Oil-source correlation study of the Paleogene red beds in the Boxing sag of the Dongying depression, eastern China

 

Estudio de correlación del origen del petróleo en lechos rojos del Paleógeno en la cuenca intracratónica de la depresión Dongying, oriente de China

 

Ying Wang^1,2, Luofu Liu^1,2*, Jianghui Meng^1,2, Zhenxue Jiang^1,2, Yongjin Gao³ and Shuhui Liu³

 

¹State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum (Beijing), Beijing 102249, China.

²Basin and Reservoir Research Center, China University of Petroleum (Beijing), Beijing 102249, China. ^*liulf@cup.edu.cn

³Research Institute of Geological Science, Shengli Oilfield Company Limited, Dongying Shandong 257015, China.

 

Manuscript received: December 19, 2011
Corrected manuscript received: June 11, 2012
Manuscript accepted: September 4, 2012

 

ABSTRACT

We present a correlation study of the oil occurrence in the Paleogene red beds of the Boxing sag of the Dongying depression, eastern China. The reservoir includes the lower 4^th Member of the Shahejie Formation (Es₄¹) and 1^st Member of the Kongdian Formation (Ek₁). Sixteen source rock samples and 17 oil sand samples from the Boxing sag were collected and the biomarkers were analyzed to perform oil-source correlation. The results show that three oil types characterize the petroleum stored in the Paleogene red beds of the Boxing sag. The oil in Es₄¹ is classified as Type A oil and is derived from the Es₃¹ (lower 3^rd Member of the Shahejie Formation) source rock, which was deposited in a freshwater-brackish lacustrine environment. The oil in Ek₁ of the eastern sag (well Bo-8) is originated from the Es₄^u (upper 4^th Member of the Shahejie Formation) source rock, characterized by saline-hypersaline lacustrine environment, and classified as Type B oil. The oil within Ek₁ is a mixture of oil generated from both Es₃¹ and Es₄^u source rocks and classified as Type C oil. The distribution of the different oil types in the Paleogene red beds in the Boxing sag is controlled by faults that connect the source rocks with the reservoir bed, which are here named "oil-source faults". The Paleogene red beds in the footwall blocks of these "oil-source faults" are the most promising oil and gas exploration target.

Key words: source rock, oil-source correlation, red beds, Boxing sag, Dongying depression, China.

 

RESUMEN

Presentamos un estudio de correlación de la presencia de petróleo en los lechos rojos del Paleógeno de la cuenca intracratónica (sag) Boxing en la depresión Dongying, este de China. El yacimiento incluye el cuarto miembro inferior de la Formación Shahejie (Es₄¹) y primer miembro de la Formación Kongdian (Ek₁). Se colectaron 16 muestras de roca fuente y 17 muestras de arena bituminosa de la cuenca Boxing y se analizaron los biomarcadores para establecer la correlación petróleo-fuente. Los resultados muestran que tres tipos de aceites caracterizan el petróleo almacenado en los lechos rojos del Paleógeno de la cuenca Boxing. El aceite en Es₄¹ se clasifica como aceite del Tipo A y se deriva de roca fuente Es₃¹ (tercer miembro inferior de la Formación Shahejie), la cual fue depositada en un ambiente lacustrino de agua dulce-salobre. El aceite en Ek₁ de la porción oriental de la cuenca (pozo Bo-8) se origina de roca fuente Es₄^u (cuarto miembro superior de la Formación Shahejie), caracterizada por un ambiente lacustre salino-hipersalino, y clasificado como aceite del Tipo B. El aceite en Ek₁ es una mezcla del aceite generado de las roca fuente Es₃¹ and Es₄^u y se clasifica como aceite del Tipo C. La distribución de los diferentes tipos de aceite en los lechos rojos del Paleógeno en la cuenca Boxing está controlada por fallas que conectan las rocas fuente con los lechos que conforman el yacimiento, las cuales son llamadas en este trabajo "fallas de fuente de aceite". Los lechos rojos del Paleógeno en los bloques de piso de esas "fallas de fuente de aceite" son los blancos de exploración de aceite y gas más prometedores.

Palabras clave: roca fuente, correlación aceite-fuente, lechos rojos, cuenca intracratónica Boxing, depresión Dongying, China.

