Citation: | He-sheng Hou, Cheng-shan Wang, Jiao-dong Zhang, Feng Ma, Wei Fu, Pu-jun Wang, Yong-jian Huang, Chang-chun Zou, You-feng Gao, Yuan Gao, Lai-ming Zhang, Jin Yang, Rui Guo, 2018. Deep Continental Scientific Drilling Engineering Project in Songliao Basin: progress in Earth Science research, China Geology, 1, 173-186. doi: 10.31035/cg2018036 |
The Songke No.2 well (eastern hole) (referred to as Well SK-2), one of the “two wells and four holes” of the Deep Continental Scientific Drilling Engineering Project in the Songliao Basin, is in Anda City, Heilongjiang Province, and was officially completed on May 26, 2018. The scientific goals of Well SK-2 cover four aspects: paleoclimate research, resource and energy exploration, primary geological research, and development of deep earth exploration techniques. Since the official commencement of drilling in 2014, the Well SK-2 scientific drilling engineering team has organized and implemented drilling for coring, in situ logging, chemical analysis of core elements, and deep structural exploration around the well. Currently, the following preliminary scientific research progress has been made: 4334.81 m in situ core data has been obtained; the centimeter-level high-resolution characterization of the most complete and continuous Cretaceous continental strata ever unearthed has been completed, and the standard profile of continental strata has been initially established; the unconventional natural gas resources and basin-type hot dry rocks in the deep Songliao Basin were found to have good prospects for exploration and development; the climatic evolutionary history of the Cretaceous continental strata was rebuilt for the first time, covering hundreds of thousands to millions of years, and the major events of Cretaceous climate fluctuations have been discovered; all these reveal strong evidence for the subduction and aggregation of paleo-ocean plates, providing a theoretical basis for the re-recognition of the genesis of the Songliao Basin and for deep earth oil and gas exploration. The implementation of the Deep Continental Scientific Drilling Engineering Project in the Songliao Basin is of great significance for exploring the mysteries of the Earth and solving major problems such as those related to the deep energy environment. It is a solid step along the road of "going deep into the Earth".
[1] | Berzin R, Oncken O, Knapp James, Pérez-Estaún A, Hismatulin T, Yunusov N, Lipilin A. 1996. Orogenic evolution of the Ural Mountains, results from an integrated seismic experiment. Science, 274(5285), 220–221. |
[2] | Chamberlain C, Wan XQ, A. Graham S, Carroll A, C. Doebbert A, Sageman B, Blisniuk P, L.Kent-Corson M, Wang Z, Wang CS. 2013. Stable isotopic evidence for climate and basin evolution of the Late Cretaceous Songliao Basin China. Palaeogeography, Palaeoclimatology, Palaeoecology, 385, 106–124. |
[3] | Cheng YH, Li Y, Liu YS, Teng XJ, Li YF, Yang JQ, Ao Z. 2016. The tectonic extensional event during the early cretaceous in the west margin of songliao basin, U-Pb dating, geochemistry and petrogenesis of rhyolites. Acta Geologica Sinica, 90(12), 3492–3507 (in Chinese with English abstract). |
[4] | Clowes RMCM. 2010. Initiation development and benefits of Lithoprobe-shaping the dire. Revue Canadienne Des Sciences De La Terre, 47(4), 291–314. |
[5] | Cook FA, Velden AJVD. 2012. 7-Crustal seismic reflection profiles of collisional orogen. Regional Geology and Tectonics Principles of Geologic Analysis, , 178–213. |
[6] | Dai JX, Zou CN, Zhang SC, Li J, Ni YY, Hu GY, Luo X, Tao SZ, Zhu GY, Mi JK. 2008. Identification of abiogenic and organic alkane gas. Science in China (D), 38(11), 1329–1341. |
