Constrains of eruption environment and hydrothermal fluid on the Permian pyroclastic reservoirs in the Sichuan Basin, SW China

Abstract

A breakthrough has been recently made in the hydrocarbon exploration of the Permian pyroclastic rocks in the Jianyang Area, western Sichuan Basin, China. With an aim to decipher the impacts of the eruption environment, the temperature of hydrothermal fluids, and the paleo-salinity on the formation of authigenic mineral assemblage and pores, this study implements comprehensive petrographic and geochemical studies through the integrated core and thin section analyses. The data presented demonstrate that the Permian volcanic intervals are intensively affected by an event of Emei taphrogeny. During basaltic magma upward migration, fractional crystallization of anorthose results in slightly-alkaline magma. The specific pyroclastic rocks are formed by the eruption of slightly-alkaline magma in the sea or a salt lake and subsequent hydrothermal alteration. During deposition and diagenesis, the authigenic mineral association is constrained jointly by the sodium-rich and high salinity water environment, and mid-high temperature, high-salinity hydrothermal fluid. Specifically, the sodium-rich hydrothermal fluid, which may sustain till the late diagenesis stage, caused pervasive albitization of pyroclastic rocks, then leading to mineral transformation and formation of a series of mineral associations. Therefore, zeolitization of volcanic glass and vesicle-infillings of zeolite is an essential condition for later mineral transformation and dissolution. Albitization of analcite, recrystallization induced by deep hydrothermal fluids, and both meteoric and deep burial dissolution expanding the micro-pore space ultimately formed porous pyroclastic reservoirs.

Keywords

Permian / Pyroclastic rock / Eruption environment / Hydrothermal fluid / Sichuan basin / Southwest China

Author contributions

Conceptualization and Data curation, Y.Z.; Writing-original draft, X. L.; Writing-review & editing, M.F.; Resources, B.Z.; Investigation, M.X.; Supervision, X.W.

Declaration of competing interests

The authors declare no conflicts of interest.

Acknowledgments

This work was granted by the National Natural Science Foundation of China (Grant No. 41202109), the National Major Science and Technology Projects of China (Grant No. 2016ZX05007004001), the Innovation Foundation of PetroChina Carbonate Key laboratory (RIPED-HZDZY-2019-JS-695) and the China Scholarship Council. Thanks are expressed to our colleagues involved in igneous rocks researching in the Sichuan Basin, as well as to several anonymous reviewers from which this article has benefited.

References

[1] W.Z. Zhao, C.N. Zou, J.Z. Li, et al., Comparative study on volcanic hydrocarbon accumulations in western and eastern China and its significance, Petrol. Explor. Dev. 36 (2009) 1-11.

[2] C.N. Zou, W.Z. Zhao, C.Z. Jia, et al., Formation and distribution of volcanic hydrocarbon reservoirs in sedimentary basins of China, Petrol. Explor. Dev. 35 (2008) 257-271.

[3] J.L. Luo, Z.H. Qu, W. Sun, et al., The relations between lithofacies, reservoir lithology and oil and gas of volcanic rocks in Fenghuadian area, Acta Petroilei Sin (1996) 32-39.

[4] Y.C. Cao, Z.X. Jiang, L.W. Qiu, Study on the type and origin of the reservoir space of igneous oil reservoir in Shang 741 block, Huimin depression, Shandong, Acta Petrol. Sin. 15 (1999) 129-136.

[5] J.L. Yang, J.L. Luo, F.Q. He, et al., Permian Volcanic Reservoirs in the Tahe Region, Petroleum Exploration And Development, 2004, pp. 44-47.

[6] P.J. Wang, S.M. Chen, W.Z. Liu, et al., Relationship between volcanic facies and volcanic reservoirs in songliao basin, Oil Gas Geol. 23 (2003) 18-23+27.

[7] H. Yang, Y. Zhang, C.N. Zou, et al., Exploration Scheme of Gas in Deep-Seated Volcanic Rocks in Songliao Basin, Petroleum Exploration And Development, 2006, pp. 274-281.

