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Article

Spatiotemporal Variation in Mature Source Rocks Linked to the Generation of Various Hydrocarbons in the Fuxin Basin, Northeast China

by
Xin Su
1,
Jianliang Jia
2,* and
Xiaoming Wang
3
1
CHN Energy Hydrogen Innovation Technology Co., Ltd., Beijing 100007, China
2
Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China
3
107 Exploration Team, Northeast Bureau of Coal Geology, Fuxin 123000, China
*
Author to whom correspondence should be addressed.
Energies 2024, 17(22), 5654; https://doi.org/10.3390/en17225654
Submission received: 4 October 2024 / Revised: 5 November 2024 / Accepted: 11 November 2024 / Published: 12 November 2024
(This article belongs to the Special Issue Prospects of Deep and Ultra-Deep Oil and Gas Exploration and Development)
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Abstract

:
The assessment of highly mature source rocks linked to hydrocarbon generation remains a challenge in oil and gas exploration. However, substantial terrigenous influences and thermal variations have complicated the formation and evolution of source rocks. This study presents an integrated assessment of highly mature source rocks in the Fuxin Basin, based on sedimentological, geochemical, and organic petrological analyses. Two types of oil- and coal-bearing source rocks were deposited in the semi-deep lake and shore–shallow lake facies during the Jiufotang and Shahai periods. The development of source rocks migrated eastward alongside the lacustrine depocenter, influenced by basin evolution related to extensional detachment tectonism. Furthermore, a gradual increase in thermal records was detected from the western to eastern basins. Consequently, thermal decomposition of source rocks in the Jiufotang formation reduced the organic matter (OM) abundance in the central and eastern basins. Meanwhile, OM types of source rocks range from kerogen type-II1/-I to type-II2/-III, with intense hydrogen generation observed from the western to eastern basins. Consequently, the quality and hydrocarbon accumulation of source rocks are influenced by sedimentation and thermal maturity variation. The spatiotemporal variation in mature source rocks enhances the potential for exploring conventional petroleum, coalbed methane, and shale gas across different strata and locations. Our findings illustrate the significance of the sedimentary and thermal effects in characterizing the evolution of highly mature source rocks, which is relevant to determine oil and gas exploration in similar geological settings.

1. Introduction

The evaluation of highly mature source rocks continues to be a major focus in conventional petroleum exploration, especially regarding shale oil and gas [1,2,3]. Source rock evaluation involves assessing hydrocarbon generation potential, organic matter (OM) type, hydrocarbons that might be generated, and thermal maturity [4,5,6]. Generally, excellent source rocks can form in marine, transitional, or continental environments, particularly within cratonic, foreland, and rift basins [7,8]. The thermal evolution of source rocks determines the timing of hydrocarbon generation and its subsequent expulsion [9,10]. Recent studies of marine shale gas have improved our understanding of the formation and evolution of mature source rocks [11,12,13,14]. However, confined continental environments are more prone to terrigenous influences compared to marine environments [15,16,17,18]. This leads to significant differences in lithofacies types, material compositions, and the spatiotemporal distribution of source rocks across different environments [19], complicating the formation and thermal maturity of terrestrial source rocks. In this context, evaluating the development of mature source rocks and clarifying the various parameters of sedimentary environments may reduce their indicators [20]. Therefore, a thorough evaluation of highly mature source rocks necessitates additional investigations in the continental environment.
The Fuxin Basin is a typical Mesozoic continental half-graben basin in Northeast China [21,22]. A substantial variety of energy resources, including coal, coalbed methane, conventional petroleum, shale gas, and volcanic reservoirs, have been identified in the Fuxin Basin [23,24,25]. Previous studies in the Fuxin Basin have concentrated on volcanic rocks [24], regional structure [26], basin evolution [24,27], sedimentary environments [28,29], and petroleum geology [30]. Notably, the development of excellent source rocks in the Fuxin Basin has attracted considerable attention [21,25,29,31]. The initial study suggested that lacustrine source rocks experienced low thermal evolution, whereas source rocks exhibiting unusually higher maturity are believed to be influenced by volcanic intrusion [31]. Recently, detailed sedimentation and thermal history analyses associated with basin genesis have uncovered high-maturity source rocks in the Fuxin supra-detachment basin [21]. Subsequently, the formation of basin and source rocks was influenced by extensional tectonism related to lithospheric thinning and craton destruction [25]. However, the integrated evaluation and genesis of mature source rocks in the Fuxin Basin remains poorly understood, thereby constraining hydrocarbon geology and exploration efforts.
This study aims to investigate the connections between source rock development, sedimentary environments, and thermal maturity variation in the Fuxin Basin through an integrated analysis of sedimentology, geochemistry, and organic petrology. We collected high-resolution data from three cored boreholes, each located in areas with well-exposed early Cretaceous strata, to document the overall evolutionary processes of source rocks. This study focuses on the importance of sedimentary and thermal effects in characterizing the evolution of terrigenous mature source rocks in a continental basin, which is relevant to determine hydrocarbon exploration in similar geological settings.

2. Geologic Setting

The Fuxin area, located in western Liaoning, resides in the eastern section of the Yanshan orogenic belt at the northern margin of the North China Craton (NCC) [32]. The lithosphere thinning and crust detachment caused strong extension and magmatic activity in the early Cretaceous of the NCC [33]. The Fuxin area developed a well-preserved extensional detachment system, including the Fuxin Basin, the Yiwulüshan metamorphic core complex (MCC), and the Waziyu detachment fault [34,35]. The Fuxin Basin covers an area of 1500 km2 that is 11–22 km wide and 80 km long (Figure 1a) [21]. The basin is classified as a half-graben basin, which is associated with upwelling of asthenospheric materials along a lithospheric-scale tear fault during the early Cretaceous period [22]. The basin is composed of two structural layers: a Pre-Mesozoic basin basement and Early Cretaceous basin cover (Figure 1b). After a brief period of compression at the end of the Jurassic, the Fuxin area transitioned to an extensional stage during the Early Cretaceous (~135 Ma) [32,35]. This process led to the formation of the NNE-trending Waziyu detachment fault (also called Lüshan fault; 132–123 Ma) (Figure 1a), which governs the formation and evolution of the Fuxin Basin, as well as the uplift and exhumation of the Yiwulüshan MCC [34,35].
The Fuxin Basin features a maximum stratum thickness of approximately 6000 m since the early Cretaceous and is composed of volcanic and terrigenous sedimentary rocks (Figure 1b) [21]. Initially, the Fuxin Basin was filled with intermediate-basic volcanic rocks from the Yixian Formation (K1y) (Figure 1b). This was followed by lacustrine-fluvial clastic deposits from the Jiufotang (K1jf), Shahai (K1sh), Fuxin (K1f), and Sunjiawan (K1s) Formations (Figure 1b). Lastly, Quaternary sediments accumulated within the basin (Figure 1b) [23,36]. The Early Cretaceous strata document four distinct phases of tectonic evolution: proto-rift, early fault subsidence, late fault subsidence, and transpression (Figure 1b) [21,36]. Excellent source rocks developed during the fault subsidence phase of the K1jf and K1sh strata, featuring oil- and coal-bearing deposits from shallow and deep water settings, respectively (Figure 1b) [29].