[7] | Daqing oilfield petroleum geology chronicle writing group. 1993. Petroleum geology of China (Volume 2). Beijing, Petroleum Industry Press (in Chinese with English abstract) |
[8] | Dekorp Research Group. 1990. Results of deep-Seismic reflection investigations in the Rhenish Massif. Tectonophysics, 173(1-4), 507–515. |
[9] | Dong SW, Zhang YQ, Long CX, Yang ZY, Ji Q, Wang T, Hu JM, Chen XH. 2007. Jurassic Tectonic Revolution in China and New Interpretation of the “Yanshan Movement”. Acta Geological Sinica, 81(11), 1449–1461 (in Chinese with English abstract). |
[10] | Dong SW, Li TD, Chen XH, Gao R, Lü QT, Shi YL, Huang DN, Yang JS, Wang QX. 2014. SinoProbe revealed crustal structures, deep processes, and metallogenic background within China continent. Earth Science Frontiers, 21(3), 201–225 (in Chinese with English abstract). |
[11] | Echtler H, Stiller M, Steinhoff F, Krawczyk C.M., Suleimanov A, Spiridonov V, Knapp J, Menshikov Y, Alvarez−Marron J, Yunusov N. 1996. Preserved Collisional Crustal Structure of the Southern Urals Revealed by Vibroseis Profiling. Science, 274(5285), 224–226. |
[12] | Feng ZH, Shao HM, Wang C, Lu X. 2015. Pore structure characterization and classification of the in-source tight oil reservoirs in northern Songliao Basin. Acta Geologica Sinica (English edition), 89(z1), 29–30. |
[13] | Föllmi KB. 2012. Early Cretaceous life climate and anoxia. Cretaceous Research, 35, 230–257. |
[14] | Gao R, Wang HY, Wang CS, Yin A, Zhang YX, Li QS, Guo TL, Li WH. 2011. Lithospheric deformation shortening of the northeastern Tibetan Plateau, evidence from reprocessing of deep seismic reflection data. Acta Geoscientica Sinica, 32(5), 513–520 (in Chinese with English abstract). |
[15] | Gao R, Lu ZW, Klemperer S, Wang HY, Dong SW, Li WH, Li HQ. 2016. Crustal-scale duplexing beneath the Yarlung Zangbo suture in the western Himalaya. Nature Geoscience, 9(7), 555–560. |
[16] | Gao Y, Ibarra D, Caves RJ, Wang CS, Chamberlain C, A. Graham S, Wu HC. 2015. Mid-latitude terrestrial climate of East Asia linked to global climate in the Late Cretaceous. Geology, 43(4), 287–290. |
[17] | Gold T, Soter S. 1980. Deep-earth-gas hypothesis. Scientific American. 242 |
[18] | Guo ZQ, Wang XB. 1997. Characteristics of inorganic gas reservoirs in the Songliao basin. Science in China (Series D), (2), 143–148 (in Chinese with English abstract). |
[19] | Han GQ, Liu YJ, Jin W, Wen QB, Li W, Liang CY, Liang DJ. 2009. The distribution of Xar Moron river fault under Songliao Basin. Geology in China, 36(5), 1010–1020 (in Chinese with English abstract). |
[20] | Haq BU, Hardenbol J, Vail PR. 1987. Chronology of fluctuating sea levels since the Triassic. Science, 235(4793), 1156–1167. |
[21] | Hou D, Li MW, Huang QH. 2000. Marine transgressional events in the gigantic freshwater lake Songliao, paleontological and geochemical evidence. Organic Geochemistry, 31, 763–768. |
[22] | Hou HX, Wang HY, Gao R, Li QS, Li HQ, Xiong XS, Li WH, Tong Y. 2015. Fine crustal structure and deformation beneath the Great Xing’an Ranges CAOB, Revealed by deep seismic reflection profile. Journal of Asian Earth Sciences., 113, 491–500. |
[23] | Hu JF, A Peng P, Liu MY, Xi DP, Song JZ, Wan XQ, Wang CS. 2015. Seawater incursion events in a Cretaceous Paleo-lake revealed by specific marine biological markers. Scientific Reports, 5, 9508. |
[24] | Huang YJ, Yang GS, Gu J, Wang PK, Huang QH, Feng ZH, Feng LJ. 2013. Marine incursion events in the Late Cretaceous Songliao Basin, Constraints from sulfur geochemistry records. Palaeogeography, Palaeoclimatology, Palaeoecology, 385, 152–161. |
[25] | Hu WS, Lü BQ, Zhang WJ, Mao ZG, Leng J, Guan DY. 2005. An approach to tectonic evolution and dynamics of the Songliao Basin. Chinese Journal of Geology, 40(1), 16–31 (in Chinese with English abstract). |