 

INTRODUCTION

The Dongying Depression is located in the south of the Bohai Bay basin (Figure 1) and has the most abundant oil and gas resources in the eastern China (Sun et al., 2006; Qiu et al., 2010). In the last 40 years, the petroleum exploration of the Dongying depression has been focused on the shallow Eocene Shahejie Formation. However, with the decreasing exploitation potential of former strata, the Paleogene red beds becomes the potential reservoir bed in the Dongying depression, where several wells with commercial oil production have been drilled since 2008.

The Paleogene red beds in the Dongying depression refers to the local deep Eocene strata -lower 4^th Member of the Shahejie Formation (Es₄¹) and 1^st Member of the Kongdian Formation (Ek₁). They consist of a series of continental clastic strata that show red color due to the oxidizing depositional environment. Since this is a new petroleum exploration target, the study on the source of the oil stored in the Paleogene red beds (red-bed oil) can directly help to understand the oil and gas accumulation pattern, as well as to understand the distribution of potential oil reservoirs in the Dongying depression.

Many earlier studies (Li et al., 2003, 2005, 2010; Zhang et al., 2003a, 2003b; Zhu and Jin, 2003; Zhang et al., 2004; Zhu et al., 2004, 2005; Pang et al., 2005; Liu, et al., 2006; Wang, et al., 2008; Meng et al, 2010, 2011) have demonstrated that there are two main source rocks in the Dongying depression: the lower 3^rd and the upper 4^th Members of the Eocene Shahejie Formation (Es₃¹ and Es4^u), respectively, and that oils from the Dongying depression are all associated to these two source rocks. However, scarce research has been conducted on the source of the red-bed oil in the Dongying depression, especially in the Boxing sag, a fact that hinder oil and gas exploration. As one of the main sags in the Dongying depression, the Boxing sag was chosen as a case to study the source of Paleogene red-bed oil in the Dongying depression by means of oil-source correlation according to biomarker signatures.

 

GEOLOGICAL SETTING

The Boxing sag is located in the southwestern portion of the Dongying depression, in the southern Bohai Bay basin, eastern China (Figure 1). According to the seismic and logging data, the study area is divided into four step-fault zones by three main normal faults with east-west strike, which were active at the time the Paleogene strata were deposited, namely Gaoqing-Pingnan, Gao89 and Jin32-Boxing faults, and the major part of Boxing sag is to the south of the Gaoqing-Pingnan fault (Figure 1). The Paleogene strata in the Boxing sag are represented from bottom to top by the Kongdian, Shahejie and Dongying formations (Figure 2). There are four source rocks in the Boxing area, namely Es₁ (1^st Member of the Shahejie Formation), Es₃^m (middle 3^rd Member of the Shahejie Formation), Es₃,¹ and Es₄^u. The two main source rocks are Es₃¹ and Es₄^u shale, most of which were deposited in a semi-deep to deep lacustrine basin and the rest in a shallow lacustrine basin (Rong and Wang, 2004; Yang and Chen, 2004; Su et al, 2005; Xu and Wu, 2011). The Paleogene red beds (Es₄¹ and Ek₁) are the favorable as well as the potential reservoir bed. Two regionally extensive units represent the cap rock: the thick Ed₃-Es₁ (3^rd Member of the Dongying Formation and 1^st Member of the Shahejie Formation) and the Es₃¹-Es₄^u dark mudstone. The study on the source of Paleogene red-bed oil in the Boxing sag has important geological significance for further oil and gas exploration in the Boxing area.

 

SAMPLES AND EXPERIMENTAL METHODS

In this research, 16 source rock samples and 13 oil sand samples were collected from Es₃¹, Es₄^u, Es₄¹ and Ek₁ in the Boxing sag of the Dongying depression. Sampled wells are representative for the whole study area (Figure 1).

