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Article

Controls of Zeolite Development on Reservoir Porosity from Lower Permian Formations in Shawan and Its Adjacent Areas, Western Junggar Basin

by
Houkuan Lv
1,
Hao Kuang
1,*,
Lei Zhang
2,
Fangpeng Dou
2,
Chun Li
1 and
Lang Pan
1
1
School of Petroleum Engineering, Chongqing University of Science and Technology, Chongqing 401331, China
2
Research Institute of Exploration and Development, Xinjiang Oilfield Company, PetroChina, Karamay 834000, China
*
Author to whom correspondence should be addressed.
Minerals 2025, 15(12), 1247; https://doi.org/10.3390/min15121247
Submission received: 9 October 2025 / Revised: 19 November 2025 / Accepted: 22 November 2025 / Published: 26 November 2025
(This article belongs to the Special Issue Geochronology, Geochemistry, and Tectonic Significance of Pyroclastic Rocks)
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Abstract

The Shawan Sag and its adjacent areas are rich in hydrocarbon resources. Moreover, the genesis and evolution patterns of zeolite cements in the sandy conglomerate reservoirs have resulted in diverse types of reservoir spaces, a complex composition, and significant heterogeneity. To investigate their impact on reservoir quality, this study integrates core observations, thin-section petrography, scanning electron microscopy (SEM), whole-rock X-ray diffraction (XRD), and energy-dispersive spectroscopy (EDS) for macro–micro comparative analysis of zeolite cement types, formation mechanisms, and pore systems in the Lower Permian strata of the Shawan Sag and adjacent areas. Research demonstrates that provenance exerts a control on type and origin of the diagenetic zeolites: In the Shawan Sag, zeolites form through hydration of volcanic glass in tuff, while adjacent areas develop zeolites via albitization of plagioclase derived from andesite. This genetic divergence drives pore differentiation: Zeolite (heulandite and laumontite) evolution in the Sag generates grain-edge fractures through cement volume shrinkage and crystalline water release. In contrast, the adjacent areas exhibit reservoir spaces dominated by dissolution pores, resulting from the dissolution of laumontite and calcite, along with a relatively higher overall rock porosity.

1. Introduction

The Shawan Sag is rich in hydrocarbon resources, which is attributed to the presence of thick source rocks and a favorable configuration of key petroleum system elements, including high-quality seals and well-developed structural traps [1,2,3,4]. Zeolite cements extensively developed in the Shawan Sag and adjacent areas exhibit close genetic links to volcaniclastic reservoirs. The intricate formation mechanisms of sandstones and conglomerates with zeolite cementation contribute to significant reservoir heterogeneity in the study area [5,6,7,8,9,10,11].
Wopfner et al. [12] demonstrated in the Ruhuhu Basin that laumontite forms in pore waters with high pH and low PCO2, significantly reducing reservoir porosity and permeability through Ca-rich plagioclase replacement during early diagenesis. Kralj et al. [13] revealed that the transformation from heulandite to laumontite in the Smrekovec area markedly decreases rock porosity and permeability. Zeolite-rich reservoirs typically contain intercrystalline pores, pressure-solution fractures, and secondary dissolution pores [14]. Tao et al. [7] through a systematic review of global studies on zeolites in petroliferous basins, concluded that diverse zeolite genetic types critically control reservoir quality. Extensive research has been conducted on zeolite reservoirs in the Junggar Basin. Chaowei et al. [15] proposed that early-diagenetic zeolites fill pores and inhibit compaction, while later organic acid dissolution generates secondary pores, forming irregular dissolution pits and intergranular pores. The transition from early unstable hydrous zeolites (e.g., clinoptilolite, heulandite) to late stable low-hydration zeolites (laumontite) creates intercrystalline pores through dehydration, enhancing deep reservoir properties [16]. Laumontite, with weak cement-grain bonding, commonly develops grain-edge fractures, yielding pore systems including dissolution pores, intercrystalline pores, and fractures [17]. Exploration in the Permian strata of the Shawan Sag and adjacent areas reveals significant pore-type variations impacting hydrocarbon productivity. Previous studies on zeolite genesis in the northwestern Junggar Basin failed to uncover regional genetic differences and their pore impacts. Therefore, this study focuses on zeolite-cemented intervals in the Lower Permian of these areas, aiming to clarify the response relationships between zeolite genetic mechanisms and reservoir pore architectures.

2. Geological Setting

The study area is located in the central depression belt of the northwestern margin of the Junggar Basin, primarily encompassing the Shawan Sag and its adjacent Zhongguai and Chepai uplifts (Figure 1). This region has undergone a complex tectonic evolutionary history and possesses a well-developed stratigraphic sequence, making it a significant hydrocarbon-rich zone within the basin. The Shawan Sag, a second-order tectonic unit within the central depression of the Junggar Basin, has its structural framework constrained by surrounding units: it is bounded by the Zhongguai Uplift and the Western Pen-1 Well Sag to the north, adjacent to the Huomatu anticlinal belt to the south, close to the Chepai Uplift to the west, and abuts the Mosuowan and Monan uplifts to the east [2,3]. It is a typical superimposed petroliferous sag having experienced multiple phases of tectonic activity.
The Chepai Uplift features a large-scale, approximately 70-km-long fault zone exhibiting an arcuate (anti-S-shaped) trend. This zone is a key structure controlling the western boundary of the sag, whose intense thrusting activity has decisively influenced regional sedimentary filling, structural deformation, and hydrocarbon migration and accumulation. The Zhongguai Uplift, a NW-SE trending nasal uplift located north of the Mahu Sag and south of the Shawan Sag, has served as a favorable conduit for long-term hydrocarbon migration. Its axial trend follows the fault east of the Hong-3 well, with local development of broad, gentle nose-like structures. The study area exhibits a complete sedimentary sequence from the Carboniferous to the Cenozoic. The Permian system is the key target interval, buried at depths of approximately 5000–7000 m with a total thickness of about 1700–2200 m [1]. It is subdivided, in ascending order, into the Jiamuhe (P1j), Fengcheng (P1f), Xiazijie (P2x), Lower Wu’erhe (P2w), and Upper Wu’erhe (P3w) formations. The Jiamuhe Formation (P1j), consisting mainly of sandy conglomerate, mudstone, and tuffaceous sandy conglomerate with a thickness of 700–800 m, is the primary reservoir in the adjacent uplift areas. The Fengcheng Formation (P1f), characterized by gray-green tuffite, tuffaceous sandy conglomerate, and dolomitic mudstone with a thickness of 400–500 m, is a significant source rock and the study’s target horizon within the Shawan Sag [18].
This study focuses on the Lower Permian Fengcheng Formation (P1f) in the Shawan Sag and the contemporaneous Jiamuhe Formation (P1j) in the adjacent Zhongguai and Chepai uplifts. During the Permian, the northwestern Zhongguai-Chepai Uplift served as the primary provenance for the Shawan Sag, a major depositional center. Controlled by the fault east of the Hong-3 well and the Hongche fault, fan delta systems sourced from the northwest developed in the proximal Zhongguai and Chepai areas. The sediment source composition differs significantly: the Fengcheng Formation in the Shawan Sag is dominated by tuff rich in volcanic glass, whereas the Jiamuhe Formation in the adjacent uplifts is characterized by andesitic rocks rich in plagioclase. This fundamental contrast in sediment source composition governs the types and genetic mechanisms of subsequent zeolite cements during diagenesis, ultimately leading to significant differentiation in reservoir pore systems.