3. Materials and Methods

All analyzed samples were collected from three boreholes, namely, DY-1, FY-1, and FY-2, located in the eastern, central, and western parts of the Fuxin Basin (Figure 1a). Borehole DY-1 reached a total depth of 1900.51 m and intersected the late K1jf3, K1sh, K1f, and K1s strata. Borehole FY-1 reached a maximum depth of 2760.85 m and intersected the middle-late K1jf, K1sh, and K1f strata. Borehole FY-2 reached a total depth of 1862.04 m and intersected the late K1y, middle-late K1jf, and K1sh strata. A total of 287 high-resolution samples from the three boreholes were selected for LECO and Rock-Eval analyses [21]. Additionally, vitrinite reflectance (Ro) of 104 samples and maceral composition of 44 samples from three boreholes were analyzed.
Total organic carbon (TOC) content of pulverized samples (≤200 mesh) was measured using a LECO-CS230 elemental analyzer from LECO Corporation, St. Joseph, MI, USA. Prior to measurement, the samples were pre-treated with 5% concentrated HCl for 6 h to eliminate inorganic carbon. A 100 mg aliquot of each sample was combusted at approximately 1100 °C. The released CO2 was measured using an infrared cell, achieving an analytical precision of better than 0.2%.
Pyrolysis of pulverized samples (≤200 mesh) was conducted using a Vinci Rock-Eval 6 instrument, manufactured by Vinci Technologies Corporation in Nanterre, France. Approximately 60 mg of powdered sample was transferred to a crucible with the aid of a funnel. The amount of pyrolyzate produced from the kerogen during gradual heating under a helium stream was quantified as follows: free hydrocarbons (S1, mg HC/g rock) at 300 °C for 3 min and hydrocarbons generated during pyrolysis (S2 and S3, mg HC/g rock) at 650 °C with a rate of 25 °C min−1. These data were normalized to TOC to calculate the hydrogen index (HI = 100 × S2/TOC, mg HC/g TOC) and production index (PI = S1/(S1 + S2)). The temperature of maximum generation (Tmax) serves as an indicator of maturation.
Ro values were measured using oil immersion reflected optical light with a Zeiss MSP2000 microscope from Zeiss AG (Oberkochen, Germany) equipped with a TIDAS MSP400 spectrophotometer supplied by J&M Analytik AG (Essingen, Germany). The mudrock samples after cutting were polished with emery powders and various polishing liquids using a polishing machine. The target for Ro measurement was identified as telocollinite or desmocollinite corresponding to the stages of organic matter (OM) maturity to over-maturity. A minimum of 25 vitrinite observation points were selected for sample measurements, and the average values were utilized for analysis. Maceral analysis was conducted using a single-scan method with a Leica MPV microscope that utilized reflected white and fluorescent light [37].

4. Results

4.1. Sedimentary Fillings

Previous studies have identified two depositional systems in the Fuxin Basin: the fan delta-slump turbidite fan–shore–shallow lake system and the subaqueous fan–semi-deep lake system [21]. In this study, we document the sedimentary filling process that occurred during the Early Cretaceous in the basin (Figure 2).
The Fuxin Basin experienced initial tension due to reduced volcanic activity during the Yixian period (Figure 1b). Subsequently, the basin expanded and entered an early phase of mechanical subsidence during the deposition of K1jf (Figure 1b). A prominent fan delta and confined shore–shallow lake facies formed on both slopes during the early period of K1jf (K1jf1; Figure 2). Then a nearshore subaqueous fan–semi-deep lake depositional system was identified on the eastern steep slope during the middle period of K1jf (K1jf2; Figure 2). The fan delta–slump turbidite fan–shore–shallow lake depositional system remained prevalent on the western gentle slope. Ultimately, the fan delta–shore–shallow lake depositional system expanded toward the eastern basin, while semi-deep lake deposits diminished during the late period of K1jf (K1jf3; Figure 2). The eastern steep slope zone is characterized by nearshore subaqueous fan and semi-deep lake deposits.
The Fuxin Basin gradually expanded during the deposition of K1sh, with the depocenter migrating eastward (Figure 2). During the early period of K1sh (K1sh1-2), a wide range of fan deltas developed on the western gentle slope, while expanded nearshore and offshore subaqueous fans formed in the deep-water environment of the eastern steep slope (Figure 2). Subsequently, ongoing basin extension and pre-existing overfilled deposition resulted in increased shore–shallow lake deposition, while a reduced subaqueous fan–semi-deep lake depositional system formed on the eastern steep slope during the middle period of K1sh (K1sh3; Figure 2). Finally, intensified basin extension and subsidence resulted in the development of subaqueous fan–semi-deep lake depositional system along the eastern steep slope during the late period of K1sh (K1sh4; Figure 2). In contrast, reduced fan delta–slump turbidite fan–shore–shallow lake deposition occurred on the western gentle slope (Figure 2). Subsequently, the area of deep-water lake was constrained by the reduced accommodation space of the lake basin (Figure 2).
During the deposition of K1f, large-scale fan delta plain deposits were observed in the eastern basin (Figure 2). The fan delta front extended toward the center of the lake basin, resulting in decreased shore–shallow lake deposition (Figure 2). During the deposition of K1s, the limited basin fill near the Waziyu fault was influenced by the rapid uplift of the Yiwulüshan MCC (Figure 2). The rapid sedimentary filling of the eastern basin led to the formation of a relatively large and narrow alluvial fan deposit (Figure 2). Therefore, the sedimentary filling process exhibited an initial expansion followed by gradual shrinkage toward the eastern depocenter during the Early Cretaceous deposition.

