Oil cracking of deep petroleum in Minfeng sag in north Dongying depression, Bohai Bay basin, China: Evidence from natural fluid inclusions

Abstract

A fluid inclusion fluorescence and microthermometric study was performed on sandstones from the deep Es ₄ reservoir rocks of the Minfeng (民丰) sag, north of Dongying (东营) depression. Two types of oil inclusions (yellow and blue white fluorescence), one type of gas inclusions (blue white fluorescence), and bitumen inclusions (no fluorescence) were detected within quartz and feldspar minerals. The evolution of hydrocarbon fluid inclusions in the lower Es ₄ sequence indicates that present oil accumulation was predominantly thermal stress controlled. Homogenization temperatures of aqueous fluid inclusions coexisting with gas-bearing and bitumen-bearing fluid inclusions indicate that oil cracking occurred at temperatures up to 160 °C, primary condensate or wet gas generation occurred during 170–195 °C. Oil has cracked into condensate or wet gas in the depth of 4 300–4 410 m and dry gas and abundant pyrobitumen in the depth of more than 4 410 m in the geological history based on the fluid inclusion extrapolation. Secondary oil cracking is undergoing in present day when the depth of reservoir is more than 4 150 m whose temperature is the threshold temperature of oil cracking (160 °C). However, because of the consumption of oil in the first oil cracking process, it may have few chances to find liquid petroleum, and only natural gas can be found when the depth of reservoir is more than 4 410 m, where oil cracks into condensate gas or wet gas according to present-day formation temperature. This study is preliminary but foreshadows a new insight into oil cracking using natural fluid inclusions to trace hydrocarbon evolution in sedimentary basins.

Keywords

oil cracking / fluid inclusion / homogenization temperature / fluorescence / bitumen / pyrobitumen / natural gas / Dongying depression

References

Al Darouich T., Behar F., Largeau C.. Thermal Cracking of the Light Aromatic Fraction of Safaniya Crude Oil—Experimental Study and Compositional Modelling of Molecular Classes. Organic Geochemistry, 2006, 37(9): 1130-1154.

Aplin A. C., Macleod G., Larter S. R., . Combined Use of Confocal Laser Scanning Microscopy and PVT Simulation for Estimating the Composition and Physical Properties of Petroleum in Fluid Inclusions. Marine and Petroleum Geology, 1999, 16(2): 97-110.

Barker C.. Thermal Modeling of Petroleum Generation: Theory and Applications, 1996, New York, Amsterdam: Elsevier

Baron M., Parnell J., Mark D., . Evolution of Hydrocarbon Migration Style in a Fractured Reservoir Deduced from Fluid Inclusion Data, Clair Field, West of Shetland, UK. Marine and Petroleum Geology, 2008, 25(2): 153-172.

Behar F., Kressmann S., Rudkiewicz J. L., . Experimental Simulation in a Confined System and Kinetic Modelling of Kerogen and Oil Cracking. Organic Geochemistry, 1992, 19(1–3): 173-189.

Blanc P., Connan J.. Preservation, Degradation, and Destruction of Trapped Oil. AAPG Memoir, 1994, 60: 237-247.

Blanchet A., Pagel M., Walgenwitz F., . Microspectrofluorimetric and Microthermometric Evidence for Variability in Hydrocarbon Fluid Inclusions in Quartz Overgrowths: Implications for Inclusion Trapping in the Alwyn North Field, North Sea. Organic Geochemistry, 2003, 34(11): 1477-1490.

Bourdet J., Pironon J., Levresse G., . Petroleum Accumulation and Leakage in a Deeply Buried Carbonate Reservoir, Níspero Field (Mexico). Marine and Petroleum Geology, 2010, 27(1): 126-142.

Braun R. L., Burnham A. K.. PMOD—A Flexible Model of Oil and Gas Generation, Cracking, and Expulsion. Organic Geochemistry, 1992, 19(1–3): 161-172.

Burruss, R. C., 1981. Hydrocarbon Fluid Inclusions in Studies of Sedimentary Diagenesis. In: Hollister, L. S., Crawford, M. L., eds., Fluid Inclusions: Applications to Petrology. Mineralogical Association of Canada Short Course Notes, 6: 138–156

Burruss, R. C., 2003. Petroleum Fluid Inclusions: An Introduction. In: Samson, I., Anderson, A., Marshall, D., eds., Fluid Inclusions: Analysis and Interpretation. Mineral. Assoc. Can. Short Course Ser., 159–174

Chang Y. J., Huang W. L.. Simulation of the Fluorescence Evolution of “Live” Oils from Kerogens in a Diamond Anvil Cell: Application to Inclusion Oils in Terms of Maturity and Source. Geochimica et Cosmochimica Acta, 2008, 72(15): 3771-3787.