3. Sampling and Analytical Program

3.1. Sample Sources

A total of 89 core samples (including sandstones, tuffs, and andesites) were collected from approximately 15 boreholes (e.g., st1, st002, zj15, zj14, zj4, cp3, cp10) (Table A1, Figure 1b) penetrating the Lower Permian strata in the Shawan Sag and adjacent Chepai and Zhongguai areas. All samples were provided by the Exploration and Development Research Institute of PetroChina Xinjiang Oilfield Company (Karamay, China).

3.2. Clastic Rock Composition Analysis

Representative rock samples were vacuum-impregnated with blue epoxy resin and polished into thin sections using a BROT thin-section preparation system. A total of 193 thin sections were analyzed under a DMWBA300POL-B polarized light microscope (JEOL Ltd., Tokyo, Japan). Point counting (300–500 points per section) was performed to quantify the volumetric fractions of detrital grains, cements, and pores. The counting interval was set at twice the average grain size to ensure statistical representativeness. Special emphasis was placed on identifying zeolite types (analcime, heulandite, laumontite) and their occurrence modes.

3.3. X-Ray Diffraction (XRD) Analysis

Whole-rock XRD analysis was conducted on 40 samples using an XRD-7000 powder diffractometer (Shimadzu Corporation, Tokyo, Japan), with samples pulverized to 250-mesh (grain size ≤ 58 μm) and prepared as powder pellets; testing parameters included a scanning range of 3–65° 2θ, step size of 0.02°, scanning speed of 2°/min, Cu-Kα radiation (λ = 1.5418 Å), operating voltage of 40 kV, and current of 40 mA, while mineral identification involved matching peaks with the ICDD reference database. Powder samples for whole-rock XRD analysis were collected to represent the average mineral composition of the main lithofacies, primarily serving the purpose of deciphering provenance signatures and bulk rock properties (Figure A1 and Figure A2).

3.4. Scanning Electron Microscopy with Energy-Dispersive Spectroscopy (SEM-EDS)

Field-emission scanning electron microscopy (FE-SEM) analysis was performed using a JSM-7800F instrument (JEOL Ltd., Tokyo, Japan) to characterize zeolite cement morphology, dissolution pore structures, and spatial relationships with associated minerals, coupled with EDS spot analysis on representative zeolite-cemented regions to determine micro-scale major element compositions (e.g., Si/Al ratios, Na/K/Ca contents) for validating zeolite mineral types and transformation processes.

4. Results

4.1. Sediment Composition Differences Between Shawan Sag and Adjacent Areas

Due to proximity to paleo-volcanic provenances and proximal sediment-source settings, the Chepaizi and Zhongguai areas exhibit significantly different provenance-derived sediment compositions compared to the Shawan Sag (Figure 2). Integrated core and thin-section analyses reveal distinct source material compositions: tuff dominates (52.97%) in the Shawan Sag, while the Chepazi and Zhongguai areas yield mainly andesitic fragments at 47.99 and 54.06%, respectively (Figure 2a, Table A2), with laumontite-filled vesicles in amygdaloidal andesitic clasts observed in cores showing laumontite-filled vesicles. The lithology of the Shawan Sag is dominated by tuff grains rich in volcanic glass; in contrast, the adjacent areas are characterized by andesitic grains containing abundant plagioclase Whole-rock XRD analyses confirm quartz predominates in the Shawan Sag, while plagioclase dominates adjacently (Figure 3, Table A3).

4.2. Zeolite Types in the Shawan Sag and Adjacent Areas

Zeolite minerals (predominantly laumontite, heulandite, and analcime) are extensively developed in the glutenite reservoirs of the Shawan Sag and adjacent areas, yet exhibit significant differences in crystal morphology, occurrence modes, and abundance (Figure 4 and Figure 5). The zeolite assemblages in the Lower Permian sandy conglomerate reservoirs of the Shawan Sag and adjacent areas were characterized using an integrated approach. Analytical techniques included petrographic thin section analysis, whole-rock XRD, EDS, and SEM. In the Shawan Sag, laumontite is the dominant zeolite, followed by subordinate heulandite and trace analcime. Microscopy reveals laumontite-heulandite intergrowths and iron-stained heulandite coexisting with analcime. In peripheral areas, laumontite remains predominant but heulandite is markedly reduced and analcime is virtually absent. There, laumontite primarily replaces plagioclase in andesitic fragments.

4.2.1. Laumontite Mineralogy

Laumontite (CaAl2Si4O12·4H2O) is a monoclinic hydrous layered aluminosilicate mineral. It typically forms columnar crystals, often occurring as acicular, fibrous, or radial aggregates with significant brittleness that readily fractures under stress (Figure 4c,d,g,h and Figure 5a–g,j–l). Under polarized light microscopy, it appears colorless and transparent in thin sections, displaying first-order gray-white to pale yellow interference colors under parallel extinction. Optical characteristics include a maximum extinction angle of 20–30°, biaxial negative optical character, and low negative relief with refractive indices approximating Canada balsam. Perfect cleavage is observed along one or two directions.
In the Shawan Sag glutenite reservoirs, columnar and intergrown laumontite semi-to-fully cements intergranular pores (Figure 4a,c,d), whereas in adjacent areas, laumontite replaces plagioclase along cleavage and twin planes within feldspar fragments and andesite fragments (Figure 5a–c,j), associated with albitization. Columnar/intergrown laumontite co-occurs with calcite cementing intergranular pores (Figure 5a,g,k,l).