The oils were extracted from oil sand samples with chloroform (CHCl₃) for 24 hours under room temperature and the soluble organic matter were extracted from powdered source rock samples with chloroform in a Soxhlet apparatus for 72 hours. After solvent removal by rotary evaporation, the oils or rock extracts were further treated with chloroform for 12 hours under room temperature to precipitate asphaltenes. The filtrates were subsequently fractionated by using column chromatography (silica gel/ alumina, 3:1) into saturated and aromatic hydrocarbons, and non-hydrocarbons. The used elution solvents were hexane, dichloromethane-hexane (7:3) and chloroform-methanol (1:1), sequentially (Wang et al., 2010). The saturated hydrocarbons of oils or rock extracts were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS).

Gas chromatography (GC) analysis was performed on an Agilent 6890N equipped with a 30 m x 0.25 mm x 0.25 um HP-5 fused silica capillary column and the carrier gas was He at a constant flow of 1.0 mLmin^-1. The GC oven was programmed and the temperature was kept at 100 °C for 1 minute, then rose to 300 °C at a rate of 4 °Cmin^-1 and held at 300 °C for 25 minutes. The temperature of injector and flame ionization detector (FID) was 300 °C.

Gas chromatography-mass spectrometry (GC-MS) analysis was performed on an Agilent 6890GC/5975iMS equipped with a 60 m x 0.25 mm x 0.25 um HP-5MS fused silica capillary column and the flow of carrier gas (He) was at a constant rate of 1.0 mLmin^-1. The GC oven was programmed to be hold at 50 °C for 1 minute, then rose to 120 °C at a rate of 20 °Cmin^-1 and continued to rise to 310 °C at a rate of 3 °Cmin^-1, finally held at 310 °C for 25 minutes. The mass spectrometer was operated in both full scan and selected ion monitoring (SIM) modes with a ionization energy of 70 eV

 

BIOMARKER SIGNATURES AND DEPOSITIONAL ENVIRONMENT OF SOURCE ROCKS IN THE BOXING SAG

The signatures of biomarkers of 16 samples from Es₃¹ and Es₄^u source rocks are summarized in Table 1 and Figure 3 and are described in the following section.

 

Es₃¹ source rock

The n-alkanes show Gaussian distribution or weak double peak pattern and the peak is between n-C₂₂-n-C₂₅, carbon preference index (CPI) is 1.01-1.15 (Table 1). For example, the sample from well Fan-118 shows weak double peak pattern and n-C₂₂ as the peak of n-alkanes (Figure 3a). The concentration of pristane is higher than that of phytane (Pr/Ph > 1), Pr/n-C₁₇ is lower than 0.63 and Ph/n-C₁₈ is lower than 0.6 (Table 1, Figure 3a).

Concentrations of tricyclic terpanes and gammacerane are very low, with tricyclic terpanes/17 α-hopanes lower than 0.07 and gammacerane/C₃₁ homohopane lower than 0.20 (Table 1, Figure 3b). The C₃₅ homohopane index is between 5.42% and 7.15% (Table 1).

The ααα-20R C₂₇/C₂₉ sterane is 0.72-1.41, ααα20R C₂₈ sterane shows lower concentration than that of ααα-20R C₂₇ and C₂₉ steranes, and the concentration 4-methly steranes is very high (Table 1, Figure 3c).

 

Es₄^u source rock

The Es₄^u source rock can be subdivided into two types according to the relative distribution of n-alkanes (Table 1, Figure 3a): Type 1 Es₄^u source rock extracts show Gaussian distribution centered between n-C₂₃-n-C₂₅ (e.g., well Gao-891, peak of w-alkanes is n-C₂₃); Type 2 Es₄^u source rock extracts show double peak pattern, namely n-C₁₄-n-C₁₈ or n-C₂₀-n-C₂₅ (e.g., well Gao-351, peak of w-alkanes is n-C₁₄).

The CPI is higher than 1 except for three samples (CPI = 0.78-1.32; Table 1). Pr/Ph is lower than 1 except for one sample, Pr/n-C₁₇ is higher than 1 except for one sample, and Ph/n-C₁₈ is higher 1.52 (Table 1, Figure 3a).

Concentration of tricyclic terpanes and gammacerane are higher than those of Es₃¹ source rock samples (tricyclic terpanes/17α-hopanes = 0.05-0.79, gammacerane/C₃₁ homohopane = 0.37-8.1). The C₃₅ homohopane index is between 3.50% and 21.41%, half of which is bigger than that of the Es₃¹ source rock samples (Table 1, Figure 3b).