Chen H. H., Ping H. W., Zhao Y. J.. Effects of Oil Inclusion Homogenization Temperatures and Their Geological Meanings. Journal of Geochemical Exploration, 2009, 101 1 25

Dutkiewicz A., Rasmussen B., Buick R.. Oil Preserved in Fluid Inclusions in Archaean Sandstones. Nature, 1998, 395(6705): 885-888.

Dutkiewicz A., Ridley J., Buick R.. Oil-Bearing CO₂-CH₄-H₂O Fluid Inclusions: Oil Survival since the Palaeoproterozoic after High Temperature Entrapment. Chemical Geology, 2003, 194(1–3): 51-79.

Evans C. R., Rogers M. A., Bailey N. J. L.. Evolution and Alteration of Petroleum in Western Canada. Chemical Geology, 1971, 8(3): 147-170.

Feng W. G.. Study on Formation Mode of Splitting Gas of Minfeng Depression. Petroleum Geology and Engineering, 2008, 22(4): 33-35.

George S. C., Llorca S. M., Hamilton P. J.. An Integrated Analytical Approach for Determining the Origin of Solid Bitumens in the McArthur Basin, Northern Australia. Organic Geochemistry, 1994, 21(3–4): 235-248.

George S. C., Volk H., Dutkiewicz A., . Preservation of Hydrocarbons and Biomarkers in Oil Trapped inside Fluid Inclusions for >2 Billion Years. Geochimica et Cosmochimica Acta, 2008, 72(3): 844-870.

Goldstein R. H.. Fluid Inclusions in Sedimentary and Diagenetic Systems. Lithos, 2001, 55(1–4): 159-193.

Goldstein, R. H., Reynolds, T. J., 1994. Systematics of Fluid Inclusions in Diagenetic Minerals. SEPM Short Course 31, Tulsa. 199

Grimmer J. O. W., Pironon J., Teinturier S., . Recognition and Differentiation of Gas Condensates and Other Oil Types Using Microthermometry of Petroleum Inclusions. Journal of Geochemical Exploration, 2003, 78–79: 367-371.

Hagemann H. W., Hollerbach A.. The Fluorescence Behaviour of Crude Oils with Respect to Their Thermal Maturation and Degradation. Organic Geochemistry, 1986, 10(1–3): 473-480.

Hanor J. S.. Dissolved Methane in Sedimentary Brines: Potential Effect on the PVT Properties of Fluid Inclusions. Economic Geology, 1980, 75(4): 603-609.

Helgeson H. C., Richard L., McKenzie W. F., . A Chemical and Thermodynamic Model of Oil Generation in Hydrocarbon Source Rocks. Geochimica et Cosmochimica Acta, 2009, 73(3): 594-695.

Hill R. J., Tang Y. C., Kaplan I. R.. Insights into Oil Cracking Based on Laboratory Experiments. Organic Geochemistry, 2003, 34(12): 1651-1672.

Horsfield B., Schenk H. J., Mills N., . An Investigation of the In-Reservoir Conversion of Oil to Gas: Compositional and Kinetic Findings from Closed-System Programmed-Temperature Pyrolysis. Organic Geochemistry, 1992, 19(1–3): 191-204.

Huang W. L., Otten G. A.. Cracking Kinetics of Crude Oil and Alkanes Determined by Diamond Anvil Cell-Fluorescence Spectroscopy Pyrolysis: Technique Development and Preliminary Results. Organic Geochemistry, 2001, 32(6): 817-830.

Huc A. Y., Nederlof P., Debarre R., . Pyrobitumen Occurrence and Formation in a Cambro-Ordovician Sandstone Reservoir, Fahud Salt Basin, North Oman. Chemical Geology, 2000, 168(1–2): 99-112.

Hwang R. J., Teerman S. C., Carlson R. M.. Geochemical Comparison of Reservoir Solid Bitumens with Diverse Origins. Organic Geochemistry, 1998, 29(1–3): 505-517.

