scholarly journals Distribution and controls of petroliferous plays in subtle traps within a Paleogene lacustrine sequence stratigraphic framework, Dongying Depression, Bohai Bay Basin, Eastern China

2019 ◽  
Vol 17 (1) ◽  
pp. 1-22 ◽  
Author(s):  
Ji-Chang Zhu ◽  
Cai-Neng Zou ◽  
You-Liang Feng ◽  
Shu Jiang ◽  
Wei-An Wu ◽  
...  
Keyword(s):  
Eastern China ◽  
Source Rocks ◽  
Normal Faults ◽  
Dynamic Factor ◽  
Bohai Bay ◽  
Sequence Stratigraphic ◽  
Dongying Depression ◽  
Stratigraphic Framework ◽  
Incised Channel ◽  
Sand Bodies

AbstractThe characteristics of petroliferous plays in subtle traps within a sequence stratigraphic framework in the Dongying Depression are investigated in this study. Sand bodies within lowstand systems tracts (LSTs) of sequences, comprising incised-channel fills, sublacustrine fans, deltas in LSTs, controlled by syndepositional normal faults, and sand bodies within transgressive systems tracts (TSTs) to early highstand systems tracts (HSTs), consisting of beach bars, and turbidites, controlled by the prodelta slope, paleorelief, and syndepositional normal faults, are good subtle reservoirs. Mudstones and shale of deep lake subfacies in TSTs to early HSTs of sequences are source and cap rocks. Abnormal overpressure is the dominant dynamic factor for hydrocarbon migration from source rock to the subtle traps. Normal faults, sand bodies, and unconformities function as conduit systems. Sand bodies distributed in the abnormal overpressure source rocks within LSTs to early HSTs are petroliferous plays in lithologic traps. The petroliferous plays in stratigraphic traps are controlled by unconformities at margins of the Depression.

scholarly journals Thermal Maturation Regime Revisited in the Dongying Depression, Bohai Bay Basin, East China

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Haiping Huang ◽  
Hong Zhang ◽  
Zheng Li ◽  
Mei Liu
Keyword(s):  
Organic Geochemistry ◽  
Vitrinite Reflectance ◽  
Source Rocks ◽  
East China ◽  
Burial Depth ◽  
Bohai Bay ◽  
Hydrocarbon Generation ◽  
Bohai Bay Basin ◽  
Dongying Depression ◽  
Hydrocarbon Maturation

To the accurate reconstruction of the hydrocarbon generation history in the Dongying Depression, Bohai Bay Basin, East China, core samples of the Eocene Shahejie Formation from 3 shale oil boreholes were analyzed using organic petrology and organic geochemistry methods. The shales are enriched in organic matter with good to excellent hydrocarbon generation potential. The maturity indicated by measured vitrinite reflectance (%Ro) falls in the range of 0.5–0.9% and increases with burial depth in each well. Changes in biomarker and aromatic hydrocarbon isomer distributions and biomarker concentrations are also unequivocally correlated with the thermal maturity of the source rocks. Maturity/depth relationships for hopanes, steranes, and aromatic hydrocarbons, constructed from core data indicate different well locations, have different thermal regimes. A systematic variability of maturity with geographical position along the depression has been illustrated, which is a dependence on the distance to the Tanlu Fault. Higher thermal gradient at the southern side of the Dongying Depression results in the same maturity level at shallower depth compared to the northern side. The significant regional thermal regime change from south to north in the Dongying Depression may exert an important impact on the timing of hydrocarbon maturation and expulsion at different locations. Different exploration strategies should be employed accordingly.

Hydrocarbon generation and evolution of the source rocks of the lower Es3 and upper Es4 members of the Shahejie Formation in the Niuzhuang Sub-sag, Jiyang Depression, Bohai Bay Basin, eastern China

2018 ◽  
Vol 6 (4) ◽  
pp. SN11-SN21
Author(s):  
Zhenkai Huang ◽  
Maowen Li ◽  
Quanyou Liu ◽  
Xiaomin Xie ◽  
Peng Liu ◽  
...  
Keyword(s):  
Activation Energy ◽  
Eastern China ◽  
Source Rocks ◽  
Bohai Bay ◽  
Hydrocarbon Generation ◽  
Bohai Bay Basin ◽  
Jiyang Depression ◽  
Generation Threshold ◽  
Oil Generation ◽  
Shahejie Formation

Systematic organic petrology and geochemistry analyses have been conducted in the source rocks of the lower Es3 and upper Es4 members of the Shahejie Formation in the Niuzhuang Sub-sag, Jiyang Depression, Bohai Bay Basin, eastern China. The results indicate that the main organic types of shale and nongypsum mudstone in the lower Es3 and upper Es4 member are I-II1 kerogen, and the predominant ([Formula: see text]) activation energy frequencies range from 57 to [Formula: see text]. The similar distribution characteristics in the two source rocks indicate that they have a similar hydrocarbon maturation process. An extensive pyrolysis analysis indicates that the source rocks of the upper Es4 member do not have an obvious double peak hydrocarbon generation model. Previous studies indicate that the hydrocarbon index peak at a depth of 2500–2700 m is affected by migrating hydrocarbon. Major differences are not observed in the hydrocarbon generation and evolution process of the shale and nongypsum mudstone. The primary oil generation threshold of the lower Es3 and upper Es4 members is approximately 3200 m, and the oil generation peak is approximately 3500 m. The activation energy distribution of the gypsum mudstone of the upper Es4 member is wider than that of the shale and nongypsum mudstone, and lower activation energies account for a larger proportion of the activation energies. The above factors may lead to a shallower oil generation threshold for gypsum mudstone compared with that for shale and nongypsum mudstone.