4.2. Abundance of Organic Matter

TOC and potential yield (S1 + S2) serve as effective indicators for assessing OM abundance in source rocks. In the western basin (FY-2), we obtained TOC values from deep to shallow mudrocks as follows: 1.17 wt.% in K1jf2, 2.10 wt.% in K1jf3, 2.36 wt.% in K1sh1-2, 3.05 wt.% in K1sh3, and 2.60 wt.% in K1sh4 on average (Table 1). For S1 + S2 values, we observed values of 1.78 mg/g in K1jf2, 6.42 mg/g in K1jf3, 11.47 mg/g in K1sh1-2, 12.91 mg/g in K1sh3, and 9.01 mg/g in K1sh4 on average (Table 1). Our findings indicate that higher OM abundance is present in K1sh3 and K1sh4 strata, compared to those of K1jf2 and K1jf3 (Figure 3a).
In the central basin (FY-1), TOC values were measured in deep to shallow mudrocks with the following results: 0.60 wt.% in K1jf2, 1.55 wt.% in K1jf3, 1.86 wt.% in K1sh1-2, 2.60 wt.% in K1sh3, 2.31 wt.% in K1sh4, and 18.58 wt.% in K1f on average (Table 1). Additionally, the following S1 + S2 values were obtained: 0.33 mg/g in K1jf2, 1.40 mg/g in K1jf3, 2.47 mg/g in K1sh1-2, 4.22 mg/g in K1sh3, 7.61 mg/g in K1sh4, and 47.54 mg/g in K1f on average (Table 1). The results indicate that the OM abundance of K1sh and K1jf in the central basin is lower than that of the western basin (Figure 3b). However, anomalously high OM abundance is observed in the coal-bearing deposits of K1f (Figure 3b).
In the eastern basin (DY-1), we obtained TOC values from deep to shallow mudrocks as follows: 0.42 wt.% in K1jf3, 1.18 wt.% in K1sh1-2, 1.87 wt.% in K1sh3, 2.73 wt.% in K1sh4, and 2.44 wt.% in K1f on average (Table 1). Additionally, S1 + S2 values were recorded as follows: 0.24 mg/g in K1jf3, 0.45 mg/g in K1sh1-2, 1.89 mg/g in K1sh3, 6.65 mg/g in K1sh4, and 1.54 mg/g in K1f on average (Table 1). Our findings indicate that high OM abundance of source rocks is observed in the K1sh4 of the eastern basin, in contrast to the western and central basins (Figure 3c).

4.3. Maturity of Organic Matter

Ro and Tmax are commonly recognized as indicators of thermal maturity in source rocks [38]. In the western basin (FY-2), we obtained Tmax values from deep to shallow mudrocks as follows: 454 °C in K1jf2, 446 °C in K1jf3, 439 °C in K1sh1-2, 437 °C in K1sh3, and 435 °C in K1sh4 on average (Table 1). Additionally, the following Ro values were obtained: 1.03% in K1jf2, 0.92% in K1jf3, 0.78% in K1sh1-2, 0.66% in K1sh3, and 0.56% in K1sh4 on average (Table 1). Consequently, source rocks in the western basin reached an oil generation peak during the mature phase at K1jf, indicating that they entered a low-mature phase (Figure 3a).
In the central basin (FY-1), Tmax values from deep to shallow mudrocks were recorded as follows: 488 °C in K1jf2, 463 °C in K1jf3, 453 °C in K1sh1-2, 448 °C in K1sh3, 442 °C in K1sh4, and 433 °C in K1f on average (Table 1). The corresponding Ro values were 2.10% in K1jf2, 1.75% in K1jf3, 1.38% in K1sh1-2, 0.98% in K1sh3, 0.68% in K1sh4, and 0.59% in K1f on average (Table 1). Our results indicate that source rocks in the central basin underwent over-mature (~K1jf2), high-mature (~K1jf3 to K1sh1-2), mature (~K1sh3), and low-mature (~K1sh4 to K1f) phases (Figure 3b).
In the eastern basin (DY-1), Tmax values were measured in deep to shallow mudrocks as follows: 520 °C in K1jf3, 519 °C in K1sh1-2, 487 °C in K1sh3, 443 °C in K1sh4, and 435 °C in K1f on average (Table 1). The following Ro values were obtained: 2.14% in K1jf3, 2.08% in K1sh1-2, 1.68% in K1sh3, 0.80% in K1sh4, and 0.58% in K1f on average (Table 1). Consequently, source rocks in the eastern basin experienced over-mature (~K1jf3 to K1sh1-2), high-mature (~K1sh3), mature (~K1sh4), and low-mature (~K1f) phases (Figure 3c). Furthermore, the presence of thicker diabase dykes significantly enhanced the thermal records of adjacent strata, such as K1sh4 in borehole FY-2 (457–605 °C Tmax, 0.72–2.32% Ro; Figure 3a) and K1f in boreholes FY-1 (464–520 °C Tmax; Figure 3b) and DY-1 (474–551 °C Tmax; Figure 3c).

4.4. Type of Organic Matter

The OM types of source rocks can be inferred from the crossplots of Tmax vs. HI (e.g., [39]) and S2 vs. TOC correlations (e.g., [40]). These analyses show a strong correlation in the Fuxin Basin (Figure 4). Our results show that OM types in mudrocks of K1sh and K1jf are dominated by kerogen type-II1/-I in the western basin (Figure 4a). In the central basin, kerogen type-II2 in K1sh3 to K1f and type-III in K1jf2-3 are predominantly detected in mudrocks (Figure 4b). In the eastern basin, OM types of mudrocks primarily consist of kerogen type-II2/-I in K1sh4, type-II2 in K1sh3, and type-III in K1f (Figure 4c). Thus, contemporary mudrocks demonstrate a predominance of OM types ranging from kerogen type-II1/-I to type-II2/-III from west to east in the basin (Figure 4).
In particular, type-II1/-I kerogen is infrequently observed in the well-developed semi-deep lake facies of central and western basins, as indicated by the original crossplots of OM types (Figure 4b,c). Furthermore, lower mature source rocks in the western basin exhibit elevated S2 values (5–35 mg/g) and HI values (300–750 mg HC/g TOC) (Figure 4a). However, S2 (2–15 mg HC/g TOC) and HI values (50–350 mg HC/g TOC) of high-mature source rocks in central and eastern basins significantly decreased (Figure 4b,c).

