Origin of the reservoir quality difference between Chang 8 and Chang 9 Member sandstones in the Honghe Oil Field of the Southern Ordos Basin, China

Liu, Hongping; Zhao, Yang; Yong, Luo; Xiao, Gaojian; Meng, Yujing; Zhou, Sibin; Shao, Longkan

doi:10.1016/j.petrol.2019.106668

Cited by 16 publications

(2 citation statements)

References 12 publications

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“…The Chang 8 sandstones, which are close to the Chang 7 source rock, have a high content of feldspar and lithic dissolution and grain collapse from the acidic fluid injection. This also indirectly leads to the deterioration of reservoir physical properties [25]. The detrital composition is mainly metamorphic rocks and igneous rock (Figure 2b), and the interstitial matter is mainly composed of ferrocalcite and chlorite (Figure 2c).…”

Section: Lithologic Featuresmentioning

confidence: 99%

Formation Characterization and Type Prediction Based on Geophysical Well Log Data in Horizontal Well: A Case Study of Triassic Chang 8 Formation in Shunning Region, Central Ordos Basin

Li,

Xiao,

et al. 2023

Processes

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The role of the horizontal well in developing unconventional oil and gas reservoirs is particularly significant. Different from vertical wells, horizontal wells are greatly affected by many factors, e.g., well track, surrounding mudstone, resistivity, and pore structure heterogeneity in horizontal and vertical directions. These make it difficult to evaluate reservoir parameters and determine optimized test layers. In order to improve formation evaluation in horizontal wells, it is necessary to carry out the research of analyzing formation anisotropy, predict physical property parameters, and classify formation to determine high-quality intervals. In this study, taking Triassic Chang 8 Formation in Shunning Region, Central Ordos Basin as an example, 40 core samples were drilled and applied for nuclear magnetic resonance (NMR), mercury injection capillary pressure (MICP), and resistivity experiments. The porosity, permeability, resistivity, and pore structure anisotropy are analyzed. Results illustrate that the physical properties and pore structure in horizontal direction are superior to vertical direction. Meanwhile, NMR log loses its role in pore structure characterization in horizontal wells. Afterward, methods of correcting interval transit time (DT) and resistivity anisotropy are raised, and models of predicting formation physical property parameters, such as porosity, permeability, and water saturation, are established. A parameter, named as the formation type indicator (FTI), is proposed to reflect reservoir oil-bearing properties and pore structure. Finally, our target horizontal intervals are classified into four types, and the highest-quality “sweet spot” is determined.

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Section: Lithologic Featuresmentioning

confidence: 99%

Formation Characterization and Type Prediction Based on Geophysical Well Log Data in Horizontal Well: A Case Study of Triassic Chang 8 Formation in Shunning Region, Central Ordos Basin

Li,

Xiao,

et al. 2023

Processes

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“…The Yanchang Formation is about 200–1400 m in thickness, and deposited in a large lacustrine system in the Upper Triassic (Wang et al., 2017). There are ten oil reservoirs (Chang 1 Member to Chang 10 Member) from top to bottom in the Yanchang Formation (Liu et al., 2020). The Yanchang Formation experienced multiple stages of transgression and regression, giving rise to many sets of sandstone and mudstone.…”

Section: Geological Settingmentioning

confidence: 99%

Formation mechanism of authigenic chlorite in tight sandstone and its influence on tight oil adsorption, Triassic Ordos Basin, China

Zhou

et al. 2020

Energy Exploration & Exploitation

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In this study, the formation mechanism of authigenic chlorite in tight reservoirs and its influence on the adsorption capacity to tight oil have been analyzed. The occurrence states of chlorite and the formation mechanism have been analyzed by thin section (TS) and field emission scanning electron microscopy (FE-SEM) measurements. Due to the alteration of volcanic rock fragments, the mudstone pressurized water, and the dissolution of early chlorite, the material source has been provided for the formation of chlorite. The formation time of chlorite with different occurrence states is in the following order: grain-coating chlorite → pore-lining chlorite → pore-lining chlorite in dissolved pores → rosette chlorite. Authigenic chlorite developed in the reservoirs has influenced the change of the reservoir quality in two respects. On the one hand, authigenic chlorite can protect the residual pores, improve the anti-compaction capacity of the reservoir, and provide certain inter-crystalline space. On the other hand, it can hinder pore space and inhibit throat, resulting in a decrease in the connectivity of pores and the increase in the heterogeneity of the reservoir. Tight oil absorbed by the chlorite is mainly in the form of the thin film and aggregates. Through in situ testing of environmental scanning electron microscope (ESEM) and energy dispersive spectrum (EDS), the adsorption capacity of chlorite with different occurrence states to tight oil, being in the following order: rosette chlorite > pore-lining chlorite > pore-lining chlorite in dissolved pores > grain-coating chlorite. Furthermore, the controlling factors on reservoir quality, the content of chlorite and content of Fe and K have been investigated, and the adsorption capacity of different chlorite types has been studied, which can provide guidance for analysis of the control factors on the difference in adsorption capacity of different occurrence states of chlorite to tight oil in tight reservoirs.

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Logging-Based Petrophysical Estimation for Tight Sandy-Mud Reservoirs Employing a Geologically Regularized Learning System

Gu,

Zhang,

et al. 2024

Nat Resour Res

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Origin of the reservoir quality difference between Chang 8 and Chang 9 Member sandstones in the Honghe Oil Field of the Southern Ordos Basin, China

Cited by 16 publications

References 12 publications

Formation Characterization and Type Prediction Based on Geophysical Well Log Data in Horizontal Well: A Case Study of Triassic Chang 8 Formation in Shunning Region, Central Ordos Basin

Formation Characterization and Type Prediction Based on Geophysical Well Log Data in Horizontal Well: A Case Study of Triassic Chang 8 Formation in Shunning Region, Central Ordos Basin

Formation mechanism of authigenic chlorite in tight sandstone and its influence on tight oil adsorption, Triassic Ordos Basin, China

Logging-Based Petrophysical Estimation for Tight Sandy-Mud Reservoirs Employing a Geologically Regularized Learning System

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