4.2.2. Heulandite Mineralogy

Heulandite ((Ca, Na2)Al2Si7O18·6H2O), a monoclinic framework silicate mineral, exhibits isomorphous substitution of Ca2+ by Na+ in its crystal chemical formula. It appears yellowish-brown to brick-red due to iron-staining by volcanic materials (Figure 4b,c). Crystallographically, it develops well-formed subhedral to euhedral crystals showing parallel extinction.
In the Shawan Sag, hydration of volcanic glass within tuff fragments during burial diagenesis releases Na+ and Ca2+, leading to massive, intergrown bundles and platy heulandite crystals growing perpendicularly along grain edges in a semi-filling mode within intergranular pores (Figure 4b,c,e–h). Microscopically, heulandite coexists with analcime (Figure 4c). Conversely, adjacent areas rarely exhibit tabular or prismatic heulandite fully cementing volcanic rocks, with intercrystalline pores developed between heulandite crystals (Figure 5h).

4.2.3. Analcime Mineralogy

Analcime (NaAlSi2O6·H2O), an isometric framework silicate mineral, typically forms tetragonal trisoctahedrons or irregular equant grains. Under crossed-polarized light, it displays anomalous interference colors, while appearing colorless and transparent in plane-polarized light. It predominantly fills intergranular spaces as irregular to spheroidal aggregates (Figure 4c and Figure 5i).
In the Shawan Sag glutenite reservoirs, irregular granular analcime coexists with heulandite cementing intergranular pores. Conversely, adjacent areas exhibit spheroidal analcime occurring on detrital grain surfaces under SEM, consistently associated with illite-smectite (I/S) mixed-layer clay minerals coating its periphery.
In the Shawan Sag, the coexistence of heulandite and analcime (Figure 4c) indicates zeolite formation during a stage of sustained supply of volcanic glass hydration products. Furthermore, the co-occurrence of analcime and heulandite within intergranular pores in the Shawan Sag (Figure 4c) records episodic fluctuations in the Si/Al ratio of diagenetic fluids, closely linked to elemental release during progressive volcanic glass hydration. In peripheral areas, laumontite shows replacements of plagioclase and coexists with calcite. The oriented replacement of laumontite along cleavage planes of andesitic plagioclase (Figure 5a–c,j) demonstrates its direct link with Ca2+ released during plagioclase albitization (Figure 5c). The assemblage of laumontite with calcite (Figure 5g,k,l) suggests the potential transformation of laumontite to calcite under increasing pCO2 conditions.

5. Discussion

5.1. Contrast in Genesis of Zeolites Between the Shawan Sag and Adjacent Areas

The genesis of zeolites is complex, with systematic studies by domestic and international scholars generally attributing their formation to hydration alteration of volcanic glass in tuff [5,6,7,19,20,21,22,23] and albitization of plagioclase [8,22,23]. Owing to the distinct sediment provenance, the two regions exhibit substantial differences in source material composition. Based on comprehensive analysis of mineral characteristics, paragenetic relationships, associated mineral assemblages, and elemental distribution patterns of zeolite cements in the study area, it is concluded that zeolites in the Shawan Sag primarily formed through hydration of volcanic glass in tuff, whereas zeolites in the peripheral areas of the sag were mainly generated by albitization of plagioclase derived from andesite.
The Lower Permian reservoirs in the Shawan Sag contain abundant tuff fragments. Hydration of volcanic glass within these fragments, driven by changes in temperature, pressure, and fluid chemistry, releases substantial metal cations (K+, Na+, Ca2+, Mg2+) [5,6], creating an alkaline diagenetic environment that provides essential material foundations for zeolite formation. With increasing burial depth and temperature, clinoptilolite consumes significant K+ and Ca2+ to precipitate first [14]. However, deep burial in the Shawan Sag has transformed clinoptilolite into stable minerals, explaining its absence in our study. As an early-stage unstable mineral, clinoptilolite is replaced by analcime and albite [14]. In clinoptilolite, Na+ and Ca2+ are consumed by albite and analcime, whereas K+ is fixed in illite-smectite mixed-layer minerals and authigenic K-feldspar. Coexisting analcime and heulandite in the reservoirs (Figure 4c) indicate early zeolite precipitation lowered fluid pH, facilitating silica-rich heulandite formation (Figure 4f) [5,24,25]. Subsequent Ca2+ enrichment converts heulandite to laumontite [15,25,26], reducing Si/Al ratios (Figure 4i). Based on the analysis of mineral transformation relationships described above, the zeolite evolution pathway is determined as: Volcanic glass → Clinoptilolite → Analcime → Heulandite → Laumontite (Figure 6a).
In the Lower Permian reservoirs of adjacent areas to the Shawan Sag, andesite fragments dominate the source material. These fragments contain abundant plagioclase minerals, with weathering during transport preserving relatively stable plagioclase cores, resulting in high ca-rich plagioclase content in adjacent areas. Albitization of plagioclase is pervasive in adjacent areas, coexisting with laumontite (Figure 5a–c,j). Diagenetic fluids enriched in Na+ and SiO2 facilitate albitization, which releases Ca2+ essential for laumontite precipitation (Figure 6b) [14,16,22,27,28,29,30,31,32].

5.2. Contrast in Pore Types Between the Shawan Sag and Adjacent Areas

This study reveals significant differences in pore types and developmental characteristics between the Shawan Sag and adjacent areas. In the Shawan Sag, grain-edge fractures—developing along laumontite-grain boundaries—form the predominant pore system (Figure 7). Under fluorescence microscopy, these fractures display reddish-brown fluorescence, indicating asphaltene-dominated bitumen components [28] (Figure 8a). The zeolite evolution pathway involves mineral density changes and crystalline water release, causing cement shrinkage and ultimately generating characteristic grain-edge fractures along laumontite-detrital grain contacts [15,16]. Intergranular dissolution pores mainly result from laumontite dissolution.
Adjacent areas feature intergranular dissolution pores as the dominant pore type. Thin-section and SEM observations show these pores formed by dissolution of laumontite and calcite (Figure 9), with some laumontite dissolution voids filled by bitumen (Figure 9c). Due to its crystalline structure, laumontite dissolution exhibits irregular serrated edges (Figure 5e,h,i).

