Depositional environment, diagenetic evolution, and their impact on the reservoir quality of the carboniferous KT-Ⅱ carbonate in the zhanazhol reservoir, Pre-Caspian Basin, Kazakhstan

Zhu, Xiaomin; Jin, Zhenkui; Liang, Ting; Yi, Shuo; Wei, Kai; Gao, Baishui; Shi, Liang

doi:10.1016/j.marpetgeo.2020.104411

Cited by 14 publications

(4 citation statements)

References 40 publications

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“…Micritization is the first diagenetic event in marine environment and is common in studied intervals. The extensive presence of micritization in the lagoon, outer ramp and middle ramp facilitates the development of micro‐interparticle pores, because micro‐organisms likely destroy the surfaces of bioclasts due to low‐energy conditions (Flügel, 2010; Zhu et al, 2020). Isopachous rim calcite and bladed rim calcite, interpreted as early marine cements, likely follow micritization (Moore & Wade, 2013).…”

Section: Discussionmentioning

confidence: 99%

Identification of pore facies for evaluating the reservoir quality: A case study of the Hartha Formation in X Oilfield, Mesopotamian Basin, Iraq

Zhang,

Saeed,

Wang

et al. 2023

Geological Journal

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Characterization of pore systems is a key to better understand the heterogeneity of reservoir quality. However, the complicated pore types and pore facies of carbonates in the Hartha Formation of X Oilfield remain poorly understood. In this study, we recognized pore types and explored the impact of depositional environment and diagenetic alterations on pore facies and reservoir heterogeneity. Six types and nine subtypes of pore facies displaying various physical properties and fossils are classified based on the proportion of depositional pores, fabric‐ and non‐fabric‐selective pores. The distribution of pore facies are controlled by the interaction between depositional environment and diagenesis: (i) the depositional environment has an impact on the primary pore types mainly through different lithology and fossils. Micro‐interparticle pores and intraparticle pores of foraminifera are dominated in lagoon, middle ramp and outer ramp, while interparticle pores between grains are dominated in rudist shoal. Rocks deposited in medium‐ to low‐energy shoal contain interparticle pores between grains, micro‐interparticle pores and intraparticle pores of foraminifera. (ii) Major diagenetic events that modify pore types include micritization, fabric‐selective dissolution, cementation, compaction and non‐fabric‐selective dissolution. Micritization facilitates the development of micro‐interparticle pores, while compaction can cause the loss of interparticle pores between grains and micro‐interparticle pores. Cementation destroys not only interparticle pores between grains but also intraparticle pores of foraminifera. Fabric‐ and non‐fabric‐selective dissolution are the main causes for increasing the volume of pores. (iii) The intensity of the diagenetic event is linked to rock composition, rock fabric and palaeotopography that are controlled by depositional environment. Thus, the distribution of pore facies related to the environment is established, which can provide insights for areas lacking cores and adjacent fields with similar settings.

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Section: Discussionmentioning

confidence: 99%

Identification of pore facies for evaluating the reservoir quality: A case study of the Hartha Formation in X Oilfield, Mesopotamian Basin, Iraq

Zhang,

Saeed,

Wang

et al. 2023

Geological Journal

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“…However, affected by the Chardzhou uplift and Kyzyl Kumu uplift in the northwest, the areas on the right bank are high in the northwest and low in the southeast in terms of the structural pattern [20][21][22]. Based on the characteristics of the tectonic setting and regional sedimentary facies, the right bank of the Amu Darya River can be divided into a carbonate platform depositional system and a front slope depositional system according to the petrological characteristics, paleontological markers, and logging facies markers [23][24][25]. The carbonate platform is subdivided into such subfacies as evaporation platform, restricted platform, open platform, and platform margin, while the foreslope sedimentary facies are divided into such subfacies as upper slope and lower slope and further divided into 9 microfacies [26,27] (Table 1).…”

Section: Characteristics Of Callovian-oxfordian Sedimentary Faciesmentioning

confidence: 99%

Types and Distribution Characteristics of Callovian-Oxfordian Reservoir on the Right Bank of Amu Darya River in Turkmenistan

