Effect of Organic Matter Type and Maturity on Organic Matter Pore Formation of Transitional Facies Shales: A Case Study on Upper Permian Longtan and Dalong Shales in Middle Yangtze Region, China

Wu, Zhongrui; He, Sheng; Han, Yuanjia; Zhai, Gangyi; Xu, He; Zhou, Zhi

doi:10.1007/s12583-019-1237-6

Cited by 39 publications

(23 citation statements)

References 60 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Many other types of highly matured transitional shales also revealed the same conditions. 27 , 54 − 56 The reason behind this poor development is the low maturity of the Es3x shale because, for OM pore development in the lacustrine shale, the R o should be more than 1.2%. 16 In the Es3x shale, OM comprises of type-I to type-II kerogens.…”

Section: Resultsmentioning

confidence: 99%

Formation and Distribution of Different Pore Types in the Lacustrine Calcareous Shale: Insights from XRD, FE-SEM, and Low-Pressure Nitrogen Adsorption Analyses

et al. 2022

View full text Add to dashboard Cite

Pore types and pore structure parameters are the important factors affecting the storage capacity of a shale oil reservoir. Pore morphology and mineralogical composition of shales have diverse effects on the upgrading of various phases of shale oil. To interpret the formation and distribution of different pore types and their structure parameters in the lacustrine calcareous shale, a combination of polarizing microscopy, X-ray diffraction, total organic carbon (TOC), field-emission scanning electron microscopy, and low-pressure nitrogen adsorption experiments were conducted on the Es3x shale of the Eocene Shahejie Formation in the Zhanhua Depression. The interpretations regarding pore types, pore structure parameters, and pore size distribution indicate that the pore morphology and pore size distribution in the lacustrine shale are very complicated and demonstrate strong heterogenic behavior. Inorganic pores (interparticle pores, intraparticle pores, intercrystalline pores, dissolution pores, and microfractures) are the most commonly distributed pore types in the studied shale. However, organic matter pores are poorly developed due to the lower thermal maturity of the Es3x shale. The Brunauer–Emmett–Teller specific surface and pore volume range from 0.026 to 1.282 m 2 /g (average 0.697 m 2 /g) and 0.003 to 0.008 cm 3 /g (average 0.005 cm 3 /g), respectively. The shape of the pores varies from slit-like to narrow slit. Different minerals develop different types of pores with various sizes extending from micropores (<2 nm), mesopores (2–50 nm), to macropores (>50 nm). The relationship between mineral components and pore parameters indicates that the carbonate minerals act as the main contributors to the formation and distribution of different pore types in the studied shale. Pore volume and the pore specific surface area did not show a good relationship with mineral composition and TOC due to disordered pores, but pore size shows a good relationship with mineral composition and TOC of the Es3x shale. The whole pore system description showed that the mesopores and macropores are abundantly distributed and are the main contributors to the pore system in the Es3x shale. A comprehensive understanding of the formation mechanism and structural features of various sized pores in a variety of different minerals can provide a good tool for the exploration and development of shale oil reservoirs.

show abstract

Section: Resultsmentioning

confidence: 99%

Formation and Distribution of Different Pore Types in the Lacustrine Calcareous Shale: Insights from XRD, FE-SEM, and Low-Pressure Nitrogen Adsorption Analyses

et al. 2022

View full text Add to dashboard Cite

show abstract

“…The source rock data in the study area show that the kerogen carbon isotope values of the various marine source rocks exhibit different distribution ranges. The kerogen δ 13 C value of the Longtan Formation ranges from −23.0 ‰ to −24.8 ‰, that of the Mao‐1 member ranges from −29.4 ‰ to −27.1 ‰, that of the Longmaxi Formation ranges from −30.5 ‰ to −28.6 ‰, and that of the Qiongzhusi Formation ranges from −29.4 ‰ to −31.8 ‰ (Liu et al, 2020; Wu et al, 2020; Zhang et al, 2020; Zheng et al, 2020). Therefore, it is inferred that both the Mao‐1 member and the Longmaxi Formation may be the source rocks of the natural gas occurring in the Mao‐1 member.…”

Section: Discussionmentioning

confidence: 99%

“…Two key factors of organic matter enrichment in sediments are a high biological productivity and an anoxic reducing environment (Demaison & Moore, 1980; Jarvie, Hill, Ruble, & Pollastro, 2007; Liu et al, 2020; Shi, Feng, Shen, Ito, & Chen, 2016; Wu et al, 2020; Zeynep, Mustafa, Ismail, & Hu, 2019; Zheng et al, 2020; Zou et al, 2019). The Middle Permian Mao‐1 member in the study area was deposited on an outer gentle slope, and the oxygen‐rich surface water in the euphotic zone of the shallow sea was conducive to the growth of plankton.…”