5.3. Impact of Zeolites on Petrophysical Properties

To investigate the controlling effect of zeolite cementation on reservoir quality, this study integrates thin-section point-counting data with petrophysical measurements. The integrated data reveal that the Shawan Sag is characterized by the co-occurrence of heulandite and laumontite (with average contents of approximately 7.5% and 6.0%, respectively), whereas adjacent areas are generally devoid of heulandite but contain higher abundances of laumontite (averaging ~15.0%), accompanied by comparatively higher porosity. As illustrated in Figure 10, laumontite content in the Shawan Sag is lower than in adjacent areas, and porosity further decreases with increasing heulandite content. Based on the genetic analysis of zeolites and supporting experimental evidence, we propose that heulandite, with its high Si/Al ratio, exhibits strong dissolution resistance. In contrast, laumontite, characterized by a low Si/Al ratio, is prone to transformation into soluble calcite. Consequently, higher laumontite content is conducive to the development of porosity in the reservoir.

5.4. Controls of Zeolite Genesis on Pore Types in the Shawan Sag and Adjacent Areas

The genetic divergence of zeolites between the Shawan Sag and adjacent areas directly controls the development characteristics of pore types (Figure 11). In the Lower Permian reservoirs of the Shawan Sag, tuff fragments dominate the source material. Heulandite exhibits strong dissolution resistance due to its high Si content and large Si/Al ratio, hindering effective pore development and contributing minimally to porosity enhancement (Figure 4b). Laumontite evolution involves mineral density changes and crystalline water release, causing cement shrinkage and forming characteristic grain-edge fractures along laumontite-detrital grain boundaries, with fractures dominating the pore system.
Adjacent areas feature andesite fragments as the primary source material. Plagioclase albitization releases Ca2+ into pore fluids, providing the material basis for laumontite precipitation. Previous studies on Triassic Yanchang Formation sandstone reservoirs in the Ordos Basin suggested laumontite forms from calcite and kaolinite [10,29], but microscopic evidence shows calcite postdates laumontite formation (Figure 5k,l and Figure 9d). Meteoric leaching and organic decarboxylation in the Jiamuhe Formation elevate pCO2, triggering laumontite dissolution. Released Ca2+ combines with CO2 to form calcite [30,33] (Figure 9). Dissolution of laumontite and calcite develops pores dominated by dissolution voids.
This comparative study of sediment source, zeolite genesis, evolution, and pore types in glutenite reservoirs reveals that provenance differences control both zeolite pathways and pore architectures. In the Shawan Sag’s Lower Permian, volcanic glass hydration generates heulandite, whose dissolution resistance limits effective porosity development. Conversely, plagioclase albitization consumes SiO2, inhibiting quartz cementation (Figure 6). Increasing pCO2 converts laumontite to soluble calcite, enhancing dissolution porosity.

6. Conclusions

This study leads to the following conclusions:
  • Significant differences exist in sediment source compositions between the Shawan Sag and adjacent areas (Chepaizi, Zhongguai). The Shawan Sag is dominated by tuff fragments with relatively high quartz content, whereas adjacent areas feature andesite fragments with substantially higher plagioclase content. Whole-rock XRD analyses further confirm quartz predominance in the Shawan Sag versus plagioclase dominance in adjacent areas. These provenance differences directly drive mineral enrichment contrasts, establishing the foundation for divergent zeolite genesis and pore systems.
  • Zeolite types and origins in the study area are controlled by sediment source compositions. The Shawan Sag primarily develops laumontite, heulandite, and minor analcime, formed through hydration of volcanic glass in tuff: clinoptilolite → analcime → heulandite → laumontite. Adjacent areas exhibit zeolites generated by albitization of plagioclase in andesite fragments, with released Ca2+ providing the material basis for laumontite precipitation.
  • Zeolite genetic differences between the Shawan Sag and adjacent areas shape pore system differentiation. In the Sag, zeolite evolution involves mineral density changes and crystalline water release, resulting in pore systems dominated by grain-edge fractures. In adjacent areas, the albitization of plagioclase and the transformation of laumontite to calcite provide the material basis for subsequent dissolution, resulting in a pore type dominated by intergranular dissolution pores. Provenance differences control both zeolite genesis mechanisms and pore type differentiation.
  • The zeolite evolution pathway via volcanic glass hydration produces dissolution-resistant heulandite, constraining reservoir quality enhancement. Conversely, the albitization of Ca-rich plagioclase inhibits quartz precipitation by consuming SiO2, and under elevated pCO2 conditions, facilitates the transformation of laumontite to soluble calcite. This transformation enhances reservoir quality by generating easily dissolvable minerals.

Author Contributions

Writing—original draft, H.L.; Methodology, H.K.; Data curation, L.Z.; Visualization, F.D.; Investigation, C.L.; Resources, L.P. All authors have read and agreed to the published version of the manuscript.

Funding

No funding was received to assist with the preparation of this manuscript.

Data Availability Statement

Data are contained within the article.

Acknowledgments

We knowledge PetroChina Xinjiang Oilfield Company for providing the core samples. We also acknowledge the Chongqing Key Laboratory of Exploration and Development of Complex Oil and Gas Fields at Chongqing University of Science and Technology for the use of laboratory facilities.