[26] | Jin RS, Cheng YH, Li JG, Sima XZ, Miao P, Wang SY, Ao C, Li HL, Li YF, Zhang TF. 2017. Late Mesozoic continental basin "Red and Black beds" coupling formation constraints on the sandstone uranium mineralization in northern China. Geology in China, 44(2), 205–223 (in Chinese with English abstract). |
[27] | Knapp J, N.Steer D, D.Brown L, Berzin R, Suleimanov A, Stiller M, Lüschen E, Brown D, Bulgakov R, Kashubin S, Rybalka A. 1996. Lithosphere-Scale Seismic Image of the Southern Urals from Explosion-Source Reflection Profiling. Science, 274(5285), 226–228. |
[28] | Kominz MA. 1984. Oceanic ridge volumes and sea-level change-An error analysis. Schlee JS. Interregional unconformities and hydrocarbon accumulation. Tulsa, Okla, USA: AAPG memoir, 36, 109–127. |
[29] | Larson RL. 1991. Latest pulse of Earth: Evidence for a mid-Cretaceous superplume. Geology, 19(6), 547–550. |
[30] | Larson R.L, Erba E. 1999. Onset of the Mid-Cretaceous greenhouse in the Barremian-Aptian, Igneous events and the biological, sedimentary, and geochemical responses. Paleoceanography, 14(6), 663–678. |
[31] | Li CH, Yang JX. 2015. Characteristics of Tight Reservoir in Shahezi Formation of Zhaozhou Area in Songliao Basin. Acta Geologica Sinica (English edition), 89(z1), 253–253. |
[32] | Liang HD, Gao R, Hou HS, Jin S, Han JT, Han S, Liu GX. 2006. Deep electrical structure beneath the Da Hinggan Ling and the junction zone with adjacent basins and their tectonic relationship at a lithospheric scale. Chinese Journal of Geophysics, 59(5), 1696–1704 (in Chinese with English abstract). |
[33] | Liu C. 2017. Source rocks and tight conglomerate gas resource potential evaluation in Shahezi Formation of Xujiaweizi depression, Songliao Basin. Natural Gas Geoscience, 28(3), 429–438 (in Chinese with English abstract). |
[34] | Liu QY, Dai JX, Jin ZJ, Li J, Zhou QH, Feng ZH, Sun HJ. 2014. Abnormal hydrogen isotopes of natural gases from the Qingshen gas field, the Songliao Basin. Geochimica, (5), 460–468 (in Chinese with English abstract). |
[35] | Liu YJ, Li WM, Feng ZQ, Wen QB, Neubauer F, Liang CY. 2017. A review of the Paleozoic tectonics in the eastern part of Central Asian Orogenic Belt. Gondwana Research., 43, 123–148. |
[36] | Lü QT, Dong SW Tang JT, Shi DN, Chang YF. 2015. Multi-scale and integrated geophysical data revealing mineral systems and exploring for mineral deposits at depth, A synthesis from SinoProbe-03. Chinese Journal of Geophysics, 58(12), 4319–4343 (in Chinese with English abstract). |
[37] | Meng YL, Hu AW, Qiao DW, Xie XN, Pan XM, Wang JW, Tian ZW. 2012. Regional diagenetic law and control of diagenesis over gas-bearing capacity of tight reservoirs in deep Xujiaweizi fault depression, Songliao Baion. Acta Geologica Sinica, 86(2), 325–334 (in Chinese with English abstract). |
[38] | Ni YY, Dai JX, Zhou QH, Luo X, Hu AP, Yang C. 2009. Geochemical characteristics of abiogenic gas and its percentage in Xujiaweizi Fault Depression, Songliao Basin, NE China. Petroleum Exploration & Development, 36(1), 35–45 (in Chinese with English abstract). |
[39] | O'Brien C, Robinson S, D. Pancost R, Sinninghe-Damste J, Schouten S, Lunt D, Alsenz H, Bornemann A, Bottini C, Brassell S, Farnsworth A, Forster A, Huber B, Inglis G, Jenkyns H, Linnert C, Littler K, Markwick P, McAnena A, E. Wrobel N. 2017. Cretaceous sea−surface temperature evolution, Constraints from TEX 86 and planktonic foraminiferal oxygen isotopes. Earth−Science Reviews. 172 |
[40] | Oliver J, Cook F, Brown L. 1983. Cocorp and the continental crust. Journal of Geophysical Research Solid Earth, 88(B4), 3329–3347. |
[41] | Oliver J. 1978. Exploration of the continental basement by seismic reflection profiling. Nature, 275(5680), 485–488. |
