The classification and significance of fine-grained deposits of micro-laminae rich in unconventional oil and gas resources

Abstract

In this study, an in-depth analysis of the types, characteristics, and formation mechanisms of micro-laminae and microscopic laminae was conducted in order to precisely examine the link or intersection of stratigraphy and petrology. This study was essentially a sedimentary examination of the minuteness-macro and micro-tiny layers between laminae and pore structure, as well as the types of structures and sedimentation. The results of this study bear important basic subject attributes and significance, as well as practical value for the basic theories and exploration applications of unconventional oil and gas geology. The quantitative data were obtained using the following: field macroscopic observations; measurements; intensive sampling processes; XRD mineral content analysis; scanning electron microscopy; high-power polarizing microscope observations; and micro-scale measurements. The quantitative parameters, such as laminae thicknesses, laminae properties, organic matter laminae, and laminae spatial distributions were unified within a framework, and the correlations among them were established for the purpose of forming a fine-grained deposition micro-laminae evaluation system. The results obtained in this research investigation established a basis for the classification of micro-laminae, and divided the micro-laminae into four categories and 20 sub-categories according to the development thicknesses, material compositions, organic matter content levels, and the spatial distributions of the micro-laminae. The classification scheme of the micro-laminae was divided into two categories and 12 sub-categories. Then, in accordance with the comprehensive characteristics of spatial morphology, the micro-laminae was further divided into the following categories: continuous horizontal laminae; near horizontal laminae; slow wavy laminae; wavy laminae; discontinuous laminae; and lenticular laminae. According to the structural properties of the laminae development, the micro-laminae was divided into the following categories: single laminae structures; laminated laminae structures; interlaminar structures; multiple mixed laminae structures; cyclic laminae structures; and progressive laminae structures. The research results were considered to be applicable for the scientific evaluations of reservoir spaces related to unconventional oil and gas resources.

Graphical abstract

Keywords

fine-grained deposits / recognition of laminae types / microscopic laminae / recognition of fine laminae / laminae origins

References

[1] Aplin A C, Joe H S. ( 2011). Mudstone diversity: origin and implications for source, seal, and reservoir properties in petroleum systems. AAPG Bull, 95( 12): 2031– 2059

[2] Bohacs K M, Carroll A R, Neal J E, Mankiewicz P J. ( 2000). Lake-basin type, source potential, and hydrocarbon character: an integrated sequence-stratigraphic-geochemical framework. AAPG Stud Geol, 46: 3– 34

[3] Bowker K A. ( 2007). Barnett shale gas production, Fort Worth Basin: issues and discussion. AAPG Bull, 91( 4): 523– 533

[4] Curran K J, Hill P S, Milligan T G. ( 2002). Fine-grained suspended sediment dynamics in the Eel River flood plume. Cont Shelf Res, 22( 17): 2537– 2550

[5] Curran K J, Hill P S, Schell T M, Milligan T G, Piper D J W. ( 2004). Inferring the mass fraction of floc-deposited mud: application to fine-grained turbidites. Sedimentology, 51( 5): 927– 944

[6] Daniel J K, Ross R. ( 2008). Characterizing the shale gas resource potential of Devonian–Mississippian strata in the western Canada sedimentary basin: application of an integrated formation evaluation. AAPG Bull, 92( 1): 87– 125

[7] Daniel M J, Ronald J H, Tim E R. ( 2007). Unconventional shale-gas systems: the Mississippian Barnett Shale of north central Texas as one model for thermogenic shale-gas assessment. AAPG Bull, 91( 4): 475– 499

[8] Daniel M J, Richard M P, Kent A B, Montgomery L. ( 2005). Mississippian Barnett Shale, Fort Worth Basin, north central Texas: gas-shale play with multi–trillion cubic foot potential. AAPG Bull, 89( 2): 155– 175

[9] Dill H G, Köthe A, Gramann F, Botz R. ( 1996). A palaeo environmental and palaeoecological analysis of fine-gained Paleogene estuarine deposits of North Germany. Palaeogeogr Palaeoclimatol Palaeoecol, 124( 3-4): 273– 326

[10] Han W ( 2017). Geological characteristics of lacustrine fine-grained sedimentary rocks. Stand Qualit Petrol Chem Indust China, 37(19): 77− 78 (in Chinese)

[11] Han Y, Ning S. ( 2015). Resvroir condition and oil-bearirg property of Shahejie shale reservoir in western sag, Liaohe oilfield reservoir in western sag, Liaohe Oilfield. Geol Prospect, 38( 2): 6– 9

[12] Hao F, Zou H, Lu Y. ( 2013). Mechanisms of shale gas storage: implications for shale gas exploration in China. AAPG Bull, 97( 8): 1325– 1346

[13] Jiang Z, Chen D, Qiu L, Liang H B, Ma J. ( 2007). Source-controlled carbonates in a small Eocene half-graben lake basin (Shulu Sag) in central Hebei Province, north China. Sedimentology, 54( 2): 265– 292

[14] Jiang Z, Liang C, Wu J, Zhang J G, Zhang W Z, Wang Y S, Liu H M, Chen X. ( 2013). Several issues in sedimentological studies on hydrocarbon-bearing fine-grained sedimentary rocks. J Petrol, 34( 6): 1031– 1039

[15] Jin Z ( 2017). The study on sedimentary environment of fine grained rocks of the upper fourth member of paleogene Shahejie Formation, Dongying Sag. Dissertation for Doctoral Degree. Beijing: China University of Geosciences

[16] Kranck K, Smith P C, Milliga T G. ( 1996b). Grain-size characteristics of fine-grained unflocculated sediments Part I: “one-round” distributions. Sedimentology, 43( 3): 589– 596