5. Discussion

5.1. Source Rock Formation Influenced by Sedimentary Environment

OM enrichment during sedimentation provides the essential material for the formation of source rocks [41]. Continental source rocks form in various sedimentary environments, including deep lakes, semi-deep lakes, shallow lakes, and swamps [42,43]. These environments play a crucial role in determining the combination of organic sources [2]. The semi-deep and deep lake facies are more favorable for the development of large-scale excellent source rocks [44]. Two types of oil- and coal-bearing source rocks were formed during the Early Cretaceous period in the Fuxin Basin (Figure 5). Oil-bearing source rocks consist of thick layers of dark gray and gray-black massive mudstone (Figure 5a), as well as thin layers of shale (Figure 5b), found in the semi-deep lake facies of K1jf2-3 and K1sh4 (Figure 2). In contrast, coal-bearing source rocks, characterized by black and gray-black charcoal mudstone and coal seams containing abundant shell fossils (Figure 5c), are present in the shore-shallow lake facies of K1sh3 and K1f (Figure 2). These have been partially reported by [21,29]. The thickness of source rocks from K1sh4 in the eastern basin (~500 m) is significantly greater than that in the central (~250 m) and western basins (~160 m) (Figure 3). In contrast, the thickness of source rocks from K1jf2-3 in the central basin (~700 m) exceeds that in the eastern (>200 m) and western basins (~100 m) (Figure 3). Additionally, source rocks in the eastern basin of K1sh3 (~250 m) are superior to those in the central basin (~160 m) (Figure 3). Thus, the spatiotemporal characteristics of two source rocks exhibit significant differences. This is probably related to the evolution of the Fuxin supra-detachment basin [21].
The spatiotemporal evolution of Early Cretaceous source rocks was influenced by Waziyu detachment faulting associated with the rapid uplift and exhumation of the Yiwulüshan MCC [35], resulting in the eastward migration of the lacustrine depocenter since the K1jf period (Figure 2) [21]. During the middle K1jf period, extensional detachment resulted in the formation of two large semi-deep lake areas (e.g., Yimatu and Haizhou subsags) in the north-central basin [21]. These areas are significant for the development of excellent oil-bearing source rocks (Figure 3). Then, abundant lamalginites (Figure 6a) and fewer inertinites (Figure 6b) were identified in the mudrocks of semi-deep lake facies. A high salinity bottom water environment is demonstrated in [25]. During the K1sh3 period, continuous basin extension and overfilled deposition influenced the formation of extensive shore–shallow lakes (Figure 2) [21]. A lake-swamp environment in the eastern basin resulted in the deposition of thicker coal-bearing source rocks (Figure 3). Additionally, abundant vitrinites (Figure 6c) were identified in coal-bearing source rocks, including telinite (Figure 6d) and telocollinite (Figure 6e). This environment is characterized as dysoxic and brackish [25].
During the K1sh4 period, intensified detachment faulting and basin subsidence resulted in the formation of extensive, interconnected deep-water areas, including the Yimatu subsag, Dongliang area, and Haizhou subsag (Figure 2) [21]. This facilitated the formation of large-scale oil-bearing source rocks in eastern and central basins (Figure 3). This finding contrasts with earlier results [31]. Furthermore, abundant lamalginite (Figure 6f), sporinite (Figure 6g), and fusinite (Figure 6h) were identified in these large lakes, while the presence of strawberry pyrites suggests a reduced lake environment (Figure 6i). This observation is supported by a low gammacerane index [29]. During the K1f period, reduced detachment faulting and western basin uplift contributed to the development of lake-swamp facies (Figure 2) [21], resulting in high-quality coal seams exemplified by the Haizhou strip mine (Figure 1a). Consequently, the migration of source rock development shifted eastward alongside the lacustrine depocenter since the K1jf2-3 period. This could be potentially influenced by basin evolution associated with extensional detachment tectonism [21].

5.2. Source Rock Evolution Influenced by Thermal Variation

In general, Ro is considered the most robust petrographic parameter for the determination of thermal maturity [4,45]. Moreover, Tmax is generally correlated with thermal maturity, although they represent different geological meanings [46]. In this study, OM maturity recorded by Ro and Tmax parameters at different basin locations exhibits notable spatial variations (Figure 3). From the western to central and eastern basins, OM maturity of source rocks varies, showing early low-mature, late low-mature, and mature phases in K1sh4; late low-mature, mature, and high-mature phases in K1sh3; and mature, high to over-mature, and over-mature phases in K1jf2-3 (Figure 3a–c). This differs from the previous understanding regarding the lower maturity of source rocks [31]. Thus, a gradual increase in thermal records was observed from the western to eastern basins (Figure 3). Previous basin simulations indicate an increase in the maximum paleotemperature (FY-2–160 °C; FY-1–220 °C; DY-1–260 °C) toward the eastern basin [21]. Moreover, the shallow emplacement of Oligocene dolerite (~33.75 Ma; [47]) significantly enhanced thermal records (Figure 3a–c).
The quality of source rocks is significantly influenced by the variation in OM thermal maturity [21]. Except for the effect of sedimentary facies on OM abundance, increased thermal maturity can contribute to variations in TOC levels (Figure 3). This has been proven in [25]. TOC values of source rocks in the K1sh4 of eastern basin (~3.5 wt.%) are higher than those in central (~2.4 wt.%) and western basins (~2.2 wt.%) (Figure 3a–c). This implies a lesser impact on source rocks based on lower maturity. This aligns with [31]. Conversely, TOC content in the K1jf2-3 of western basin (~2.8 wt.%) exceeds that in central (~2.3 wt.%) and eastern basins, which feature more developed semi-deep lake facies (Figure 3a–c). In addition, coal-bearing source rocks in the K1sh3 of central and eastern basins typically exhibit higher TOC values (Figure 3b,c).
Subsequent studies indicate that OM types of mudrocks in the central and eastern basins, determined via crossplots of Tmax vs. HI and S2 vs. TOC correlations [39,40], are significantly influenced by OM hydrocarbon generation (Figure 4b,c). Our results show that the higher maturity of source rocks in the central and eastern basins (Figure 4b,c) results in substantial thermal decomposition of OM, leading to a significant decrease in HI values relative to S2. Consequently, contemporary source rocks exhibit a predominance of OM types ranging from kerogen type-II1/-I in the western basin to type-II2/-III in the central and eastern basins (Figure 4). This result significantly differs from prior assumptions [25,31]. Additionally, high abundances of lamalginites were detected in the K1jf2-3 and K1sh4 of eastern and central basins (Figure 6f), correlating with findings from the western basin (Figure 6a). However, the fluorescence intensity of macerals in the eastern and central basins is greater than in the western basin (Figure 6), suggesting elevated Ro values in these areas. This is consistent with [4,45]. Therefore, the increased thermal maturity from west to east across the basin affected the primary OM abundance and parameters used to determine OM types, especially the material source from aquatic organisms and its enrichment.

5.3. Influence of Source Rock Evolution on Oil-Gas Exploration

The overall increase in thermal records from west to east in the Fuxin Basin facilitated abundant hydrocarbon generation and discharge across various spatial locations (Figure 7). The production index [PI = S1/(S1 + S2)] indicates the relationship between hydrocarbon generation potential and thermal maturity [21,48]. Overall, increased thermal maturity, indicated by Tmax values ranging from 435 to 455 °C, gradually elevated the PI values, particularly from eastern to western basins during the mature phase (Figure 7a–c). This has been reported in [21]. However, dolerite intrusion can influence the intensity of hydrocarbon discharge from adjacent source rocks (Figure 7a–c) [47,48]. Furthermore, detrital dilution and aerobic conditions facilitated the oxidative decomposition of OM, leading to high PI values (Figure 7a–c) [37].
Our findings demonstrate that oil-bearing source rocks of K1sh4 initially generated peak mature oil in the eastern basin (Figure 7c). Subsequently, significant mature oil generation was observed in the central basin (Figure 7b), along with high-mature mixed oil-gas generation in the eastern basin (Figure 7c), both occurring in coal-bearing series of K1sh3. In contrast, oil-bearing source rocks of K1jf2-3 generated peak mature oil in the western basin (Figure 7a), high-mature gas-oil and over-mature gas in the central basin (Figure 7b), as well as over-mature gas in the eastern basin (Figure 7c). These hydrocarbon generation processes are further supported by previous basin simulations with high paleotemperature [21,25]. Thus, the primary sources of conventional petroleum are found in the K1sh4 of the eastern basin and the K1jf2-3 of the western basin. The primary sources of coalbed methane are located in the K1sh3 of the eastern basin, while the major sources of shale gas are found in the K1jf2 of the central basin and the K1jf2-3 of the eastern basin.
In short, the spatial characterization of source rock evolution in the Fuxin Basin enhances the potential for diverse oil-gas exploration across various strata and locations. Specifically, the eastern basin’s areas with higher maturity are likely to be dominated by shale gas and coalbed gas exploration. Whereas the western basin’s areas with lower maturity are expected to focus on conventional petroleum exploration. This study aims to elucidate the spatial trends and genesis of source rock evolution in the Fuxin Basin, which may aid in identifying optimal strategies for oil-gas exploitation.