Like the Es₃¹ source rock samples, aaa-20R C₂₈ sterane of Es4^u source rock samples also shows obviously lower concentration compared to that of aaa-20R C₂₇ and C₂₉ steranes, and the ratio of aaa-20R C₂₇/C₂₉ sterane is lower than 1 except for two samples (0.29~1.41). Unlike to the Es₃¹ source rock samples, the concentration of 4-methly steranes of Es₄^u source rock samples is very low (Table 1, Figure 3c).

 

Depositional environments of Es₃¹ and Es₄^u source rocks

Previous studies indicated that the main source rocks of the Boxing sag are Es₃¹ (fresh-brackish or brackish lake) and Es₄^u (brackish-saline or saline lake) shales (Yang and Chen, 2004; Su et al., 2005; Han et al., 2007). However, these studies were based on few samples and their conclusions about the depositional environments of the two source rocks in the Boxing sag were essentially deduced from more general studies of the Dongying depression (e.g., Zhu and Jin, 2003; Zhu et al, 2004, 2005). Thus, based on the biomarker signatures obtained in this work, the depositional environments of these two source rocks can be refined.

The Es₃¹ source rock has biomarker signatures characterized by a dominance of pristane (Pr/Ph > 1), very low concentrations of tricyclic terpanes and gammacerane, and higher concentration of 4-methly steranes, which indicates that it was deposited in a freshwater-brackish lacustrine environment (Philp et al. 1989; Wang 1990; Fu et al. 1990, 1991).

The Es₄^u source rock has a clear phytane (Pr/Ph < 1 and Ph/n-C₁₈ > 1.52) and gammacerane predominance, higher tricyclic terpanes/17a-hopanes ratio, moderately higher C35 homohopane index, and very low concentration of 4-methly steranes, indicating that it was deposited in a saline-hypersaline lacustrine environment (Philp et al. 1989; Wang 1990; Fu et al. 1990, 1991; Zhang et al. 1998).

Besides, concentration of diasteranes (0.01-0.06) and C₂₉ sterane 20S/(20S+20R) value (0.11-0.39) of the Type 2 Es₄^u source rock samples are much lower than those of the Es₃¹ source rock samples (0.08-0.23 and 0.30-0.41, respectively; Table 1). Concentration of diasteranes and C₂₉ sterane 20S/(20S+20R) parameter increases with increasing thermal maturity (Seifert and Moldowan, 1978, 1986, respectively). Therefore, these biomarker parameters indicate that Type 2 Es₄^u source rock samples have lower thermal maturity than the Es3^l source rock samples. This is because the Type 2 Es₄^u source rock samples (except the well Liang-216) have shallower burial depth (2153.30 m-2684.80 m) than that of the Es₃¹ source rock samples (2851.85 m - 3032.20 m; Table 1) and the thermal maturity parameter (Ro) of source rock samples from the Dongying depression has a positive relation to the burial depth. Although there are many faults that affect the original burial depth of these samples, these are syn-sedimentary faults, which have not changed the relative burial relationship of these samples.

 

BIOMARKER SIGNATURES AND CLASSIFICATION OF RED-BED OIL IN THE BOXING SAG

In addition to source rocks, we studied 17 oil sand samples from 12 wells in the Boxing sag. Four samples from wells Bin-169, Liang-120, Chun-26 and Jin-32 only have gas and mass chromatograms but no specific data about concentration of each biomarker could be collected (Table 2, Figure 1). Biomarker signatures of the oil sand samples are summarized and shown in Table 2 and Figures 4 and 5.

The C₃₁ homohopane 22S/(22S+22R) and C29 sterane 20S/(20S+20R) parameters of the oil sand samples are 0.53-0.59 and 0.37-0.52, respectively (Table 2), lower than or reaching the equilibrium values of these two parameters (0.57-0.62, Seifert et al, 1980, and 0.52-0.55, Seifert and Moldowan, 1986, respectively). These two parameters increase with increasing thermal maturity and the equilibrium values indicate that the main phase of oil generation has been reached or exceeded (Peters et al., 2005), which corresponds to the low thermal maturity of the local source rocks (R_o= 0.5% - 0.8%).