Isaksen G. H.. Central North Sea Hydrocarbon Systems: Generation, Migration, Entrapment, and Thermal Degradation of Oil and Gas. AAPG Bulletin, 2004, 88(11): 1545-1572.

Jacob H.. Classification, Structure, Genesis and Practical Importance of Natural Solid Oil Bitumen (“Migrabitumen”). International Journal of Coal Geology, 1989, 11(1): 65-79.

Khorasani G. K.. Novel Development in Fluorescence Microscopy of Complex Organic Mixtures: Application in Petroleum Geochemistry. Organic Geochemistry, 1987, 11(3): 157-168.

Khorasani G. K., Michelsen J. K.. The Thermal Evolution of Solid Bitumens, Bitumen Reflectance, and Kinetic Modeling of Reflectance—Application in Petroleum and Ore Prospecting. Energy Sources, 1993, 15(2): 181-204.

Kissin Y. V.. Catagenesis and Composition of Petroleum: Origin of n-Alkanes and Isoalkanes in Petroleum Crudes. Geochimica et Cosmochimica Acta, 1987, 51(9): 2445-2457.

Kuo L. C., Eric Michael G.. A Multicomponent Oil-Cracking Kinetics Model for Modeling Preservation and Composition of Reservoired Oils. Organic Geochemistry, 1994, 21(8–9): 911-925.

Landis C. R., Castaño J. R.. Maturation and Bulk Chemical Properties of a Suite of Solid Hydrocarbons. Organic Geochemistry, 1995, 22(1): 137-149.

Li P. L.. Oil/Gas Distribution Patterns in Dongying Depression, Bohai Bay Basin. Journal of Petroleum Science and Engineering, 2004, 41(1–3): 57-66.

Li Y. J., Song G. Q., Li W. T., . A Fossil Oil-Reservoir and Gas Origin in the Lower Sha-4 Member of the Well Fengshen-1 Area, the North Dongying Zone of the Jiyang Depression. Oil and Gas Geology, 2010, 31(2): 173-179.

Luo X., Li J., Sun F. J., . The Origin of Deep Layer Gases in the Jiyang Depression of Bohaibay Basin, China. Journal of Geochemical Exploration, 2009, 101 1 66

McLimans R. K.. The Application of Fluid Inclusions to Migration of Oil and Diagenesis in Petroleum Reservoirs. Applied Geochemistry, 1987, 2(5–6): 585-603.

Mcnab J. G., Smith P. V., Betts R. L.. Evolution of Petroleum. Industrial & Engineering Chemistry, 1952, 44(11): 2556-2563.

Munz I. A.. Petroleum Inclusions in Sedimentary Basins: Systematics, Analytical Methods and Applications. Lithos, 2001, 55(1–4): 195-212.

Munz I. A., Wangen M., Girard J. P., . Pressure-Temperature-Time-Composition (P-T-t-X) Constraints of Multiple Petroleum Charges in the Hild Field, Norwegian North Sea. Marine and Petroleum Geology, 2004, 21(8): 1043-1060.

Okubo S.. Effects of Thermal Cracking of Hydrocarbons on the Homogenization Temperature of Fluid Inclusions from the Niigata Oil and Gas Fields, Japan. Applied Geochemistry, 2005, 20(2): 255-260.

Pang X. Q., Li M. W., Li S. M., . Geochemistry of Petroleum Systems in the Niuzhuang South Slope of Bohai Bay Basin: Part 2, Evidence for Significant Contribution of Mature Source Rocks to “Immature Oils” in the Bamianhe Field. Organic Geochemistry, 2003, 34(7): 931-950.

Parnell J., Carey P. F., Monson B.. Fluid Inclusion Constraints on Temperatures of Petroleum Migration from Authigenic Quartz in Bitumen Veins. Chemical Geology, 1996, 129(3–4): 217-226.

Pironon J., Bourdet J.. Petroleum and Aqueous Inclusions from Deeply Buried Reservoirs: Experimental Simulations and Consequences for Overpressure Estimates. Geochimica et Cosmochimica Acta, 2008, 72(20): 4916-4928.

Powers S., Clapp F. G.. Nature and Origin of Occurrences of Oil, Gas, and Bitumen in Igneous and Metamorphic Rocks. AAPG Bulletin, 1932, 16(8): 719-726.