6. Conclusions

(1)
Two types of oil- and coal-bearing source rocks are developed in the fault subsidence phase of the Fuxin Basin. These are deposited in semi-deep lake facies of K1jf2-3 and K1sh4, and shore–shallow lake facies of K1sh3 and K1f. The thickest oil-bearing source rocks are located in the K1jf2-3 of the central basin (~700 m). Whereas the thickest coal- and oil-bearing source rocks are present in the K1sh3 (~250 m) and K1sh4 (~500 m) of the eastern basin, respectively. Thus, the development of source rocks migrated eastward alongside the lacustrine depocenter since the K1jf2-3 period, influenced by basin evolution associated with extensional detachment tectonism.
(2)
A gradual increase in thermal records was observed from west to east across the basin. The thermal variation in different source rocks across the western, central, and eastern basins exhibited early low-mature, late low-mature, and mature phases in the K1sh4, late low-mature, mature, and high-mature phases in the K1sh3, as well as mature, high- to over-mature and over-mature phases in the K1jf2-3. Furthermore, the emplacement of the Oligocene dolerite dyke significantly elevated thermal values in shallow stratum.
(3)
The quality of source rocks is influenced by the variation in OM thermal maturity. The thermal decomposition of highly mature source rocks in the K1jf2-3 reduced OM abundance in the central and eastern basins (<2.3 wt.%) compared to the western basin (~2.8 wt.%). TOC values of low-mature source rocks in the K1sh4 of the eastern basin (~3.5 wt.%) exceed those found in central and western basins (<2.4 wt.%). Consequently, source rocks from west to east across the basin predominantly exhibit OM types ranging from kerogen type-II1/-I to type-II2/-III. This variation is influenced by strong hydrogen generation of OM in relation to thermal variability.
(4)
The spatiotemporal variation of mature source rocks increases the potential for diverse oil and gas exploration across different strata and locations. Our findings demonstrate that the primary sources of conventional petroleum are located in the K1sh4 of the eastern basin and the K1jf2-3 of the western basin. The primary sources of coalbed methane are situated in the K1sh3 of the eastern basin, while the significant sources of shale gas are present in the K1jf2 of the central basin and the K1jf2-3 of the eastern basin.

Author Contributions

Conceptualization, Investigation, Methodology, Writing—original draft, X.S.; Supervision, Funding acquisition, Project Administration, Writing—review and editing, J.J.; Resources, X.W. All authors have read and agreed to the published version of the manuscript.

Funding

This study is supported by the National Natural Science Foundation of China (No. 42372138), the Basic Scientific Research Fund of the Ministry of Science and Technology of China (No. J2304), and the Project of China Geological Survey (No. DD20221807).

Data Availability Statement

The original contributions presented in the study are included in the article, further inquiries can be directed to the corresponding author.

Acknowledgments

We thank Changsheng Miao, Jianyi Qin, Bo Lan, and Yanjia Wu for their assistance with core observations, sampling, and field work, as well as Wenquan Xie, Yuan Gao, and Xiuhong Wang for laboratory assistance. We gratefully acknowledge detailed comments and constructive criticism from two anonymous reviewers that greatly improved this manuscript.

Conflicts of Interest

Author Xin Su was employed by the CHN Energy Hydrogen Innovation Technology Co., Ltd. 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.