An integrated organic–inorganic geochemical characterization of Paleogene sediments in No.1 Structural Belt of the Nanpu Sag, Bohai Bay Basin, eastern China: implications for the origin of organic matter

2020 ◽  
Vol 21 (1) ◽  
pp. geochem2019-060
Author(s):  
Yu Guo ◽  
Wenzhe Gang ◽  
Gang Gao ◽  
Shangru Yang ◽  
Chong Jiang ◽  
...  
Keyword(s):  
Organic Matter ◽  
Higher Plants ◽  
Eastern China ◽  
Source Rocks ◽  
Bohai Bay ◽  
Type Ii ◽  
Lacustrine Environment ◽  
Anoxic Conditions ◽  
Supplementary Material ◽  
Nanpu Sag

Paleogene sediments, especially the third member of the Dongying Formation (Ed3) and the first and third members of the Shahejie Formation (Es1 and Es3), have been regarded as the most important source rocks in the Nanpu Sag. Organic and inorganic analyses, including Rock-Eval pyrolysis, gas chromatography-mass spectrometry, and element geochemistry, in 91 mudstone samples, were used to reconstruct the palaeoenvironmental conditions, such as palaeoclimate, palaeo-salinity and palaeo-redox conditions, and to recognize the origin of organic matter. The results show that Es3 has a higher TOC content than Es1 and Ed3. Hydrocarbon genetic potential (S1 + S2) of the samples indicate fair to good hydrocarbon potential. The kerogen type of Ed3 and Es1 source rocks are Type II1–II2, while Es3 source rocks are dominated by Type II2–III kerogens. Biomarkers and inorganic geochemical indicatives of source rocks, such as Pr/Ph, V/(V + Ni) and Cu/Zn, indicate a lacustrine environment with fresh to brackish water under suboxic to anoxic conditions during deposition. Ed3 source rocks are characterized by low G/C30H (gamacerane/C30hopane) (<0.1), TT/C30H (tricyclic terpane/C30hopane) and S/H (serane/hopane), high Pr/Ph (pristane/phytane) and C24TeT/C23TT (C24tetracyclic terpane/C23tricyclic terpane), indicating mixed input of both algae and terrestrial higher plants, dominated by terrestrial higher plants. Es1 source rocks display medium G/C30H, TT/C30H, S/H, Pr/Ph and C24TeT/C23TT, indicative of a mixed input of both algae and terrestrial higher plants. Es3 source rocks are characterized by high G/C30H (>0.1), TT/C30H and S/H, low Pr/Ph and C24TeT/C23TT, typical of a mixed input of algae and terrestrial higher plants, with algal dominance. Ed3, Es1 and Es3 source rocks were mostly deposited in semi-arid to humid-warm climate conditions, with an average temperature higher than 15°C. This study suggests that suitable temperatures, a fresh to brackish lacustrine environment and suboxic to anoxic conditions could result in a high organic matter concentration and preservation, thus providing prerequisites for the formation of high-quality source rocks.Supplementary material: Tables S1–S3 are available at https://doi.org/10.6084/m9.figshare.c.5227684

scholarly journals Controls on Reservoirs Quality of the Upper Jurassic Mengyin Formation Sandstones in Dongying Depression, Bohai Bay Basin, Eastern China

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 646 ◽  
Author(s):  
Shaochun Yang ◽  
Ya Wang ◽  
Shiqi Zhang ◽  
Yongchao Wang ◽  
Yifan Zhang ◽  
...  
Keyword(s):  
Thin Section ◽  
Thermal History ◽  
Eastern China ◽  
Upper Jurassic ◽  
Reservoir Quality ◽  
Burial Depth ◽  
Bohai Bay ◽  
Bohai Bay Basin ◽  
Reservoir Rocks ◽  
Dongying Depression