[8] L. Kuang, X. Xue, C. Zou, et al., Oil accumulation and concentration regularity of volcanic lithostratigraphic oil reservoir: a case from upper-plate Carboniferous of KA-Bai fracture zone, Junggar Basin, Petrol. Explor. Dev. 34 (2007) 285-290.

[9] X.H. Liu, M.Y. Feng, A.H. Xi, et al., Diagenesis and pore evolution of carboniferous volcanic reservoirs in Dixi area, Kelameili gas field, Lithol Reservoirs 28 (2016) 38-48.

[10] R.K. Zhu, Z.G. Mao, H.L. Guo, et al., Volcanic oil and gas reservoir geology: thinking and forecast, NW Oil Gas Explor. 22 (2010) 7-13.

[11] L.Y. Zhang, Y.L. Ji, L. Liu, et al., Origin of anomalously high porosity in pyroclastic reservoirs: a case study on the northern region of the east sub-sag in Nanbeier sag, Acta Pet. Sin. 33 (2012), 814-621.

[12] ChangChao Chen, ZhiLong Huang, X. Chen, et al., The formation conditions of the Upper Carboniferous near-source tuff tight oil reservoir in Santanghu Basin, Xinjiang province, Geol. Bull. China 37 (2018) 83-92.

[13] X.X. Guo, L. Liu, Q.A. Meng, et al., Reservoir characteristics and controlling factors of pyroclastic rocks of Tongbomiao formation and Nantun formation from Tanan depression in Tamtsag basin, Mongolia, Glob. Geol. 32 (2013) 290-299.

[14] S.Q. Liu, M.D. Yao, Y.Q. Feng, et al., Influencing factor analysis of devitrification pore and its relationship with hydrocarbon in Tiaohu Formation of Malang Depression, Special Oil Gas Reservoirs 25 (2018) 16-19.

[15] Y.Q. Wang, J.D. Wang, Q.J. Wang, et al., Diagenesis of volcaniclastic rocks and its control over reservoir performance: a case study of the carboniferous system in Chepaizi area, Junggar Basin, J. China Inst. Min. Technol. 48 (2019) 405-414.

[16] Y.P. Liu, S.Y. Zhang, H.F. Zhang, Advances on mineral genesis of chlorite: a review, Adv. Geosci. 6 (2016) 264-282.

[17] X.Z. Yang, Z.L. Yang, K.Y. Tao, et al., Formation temperature of chlorite in oilbearing basalt, Acta Mineral. Sin. (2002) 365-370.

[18] R.C. Zheng, H.G. Wen, Y. Li, et al., Compositions and texture of lacustrine exhalative rocks from the lower Cretaceous Xiagou formation in Qingxi sag of Jiuxi basin, Gansu, J. Palaeogeogr. 20 (2018) 1-18.

[19] S.F. Zhu, X.M. Zhu, XuLong Wang, et al., Zeolite diagenesis and its control on petroleum reservoir quality of Permian in northwestern margin of Junggar Basin, China, Sci. China Earth Sci. 41 (2011) 1602-1612.

[20] X.H. Ma, G.H. Li, D.L. Ying, et al., Distribution and gas-bearing properties of Permian igneous rocks in Sichuan Basin, SW China, Petrol. Explor. Dev. 46 (2019a) 216-225.

[21] W. Chen, Y.J. Qin, Y.Y. Hu, Characterization and genesis of FESEM micro-nano pores in volcanic reservoirs: a case study of well Yongtan 1 in Sichuan Basin,in:Proceedings of the 2019 AnnualMeeting of the Geological Society of China, 2019.

[22] Q.L. He, X. Chen, Q. Ran, et al., Seismic-reflection characteristics and lithofacies-distribution prediction of Permian volcanic rocks, Chengdu-Jianyang area, Nat. Gas Explor. Dev. 42 (2019) 35-41.