On the basis of the combined biomarkers characteristics of these oil sand samples, the red-bed oil in the Boxing sag can be divided into three types.

 

Type A oil

This oil type has n-alkanes with a Gaussian distribution with a n-C₂₂-n-C₂₅ peak, CPI is 1.01-1.10; Pr/Ph is 0.55-0.89, Pr/w-C₁₇ is 0.48-0.93 and Ph/w-C₁₈ is 0.39-0.77 (Table 2, Figure 4a). The concentrations of tricyclic ter-panes and gammacerane are low (tricyclic terpanes/17α-hopanes = 0.08-0.24, gammacerane/C₃₁ homohopane = 0.14-0.27), and the C₃₅ homohopane index is low (2.88%-5.65%) (Table 2, Figure 4b). The ααα-20R C27/C29 sterane is 0.79-0.94, ααα-20R C₂₈ sterane shows notable lower concentration than that of aaa-20R C₂₇ and C₂₉ steranes, and diasteranes and 4-methly steranes concentrations are very high (Table 2, Figure 4c).

Type B Oil

This oil type is only found in well Bo-8. The n-alkanes display a double peak pattern with n-C₁₆ as the main peak, CPI is 1.17; Pr/Ph is 0.71, Pr/w-C₁₇ is 0.98 and Ph/n-C₁₈ is 1.55 (Table 2, Figure 4a). The concentration of gam-macerane and the C₃₅ homohopane index are very high (gammacerane/C₃₁ homohopane = 1.66, C₃₅ homohopane index is 12.42%), tricyclic terpanes/17a-hopanes is 0.12 (Table 2, Figure 4b). The ααα-20R C27/C29 sterane is 1.22, ααα-20R C₂₈ sterane shows a significant lower concentration than that of ααα-20R C₂₇ and C₂₉ steranes (Table 2, Figure 4c). Diasteranes show less concentration than that of Type A oil, and 4-methly steranes are present in low concentration (Figure 4c).

Type C oil

In this oil type, the w-alkanes show a weak double peak pattern: sample from well Gao-891 plot mainly in the right part with n-C₂₅ as the main peak (Figure 4a), whereas the sample from well Bin-425 plot mostly in the left part with n-C₁₆ as the main peak (Table 2, Figure 4a). CPI is 0.93-1.45, Pr/Ph is 0.93-1.45, Pr/n-C₁₇ is 0.52-1.54 and Ph/n-C₁₈ is 0.69-1.01 (Table 2). Tricyclic terpanes/17α-hopanes is 0.14-0.85, gammacerane/C₃₁ homohopanes is 0.28-1.03, C₃₅ homohopane index is 5.18% - 6.94% (Table 2, Figure 4b). The aaa-20R C₂₇/C₂₉ sterane is 0.68-1.04 (Table 2), ααα-20R C₂₈ sterane shows a lower concentration than that of ααα-20R C₂₇ and C₂₉ steranes, and a medium concentration of diasteranes and 4-methly steranes (Table 2, Figure 4c). In summary, the values of biomarker parameters of Type C oil are intermediate between those of Type A and Type B oils (Table 2).

Four of the biomarker parameters, namely Pr/Ph, gam-macerane/C₃₁ homohopane, tricyclic terpanes/17α-hopanes and C35 homohopane index, are very useful to study the re-dox conditions and salinity of lacustrine environments, and were chosen to illustrate the classification of the Paleogene red-bed oil in the Boxing sag (Figure 5). In the biomarker scatter plots of Figure 5, the three types of red-bed oil can be clearly distinguished.

 

DISCUSSION

Type A oil includes the samples listed in Table 2 and the sample from well Bin-169 shown in Figure 6. Due to the common biomarker signatures, such as pristane predominance (Pr/Ph > 1), very low concentrations of tricyclic terpanes and gammacerane, relatively low C₃₅ homohopane index, and high concentrations of diasteranes and 4-methly steranes, we consider that Type A oil (e.g., sample from well Fan-143, 3115.20 m) is derived from Es₃¹ source rock (e.g., sample from well Fan-118, 3032.20 m; Figures 3 and 4).