References

  1. Leythaeuser, D.; Schaefer, R.G. Effects of hydrocarbon expulsion from shale source rocks of high maturity in Upper Carboniferous strata of the Ruhr area, Federal Republic of Germany. Org. Geochem. 1984, 6, 671–681. [Google Scholar] [CrossRef]
  2. Peters, K.E.; Magoon, L.B.; Bird, K.J.; Valin, Z.C.; Keller, M.A. North Slope, Alaska: Source rock distribution, richness, thermal maturity, and petroleum charge. AAPG Bull. 2006, 90, 261–292. [Google Scholar] [CrossRef]
  3. Zhao, W.; Zhang, B.; Wang, X.; Wu Songtao, W.; Zhang, S.; Liu, W.; Wang, K.; Zhao, X. Differences in source kitchens for lacustrine in-source and out-of-source hydrocarbon accumulations. Petrol. Explor. Dev. 2021, 48, 541–554. [Google Scholar] [CrossRef]
  4. Dembicki, H., Jr. Three common source rock evaluation errors made by geologists during prospect or play appraisals. AAPG Bull. 2009, 93, 341–356. [Google Scholar] [CrossRef]
  5. Spacapan, J.B.; Comerio, M.; Brisson, I.; Rocha, E.; Cipollone, M.; Hidalgo, J.C. Integrated source rock evaluation along the maturation gradient. Application to the Vaca Muerta Formation, Neuquén Basin of Argentina. Basin Res. 2021, 33, 3183–3211. [Google Scholar] [CrossRef]
  6. Farouk, S.; Saada, S.A.; Fagelnour, M.; Tawfik, A.Y.; Arafat, M.; El-Kahtany, K. Geochemical evaluation and basin modelling of the Cretaceous succession in the Azhar Oil field, West Beni Suef Basin, Egypt. Geol. J. 2024, 59, 1949–1967. [Google Scholar] [CrossRef]
  7. Zou, C.; Dong, D.; Wang, S.; Li, J.; Li, X.; Wang, Y.; Li, D.; Cheng, K. Geological characteristics and resource potential of shale gas in China. Petrol. Explor. Dev. 2010, 37, 641–653. [Google Scholar] [CrossRef]
  8. Zhang, J.; Li, Z.; Wang, D.; Xu, L.; Li, Z.; Niu, J.; Chen, L.; Sun, Y.; Li, Q.; Yang, Z.; et al. Shale gas accumulation patterns in China. Nat. Gas. Ind. 2022, 42, 78–95. [Google Scholar] [CrossRef]
  9. Carminati, E.; Cavazza, D.; Scrocca, D.; Fantoni, R.; Scotti, P.; Doglioni, C. Thermal and tectonic evolution of the southern Alps (northern Italy) rifting: Coupled organic matter maturity analysis and thermokinematic modeling. AAPG Bull. 2010, 94, 369–397. [Google Scholar] [CrossRef]
  10. Hudson, S.M.; Hanson, A.D. Thermal maturation and hydrocarbon migration within La Popa Basin, northeastern Mexico, with implications for other salt structures. AAPG Bull. 2010, 94, 273–291. [Google Scholar] [CrossRef]
  11. Curtis, J.B. Fractured shale-gas systems. AAPG Bull. 2002, 86, 1921–1938. [Google Scholar]
  12. Bernard, S.; Horsfield, B. Thermal maturation of gas shale systems. Annu. Rev. Earth Planet. Sci. 2014, 42, 635–651. [Google Scholar] [CrossRef]
  13. Dai, J.; Zou, C.; Liao, S.; Dong, D.; Ni, Y.; Huang, J.; Huang, J.; Fang, C.; Hu, G. Geochemistry of the extremely high thermal maturity Longmaxi shale gas, southern Sichuan Basin. Org. Geochem. 2014, 74, 3–12. [Google Scholar] [CrossRef]
  14. Zhao, W.; Li, J.; Yang, T.; Wang, S.; Huang, J. Geological difference and its significance of marine shale gases in South China. Petrol. Explor. Dev. 2016, 43, 547–559. [Google Scholar] [CrossRef]
  15. Ransom, B.; Kim, D.; Kastner, M.; Wainwright, S. Organic matter preservation on continental slops: Importance of mineralogy and surface area. Geochim. Cosmochim. Acta 1998, 62, 1329–1345. [Google Scholar] [CrossRef]
  16. Nederbragt, A.J.; Thurow, J.; Vonhof, H.; Brumsack, H.J. Modelling oceanic carbon and phosphorus fluxes: Implications for the cause of the late Cenomanian Oceanic Anoxic Event (OAE2). J. Geol. Soc. 2004, 161, 721–728. [Google Scholar] [CrossRef]
  17. Galy, V.; France-Lanord, C.; Beyssac, O.; Faure, P.; Kudrass, H.; Palhol, F. Efficient organic carbon burial in the Bengal fan sustained by the Himalayan erosional system. Nature 2007, 450, 407–411. [Google Scholar] [CrossRef]
  18. Kennedy, M.J.; Wagner, T. Clay mineral continental amplifier for marine carbon sequestration in a greenhouse ocean. Proc. Natl. Acad. Sci. USA 2011, 108, 9776–9781. [Google Scholar] [CrossRef]
  19. Wang, X.; Zhang, S.; Wang, H.; Su, J.; He, K.; Yu, W.; Wang, X. Significance of source rock heterogeneities: A case study of Mesoproterozoic Xiamaling Formation shale in North China. Petrol. Explor. Dev. 2017, 44, 32–39. [Google Scholar] [CrossRef]
  20. Yin, H.; Xie, S.; Yan, J.; Hu, C.; Huang, J.; Tenger; Qie, W.; Qiu, X. Geobiological approach to evaluating marine carbonate source rocks of hydrocarbon. Sci. China Earth Sci. 2011, 54, 1121–1135. [Google Scholar] [CrossRef]
  21. Jia, J.; Wu, Y.; Miao, C.; Fu, C.; Xie, W.; Qin, J.; Wang, X. Tectonic Controls on the Sedimentation and Thermal History of Supra-detachment Basins: A Case Study of the Early Cretaceous Fuxin Basin, NE China. Tectonics 2021, 40, e2020TC006535. [Google Scholar] [CrossRef]
  22. Meng, Q.; Zhou, Z.; Zhu, R.; Xu, Y.; Guo, Z. Cretaceous basin evolution in northeast Asia: Tectonic responses to the paleo-Pacific plate subduction. Natl. Sci. Rev. 2022, 9, nwab088. [Google Scholar] [CrossRef]
  23. Wu, B.; Guo, Y.; Wang, X.; Jiang, L.; Wang, H.; Ji, Z. The oil-gas exploration direction of Fuxin Basin. Geol. Resour. 2015, 24, 473–477. [Google Scholar]
  24. Jia, J.; Wu, Y.; Yang, D.; Qin, J. Discovery and accumulation mechanism of Early Cretaceous volcanogenic buried-hill reservoir in the Fuxin basin. Acta Geol. Sin. 2022, 96, 3977–3993. [Google Scholar]
  25. Xie, W.; Jia, J.; Mansour, A.; Wang, X. Hydrocarbon generation and migration in the Fuxin Basin during the Cretaceous evolution of the North China Craton, NE China. Geomech. Geophys. Geo-Energy Geo-Resour. 2023, 9, 148. [Google Scholar] [CrossRef]
  26. Wu, Z.; Yue, H.; Han, J. The Meso-Cenozoic tectonic transitions in the Fuxin Basin, Liaoning and their geological significances. Acta Geol. Sichuan 2007, 27, 239–244. [Google Scholar]
  27. Sun, S.; Qiu, L.; Yan, D.P.; Zhou, Z.; Zhang, J.; Wang, X.; Wu, B.; Shi, H.; Ariser, S.; Chu, R.; et al. Formation and Evolution of Supradetachment Basins During Continental Extension: Insights from the Fuxin Basin in NE China. Front. Earth Sci. 2022, 10, 845812. [Google Scholar] [CrossRef]