[23] L. Wen, Y. Li, H.Y. Yi, et al., Lithofacies and reservoir characteristics of Permian volcanic rocks in the Sichuan Basin, Nat. Gas. Ind. 39 (2019) 17-27.

[24] B. Bing Luo, M.L. Xia, H. Wang, et al., Hydrocarbon accumulation conditions of Permian volcanic gas reservoirs in the western Sichuan Basin, Nat. Gas. Ind. 39 (2019) 9-16.

[25] X. Chen, Q.L. He, Q. Ran, et al., Features and recognition for seismic facies of Permian volcanic reservoirs in the Sichuan Basin, Nat. Gas. Ind. 39 (2019) 28-36.

[26] J.L. Jian, Lin Lu, Z.X. Zong, Xin Zuo, Z. Zheng Shi, et al., Characteristics of Permian volcanism in the western Sichuan Basin and its natural gas exploration potential, Nat. Gas. Ind. 39 (2019) 46-53.

[27] X.H. Ma, Y. Yang, J. Zhang, et al., A major discovery in Permian volcanic rock gas reservoir exploration in the Sichuan Basin and its implications, Nat. Gas. Ind. B 6 (2019b) 419-425.

[28] J.Y. Xie, Identification of magma fragment and pumice in ignimbrites, Volcanol. Miner. Resour. (1994) 62-63.

[29] W.A. Deer, R.A. Howie, J. Iussman, Rock-Forming Minerals: Sheet Silicates, Longman, London, 1962.

[30] J.A. Winchester, P.A. Floyd, Geochemical discrimination of different magma series and their differentiation products using immobile elements, Chem. Geol. 20 (1977) 325-343.

[31] P. Kranidiotis, W.H. Maclean, Systematics of chlorite alteration at the Phelps Dodge massive sulfide Deposit, Matagami, Quebec, Econ. Geol. 82 (1987) 1898-1911.

[32] L. Xiao, Y.G. Xu, H.J. Mei, et al., Geochemistry of Emeishan flood basalts at Binchuan area, SW China: rock Types and temporal evolution, Chin. J. Geol. (2003) 478-494.

[33] Y. Zhang, P. Shu, P.J. Wang, et al. Comparison between subaerial and subaqueous volcanic rocks and the reservoir significance dtaking Yingcheng Formation in Songliao Basin as example, J. Jilin Univ. (, Earth Sci. Ed.) (2007) 1259-1265.

[34] L. Wang, W.H. Li, T. Lin, et al., A comparative analysis of submarine eruptive and subaerial eruptive volcaniclastic reservoir on characteristics of reservoir and reservoir forming dominated factors: taking Carboniferous volcaniclastic reservoir in Santanghu Basin as example, Chin. J. Geol. 45 (2010) 1088-1097.

[35] Y.X. He, B.Z. Xian, H.P. Niu, et al., Discrimination of volcanic eruption environment using oxidation index: a case study of lower Permian volcanic rocks in northwestern margin of Junggar Basin, Geol. J. China Univ. 23 (2017) 737-749.

[36] M. Deng, M.C. Hou, B.J. Zhang, et al., Favorable reservoir analysis of Emeishan basalt in Zhougongshan area of southwest Sichuan Province, Chin. Geol. 41 (2014) 378-386.

[37] M.C. Hou, W.K. Wang, B.J. Zhang, et al., Fluid types and activities of Emeishan basalt in Zhougong mountain-Hanwang field of Sichuan Province, Acta Petrol. Sin. 29 (2013) 2709-2718.

[38] X.H. Liu, N.X. Li, M.Y. Feng, et al., Fracture fillings and alteration halo in volcanic reservoirs as indicator of fluid activities in the Dixi area in the Kelameili gas field, Junggar Basin, northwestern China, Bull. China Soc. Mineral Petrol. Geochem. 38 (2019) 539-548.

[39] Y.G. Han, S.H. Zhang, Z.D. Bai, et al., Albitization of the volcanic rocks of the Xiong’er group, western Henan, and its implications, J. Mineral. Petrol. (2006) 35-42.