[42] | Parrish JT. 2001. Interpretation pre-Quaternary climate from the geologic record. Irvington, NY, USA: Columbia University Press |
[43] | Percival JA, Cook FA, Clowes RM. 2012. Tectonic styles in Canada, the Lithoprobe perspective. Geological Association of Canada−Special Paper, 49 |
[44] | Ren SM, Qiao DW, Zhang XZ, Liu YJ, Wang N, Sun YW, Tang ZX, Cui YQ. 2011. The present situation of oil & gas resources exploration and strategic selection of potential area in the Upper Paleozoic of Songliao Basin and surrounding area, NE China. Geological Bulletin of China, 30(2), 197–204 (in Chinese with English abstract). |
[45] | Sengör AMC, Natal'in BA. 1996. Paleotectonics of Asia, Fragments of a syn thesis |
[46] | Skelton PW, Spicer RA, Kelley SP, Gilmour I, Skelton PW (Ed.). 2003. The Cretaceous Word. Cambridge University Press U.K |
[47] | Su DC, Yang JS. 2010. Advances of international continental scientific drilling program. Acta Geologica Sinica, 84(6), 873–886 (in Chinese with English abstract). |
[48] | Tomurtogoo O, Windley B, Kröner A, G Badarch, DY Liu. 2005. Zircon age and occurrence of the Adaatsag ophiolite and Muron shear zone central Mongolia, constraints on the evolution of the Mongol-Okhotsk ocean suture and orogen. Journal of the Geological Society, 162(1), 197–229. |
[49] | Wang CS, Feng ZQ, Wu HY, Wang PJ, Kong FJ, Feng ZH, Ren YG, Yang GS, Wang XQ, Huang YJ. 2008. Preliminary achievement of the Chinese Cretaceous continental scientific drilling project-SK-I. Acta Geologica Sinica, 82(1), 9–20 (in Chinese with English abstract). |
[50] | Wang CS, Feng ZQ, Zhang LM, HuangYJ, Cao K, Wang PJ, Zhao B. 2013a. Cretaceous paleogeography and paleoclimate and the setting of SKI borehole sites in Songliao Basin northeast China. Palaeogeography, Palaeoclimatology, Palaeoecology, 385, 17–30. |
[51] | Wang CS. 2013b. Environmental/climate change in the Cretaceous greenhouse world: Records from Terrestrial scientific drilling of Songliao Basin and adjacent areas of China. Palaeogeography, Palaeoclimatology, Palaeoecology, 385, 1–5. |
[52] | Wang CW, Sun YW, Li N, Zhao GW, Ma XQ. 2009. Tectonic implications of Late Paleozoic stratigraphic distribution in Northeast China and adjacent region. Science in China, (10), 1429–1437 (in Chinese with English abstract). |
[53] | Wang DP, Liu ZJ, Liu L. 1994. Evolution of the Songliao Basin and Eustacy. Beijing, Geological Publishing House |
[54] | Wang PJ, Mattern F, Didenko NA, Zhu DF, Singer B Sun XM. 2016. Tectonics and cycle system of the Cretaceous Songliao Basin, An inverted active continental margin basin. Earth-Science Reviews, 159, 82–102. |
[55] | Wang PJ, Liu HB, Ren YG, Wang XQ, Wang SX, Zhai XJ, Meng QA, Huang YJ, Huang QH, Gao YF. 2017. How to choose a right drilling site for the ICDP Cretaceous Continental Scientific Drilling in the Songliao Basin (SK2), Northeast China. Earth Science Frontiers, 24(1), 216–228 (in Chinese with English abstract). |
[56] | Wang T, Zheng YD, Zhang JJ, Zeng LS, T. Donskaya, Guo L, Li JB. 2011. Pattern and kinematic polarity of late Mesozoic extension in continental NE Asia, Perspectives from metamorphic core complexes. Tectonics, 30, TC6007. |
[57] | Wang T, Guo L, Zhang L, Yang QD, Zhang JJ, Tong Y, Ye K. 2015. Timing and evolution of Jurassic–Cretaceous granitoid magmatisms in the Mongol–Okhotsk belt and adjacent areas NE Asia, Implications for transition from contractional crustal thickening to extensional thinning and geodynamic settings. Journal of Asian Earth Sciences, 97, 365–392. |
[58] | Wei WB, Jin S, Ye GF, Deng M, Jing JN, Li YJ, Zhang LT, Dong H, Zhang F, Xie CL. 2010. On the Conductive Structure of Chinese Continental Lithosphere—Experiment on "Standard Monitoring Network" of Continental EM Parameters (SinoProbe-01). Acta Geologica Sinica, 84(6), 788–800 (in Chinese with English abstract). |
