qingshankou Formation [Formula: see text] in the Songliao Basin, the largest petroliferous basin in East China, has favorable geological conditions for the shale oil reservoir. Although the first member of Qingshankou formation [Formula: see text] has the maximum value of the organic matter content (total organic carbon (TOC)) comparing with other members, most of the layers are less than 1[Formula: see text]cm. This limits the application of surface seismic survey and logging methods. To explore “sweet spots” of the shale oil and to evaluate resource potential, it is of great significance to determine the thickness and distribution of silty beds/laminae in the thick shale system. In this study, the observed data of the outcrops, cores, and thin sections of [Formula: see text] are used to analyze the characteristics of reservoir space in silty laminae. Distribution model of silty beds/laminae was established by using fractal method. The results show that the silty beds/laminae have large particle size, poor sorting, and relatively developed reservoir space. The pore sizes in silty laminae vary greatly, and the diameters are mostly larger than 50[Formula: see text]nm. The connectivity between pores is good. Although the thickness of single silty bed/laminae mostly ranges from 1[Formula: see text]mm to 6[Formula: see text]mm, the average layers per meter (layers/m) of silty bed/laminae range from 2 to 64. This contributes the cumulative thickness 2.73–31.79% of the total thickness of the whole shale reservoir. According to the fractal analysis, the silty beds/laminae have the uniform fractal characteristics in the decimeter, centimeter, and millimeter levels. And the fractal dimension keeps the scale invariance. The layers and thickness of the thin silty laminae, calculated from Number–Size (NS) fractal model, are in good agreement with observations. This indicates that the fractal-based NS model is an effective method to estimate the parameters of the silty laminae, such as layer number, cumulative thickness, and the ratio of sand to formation. This method provides a reliable reference for the “sweet spot” exploration.

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Enrichment and distribution of shale oil in the Cretaceous Qingshankou Formation, Songliao Basin, Northeast China

Cited by 58 publications

References 23 publications

Pore Structure Petrophysical Characterization of the Upper Cretaceous Oil Shale from the Songliao Basin (NE China) Using Low-Field NMR

Pore Structure Petrophysical Characterization of the Upper Cretaceous Oil Shale from the Songliao Basin (NE China) Using Low-Field NMR

The petroleum system: a new classification scheme based on reservoir qualities

Fractal Characterization of Silty Beds/Laminae and Its Implications for the Prediction of Shale Oil Reservoirs in Qingshankou Formation of Northern Songliao Basin, Northeast China

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