  28. Xu, X.; Shao, L.; Fu, Y.; Wang, D.; Cai, H.; Qin, J.; Hou, H.; Zhao, J. Sequence palaeogeography, lacustrine basin evolution, and coal accumulation in the Lower Cretaceous Fuxin continental faulted basin, China. Geol. J. 2020, 55, 1195–1215. [Google Scholar] [CrossRef]
  29. Xie, W.; Jia, J.; Miao, C.; Wu, Y.; Wang, X.; Qin, J. Formation and evolution of coal–and oil–bearing source rocks in the Lower Cretaceous Shahai Formation in the Fuxin Basin (NE China): Evidence from organic and inorganic geochemical analyses. J. Petrol. Sci. Eng. 2021, 202, 108544. [Google Scholar] [CrossRef]
  30. Jia, J.; Ji, Z. Progress in geological researches on the petroleum and gas exploration in the Cretaceous Shahai Formation of Fuxin Basin. News Lett. China Geol. Surv. 2017, 3, 39–42. [Google Scholar]
  31. Wang, H.; Liu, Y. Characteristics of cretaceous source rocks and the origin of natural gas in Fuxin sag. Mar. Geol. Front. 2013, 29, 33–40. (In Chinese) [Google Scholar]
  32. Zhang, B.; Zhu, G.; Jiang, D.; Li, C.; Chen, Y. Evolution of the Yiwulüshan metamorphic core complex from distributed to localized deformation and its tectonic implications. Tectonics 2012, 31, TC4018. [Google Scholar] [CrossRef]
  33. Zhu, G.; Jiang, D.; Zhang, B.; Chen, Y. Destruction of the eastern North China Craton in a backarc setting: Evidence from crustal deformation kinematics. Gondwana Res. 2012, 22, 86–103. [Google Scholar] [CrossRef]
  34. Darby, B.; Davis, G.; Zhang, X.; Wu, F.; Simon, W.; Yang, J. The newly discovered Waziyu metamorphic core complex, Yiwulüshan, western Liaoning Province, Northwest China. Earth Sci. Front. 2004, 11, 145–155. [Google Scholar]
  35. Li, G.; Liu, Z.; Liu, J.; Li, Y.; Xu, Z.; Dong, X. Formation and timing of the extensional ductile shear zones in Yiwulü mountain area, western Liaoning Province, North China. Sci. China Earth Sci. 2012, 55, 733–746. [Google Scholar] [CrossRef]
  36. Jia, J.; Miao, C.; Xie, W. Terrestrial paleoclimate transition associated with continental weathering and drift during the Aptian–Albian of East Asia. GSA Bull. 2023, 135, 467–480. [Google Scholar] [CrossRef]
  37. Jia, J.; Bechtel, A.; Liu, Z.; Strobl, S.A.; Sun, P.; Sachsenhofer, R.F. Oil shale formation in the Upper Cretaceous Nenjiang Formation of the Songliao Basin (NE China): Implications from organic and inorganic geochemical analyses. Int. J. Coal Geol. 2013, 113, 11–26. [Google Scholar] [CrossRef]
  38. Hackley, P.C.; Araujo, C.V.; Borrego, A.G.; Bouzinos, A.; Cardott, B.J.; Cook, A.C.; Eble, C.; Flores, D.; Gentzis, T.; Gonçalves, P.A.; et al. Standardization of reflectance measurements in dispersed organic matter: Results of an exercise to improve interlaboratory agreement. Mar. Petrol. Geol. 2015, 59, 22–34. [Google Scholar] [CrossRef]
  39. Espitalié, J.; Marquis, F.; Barsony, I. Geochemical Logging. In Analytical Pyrolysis; Voorhess, K.J., Ed.; Butterworths: Boston, MA, USA, 1984; pp. 53–79. [Google Scholar]
  40. Langford, F.F.; Blanc-Valleron, M.-M. Interpreting Rock-Eval pyrolysis data using graphs of pyrolyzable hydrocarbons vs. total organic carbon. AAPG Bull. 1990, 74, 799–804. [Google Scholar]
  41. Schoepfer, S.D.; Shen, J.; Wei, H.; Tyson, R.V.; Ingall, E.; Algeo, T.J. Total organic carbon, organic phosphorus, and biogenic barium fluxes as proxies for paleomarine productivity. Earth Sci. Rev. 2015, 149, 23–52. [Google Scholar] [CrossRef]
  42. Shao, L.; Li, M.; Li, Y.; Zhang, Y.; Lu, J.; Zhang, W.; Tian, Z.; Wen, H. Geological characteristics and controlling factors of shale gas in the Jurassic of the northern Qaidam Basin. Earth Sci. Front. 2014, 21, 311–322. [Google Scholar]
  43. Hu, Z.; Wang, R.; Liu, Z.; Liu, G.; Feng, D.; Yang, Z.; Wang, P. Source-reservoir characteristics and coupling evaluations for the Lower Jurassic lacustrine shale gas reservoir in the Sichuan Basin. Earth Sci. Front. 2021, 28, 261–272. [Google Scholar]
  44. Feng, Z.; Fang, W.; Li, Z.; Wang, X.; Huo, Q.; Huang, C.; Zhao, J.; Zeng, H. Depositional environment of terrestrial petroleum source rocks and geochemical indicators in the Songliao Basin. Sci. China Earth Sci. 2011, 54, 1304–1317. [Google Scholar] [CrossRef]
  45. Suárez-Ruiz, I.; Flores, D.; Mendonça Filho, J.G.; Hackley, P.C. Review and update of the applications of organic petrology: Part 1, geological applications. Int. J. Coal Geol. 2012, 99, 54–112. [Google Scholar] [CrossRef]
  46. Yang, S.; Horsfield, B. Critical review of the uncertainty of Tmax in revealing the thermal maturity of organic matter in sedimentary rocks. Int. J. Coal Geol. 2020, 225, 103500. [Google Scholar] [CrossRef]
  47. Wu, Y.; Jia, J.; Qin, J.; Wang, X. The intrusion characteristics of Cenozoic diabase in the middle and northern Fuxin basin and its influence on source rocks. Acta Geol. Sin. 2022, 96, 1026–1040. [Google Scholar]
  48. Haile, B.; Klausen, T.; Jahren, J.; Braathen, A.; Hellevang, H. Thermal history of a triassic sedimentary sequence verified by a multi-method approach: Edgeøya, Svalbard, Norway. Basin Res. 2018, 30, 1075–1097. [Google Scholar] [CrossRef]
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Figure 1. Map of the structural units in the Fuxin Basin, showing the basin distribution in Northeast China (a) (after [36]), and the generalized stratigraphic column of the Fuxin Basin (b) (after [21]). Abbreviations: Ep—epoch; St—Stage; Fm—Formation; Mem—member; TE—tectonic evolution.
Figure 1. Map of the structural units in the Fuxin Basin, showing the basin distribution in Northeast China (a) (after [36]), and the generalized stratigraphic column of the Fuxin Basin (b) (after [21]). Abbreviations: Ep—epoch; St—Stage; Fm—Formation; Mem—member; TE—tectonic evolution.
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Figure 2. Sedimentary filling process in the Fuxin basin during the Early Cretaceous period (adapted from [21]).
Figure 2. Sedimentary filling process in the Fuxin basin during the Early Cretaceous period (adapted from [21]).
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Figure 3. OM abundance and maturity parameters of various mudrocks from boreholes FY-2 (a), FY-1 (b), and DY-1 (c). All Tmax and Ro data are cited from [21].