[59] | Wu FY, Sun DY, Ge WC, Zhang YB, Grant ML, Wilde SA, Jahn BM. 2011. Geochronology of the Phanerozoic granitoids in northeastern China. Journal of Asian Earth Sciences, 41, 1–30. |
[60] | Wu HC, Zhang SH, Hinnov LD, Jiang GQ, Yang TS, Li HY, Wan XQ, Wang CS. 2014. Cyclostratigraphy and orbital tuning of the terrestrial upper Santonian–Lower Danian in Songliao Basin northeastern China. Earth and Planetary Science Letters, 407, 82–95. |
[61] | Wu HC, Zhang SH, Jiang GQ, Hinnov L, Yang TS, Li HY, Wan XQ, Wang CS. 2013. Astrochronology of the Early Turonian–Early Campanian terrestrial succession in the Songliao Basin northeastern China and its implication for long-period behavior of the Solar System. Palaeogeography, Palaeoclimatology, Palaeoecology, 385, 55–70. |
[62] | Xi DP, Wan XQ, Feng ZQ, Li S, Feng ZH, Jia JZ, Jing X, Si WM. 2011. Discovery of Late Cretaceous foraminifera in the Songliao Basin, Evidence from SK-1 and implications for identifying seawater incursions. Chin Sci Bull, 56, 253–256. |
[63] | Xiang F, Zhang DY, Chen K, Feng Q. 2015. Early Cretaceous Paleoclimate Characteristics of China, Clues from Continental Climate-indicative Sediments. Acta Geologica Sinica (English edition), 89(4), 1307–1318. |
[64] | Xu ZQ. 2004. The scientific goals and investigation progresses of the Chinese Continental Drilling Project. Acta Petrologica Acta, 20(1), 1–8 (in Chinese with English abstract). |
[65] | Xu ZQ, Yang WC, Yang JS, An ZS, Wang CS, Li HB, Liu JL, Su DC, He BZ. 2016. 15 Years of Hardship and Struggle History and the Prospects for the Future of the Chinese Continental Scientific Drilling Program (CCSD), in Memory of the 15 Year Anniversary of CCSD and 20 Year Anniversary of ICDP. Acta Geologica Sinica, 90(9), 2109–2122 (in Chinese with English abstract). |
[66] | Yang C, Liu QY, Zhou QH, Feng J, Feng ZH, Li ZS. 2009. Genetic Identification of Natural Gases in Qingshen Gas Field, Songliao Basin. Earth Science, 34(5), 792–798 (in Chinese with English abstract). |
[67] | Yang WC. 2003. Layered Mantle Reflectors in Dabie-Sulu Areas and their Interpretation. Chinese Journal of Geophysics, 46(2), 191–196 (in Chinese with English abstract). |
[68] | Yang YT, Guo ZX, Song CC, Li XB, He S. 2015. A short-lived but significant Mongol–Okhotsk collisional orogeny in latest Jurassic–earliest Cretaceous. Gondwana Research, 28(3), 1096–1116. |
[69] | Yu HZ. 2001. Sedimentary facies and palaeogeography of the Songliao Basin and its peripheral areas during Carboniferous-Permian time. Sedimentary Geology and Tethyan Geology, 21(4), 70–83 (in Chinese with English abstract). |
[70] | Zhang FQ, Chen HL, Dong CW, Yu X, Xiao J, Pang YM, Cao RC, Zhu DF. 2008. Evidence for the existence of Precambrian basement under the northern Songliao basin. Geology in China, 35(3), 421–428 (in Chinese with English abstract). |
[71] | Zhang LM, Wang CS, Wignall P.B, Kluge T, Wan XQ, Wang Q, Gao Y. 2018. Deccan volcanism caused coupled pCO2 and terrestrial temperature rises and pre-impact extinctions in northern China. Geology, 46, 271–274. |
[72] | Zhang JF, Xu H, Zhao JL, Ren PF. 2018. Geological characteristics and exploration potential of oil and gas in the northeast area of China. Geology in China, 45(2), 260–273 (in Chinese with English abstract). |
[73] | Zhang XZ, Zhou JB, Chi XG, Wang CW, Hu DQ. 2008. Late Paleozoic tectonic-sedimentation and petroleum resources in Northeastern China. Journal of Jilin University, 38(5), 719–725 (in Chinese with English abstract). |