[40] S.E. Humphris, G. Thompson, Hydrothermal alteration of oceanic basalts by seawater, Geochem. Cosmochim. Acta 42 (1978) 107-125.

[41] J.H. Qian, C.J. Wei, X.W. Zhou, et al., Genesis of the megacryst orthoamphibole rock from Hengshan Mts, Shanxi Province: evidence from geochemistry and Sm-Nd isotopic data, Acta Petrol. Sin. 28 (2012) 2819-2830.

[42] M.S. Smith, R.F. Dymek, J.S. Schneiderman, Implications of trace element geochemistry for the origin of cordierite-orthoamphibole rocks from Orijiarvi, SW Finland, J. Geol. 100 (1992) 545-559.

[43] S.D. Villiers, Excess dissolved Ca in the deep ocean: a hydrothermal hypothesis, Earth Planet Sci. Lett. 164 (1998) 627-641.

[44] H.R. Rollinson, Using Geochemical Data: Evaluation, Presentation, Interpretation, Long man Group UK Limit, UK, 1993.

[45] J. Wang, F.W. Tan, XiuGen Fu, Working Method of Sedimentary Rock -Guide Manual of Geological Survey Working Method, Geological publishing House, Beijing, 2015.

[46] A. Wang, Discriminant effect of sedimentary environment by the Sr/Ba ratio of different existing forms, Acta Sedimentol. Sin. 4 (1996) 169-174.

[47] L. Ren, Y. Gao, The role of volatiles in the formation of scapolite in amphibolites of southern West Kunlun Mountains, Acta Petorl. Mineral. 4 (2002) 398-406.

[48] Y. Liu, F. Stoppa, Investigation of volatile compositions in apatites from Vesuvio and volcano islands, Acta Mineral. Sin. 31 (2011) 180-184.

[49] S.F. Zhu, X.M. Zhu, D. Wu, et al., Alteration of volcanics and its controlling factors in the Lower Permian reservoirs at northwestern margin of Junggar Basin, Oil Gas Geol. 35 (2014) 77-85.

[50] Y.S. Sun, Mineralogical characteristics of zeolite minerals and theirs bearings to the reservoir beds in the Karamay oil field, Sediment. Facies Palaeogeogr. (1993) 37-48.

[51] A. Iijima (Ed.), Zeolites in Petroleum and Natural Gas Reservoirs, Mineralogical Society America, Washington, 2001.

[52] S.X. Hu, Y. Ye, C.Q. Fang, Petrology of Metasomatic Altered Rocks and its Implication in Ore Prospecting, Geological Publishing House, Beijing, 2004.

[53] J.S. Jahren, Evidence for Ostwald ripening related recrystallization of diagenetic chlorites from reservoir rocks offshore Norway, Clay Miner. 26 (1991) 169-178.

[54] M. Zhao, J.F. Ji, X.M. Chen, et al., Effects of paleosalinity on clay mineral assemblages and chlorite composition in mudstone of Tabei uplift, Xinjiang, China, Geol. J. China Univ. 21 (2015) 365-375.

[55] C.D. Curtis, C.R. Hughes, J.A. Whiteman, et al., Compositional variation within some sedimentary chlorites and some comments on their origin, Mineral. Mag. 49 (1985) 375-386.

[56] Z.S. Shi, KaiYuan Chen, J. Shi, et al., Feasibility Analysis of the Application of the Ratio of Strontium to Barium on the Identifying Sedimentary Environment, Fault-Block Oil & Gas Field, 2003, 12-16+89-90.

[57] M. Honty, P. Uhlik, V. Sucha, Smectite-to-illite alteration in salt-bearing bentonites (the east Slovak basin), Clay Clay Miner. 52 (2004) 533-551.

[58] K.V. Cashman, R.S. Fiske, Fallout of pyroclastic debris from submarine volcanic eruptions, Science 253 (1991) 275-280.