Only the sample from well Bo-8 is classified as Type B oil. It shows a clear phytane (Pr/Ph < 1, Ph/n-C₁₈ > 1) and gammacerane predominance, relatively higher tricyclic terpanes/17α-hopanes ratio and C35 homohopane index, and very low concentrations of diasteranes and 4-methly steranes. Based on these features we propose that Type B oil (sample from well Bo-8, 2678.80 m) is originated from Type 2 Es₄^u source rock (e.g., sample from well Gao-351, 2440.15 m; Figures 3 and 4).

Type C oil includes the samples listed in Table 2 and the samples from wells Liang-120, Chun-26 and Jin-32 shown in Figure 6. All the biomarker parameters values of Type C oil are between those of Type A and Type B oils, suggesting that it could be a mixed oil generated from both Es₃¹ and Es₄^u source rocks. According to the distribution of w-alkanes, oil sand sample from well Gao-891 (3234.90 m) is a mixed oil generated from Es₃¹ (e.g., sample from well Fan-118, 3032.20 m) and Type 1 Es₄^u (e.g., sample from well Gao-891, 2813.00 m) source rocks (Figures 3 and 4). While the other Type C oils (e.g., sample from well Bin-425, 2769.50 m) are mixed oils generated from Es₃¹ (e.g., sample from well Fan-118, 3032.20 m) and Type 2 Es₄^u (e.g., sample from well Gao-351, 2440.15 m) source rocks (Figures 3 and 4).

Figure 6 shows the distribution of different oil types of the Paleogene red beds in the Boxing sag. The Type A oil occurs within the Es4^l red beds (except for well Liang-902) in the western part of the basin, mostly in the footwall block of the Gaoqing-Pingnan, Gao 89, and Jin 32 normal faults. The Type B oil is within the Ek1 red beds in the eastern part of the basin, and the Type C oil mainly occurs within the Ek1 red beds in the footwall blocks of other normal faults in the basin (Figure 6).

The results of our oil-source correlation indicate that the red-bed oil essentially move from the source rocks to the overlying strata along the faults. In fact, the red-bed reservoirs are in the footwall blocks and the source rocks in the hangingwall blocks, indicating that the main normal faults of the basin are providing the connection between the two. All found oilfields and collected oil sand samples occur along the faults and mostly in the uplifted blocks. Therefore, the distribution of the Paleogene red-bed oil in the Boxing sag is controlled by these "oil-source faults" and the Paleogene red beds in the footwall blocks are the most promising oil and gas exploration target of the area.

 

CONCLUSIONS

There are two main source rocks in the Boxing sag: Es₃¹ source rock deposited in a freshwater-brackish lacustrine environment and Es4^u source rock deposited in a saline-hypersaline lacustrine environment.

The oil stored in Paleogene red beds of the Boxing sag can be divided into three types: the oil in Es4^l in the western part of the basin is classified as Type A oil, the oil in Ek₁ in the eastern part of the basin (well Bo-8) is classified as Type B oil, and the oil in Ek1 in other places in the basin is classified as Type C oil.

The results of oil-source correlation indicates that Type A oil is derived from the Es₃¹ source rock, Type B oil is originated from the Es₄^u source rock, and Type C oil is a kind of mixed oil generated from both Es₃¹ and Es₄^u source rocks.

Distribution of the Paleogene red-bed oil in the Boxing sag is controlled by "oil-source faults" and the Paleogene red beds in the footwall blocks are the most promising oil and gas exploration target.

 

ACKNOWLEDGEMENTS

Many thanks to the Research Institute of Geological Science, Shengli Oilfield Company Limited, especially Kefeng Wu and Zhiyong Liu for helping with sampling, and Guanghua Jia, Dong Tang, Honglei Sun and Dongxu Wang for providing data for this research.