[74] | Zhang XZ, Guo Y, Zeng Z, Fu QL, Pu JB. 2015. Dynamic evolution of the Mesozoic-Cenozoic basins in the northeastern China. Earth Science Frontiers, 22(3), 88–98 (in Chinese with English abstract). |
[75] | Zhao WJ, Zhao X, Shi DN, Liu K, Jiang W, Wu ZH, Xiong JY, Zheng YK. 2002. Progress in the study of deep (INDEPTH) profiles in the Himalayas and Qinghai-Tibet Plateau. Regional Geology of China, 21(11), 691–700 (in Chinese with English abstract). |
[76] | Zhao ZH, Xu SJ, Jiang XH, Lin CS, Cheng HG, Cui JF, Jia L. 2016. Deep strata geologic structure and tight sandy conglomerate gas exploration in Songliao Basin, East China. Petroleum Exploration & Development Online, 43(1), 13–23 (in Chinese with English abstract). |
[77] | Zhou JB, Wilde S.A., Zhang XZ, Zhao GC, Zheng CQ, Wang YY, Zhang XH. 2009. The onset of Pacific margin accretion in NE China, Evidence from the Heilongjiang high-pressure metamorphic belt. Tectonophysics, 478, 230–246. |
[78] | Zhou JB, Cao JL, Wilde SA, Zhao GC, Zhang JJ, Wang B. 2014. Paleo-Pacific subduction-accretion, Evidence from Geochemical and U-Pb zircon dating of the Nadanhada accretionary complex NE China. Tectonics, 33(12), 2444–2466. |
[79] | Zhou J, Wilde S, Zhao GC, Han J. 2017. Nature and assembly of microcontinental blocks within the Paleo-Asian Ocean. Earth-Science Reviews |
[80] | Zorin Y.A. 1999. Geodynamics of the western part of the Mongolia–Okhotsk collisional belt Trans-Baikal region (Russia) and Mongolia. Tectonophysics, 306(1), 33–56. |
[81] | Zou CC, Xiao L, Niu YX, Hou J, Peng C. 2016. General design of geophysical logging of the CCSD-SK-2 East Borehole in the Songliao Basin of Northeast China. Earth Science Frontiers, 23(3), 279–287 (in Chinese with English abstract). |
Borehole distribution of the Deep Continental Scientific Drilling Engineering Project in Songliao Basin (modified from Wang PJ et al., 2017).
Structural cross section across the central part of the Songliao Basin, based on regional seismic analyses and the borehole distribution of the Deep Continental Scientific Drilling Engineering Project (after Wang CS et al., 2013a).
The statistical histogram of gas logging abnormal lithology and the thickness of the Shahezi Formation in Well SK-2.
The statistical histogram of gas logging abnormal ratio for Well SK-2.
The statistical histogram of gas logging abnormal lithology and the thickness of the Shahezi and Huoshiling Formation in Well SK-2 (the abnormal ratio of gas logging is counted as those greater than 5).
Temperature log of Well SK-2.
The log response of two layers with radioactive anomalies in the Yingcheng Formation from Well SK-2.
Carbon-oxygen stable isotope curves of paleosol calcium carbonates in the Sifangtai-Mingshui Formation of the Songliao Basin and their correlations with global records (modified from Gao Y et al., 2015).
Variation of temperature, CO2 and mass extinction at the Cretaceous-Paleocene boundary (after Zhang LM et al., 2018).
A. Box-plot of pyrite framboids in Unit 1 of the Nenjiang Formation (stars mark the foraminifera-bearing layers); B. Correlations of organic geochemical data of Unit 1 of the Nenjiang Formation (after Hu D et al., 2015).
Integrated core histogram of Well SK-2.
The lithospheric cross section of the Songliao Basin from east to west. Mantle refection marked by Ⅱ and Ⅲ, dipping to each other, is found beneath the Songliao Basin. The mantle reflection is evidence of bi-directional plate subduction and convergence prior to the formation of the Songliao Basin. The location is shown in Figure 1 (B−B’). NJ FZ: Nenjiang fault zone.
Interpreted model from the deep seismic reflection profile trending north to south crossing Well SK-2. Location is shown in Fig. 1 (C−C’). SK-2−Well SK-2; T2−top of Quantou Formation; T3−top of Yingcheng Formation; T42−bottom of Yingcheng Formation.