Figure 3. OM abundance and maturity parameters of various mudrocks from boreholes FY-2 (a), FY-1 (b), and DY-1 (c). All Tmax and Ro data are cited from [21].
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Figure 4. Crossplots of Tmax vs. hydrogen index (HI) (according to [39]), and S2 vs. TOC correlations (according to [40]) from mudrocks of boreholes FY-2 (a), FY-2 (b), and DY-1 (c).
Figure 4. Crossplots of Tmax vs. hydrogen index (HI) (according to [39]), and S2 vs. TOC correlations (according to [40]) from mudrocks of boreholes FY-2 (a), FY-2 (b), and DY-1 (c).
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Figure 5. Petrographic photos of various source rocks, exhibiting oil-bearing mudrocks from the K1jf3 of borehole FY-2 (a) and the K1sh4 of borehole DY-1 (b), as well as coal-bearing mudrocks from the K1sh3 of borehole DY-1 (c).
Figure 5. Petrographic photos of various source rocks, exhibiting oil-bearing mudrocks from the K1jf3 of borehole FY-2 (a) and the K1sh4 of borehole DY-1 (b), as well as coal-bearing mudrocks from the K1sh3 of borehole DY-1 (c).
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Figure 6. Photomicrographs of macerals from oil- (a–f) and coal-bearing source rocks (g–i) in the Fuxin Basin. (a) Lamalginite and bitumen from black-gray mudstone, FY2-60, 1288.64 m, K1jf3; (b) Inertinite from dark-gray silty mudstone, FY2-1, 1731.3 m, K1jf2; (c) Vitrinite from black coal, DY1-C5, 1250.0 m, K1sh3; (d) Telinite from gray-black carbonaceous mudstone, DY1-C4, 1266.0 m, K1sh3; (e) Telocollinite from black coal, DY1-C3, 1282.0 m, K1sh3; (f) Lamalginite and bitumen from dark-gray mudstone, DY1-22, 718.3 m, K1sh4; (g) Sporinite from black-gray mudstone, FY2-104, 435.1 m, K1sh4; (h) Fusinite from dark-gray mudstone, DY1-28, 718.3 m, K1sh4; (i) Pyrite from dark-gray mudstone, FY2-98, 530.0 m, K1sh4.
Figure 6. Photomicrographs of macerals from oil- (a–f) and coal-bearing source rocks (g–i) in the Fuxin Basin. (a) Lamalginite and bitumen from black-gray mudstone, FY2-60, 1288.64 m, K1jf3; (b) Inertinite from dark-gray silty mudstone, FY2-1, 1731.3 m, K1jf2; (c) Vitrinite from black coal, DY1-C5, 1250.0 m, K1sh3; (d) Telinite from gray-black carbonaceous mudstone, DY1-C4, 1266.0 m, K1sh3; (e) Telocollinite from black coal, DY1-C3, 1282.0 m, K1sh3; (f) Lamalginite and bitumen from dark-gray mudstone, DY1-22, 718.3 m, K1sh4; (g) Sporinite from black-gray mudstone, FY2-104, 435.1 m, K1sh4; (h) Fusinite from dark-gray mudstone, DY1-28, 718.3 m, K1sh4; (i) Pyrite from dark-gray mudstone, FY2-98, 530.0 m, K1sh4.
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Figure 7. Graphs illustrating the production index and Tmax values for various mudrocks in the western (a), central (b), and eastern (c) parts of the Fuxin Basin (after [21]).
Figure 7. Graphs illustrating the production index and Tmax values for various mudrocks in the western (a), central (b), and eastern (c) parts of the Fuxin Basin (after [21]).
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Table 1. The evaluation indicator of organic-rich mudrocks in the Fuxin Basin.
Table 1. The evaluation indicator of organic-rich mudrocks in the Fuxin Basin.
IndicatorBoreholeK1jf2K1jf3K1sh1-2K1sh3K1sh4K1f
Range/
Average		Range/
Average		Range/
Average		Range/
Average		Range/
Average		Range/
Average
TOC
(wt.%)		FY-20.59–1.81
1.17 (n = 12)		1.31–3.69
2.10 (n = 25)		0.91–3.36
2.36 (n = 14)		1.59–5.15
3.05 (n = 14)		0.95–5.39
2.60 (n = 20)		n.d. 1
FY-10.31–1.20
0.60 (n = 6)		1.03–2.25
1.55 (n = 25)		1.15–3.38
1.86 (n = 8)		0.95–8.18
2.60 (n = 10)		1.53–4.38
2.31 (n = 21)		0.98–51.60
18.58 (n = 13)
DY-1n.d. 10.16–0.55
0.42 (n = 3)		0.41–2.42
1.18 (n = 9)		0.20–11.50
1.87 (n = 26)		1.12–4.71
2.73 (n = 53)		0.98–3.97
2.44 (n = 12)
S1 + S2
(mg/g)		FY-20.41–4.03
1.78 (n = 12)		1.69–20.89
6.42 (n = 25)		1.86–24.92
11.47 (n = 14)		2.55–23.93
12.91 (n = 14)		0.52–35.55
9.01 (n = 20)		n.d. 1
FY-10.16–0.64
0.33 (n = 6)		0.89–2.34
1.40 (n = 25)		1.21–3.55
2.47 (n = 8)		1.18–15.50
4.22 (n = 10)		0.73–76.89
7.61 (n = 21)		0.57–143.76
47.54 (n = 13)
DY-1n.d. 10.14–0.34
0.24 (n = 3)		0.08–1.11
0.45 (n = 9)		0.11–18.41
1.89 (n = 26)		0.79–12.50
6.65 (n = 53)		0.34–3.70
1.54 (n = 12)
Tmax
(°C)		FY-2448–459
454 (n = 12)		433–454
446 (n = 25)		437–441
439 (n = 14)		432–443
437 (n = 14)		431–439
435 (n = 20)		n.d. 1
FY-1480–492
488 (n = 6)		443–489
463 (n = 25)		449–456
453 (n = 8)		443–451
448 (n = 10)		429–450
442 (n = 21)		424–443
433 (n = 13)
DY-1n.d. 1513–527
520 (n = 3)		482–529
519 (n = 9)		457–519
487 (n = 26)		435–465
443 (n = 53)		425–439
435 (n = 12)
Ro
(%)		FY-20.99–1.06
1.03 (n = 5)		0.84–1.00
0.92 (n = 12)		0.74–0.82
0.78 (n = 4)		0.60–0.75
0.66 (n = 9)		0.51–0.61
0.56 (n = 10)		n.d. 1
FY-11.94%–2.25
2.10 (n = 2)		1.50%–2.12
1.75 (n = 11)		1.31%–1.45
1.38 (n = 3)		0.77%–1.27
0.98 (n = 7)		0.61%–0.75
0.68 (n = 8)		0.59–0.59
0.59 (n = 1)
DY-1n.d. 12.03%–2.25
2.14 (n = 2)		1.99%–2.19
2.08 (n = 3)		1.23%–1.98
1.68 (n = 6)		0.62%–1.11
0.80 (n = 9)		0.55%–0.62
0.58 (n = 3)
1 No data available. Detailed date of three boreholes are quoted from [21].
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Su, X.; Jia, J.; Wang, X. Spatiotemporal Variation in Mature Source Rocks Linked to the Generation of Various Hydrocarbons in the Fuxin Basin, Northeast China. Energies 2024, 17, 5654. https://doi.org/10.3390/en17225654

AMA Style

Su X, Jia J, Wang X. Spatiotemporal Variation in Mature Source Rocks Linked to the Generation of Various Hydrocarbons in the Fuxin Basin, Northeast China. Energies. 2024; 17(22):5654. https://doi.org/10.3390/en17225654

Chicago/Turabian Style

Su, Xin, Jianliang Jia, and Xiaoming Wang. 2024. "Spatiotemporal Variation in Mature Source Rocks Linked to the Generation of Various Hydrocarbons in the Fuxin Basin, Northeast China" Energies 17, no. 22: 5654. https://doi.org/10.3390/en17225654

APA Style

Su, X., Jia, J., & Wang, X. (2024). Spatiotemporal Variation in Mature Source Rocks Linked to the Generation of Various Hydrocarbons in the Fuxin Basin, Northeast China. Energies, 17(22), 5654. https://doi.org/10.3390/en17225654

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