Section: Discussionmentioning

confidence: 99%

A new type of unconventional gas reservoir from the nodular limestones of the Middle Permian Maokou Formation in the south‐eastern Sichuan Basin, south‐west China

Shan

Luo

et al. 2021

Geological Journal

View full text Add to dashboard Cite

A set of nodular limestones was developed in the first member of the Middle Permian Maokou Formation (denoted as the Mao‐1 member) in the south‐eastern Sichuan Basin, south‐west China. Borehole coring has shown excellent signals of oil and gas from the Mao‐1 member carbonates, and many drilling wells have obtained industrial‐level gas flow. To assess the natural gas exploration potential of the Mao‐1 member in this area, sedimentary characteristics of drilling cores are described, and the formation mechanism of natural gas reservoir and its key controlling factors are also evaluated using data obtained from field geological survey, core observation, and laboratory experimental analysis. On this basis, the process of natural gas accumulation and evolution is examined. The results show that the Mao‐1 member nodular limestone comprises abundant marls and packstone to wackestone, and they were deposited in a lower part of the carbonate ramp setting. The marls exhibit rather high organic‐matter abundance and hydrocarbon generation capacity. Natural gas is mostly enriched in the marls developed talc diagenetic shrinkage pores and a certain number of organic‐matter pores, and their reservoir properties are much better than that of packstone‐wackestone. The natural gas in the Mao‐1 member is mainly self‐generated oil pyrolysis gas. The gas reservoir is characterized by the co‐existence of source rocks and reservoir, a lithology‐controlled reservoir, and a structure‐fracture‐controlled enrichment mechanism. Organic‐matter‐rich marl constitutes the material basis for natural gas accumulation. Talc diagenetic shrinkage pores provide storage space for natural gas. Preservation conditions are the key to natural gas accumulation, and natural fractures are beneficial to high gas production. The gas reservoir is characterized by early intraformational enrichment and late interformational adjustment. The finding of the nodular limestone gas reservoir of the Mao‐1 member provides new insights into unconventional gas exploration in the Sichuan Basin, and shows great potential for increasing natural gas reserves and production in China.

show abstract

“…Shale oil is a new hotspot of unconventional resources exploration and development, after shale gas. Shale oil has achieved great success in North America [1], forming the second peak growth of crude oil production in the United States, which has greatly alleviated the energy pressure of the US and made the energy independence of the US a reality [2]. The successful commercial development of the US shale oil has profoundly affected international energy and reshaped the global energy industry [3,4].…”

Section: Introductionmentioning

confidence: 99%

Microscale Evaluation of Tight Oil Mobility: Insights from Pore Network Simulation

et al. 2021

View full text Add to dashboard Cite

Pore network modeling based on digital rock is employed to evaluate the mobility of shale oil in Qingshankou Formation, Songliao Basin, China. Computerized tomography technology is adopted in this work to reconstruct the digital rock of shale core. The pore network model is generated based on the computerized tomography data. We simulate the dynamics of fluid flow in a pore network model to evaluate the mobility of fluid in shale formation. The results show that the relative permeability of oil phase increases slowly in the initial stage of the displacement process, which is mainly caused by the poor continuity of the oil phase. In the later stages, with the increase in the oil phase continuity, the range of relative permeability increases. With the increase of organic matter content, the permeability of the water phase remains unchanged at low water saturation, but gradually increases at high water saturation. At the same time, it can be seen that, with the increase in organic matter content, the isosmotic point of the oil–water phase permeability shifts to the left, indicating that the wettability to water phase gradually weakens.

show abstract

Effect of Organic Matter Type and Maturity on Organic Matter Pore Formation of Transitional Facies Shales: A Case Study on Upper Permian Longtan and Dalong Shales in Middle Yangtze Region, China

Cited by 39 publications

References 60 publications

Formation and Distribution of Different Pore Types in the Lacustrine Calcareous Shale: Insights from XRD, FE-SEM, and Low-Pressure Nitrogen Adsorption Analyses

Formation and Distribution of Different Pore Types in the Lacustrine Calcareous Shale: Insights from XRD, FE-SEM, and Low-Pressure Nitrogen Adsorption Analyses

A new type of unconventional gas reservoir from the nodular limestones of the Middle Permian Maokou Formation in the south‐eastern Sichuan Basin, south‐west China

Microscale Evaluation of Tight Oil Mobility: Insights from Pore Network Simulation

Contact Info

Product

Resources

About