Conflicts of Interest

Author Lei Zhang and Fangpeng Dou were employed by the Xinjiang Oilfield Company. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Abbreviations

The following abbreviations are used in this manuscript:
XPLCross-Polarized Light
PPLPlane-Polarized Light
SEMScanning electron microscopy
SEPSecondary Electron Photomicrographs
EDSEnergy-dispersive spectroscopy
XRDX-ray diffraction

Appendix A

Table A1. Summary of well samples, depths, and analytical methods conducted.
Table A1. Summary of well samples, depths, and analytical methods conducted.
WellAreaFormationDepth (m)LithologyNumber of Thin SectionsNumber of XRDNumber of SEM-EDS
sp002Shawan SagFengcheng
Formation (P1f)		4514.27~4517.87Sandy
conglomerate		4
sp0024689.07~4693.6Sandy
conglomerate		4
sp145543.32~5549.06Sandy
conglomerate		2
sp164877.7~5087.7Sandy
conglomerate		5
sp25555.31~5559.85conglomerate3
sp34693.3~4698.72Sandy
conglomerate		3 1
sp34718.27~4721.7Sandy
conglomerate		3 3
sp44354.57Sandy
conglomerate		 1
sp54658.68~4781.07Sandy
conglomerate		5
st0025400.15~5407.29Sandy
conglomerate		5 2
st25720.71~5725.64conglomerate334
st25539.18~5542.78conglomerate526
st25495conglomerate1
cp244600.07~4610.98Sandy
conglomerate		3 2
zj14Zhongguai
Uplift		Jiamuhe
Formation (P1j)		4294.89~4302Sandy
conglomerate		13 4
zj1414335.34~4341.88Sandy
conglomerate		8 2
zj1414403.3~4410.66Sandy
conglomerate		5 2
zj154042.7~4050.2Sandstone4 3
zj44407.74Sandy
conglomerate		1 1
zj44408.3~4413.6Sandy
conglomerate		5 1
zj44436.98~4445.37Sandy
conglomerate		1012
zj44465.72~4473.91Sandy
conglomerate		3
zj44537.52~4543.15Sandy
conglomerate		641
zj44628.39~4634.21Sandy
conglomerate		512
zj53884.11Sandy
conglomerate		 1
zj64880.45~5597.55Sandy
conglomerate		 15
zj74000.7~4339.52Sandy
conglomerate		 3
zj903x4726.32~4733.2Sandy
conglomerate		 3
cp001Chepai
Uplift		Jiamuhe
Formation (P1j)		2331.73~2417.99Sandy
conglomerate		 2
cp0022655.23~2779.13Sandy
conglomerate		 21
cp0042962conglomerate1
cp0052851.3~2858.2Sandy
conglomerate		3
cp0052972.59Sandy
conglomerate		1
cp103492.5Sandy
conglomerate		 1
cp182437.4~2455.8conglomerate 3
cp192772~2777.42conglomerate11
cp212527.43~2538.5Sandy
conglomerate		21
cp274456.65~4459.17Sandy
conglomerate		2
cp22836.63Sandy
conglomerate		 1
cp54670.99~4673.92conglomerate3
cp54704.25~4709.18conglomerate5
cp54732.71~4734.14conglomerate1 1
Table A2. Rock composition of samples from the Lower Permian sandy conglomerate reservoirs in the Shawan Sag, Chepaizi area, and Zhongguai Uplift based on point-counting data. “/” denotes low content. QG = quartz gravel; FG = feldspar gravel; TG = tuff gravel; AG = andesite gravel; GG = granite gravel; FELG = felsite gravel; BG = basalt gravel.
Table A2. Rock composition of samples from the Lower Permian sandy conglomerate reservoirs in the Shawan Sag, Chepaizi area, and Zhongguai Uplift based on point-counting data. “/” denotes low content. QG = quartz gravel; FG = feldspar gravel; TG = tuff gravel; AG = andesite gravel; GG = granite gravel; FELG = felsite gravel; BG = basalt gravel.
WellAreaFormationDepth (m)Gravel Content/%
QGFGTGAGGGFELGBG
sp002Shawan SagFengcheng
Formation (P1f)		4514.27274923///
sp0024515.42175318///
sp0024516.69/56213///
sp0024517.85/553201//
sp0024689.07145820///
sp0024690.28/45217///
sp0024692.91175910///
sp0024693.65114372//
sp145543.3224756/1/
sp145549.06/21362///
sp165087.72223810/3/
sp164877.7//63////
sp164906.3/44319/1/
sp164939.4/35627///
sp164976.3/31955///
sp25555.31195471//
sp25557.13412454///
sp25559.8581359/2//
sp34693.3455437///
sp34718.2715174112///
sp34695.6118676///
sp34698.415686///
sp34719.14275081//
sp34721.71135014///
sp54659.98/16021///
sp54662.28//6317///
sp54664.72/2793///
sp54778.82/1732///
sp54780.92664111//
st0025400.15//752///
st0025404.55/159182//
st0025407.291/772///
st0025401.28/146311//
st0025404.86//57271//
st25722.56568////
st25720.718568////
st25541.185452/10//
st25539.18565120///
st25540.2//5224///
st2549558702///
st25539.65/13543///
st25541.93/24639///
st25724.21355620///
cp244600.07564538///
cp244604.891086015///
cp244610.9810255012///
zj14Zhongguai
Uplift		Jiamuhe