The Upper Jurassic Mengyin Formation sandstones are important targets for petroleum exploration in Dongying Depression of Bohai Bay Basin, Eastern China. Although the current burial depth of the Upper Jurassic Mengyin Formation sandstones is shallow (900–2500 m), the reservoir rocks are characterized by low porosity and low permeability due to the complex diagenetic modifications after deposition. Experimental tests and statistical methods, such as thin section, scanning electron microscopy (SEM), cathodoluminescence (CL), high pressure mercury injection (HPMI) and fluid inclusion analysis are conducted to delineate the mineralogical, petrographic and petro-physical characteristics. Results show that physical and chemical processes, including burial depth, burial and thermal history and pore fluid evolution, are both important for the diagenetic modifications that result in a variety changes in pore system and reservoir quality. According to numerical simulation of porosity evolution during lengthy burial and thermal history, porosity loss due to the early deep burial process under the high paleo-geothermal gradient can reach about 20%. Moreover, the burial history (effective stress and temperature) has a better guidance to reservoir quality prediction compared with current burial depth. The extensive compaction in sandstones also resulted in extremely low pore fluid flow during subsequent diagenetic processes, thus, the reaction products of dissolution cannot be removed, which would be precipitated as carbonate cements during stable reburial phase. Dissolution resulted from uncomformity-related meteoric flushing have been the most important porosity-enhancing factor in Mengyin Formation sandstones in spite of low thin section porosity averaged out to 3.22%. Secondary pores derived from dissolution of unstable silicates are more likely to develop in sandstones near the regional unconformity. The oil source fault activities may enhance the heterogeneity of reservoir rocks and control the reservoir quality by inducing micro-fractures and providing the main pathways for hydrocarbon migration.

Biomarker Molecular Indicators Predict Biodegraded Heavy Oil Physical Properties: A Case from Dongying Depression, Eastern China

2012 ◽  
Vol 524-527 ◽  
pp. 2069-2073
Author(s):  
Zhong Hong Chen
Keyword(s):  
Physical Properties ◽  
Eastern China ◽  
Bohai Bay ◽  
Thermal Maturity ◽  
Dongying Depression ◽  
Wide Range ◽  
Biodegraded Oils ◽  
Tricyclic Terpanes ◽  
Molecular Indicators ◽  
Maturity Parameters

To determine reliable molecular thermal maturity parameters for prediction of the physical properties of biodegraded oils, a suite of oils including 11 biodegraded oils from Caoqiao oilfield and 5 non-biodegraded oils from Wangjiagang oilfield in Dongying depression in Bohai-bay basin, eastern of China were analyzed. The oils were selected in a wide range of viscosity in order to investigate the relation between the parameters and oil properties. The data show the effects of biodegradation on some molecular thermal maturity parameters: C29 sterane parameters C2920S/(20S+20R) and C29ββ/(ββ+αα) increased apparently under heavy biodegradation (rank 6~7); parameters C3122S/(22S+22R), C3222S/(22S+22R), C293-methyl/C29 4-methyl, (C28+C29Tricyclics)/Ts and (C28+C29Tricyclics)/ (C28+C29Tricyclics +Ts) showed effects from heavy biodegradation (rank 6~7), and terpanes parameters Ts/(Ts+Tm), C29Ts/(C29Ts+C29Tm) and aromatic C20/(C28+C20), (C20+C21)/(C20+C21+C26+C27+C28) and D(3-6)/(D3-6+ C29 4-methylstigmastane 20R showed no effect from heavy biodegradation. Based on the comparison, the molecular maturity parameters C26 to C28 triaromatic parameters C26S/ (C26S+C28S), C27R/(C27R+C28R), C28/(C26+C27+C28) and tricyclic terpanes parameters C19/(C19+C23) were recommended to predict the physical properties of biodegraded oil for these parameters showed no effects from biodegradation(rank 6~7) and better relations with oil physical properties compared to other parameters. Some quantificational equations between these molecular thermal maturity parameters and the physical properties of biodegraded oils were inferred, which may assist in predicting the viscosity and API gravity of reservoired oils before production.

Researches on Sequences Stratigraphy of Neogene in Huanghekou Sag, Bohai Bay Basin, China

2013 ◽  
Vol 734-737 ◽  
pp. 507-510
Author(s):  
Yong Tao Ju ◽  
Hao Liu ◽  
Chun Chen Zhao ◽  
Tao Guo
Keyword(s):  
Current Data ◽  
Petroleum Exploration ◽  
Bohai Bay ◽  
Bohai Bay Basin ◽  
Southeastern Part ◽  
Sequence Stratigraphic ◽  
Stratigraphic Framework ◽  
Sand Body ◽  
Geologic Setting ◽  
Set Up

The Huanghekou Sag, as an important oil-bearing zone, is located in the southeastern part of the Bohai Bay basin. It has higher values for petroleum exploration-especially in Neogene. The Neogene was a depressional lacustrine period and was characterized with both tectonically stable and gentle topography. Thus it is difficult to identify and subdivide sequences using the traditional method. Based on the practical geologic setting and current data of the Neogene of Huanghekou Sag, using the new method to set up the isochronous sequence stratigraphic framework. By analyzing climate cycle, drilling well and logging cycle, seismic cycle and the identification of unconformity of seismic and drilling well and logging data, the Neogene was divided into 5 third-order sequences and 10 systems tracts. In different sequence sets and systems tract, which was controlled by climate, ratio rate between sedimentary being supplied and accommodated, the sand body scale was different.

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