 

REFERENCES

Fu, J., Sheng, G., Xu, J., Eglinton, G., Gowar, A.P., Jia, R., Fan, S., Peng, P., 1990, Application of biological markers in the assessment of paleoenvironments of Chinese non-marine sediments: Organic Geochemistry 16, 769-779.         [ Links ]

Fu, J., Sheng, G., Xu, J., Jia, R., Fan, S., Peng, P., 1991, Application of biomarker compounds in assessment of paleoenvironments of Chinese terrestrial sediments: Geochimica, 1, 1-12.         [ Links ]

Han, D., Li, Z., Li, S., Xu, C., Long, L., 2007, Geochemical characteristics of Paleogene mudstones in the Boxing sag north of the west Shandong Rise and their tectonic implications (in Chinese with English abstract): Chinese Journal of Geology, 42(4), 678-689.         [ Links ]

Li, S., Li, M., Pang, X., Jin, Z., 2003, Geochemistry of petroleum systems in the Niuzhuang South Slope of Bohai Bay Basin-part 1: source rock characterization: Organic Geochemistry, 34, 389-412.         [ Links ]

Li, S., Pang, X., Qiu, G., Gao, Y., 2005, Origin of the deep oils from Kongdian Formation, Dongying Depression, Bohaibay Basin: Acta Sedimentologica Sinica, 23(4), 726-733.         [ Links ]

Li, S., Pang, X., Jin, Z., Li, M., Liu, K., Jiang, Z., Qiu, G., Gao, Y., 2010, Molecular and isotopic evidence for mixed-source oils in subtle petroleum traps of the Dongying South Slope, Bohai Bay Basin: Marine and Petroleum Geology, 27, 1411-1423.         [ Links ]

Liu, S., Shen, Z., Chen, Y., Wang, W., Liu, Q., 2006, Geochemistry characteristics of the oil source in Kongdian Formation in Dongying Depression, China (in Chinese with English abstract): Journal of Chengdu University of Technology (Science and Technology Edition), 33(4), 402-406.         [ Links ]

Meng, J., Liu, L., Jiang, Z., Gao, Y., 2010, Characteristics and origin classification of the oils from the lower member of the 4th section of Shahejie Formation and Kongdian Formation in the southern slope of Dongying depression, Bohai Bay Basin (in Chinese with English abstract): Geosciences, 24(6), 1085-1092.         [ Links ]

Meng, J., Liu, L., Jiang, Z., Wang, Y., Gao, Y., Liu, S., 2011, Geochemical characteristics of crude oil and oil-source correlation of the Paleogene "Red Bed" in the South Slope of the Dongying Depression, Bohai Bay Basin, China: Energy Exploration and Exploitation, 29(4), 397-413.         [ Links ]

Pang, X., Li, M., Li, S., Jin, Z., 2005, Geochemistry of petroleum systems in the Niuzhuang South Slope of Bohai Bay Basin-part 3 : estimating hydrocarbon expulsion from the Shahejie formation: Organic Geochemistry, 36, 497-510.         [ Links ]

Peters, K.E., Walters, C.C., Moldowan, J.M., 2005, The Biomarker Guide (Second Edition), v. 2, Biomarkers and Isotopes in Petroleum Exploration and Earth History: Cambridge, Cambridge University Press, 613-614.         [ Links ]

Philp, R.P., Li, J., Lewis, C.A., 1989, An organic geochemical investigation of crude oils from Shanganning, Jianghan, Chaidamu and Zhungeer basins, People's Republic of China: Organic Geochemistry 14, 447-460.         [ Links ]

Qiu, N., Zuo, Y., Zhou, X., Li, C., 2010, Geothermal regime of the Bohai Offshore Area, Bohai Bay Basin, North China: Energy Exploration & Exploitation, 28(5), 327-350.         [ Links ]

Research Institute of Geological Science, 2000, Cenozoic comprehensive histogram of Dongying Depression: Shengli Oilfield Company Limited (internal project sources).         [ Links ]

Research Institute of Geological Science, 2007, Paleogene strata development and depositional history of Dongying Depression: Shengli Oilfield Company Limited (internal project sources).         [ Links ]

Rong, Q., Wang, G., 2004, Geochemical signature of oil migration in Southeast Boxing Depression, Jiyang, China (in Chinese with English abstract): Journal of Chengdu University of Technology (Science & Technology Edition), 31(5), 517-521.         [ Links ]

Seifert, W.K., Moldowan, J.M., 1978, Applications of steranes, terpanes and monoaromatics to the maturation, migration and source of crude oils: Geochemica et Cosmochimica Acta, 42, 77-95.         [ Links ]