Formation (P1j)		4294.89//1161.1//1
zj144295.49//1756.4//1
zj144296.45231652.3///
zj144296.852225/.5///
zj144297221751.5///
zj144297.12//862.5///
zj144297.3//958.4///
zj144297.4/11149.1///
zj144297.66/11348.5///
zj144298.06/11149.8///
zj144298.6/21447.6///
zj144301.16/11644.7///
zj144302/21355.5///
zj1414335.34/1549.4///
zj1414335.78/21644.1///
zj1414338.36/21158.4///
zj1414338.94/2162.9///
zj1414339.19/21258///
zj1414339.54/25.561.2///
zj1414341.36/2168///
zj1414341.88/3469///
zj1414403.3/1.2747///
zj1414406.16/2167.3///
zj1414407.73/1964///
zj1414409.71/11161.3//8
zj1414410.66/1577.5//2
zj154048.999.544.794.6///
zj154049.6810.346.453.6///
zj154049.85846.42.17///
zj154050.214873///
zj44407.7411554///
zj44408.311652///
zj44410.06451737.2/72
zj44411.1611456.8///
zj44412.5611551.7///
zj4Zhongguai
Uplift		Jiamuhe
Formation (P1j)		4537.5212455.713/
zj44538.5312358.912/
zj44539.5376248.2/2/
zj44540.0376741.3/2/
zj44542.1577644.1/2/
zj44543.1587742.2/1/
zj44628.3987642.3///
zj44628.8276538/1/
zj44633.2921336.5/1/
zj44633.6121/39.3/3/
zj44634.1921139/3/
cp004Chepai UpliftJiamuhe
Formation (P1j)		2962/23346//2
cp0052851.3132061/1/
cp0052852.83/42254///
cp0052858.2452648/1/
cp0052972.59133848.2//3
cp192777.423316671//
cp212532.52229430.8//
cp212538.50.82.22966///
cp274456.65/2289///
cp274459.17/1196///
cp54670.991271845/2/
cp54671.23312449/3/
cp54673.923.151834/539
cp54704.252.77/5010//
cp54705.521351546//1
cp54705.721202029//2
cp54708.83115540/13
cp54709.181.51524409.6//
cp54734.141.215.325571/1
Table A3. Mineral composition (wt.%) of samples from the Lower Permian sandy conglomerate reservoirs in the Shawan Sag, Chepaizi area, and Zhongguai Uplift based on XRD data. All values are in wt.%. “/” denotes trace amount (<2%). Qz = quartz; Pl = plagioclase; Lmt = laumontite; Kfs = K-feldspar; Cal = calcite; Dol = dolomite; Hem = hematite; Anh = anhydrite; Ank = ankerite; Anl = analcime; Sid = siderite.
Table A3. Mineral composition (wt.%) of samples from the Lower Permian sandy conglomerate reservoirs in the Shawan Sag, Chepaizi area, and Zhongguai Uplift based on XRD data. All values are in wt.%. “/” denotes trace amount (<2%). Qz = quartz; Pl = plagioclase; Lmt = laumontite; Kfs = K-feldspar; Cal = calcite; Dol = dolomite; Hem = hematite; Anh = anhydrite; Ank = ankerite; Anl = analcime; Sid = siderite.
WellAreaFormationDepth (m)QzPlLmtKfsCalDolHemAnhAnkAnlSid
st2Shawan SagFengcheng
Formation (P1f)		5539.534.6134.619.5417.9///////
st25542.7829.6229.6213.035.923.552.379.494.74///
st25724.2166.7816.08013.6///////
st25724.7149.7920.9613.113.1////1.31//
st25725.6463.5523.3411.67////////
zj4Zhongguai
Uplift		Jiamuhe
Formation (P1j)		4466.0410.6536.2238.345.333.20/5.33////
zj44541.4014.2952.3821.428.332.38/0.00////
zj44538.212.7931.9824.5226.653.20/0.00////
zj44632.824.8836.7723.7910.823.24//////
zj44439.1422.5154.510.000.000.00/3.55//17.77/
zj44537.6725.8844.360.000.000.00/0.00//28.34/
zj64880.4525.7433.2415.018.5815.01/0.00////
zj64956.4128.8648.8414.43/6.66/0.00////
zj65009.2816.8634.7712.64/32.67/0.00////
zj65242.0728.6735.5519.49/13.76/0.00////
zj65597.5525.4143.4210.597.418.47/0.00////
zj64874.6928.6040.5016.685.965.96/0.00////
zj64878.5526.1045.407.9413.623.40/0.00////
zj64954.5941.0634.0210.564.690.00/7.04////
zj64955.8832.8034.9812.024.378.74/5.46////
zj64957.2232.4140.8114.404.806.00/0.00////
zj65007.625.9034.9211.267.8810.14/7.88////
zj65009.3728.7236.469.946.635.52/7.73////
zj65010.229.4840.3817.470.004.37/4.37////
zj65005.116.2036.7116.205.4017.28/6.48////
zj65013.313.2544.1614.356.6211.04/8.83////
zj74000.728.6741.8114.335.974.78/3.58////
zj74161.4627.9534.9318.636.994.66/2.33///2.33
zj74339.5228.8832.8126.256.563.94/0.00////
zj53884.1119.1537.1824.7813.523.38/0.00////
cp001Chepai
Uplift		Jiamuhe
Formation (P1j)		2331.7350.8633.91///////8.48/
cp0012417.9946.3343.01///////3.31/
cp0022655.2349.2043.24/////////
cp0022779.1343.5536.66//6.87////10.31/
cp103492.516.9764.26/////////
cp182437.426.7151.08//18.58//////
cp182455.833.7838.61/15.6910.86//////
cp182455.5237.7141.144.57/11.43///2.29//
cp19277225.6662.11//////3.746.75/
cp212527.4352.3939.92/////////