[17] Kranck K, Smith P C, Milligan T G. ( 1996a). Grain size characteristics of fine grained unflocculated sediments Part II: “multi-round” distributions. Sedimentology, 43( 3): 597– 606

[18] Lazar O R, Bohacs K M, Macquaker J H S, Demko T M. ( 2015). Capturing key attributes of fine-grained sedimentary rocks in outcrops, cores, and thin sections: nomenclature and description guidelines. J Sediment Res, 85( 3): 230– 246

[19] Li Y T, Lu Z S, Wu Z D, Li Y H, Li B L, Wang R K. ( 2018). Sweet spot prediction for fine-grain sediment reservoirs in the Cangdong Sag. Petrol Geophys Explor, 53( 5): 1059– 1066+884

[20] Liu C Xu J Wang P ( 2001). Algal blooms: the primary mechanism in the formation of lacustrine petroleum source rocks. Geol Rew, 47( 2): 207– 210 (in Chinese)

[21] Liu H Y, Yu B, Xie Z, Han S, Shen Z, Bai C (2018). Characteristics and implications of micro-lithofacies in lacustrine-basin organic-rich shale: a case study of Jiyang Depression, Bohai Bay Basin. Acta Petrol Sin, 39(12): 1328−1343 (in Chinese)

[22] Liu K Liu C ( 2019). “Chemo-sedimentary facies” analysis: an effective method to study fine-grained sedimentary rocks. Oil Gas Geol, 40( 3): 491− 503 (in Chinese)

[23] Ma F X Wang L Luo D Zhang Y Ge Y J Du K F ( 2018). Characteristics and genesis of lacustrine massive fine-grained sedimentary rocks: taking Eocene Jiyang Depression as an example. Fault-Block oil Gas Field, 25( 03): 278– 283 (in Chinese)

[24] Ma Y Q, Fan M J, Lu Y C, Liu H M, Hao Y Q, Xie Z H, Liu Z H, Peng L, Du X B, Hu H Y. ( 2016). Climate-driven paleolimnological change controls lacustrine mudstone depositional process and organic matter accumulation: constraints from lithofacies and geochemical studies in the Zhanhua Depression, eastern China. Int J Coal Geol, 167: 103– 118

[25] Macquaker J H S, Adams A E. ( 2003). Maximizing information from fine-grained sedimentary rocks: an inclusive nomenclature for mudstones. J Sediment Res, 73( 5): 735– 744

[26] Robert G, Ruppel S C. ( 2007). Mississippian Barnett Shale: lithofacies and depositional setting of a deep-water shale-gas succession in the Fort Worth Basin, Texas. AAPG Bull, 91( 4): 579– 601

[27] Slatt R M, O’Brien N R. ( 2011). Pore types in the Barnett and Woodford gas shales: contribution to understanding gas storage and migration pathways in fine-grained rocks. AAPG Bull, 95( 12): 2017– 2030

[28] Song G Q Xu X Y Li Z Wang X H ( 2015). Factors controlling oil production from Paleogene shale in Jiyang depression. Oil Gas Geol, 36( 3): 463− 471 (in Chinese)

[29] Sun S Y, Liu H M, Cao Y C, Zhang S, Wang Y, Yang W Q. ( 2017). Milankovitch cycle of lacustrine deepwater fine-grained sedimentary rocks and its significance to shale oil: a case study of the upper Es4 member of well NY1 in Dongying sag. J China Univ Min Technol, 46( 4): 846– 858

[30] Wang G ( 2012). Laminae combination and genetic classification of eogene shale in Jiyang depression. Jilin Daxue Xuebao Diqiu Kexue Ban, 42( 3): 666− 671 (in Chinese)

[31] Wang Y, Liu H M, Song G Q, Xiong W, Zhu D S, Yin Y, Ding J H, Yang W Q, Zhang L, Zhang S. ( 2019). Lacustrine shale fine-grained sedimentary system in Jiyang depression. J Petrol, 40( 4): 395– 410

[32] Wang Y Song G Q Liu H M Hao X F Jiang X F Yin Y Yang W Q ( 2015). Formation environment and sedimentary structures of fine-grained sedimentary rock in Jiyang depression. J Northeast Petrol U, 39( 3): 7− 14 (in Chinese)

[33] Yu B. ( 2012). Particularity of shale gas reservoir and its evaluation. Earth Sci Front, 19( 3): 252– 258

[34] Yu B. ( 2013). Classification and characterization of gas shale pore system. Earth Sci Front, 20( 4): 211– 220

[35] Zhang J, Lin L, Li Y. ( 2011). Classification and evaluation of shale oil. Earth Sci Front, 19( 5): 322– 331

[36] Zhang L H, Li J Y, Li Z, Zhu R F, Zhang S C, Liu Q, Zhang J G, Chen Z H. ( 2015). Development characteristics and formation mechanism of intra-organic reservoir space in lacustrine shales. Earth Sci J China U Geosci, 40( 11): 1824– 1833

[37] Zhang S Wang Y S Liu H M Chen S Y Tan M Y Zhang Y Y Hao X F Xie Z H ( 2016). Controlling effect of fine-grained sedimentary microfacies upon the microstructure of shale oil reservoirs in the Dongying Sag, Bohai Bay Basin. Oil Gas Geol, 37( 6): 923− 934 (in Chinese)

[38] Zhang Y G Cai J G Xu W P ( 2007). Enrichment Mechanism of Organic Matter in Argillaceous Source Rocks. Beijing: Petroleum Industry Press

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