Seifert, W.K., Moldowan, J.M., 1986, Use of biological markers in petroleum exploration, in Johns, R.B. (eds.), Methods in Geochemistry and Geophysics: Amsterdam, Elsevier, 261-290.         [ Links ]

Seifert, W.K., Moldowan, J.M., Jones, R.W., 1980, Application ofbiological marker chemistry to petroleum exploration, in Proceedings of the Tenth World Petroleum Congress, Philadelphia: Philadelphia, Heyden & Son Inc., 425-440.         [ Links ]

Su, Y., Jiang, Y., Lian, Q., Song, J., Shi, S., 2005, Forming mechanism of lithologic reservoir in the upper Es_4 and Es_3 of the Palaeogene in Boxing sag (in Chinese with English abstract): Acta Petrolei Sinica, 26(5), 28-32.         [ Links ]

Sun, J., Zhang, H., Lin, C., 2006, Source rocks and petroleum reservoirs in the Chexi Sunken of the Jiyang Depression, China: Energy Exploration & Exploitation, 24(3), 151-159.         [ Links ]

Wang, G., Wang, T., Simoneit, B.R.T., Zhang, L., Zhang, X., 2010, Sulfur-rich petroleum derived from lacustrine carbonate source rocks in Bohai Bay Basin, East China: Organic Geochemistry, 41, 340-354.         [ Links ]

Wang, J., Song, G., Song, S., Zhao, M., Gao, X., 2008, Geochemical characteristics of the oils in the Kongdian Formation in the southern slope of the Dongying Depression and their source rocks (in Chinese with English abstract): Journal of Jilin University (Earth Science Edition), 38(1), 56-62.         [ Links ]

Wang, T., 1990, A contribution to some sedimentary environmental biomarkers in crude oils and source rocks in China: Geochimica, 3, 256-262.         [ Links ]

Xu, D., Wu, M., 2011, The reservoir forming characteristic and exploration potential analysis of the Red Beds of the lower of Es4 in Boxing subsag (in Chinese with English abstract): Petroleum Geophysics, 9(2), 44-47.         [ Links ]

Yang, C., Chen, J., 2004, Petroleum genetic types and in depth exploration potential in the Boxing subsag (in Chinese with English abstract): Petroleum Geology and Recovery Efficiency, 11(3), 34-36.         [ Links ]

Zhang, L., Kong, X., Zhang, C., Zhou, W., Xu, X., Li, Z., 2003a, High quality oil prone source rocks in Jiyang Depression (in Chinese with English abstract): Geochemica, 32(1), 35-42.         [ Links ]

Zhang, L., Jiang, Y., Liu, H., Tan, L., Zhang, L., 2003b, Relationship between source rock and oil accumulation in Dongying sag: (in Chinese with English abstract) Petroleum Exploration and Development, 30(3), 61-64.         [ Links ]

Zhang, S., Wang, Y., Shi, D., Xu, H., Pang, X., Li, M., 2004, Fault-fracture mesh petroleum plays in the Jiyang Superdepression of the Bohai Bay Basin, eastern China: Marine and Petroleum Geology, 21, 651-668.         [ Links ]

Zhang, Z., Yang, F., Li, D., Fang, C., 1998, Biomarker assemblage characteristics of source rocks and associated crude oil in saline lake facies of Cenozoic in China: Acta Sedimentologica Sinica 16, 119-123.         [ Links ]

Zhu, G., Jin, Q., 2003, Geochemical characteristics of two sets of excellent source rocks in Dongying Depression (in Chinese with English abstract): Acta Sedimentologica Sinica, 21(3), 506-511.         [ Links ]

Zhu, G., Jin, Q., Zhang, S., Dai, J., Zhang, L., Li, J., 2004, Combination characteristics of lake facies source rock in the Shahejie Formation, Dongying Depression (in Chinese with English abstract): Acta Geologica Sinica, 78(3), 416-427.         [ Links ]

Zhu, G., Jin, Q., Zhang, S., Dai, J., Wang, G., Zhang, L., Li J., 2005, Characteristics and origin of deep lake oil shale of the Shahejie Formation of Paleogene in Dongying Depression, Jiyang Depression (in Chinese with English abstract): Journal of Palaeogeography, 7(1), 59-69.         [ Links ]