Wang¹

2023

Geofluids

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Given the characteristics of significant or enormous resources, a wide range, many reservoir types, and challenging exploration on the right bank of the Amu Darya River, we systematically studied the characteristics of its reservoirs. Based on the core description, thin sections in combination with logging and seismic facies characteristics as well as regional tectonic-sedimentary background, the Callovian-Oxfordian platform and the gentle slope sedimentary system in the Amu Darya Basin of Turkmenistan were summarized. Sedimentary subfacies such as evaporation platform, restricted platform, open platform, and platform margin reef are developed in block A and its west. In contrast, the upper slope, lower slope, and basin sedimentary subfacies are developed in the east of block A. On this basis, the main reservoir types on the right bank of the Amu Darya River are summarized, namely, porous reservoir, vuggy reservoir, fractured-porous reservoir, and fractured-vuggy reservoir. After describing the characteristics of various reservoirs in detail, the main controlling factors, development patterns, and distribution rules of the development of different reservoirs are summarized. Specifically, based on the platform reef, the porous reservoir and vuggy reservoirs are developed mainly on the concealed palaeouplift in the study area and are greatly influenced by atmospheric freshwater leaching and buried dissolution. Based on the dominant sedimentary facies, the fractured-porous reservoirs are mainly developed in the central areas on the right bank of the Amu Darya River. In the later period, hydrothermal fluid and hydrocarbon-generating acidic fluid can dissolve the reservoir through strike-slip faults and their associated fractures. Diagenetic fluid enters the reef through faults and associated fractures to form dissolved reservoir bodies of a certain scale. The fractured-vuggy reservoirs are mainly controlled by faults and dissolution and are mainly developed near the eastern thrust fault on the right bank of the Amu Darya River, effectively guiding the direction for further exploration and development in this area.

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“…The Pre-Caspian Basin is rich in oil and gas resources (Zhu et al, 2020;Zhanserkeyeva and Kassenov, 2022). So far, a series of large and extra-large carbonate oil and gas fields, such as Astrakhan, Kashagan, Tengiz, and Kenkiyak, have been discovered in the Lower Permian salt beds in this basin.…”

Section: Geological Settingmentioning

confidence: 99%

Evaluation of pore-throat structures of carbonate reservoirs based on petrophysical facies division

Hou

Zhao

et al. 2023

Front. Earth Sci.

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After complex geological transformation, such as sedimentation, diagenesis, and tectonic transformation, carbonate reservoirs have developed multiple reservoir spaces with significant heterogeneity and various pore-throat structures, including pores, vugs, and fractures. Due to these characteristics, many problems have been caused during the development of carbonate reservoirs, such as large differences between the initial production capacities of single wells and serious water channeling after injection, which have brought many challenges to the efficient development of carbonate reservoirs. Therefore, based on a reservoir evaluation method of petrophysical facies, this study classified and evaluated the pore-throat structures of Carboniferous carbonate reservoirs in the North Truwa oilfield of the Pre-Caspian Basin. Based on the data of the core, thin section, scanning electron microscope, high-pressure mercury injection, sedimentary facies, diagenetic facies, and the development of fractures and karst vugs, six reservoir petrophysical facies in the study area were classified and named, including the facies of favorable sedimentation-constructive diagenesis-fracture and vug, the facies of favorable sedimentation-constructive diagenesis-non-fracture or vug, the facies of favorable sedimentation-destructive diagenesis-fracture and vug, the facies of favorable sedimentation-destructive diagenesis-non-fracture or vug, the facies of unfavorable sedimentation-constructive diagenesis-non-fracture or vug, and the facies of unfavorable sedimentation-destructive diagenesis-non-fracture or vug. The recognition and division of diagenetic facies were based on the K-nearest neighbor. Four quantitative parameters were also selected to characterize the pore-throat structures, including displacement pressure (Pd), mercury removal efficiency (Em), median throat radius (R50), and sorting coefficient (Cs). Based on the principal component analysis, the classification and evaluation standards of pore-throat structures in different petrophysical facies were established. Combined with the flow profile measured by production logging tools, the relationship between different petrophysical facies and productions was also revealed. As a result, this study can provide suggestions for the adjustment strategy of water-driven production, which lays an important foundation for the fine development of carbonate reservoirs.

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Depositional environment, diagenetic evolution, and their impact on the reservoir quality of the carboniferous KT-Ⅱ carbonate in the zhanazhol reservoir, Pre-Caspian Basin, Kazakhstan

Cited by 14 publications

References 40 publications

Identification of pore facies for evaluating the reservoir quality: A case study of the Hartha Formation in X Oilfield, Mesopotamian Basin, Iraq

Identification of pore facies for evaluating the reservoir quality: A case study of the Hartha Formation in X Oilfield, Mesopotamian Basin, Iraq

Types and Distribution Characteristics of Callovian-Oxfordian Reservoir on the Right Bank of Amu Darya River in Turkmenistan

Evaluation of pore-throat structures of carbonate reservoirs based on petrophysical facies division

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