Characteristics of tight oil in Triassic Yanchang Formation, Ordos Basin

Yao, Jiayi; Deng, Xiuqin; Zhao, Yande; Han, Tao; Chu, Meijuan; Pang, Jifeng

doi:10.1016/s1876-3804(13)60019-1

Cited by 273 publications

(78 citation statements)

References 7 publications

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“…For the interbedded sandstone and siltstone in the Chang7 source rock, the predominantly tight sandstone and siltstone reservoirs exhibit overall low permeability Yao et al 2013). The interbedded sandstone and siltstone could be classified as conventional turbidite sandstones and siltstones, and sandy debrite reservoirs if the permeability value is higher than 0.1 mD (Zou et al 2012).…”

Section: Hybrid Plays Within Upper Triassic Siliciclastic Source Rockmentioning

confidence: 99%

“…The green and red dots denote oil and gas production, respectively; b Properties of Chang7 source rock interval in L189 well (After Yang et al 2013); c West-to-east cross section showing the stratigraphic variation of the Chang 7 source rock interval across the Xifeng Oilfield (Section location in a). The facies were identified based on regional facies distribution, well log characteristics, lithologic association, and well correlation; d Westto-east cross section showing the residual pressure (difference between formation pressure and hydrostatic pressure) distribution and permeability of the Chang7 source rock interval (Section location in a) (After Yao et al 2013). The ''Hybrid Plays'' were identified based on the lithofacies, geochemistry, petrophysics, pressure, and production test results Tight gas Shale gas (Jin et al 2014).…”

Section: Hybrid Plays Within Jurassic Carbonatecontaining Source Rockmentioning

confidence: 99%

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Multiple-stacked Hybrid Plays of lacustrine source rock intervals: Case studies from lacustrine basins in China

et al. 2017

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Hydrocarbon-producing lacustrine basins are widely developed in the world, and China has a large number of lacustrine basins that have developed since the early Permian. The organic-rich shale-dominated heterogeneous source rock intervals in Chinese lacustrine basins generally contain frequent thin interbeds of stratigraphically associated sandstone, siltstone, marl, dolomite, and limestone. The concept of ''Hybrid Plays'' as put forth in this article recognizes this pattern of alternating organicrich shale and organic-lean interbeds and existence of mixed unconventional and conventional plays. Hybrid Plays in lacustrine source rock intervals present a unique closed petroleum system hosting continuous hydrocarbons. The interbedded organic-lean siliciclastic and/or carbonate plays are efficiently charged with hydrocarbons via short migration pathways from the adjacent organic-rich shale that is often also a self-sourced play. We assert ''Hybrid Plays'' provide the most realistic exploration model for targeting multiple-stacked and genetically related very tight shale, tight and conventional plays together in the entire source rock interval rather than individual plays only. The Hybrid Play model has been proven and works for a wide variety of lacustrine rift, sag and foreland basins in China.

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Section: Hybrid Plays Within Upper Triassic Siliciclastic Source Rockmentioning

confidence: 99%

Section: Hybrid Plays Within Jurassic Carbonatecontaining Source Rockmentioning

confidence: 99%

Multiple-stacked Hybrid Plays of lacustrine source rock intervals: Case studies from lacustrine basins in China

et al. 2017

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“…[1][2][3] Developing tight oil reservoirs is very challenging due to the ultra-low formation permeability, which is usually less than 0.1 mD under reservoir conditions. 4 In tight formations, pore-throats are mainly on the order of tens of nanometers.…”

Section: Introductionmentioning

confidence: 99%

A Fractal Permeability Model Coupling Boundary-Layer Effect for Tight Oil Reservoirs

et al. 2017

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A fractal permeability model coupling non-flowing boundary-layer effect for tight oil reservoirs was proposed. Firstly, pore structures of tight formations were characterized with fractal theory. Then, with the empirical equation of boundary-layer thickness, Hagen-Poiseuille equation and fractal theory, a fractal torturous capillary tube model coupled with boundary-layer effect was developed, and verified with experimental data. Finally, the parameters influencing effective liquid permeability were quantitatively investigated. The research results show that effective liquid permeability of tight formations is not only decided by pore structures, but also affected by boundary-layer distributions, and effective liquid permeability is the function of fluid type, fluid viscosity, pressure gradient, fractal dimension, tortuosity fractal dimension, minimum pore radius and maximum pore radius. For the tight formations dominated with nanoscale pores, boundary-layer effect can significantly reduce effective liquid permeability, especially under low pressure gradient.

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“…Therefore, the study of the diagenetic processes and its controlling factors is of great significance to predict high-quality and favorable reservoir of low-permeable Chang 8 tight sandstone. Previous are mainly focused on reservoir characteristics, diagenesis, oil accumulation model and mechanism of the Chang 8 oil group in study area (Zeng and Li 2009;Yao et al 2013). However, the diagenetic modification to the reservoir physical property and the reservoir evolution pattern are not as well known.…”

Section: Introductionmentioning

confidence: 99%

Diagenesis and its impact on reservoir quality for the Chang 8 oil group tight sandstone of the Yanchang Formation (upper Triassic) in southwestern Ordos basin, China

Lin

Chen

et al. 2017

J Petrol Explor Prod Technol

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Based on the applications of thin section, cathode luminescence, scanning electron microscope and X-ray diffraction, this paper studies the reservoir characteristics, diagenesis features and their influences on the development of reservoir pores for the Chang 8 oil group of Yanchang Formation in southwestern Ordos Basin. Results show that the reservoir is characterized by low composition maturity, low structure maturity, low porosity/ultra-low porosity and ultra-low permeability which belong to tight reservoir. The reservoirs develop medium intensity of compaction, moderate to strong cementation, relatively strong dissolution, suggesting that it is in stage B of the middle diagenetic evolution. The main diagenetic types include mechanical compaction, cementation by carbonates, quartz and clay minerals, and dissolution which have directly influenced the reservoir quality. In the early diagenetic period, the rapid compaction and cementation of carbonate had rapidly destroyed the reservoir quality, while the particles lining of chlorites had protected the reservoir space. In the middle diagenetic stage A, secondary dissolution pores were formed as soluble clastic grains were dissolved by the acidic fluid with organic matters maturation. The dissolution has played a constructive role for the pore generation and preservation. In the middle diagenetic stage B, the later compaction and cementation further reduced the reservoir quality. The analysis of pore evolution demonstrates that the initial reservoir porosity is about 30.59%. 16.925% overall porosity is lost through compaction, 11.65% porosity loss is due to cementation, and 6.36% porosity was created by dissolution. Finally, the reservoir is holding 8.375% porosity in present.

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Characteristics of tight oil in Triassic Yanchang Formation, Ordos Basin

Cited by 273 publications

References 7 publications

Multiple-stacked Hybrid Plays of lacustrine source rock intervals: Case studies from lacustrine basins in China

Multiple-stacked Hybrid Plays of lacustrine source rock intervals: Case studies from lacustrine basins in China

A Fractal Permeability Model Coupling Boundary-Layer Effect for Tight Oil Reservoirs

Diagenesis and its impact on reservoir quality for the Chang 8 oil group tight sandstone of the Yanchang Formation (upper Triassic) in southwestern Ordos basin, China

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