Appendix B

Minerals 15 01247 g0a1
Figure A1. XRD spectra of a sandy conglomerate sample from well zj4 at a depth of 4439.14 m, showing characteristic peaks of analcime.
Figure A1. XRD spectra of a sandy conglomerate sample from well zj4 at a depth of 4439.14 m, showing characteristic peaks of analcime.
Minerals 15 01247 g0a1
Minerals 15 01247 g0a2
Figure A2. XRD pattern of a sandy conglomerate sample from well st2 at a depth of 5539.5 m, showing characteristic peaks of heulandite and laumontite.
Figure A2. XRD pattern of a sandy conglomerate sample from well st2 at a depth of 5539.5 m, showing characteristic peaks of heulandite and laumontite.
Minerals 15 01247 g0a2

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Minerals 15 01247 g001
Figure 1. Geological setting map. (a,b) Map showing the sub-tectonic units of the Junggar Basin and location of the study area; (c) Generalized stratigraphic column of the Permian system in the study area.
Figure 1. Geological setting map. (a,b) Map showing the sub-tectonic units of the Junggar Basin and location of the study area; (c) Generalized stratigraphic column of the Permian system in the study area.
Minerals 15 01247 g001
Minerals 15 01247 g002
Figure 2. (a) Dark gray tuff fragments forming the primary rock component, with white laumontite cement observed along fragment edges, well st2, 5167.15 m; (b) Tuff gravels constituting the framework, intergranular spaces filled with laumontite, well st2, 5722.50 m, cross-polarized light (XPL); (c) Amygdaloidal andesite gravel with vesicles filled by laumontite, well zj14, 4303.17 m, XPL; (d) Andesite gravel framework showing abundant plagioclase crystals, well zj14, 4437.51 m.
Figure 2. (a) Dark gray tuff fragments forming the primary rock component, with white laumontite cement observed along fragment edges, well st2, 5167.15 m; (b) Tuff gravels constituting the framework, intergranular spaces filled with laumontite, well st2, 5722.50 m, cross-polarized light (XPL); (c) Amygdaloidal andesite gravel with vesicles filled by laumontite, well zj14, 4303.17 m, XPL; (d) Andesite gravel framework showing abundant plagioclase crystals, well zj14, 4437.51 m.
Minerals 15 01247 g002
Minerals 15 01247 g003
Figure 3. Gravel composition of the Lower Permian in the Shawan Sag and adjacent areas. (a) Comparison of clastic grain composition from thin-section petrographic analysis in the Shawan Sag and adjacent areas; (b). Comparison of mineral composition from whole-rock XRD analysis in the Shawan Sag and adjacent areas.
Figure 3. Gravel composition of the Lower Permian in the Shawan Sag and adjacent areas. (a) Comparison of clastic grain composition from thin-section petrographic analysis in the Shawan Sag and adjacent areas; (b). Comparison of mineral composition from whole-rock XRD analysis in the Shawan Sag and adjacent areas.
Minerals 15 01247 g003
Minerals 15 01247 g004
Figure 4. Zeolite types in Shawan Sag. (a) Laumontite cement filling intergranular spaces among tuff fragments, well st2, 5539.18 m, XPL; (b) Brownish-red massive heulandite growing vertically along detrital grain margins with siliceous cement infilling pores, well sp4, 4355.19 m, XPL; (c). Brick-red heulandite and irregular analcime grains co-filling intergranular pores (showing anomalous birefringence), well sp3, 4693.3 m, XPL; (d) Authigenic prismatic laumontite aggregates occurring along grain boundaries, well st2, 5720.71 m, SEP; (e) Sheet-like heulandite intergrowths, well sp5, 4781.07 m, SEP; (f) EDS spectrum of heulandite (Figure 4e), Si/Al: 3.18; (g) Prismatic laumontite intergrown with heulandite, well sp5, 4658.68 m, SEP; (h) Tabular laumontite developed in intergranular spaces with minor heulandite, well sp4, 4354.57 m, SEP; (i) EDS spectrum of laumontite (Figure 4h), Si/Al: 2.35; (j) Sheet-like heulandite intergrowths, well sp4, 4354.57 m, SEP.
Figure 4. Zeolite types in Shawan Sag. (a) Laumontite cement filling intergranular spaces among tuff fragments, well st2, 5539.18 m, XPL; (b) Brownish-red massive heulandite growing vertically along detrital grain margins with siliceous cement infilling pores, well sp4, 4355.19 m, XPL; (c). Brick-red heulandite and irregular analcime grains co-filling intergranular pores (showing anomalous birefringence), well sp3, 4693.3 m, XPL; (d) Authigenic prismatic laumontite aggregates occurring along grain boundaries, well st2, 5720.71 m, SEP; (e) Sheet-like heulandite intergrowths, well sp5, 4781.07 m, SEP; (f) EDS spectrum of heulandite (Figure 4e), Si/Al: 3.18; (g) Prismatic laumontite intergrown with heulandite, well sp5, 4658.68 m, SEP; (h) Tabular laumontite developed in intergranular spaces with minor heulandite, well sp4, 4354.57 m, SEP; (i) EDS spectrum of laumontite (Figure 4h), Si/Al: 2.35; (j) Sheet-like heulandite intergrowths, well sp4, 4354.57 m, SEP.
Minerals 15 01247 g004
Minerals 15 01247 g005
Figure 5. Zeolite types in adjacent areas of Shawan Sag. (a) Irregular laumontite replacing anorthite, with calcite and laumontite filling intergranular spaces. well zj15, 4049.68 m, cross-polarized light; (b) Irregular laumontite replacing ca-rich plagioclase (anorthite) within andesitic lithic fragment. well zj4, 4436.98 m, cross-polarized light; (c) Irregular laumontite replacing ca-rich plagioclase (anorthite) along cleavage cracks in andesitic lithic fragment. well zj141, 4409.71 m, cross-polarized light; (d) EDS of laumontite (Figure 5e), Si/Al = 2.47; (e) Laumontite and quartz filling intergranular spaces. well zj141, 4410.66m, SEP; (f) EDS of quartz (Figure 5e); (g) Columnar laumontite and calcite filling intergranular spaces. well zj14, 4298.6 m, SEP; (h) Tabular heulandite filling intergranular spaces, with intercrystalline pores between crystals. well zj903x, 4730.8 m, SEP; (i) Spheroidal analcime occurring on grain surfaces, associated with I/S mixed-layer clay. well zj903x, 4730.8 m, SEP; (j) Dissolved feldspar grain containing minor columnar laumontite. well cp2, 2836.63 m, SEP; (k) Lath-like laumontite at grain edges, with calcite filling intergranular pores. well cp5, 4732.71 m, SEP; (l) Lath-like laumontite filling intergranular spaces, with calcite occurring within laumontite. well cp5, 4672.01 m, SEP.