Price L. C.. Organic Geochemistry of Core Samples from an Ultra-deep Hot Well (300 Degrees C, 7 km). Chemical Geology, 1982, 37(3–4): 215-228.

Price L. C.. Thermal Stability of Hydrocarbons in Nature: Limits, Evidence, Characteristics, and Possible Controls. Geochimica et Cosmochimica Acta, 1993, 57(14): 3261-3280.

Price L. C., Clayton J. L., Rumen L. L.. Organic Geochemistry of the 9.6 km Bertha Rogers No.1 Well, Oklahoma. Organic Geochemistry, 1981, 3(3): 59-77.

Riediger C. L.. Solid Bitumen Reflectance and Rock-Eval Tmax as Maturation Indices: An Example from the “Nordegg Member”, Western Canada Sedimentary Basin. International Journal of Coal Geology, 1993, 22(3–4): 295-315.

Rogers M. A., McAlary J. D., Bailey N. J. L.. Significance of Reservoir Bitumens to Thermal-Maturation Studies, Western Canada Basin. AAPG Bulletin, 1974, 58(9): 1806-1824.

Sajgo C.. Assessment of Generation Temperatures of Crude Oils. Organic Geochemistry, 2000, 31(12): 1301-1323.

Sellwood B. W., Wilkes M., James B.. Hydrocarbon Inclusions in Late Calcite Cements: Migration Indicators in the Great Oolite Group, Weald Basin, S. England. Sedimentary Geology, 1993, 84(1–4): 51-55.

Stasiuk L. D., Gentzis T., Rahimi P.. Application of Spectral Fluorescence Microscopy for the Characterization of Athabasca Bitumen Vacuum Bottoms. Fuel, 2000, 79(7): 769-775.

Teinturier S., Elie M., Pironon J.. Oil-Cracking Processes Evidence from Synthetic Petroleum Inclusions. Journal of Geochemical Exploration, 2003, 78–79: 421-425.

Thiéry R.. Thermodynamic Modelling of Aqueous CH4-Bearing Fluid Inclusions Trapped in Hydrocarbon-Rich Environments. Chemical Geology, 2006, 227(3–4): 154-164.

Thiéry R., Pironon J., Walgenwitz F., . PIT (Petroleum Inclusion Thermodynamic): A New Modeling Tool for the Characterization of Hydrocarbon Fluid Inclusions from Volumetric and Microthermometric Measurements. Journal of Geochemical Exploration, 2000, 69–70: 701-704.

Thiéry R., Pironon J., Walgenwitz F., . Individual Characterization of Petroleum Fluid Inclusions (Composition and P-T Trapping Conditions) by Microthermometry and Confocal Laser Scanning Microscopy: Inferences from Applied Thermodynamics of Oils. Marine and Petroleum Geology, 2002, 19(7): 847-859.

Tseng H. Y., Pottorf R. J.. Fluid Inclusion Constraints on Petroleum PVT and Compositional History of the Greater Alwyn-South Brent Petroleum System, Northern North Sea. Marine and Petroleum Geology, 2002, 19(7): 797-809.

Ungerer P., Behar F., Villalba M., . Kinetic Modelling of Oil Cracking. Organic Geochemistry, 1988, 13(4–6): 857-868.

Wilson N. S. F.. Organic Petrology, Chemical Composition, and Reflectance of Pyrobitumen from the El Soldado Cu Deposit, Chile. International Journal of Coal Geology, 2000, 43(1–4): 53-82.

Yang C. P., Geng A. S., Liao Z. W., . Quantitative Assessment of Gas Washing of Oils in the Tazhong Area of the Tarim Basin, Northwest China. Science in China (Series D), 2009, 39(1): 51-60.

Zhang S.. The Application of an Integrated Approach in Exploration of Lacustrine Turbidites in Jiyang Sub-basin, Bohai Bay Basin, China. Journal of Petroleum Science and Engineering, 2004, 41: 67-77.

Zhao M. J., Zhang S. C., Zhao L., . Geochemistry Features and Genesis of the Natural Gas and Bitumen in Paleo-oil Reservoirs of Nanpanjiang Basin, China. Science in China (Series D), 2007, 50(5): 689-701.

Zhao Y.. Research on Structure, Strata Sequence and Accumulation Dynamics in the North of Dongying Depression, 2006, Beijing: Petroleum Industry Press 12 15