Figure 5. Zeolite types in adjacent areas of Shawan Sag. (a) Irregular laumontite replacing anorthite, with calcite and laumontite filling intergranular spaces. well zj15, 4049.68 m, cross-polarized light; (b) Irregular laumontite replacing ca-rich plagioclase (anorthite) within andesitic lithic fragment. well zj4, 4436.98 m, cross-polarized light; (c) Irregular laumontite replacing ca-rich plagioclase (anorthite) along cleavage cracks in andesitic lithic fragment. well zj141, 4409.71 m, cross-polarized light; (d) EDS of laumontite (Figure 5e), Si/Al = 2.47; (e) Laumontite and quartz filling intergranular spaces. well zj141, 4410.66m, SEP; (f) EDS of quartz (Figure 5e); (g) Columnar laumontite and calcite filling intergranular spaces. well zj14, 4298.6 m, SEP; (h) Tabular heulandite filling intergranular spaces, with intercrystalline pores between crystals. well zj903x, 4730.8 m, SEP; (i) Spheroidal analcime occurring on grain surfaces, associated with I/S mixed-layer clay. well zj903x, 4730.8 m, SEP; (j) Dissolved feldspar grain containing minor columnar laumontite. well cp2, 2836.63 m, SEP; (k) Lath-like laumontite at grain edges, with calcite filling intergranular pores. well cp5, 4732.71 m, SEP; (l) Lath-like laumontite filling intergranular spaces, with calcite occurring within laumontite. well cp5, 4672.01 m, SEP.
Minerals 15 01247 g005
Minerals 15 01247 g006
Figure 6. Contrast in genesis of zeolites between the Shawan Sag (a) and adjacent areas (b).
Figure 6. Contrast in genesis of zeolites between the Shawan Sag (a) and adjacent areas (b).
Minerals 15 01247 g006
Minerals 15 01247 g007
Figure 7. Contrast in pore types between the Shawan Sag and adjacent areas.
Figure 7. Contrast in pore types between the Shawan Sag and adjacent areas.
Minerals 15 01247 g007
Minerals 15 01247 g008
Figure 8. Pore types in the Shawan Sag. (a) Reddish-brown fluorescence within grain-edge fractures, well st002, 5407.29 m, fluorescence thin-sections; (b) Intercrystalline pores among tabular laumontite crystals with grain-edge fractures along particle boundaries, well sp3, 4719.34 m, SEP; (c) Chlorite rim coatings on grain edges exhibiting grain-edge fractures, well cp24, 4604.89 m, PPL; (d) Grain-edge fractures along detrital grain margins, well st2, 5722.50 m, PPL; (e) Intergranular dissolution pores in laumontite-cemented zone, well sp3, 4718.27 m, thin-section; (f) Dissolution textures in intergranular tabular laumontite, well sp3, 4698.72 m, SEP.
Figure 8. Pore types in the Shawan Sag. (a) Reddish-brown fluorescence within grain-edge fractures, well st002, 5407.29 m, fluorescence thin-sections; (b) Intercrystalline pores among tabular laumontite crystals with grain-edge fractures along particle boundaries, well sp3, 4719.34 m, SEP; (c) Chlorite rim coatings on grain edges exhibiting grain-edge fractures, well cp24, 4604.89 m, PPL; (d) Grain-edge fractures along detrital grain margins, well st2, 5722.50 m, PPL; (e) Intergranular dissolution pores in laumontite-cemented zone, well sp3, 4718.27 m, thin-section; (f) Dissolution textures in intergranular tabular laumontite, well sp3, 4698.72 m, SEP.
Minerals 15 01247 g008
Minerals 15 01247 g009
Figure 9. Pore types in adjacent areas of the Shawan Saga. (a) Intergranular dissolution pores formed by laumontite corrosion, well zj4, 4628.39 m, XPL; (b) Intergranular dissolution pores in laumontite, well zj4, 4437.51 m, XPL; (c) Bitumen-filled intergranular pores with fractures in volcanic lithics, well zj4, 4436.98 m, PPL; (d) Intergranular laumontite and calcite with calcite dissolution, well zj4, 4634.19 m, XPL; (e) Intergranular corrosion in tabular laumontite, well zj141, 4410.66 m, SEP; (f) Intercrystalline pores and intergranular dissolution pores in tabular-prismatic laumontite, well zj15, 4048.99 m, SEP; (g) Dissolution of intergranular calcite, well cp3, 3602.87 m, SEP; (h) Intergranular tabular laumontite and partially dissolved calcite, well cp5, 4672.01 m, SEP; (i) Corroded prismatic-tabular laumontite, well cp7, 3419.19 m, SEP; (j) Intergranular dissolution pores formed by laumontite corrosion, well cp18, 2438.19 m, SEP.
Figure 9. Pore types in adjacent areas of the Shawan Saga. (a) Intergranular dissolution pores formed by laumontite corrosion, well zj4, 4628.39 m, XPL; (b) Intergranular dissolution pores in laumontite, well zj4, 4437.51 m, XPL; (c) Bitumen-filled intergranular pores with fractures in volcanic lithics, well zj4, 4436.98 m, PPL; (d) Intergranular laumontite and calcite with calcite dissolution, well zj4, 4634.19 m, XPL; (e) Intergranular corrosion in tabular laumontite, well zj141, 4410.66 m, SEP; (f) Intercrystalline pores and intergranular dissolution pores in tabular-prismatic laumontite, well zj15, 4048.99 m, SEP; (g) Dissolution of intergranular calcite, well cp3, 3602.87 m, SEP; (h) Intergranular tabular laumontite and partially dissolved calcite, well cp5, 4672.01 m, SEP; (i) Corroded prismatic-tabular laumontite, well cp7, 3419.19 m, SEP; (j) Intergranular dissolution pores formed by laumontite corrosion, well cp18, 2438.19 m, SEP.
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Figure 10. Analysis of the relationship between zeolite content and porosity.
Figure 10. Analysis of the relationship between zeolite content and porosity.
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Figure 11. Pore evolution processes in the Shawan Sag and Adjacent Areas.
Figure 11. Pore evolution processes in the Shawan Sag and Adjacent Areas.
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Lv, H.; Kuang, H.; Zhang, L.; Dou, F.; Li, C.; Pan, L. Controls of Zeolite Development on Reservoir Porosity from Lower Permian Formations in Shawan and Its Adjacent Areas, Western Junggar Basin. Minerals 2025, 15, 1247. https://doi.org/10.3390/min15121247

AMA Style

Lv H, Kuang H, Zhang L, Dou F, Li C, Pan L. Controls of Zeolite Development on Reservoir Porosity from Lower Permian Formations in Shawan and Its Adjacent Areas, Western Junggar Basin. Minerals. 2025; 15(12):1247. https://doi.org/10.3390/min15121247

Chicago/Turabian Style

Lv, Houkuan, Hao Kuang, Lei Zhang, Fangpeng Dou, Chun Li, and Lang Pan. 2025. "Controls of Zeolite Development on Reservoir Porosity from Lower Permian Formations in Shawan and Its Adjacent Areas, Western Junggar Basin" Minerals 15, no. 12: 1247. https://doi.org/10.3390/min15121247

APA Style

Lv, H., Kuang, H., Zhang, L., Dou, F., Li, C., & Pan, L. (2025). Controls of Zeolite Development on Reservoir Porosity from Lower Permian Formations in Shawan and Its Adjacent Areas, Western Junggar Basin. Minerals, 15(12), 1247. https://doi.org/10.3390/min15121247

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