Exploring the coupling relationship between hydrocarbon generation of continental shale and nanopore structure evolution—A case study of Shahejie formation in Bohai Bay Basin
Tóm tắt
The nano-scale pore structure of shale is closely related to the self-generated and self-accumulated shale oil and gas. The Bohai Bay Basin is a crucial oil-bearing basin in eastern China, and the Paleogene Shahejie Formation is the most important source rock section in this area. In order to study the internal relationship between hydrocarbon generation evolution and pore structure characteristics of source rocks, we conducted hydrocarbon generation simulation tests with a closed gold tube system, and heated up original rocks from Shahejie Formation in Laizhou Bay Sag, southern Bohai Bay Basin, from 290 °C to 440°C at different heating rates. Besides, we carried out low-temperature N2 adsorption experiments on sample residues, and measured their pore structure characteristic parameters. The results show that with the increase of simulated temperature, the specific surface area and pore volume of nano-pores below 10 nm (which are mainly organic pores) decrease first and then increase, while those of nano-pores above 10 nm increase all the way. The evolution trend of total specific surface area and pore volume is mainly controlled by pores below 10 nm which are mainly organic pores, especially micropores below 2 nm. There are two main factors affecting the development of inorganic pores: (1) Dissolution of organic acids produced by pyrolysis of organic matter in hydrocarbon-generation evolution; (2) Deformation of crystal structure of mineral components under the combined action of temperature and pressure. The experimental results at different heating rates demonstrate that rapid settlement under geological conditions is not conducive to the development of nano-pores, especially micro-pores composed of organic pores.
Tài liệu tham khảo
Bai JR, Wang Q, Jiao GJ (2012) Study on the pore structure of oil shale during low-temperature pyrolysis. Enrgy Proced 17:1689–1696. https://doi.org/10.1016/j.egypro.2012.02.299
Bernard S, Horsfield B, Schulz HM, Wirth R, Schreiber A, Sherwood N (2012) Geochemical evolution of organic-rich shales with increasing maturity: a stxm and tem study of the posidonia shale (lower toarcian, northern germany). Mar Pet Geol 31(1):70–89
Cama J, Ganor J (2006) The effects of organic acids on the dissolution of silicate minerals: a case study of oxalate catalysis of kaolinite dissolution. Geochim Cosmochim Acta 70(9):2191–2209. https://doi.org/10.1016/j.gca.2006.01.028
Curtis JB (2002) Fractured shale-gas systems. AAPG Bull 86(11):1921–1938
Curtis ME, Cardott BJ, Sondergeld CH, Rai CS (2012) Development of organic porosity in the Woodford Shale with increasing thermal maturity. Int J Coal Geol 103:26–31. https://doi.org/10.1016/j.coal.2012.08.004
Fu DL, Xu GS, Tian T, Qin JQ, Yang F (2019) Composition of the Shales in Niutitang formation at Huijunba Syncline and its influence on microscopic pore structure and gas adsorption. Petrophysics 60(3):373–383. https://doi.org/10.30632/PJV60N3-2019a1
Fu DL, Xu GS, Ma L, Yang F, He D, Duan Z, Ma Y (2020) Gas generation from coal: taking Jurassic coal in the Minhe Basin as an example. Int J Coal Sci Technol 7(3):611–622
Guo HJ, Jia WL, He RL, Yu CL, Song JZ, Peng PA (2020) Distinct evolution trends of nanometer-scale pores displayed by the pyrolysis of organic matter-rich lacustrine shales: implications for the pore development mechanisms. Mar Petrol Geol. https://doi.org/10.1016/j.marpetgeo.2020.104622
Huang H, Sun W, Ji W, Zhang R, Du K, Zhang S, Ren D, Wang Y, Chen L, Zhang X (2018) Effects of pore-throat structure on gas permeability in the tight sandstone reservoirs of the Upper Triassic Yanchang formation in the Western Ordos Basin, China. J Petro Sci Eng 162:602–616
Jarvie DM, Hill RJ, Ruble TE, Pollastro RM (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
Jiang Z, Zhang DX, Zhao JL, Zhou YQ (2017) Experimental investigation of the pore structure of triassic terrestrial shale in the Yanchang Formation, Ordos Basin, China. J Nat Gas Sci Eng 46:436–450. https://doi.org/10.1016/j.jngse.2017.08.002
Jiang ZX, Li TW, Gong HJ, Jiang T, Chang JQ, Ning CX, Su SY, Chen WT (2020) Characteristics of low-mature shale reservoirs in Zhanhua Sag and their influence on the mobility of shale oil. Ac Petro Sinica 41(12):1587–1600 ((in Chinese))
Kuila U, Mccarty DK, De Rkowski A, Fischer TB, Prasad M (2014) Total porosity measurement in gas shales by the water immersion porosimetry (wip) method. Fuel 117:1115–1129
Li JJ, Shi YL, Zhang XW, Chen X, Yan YX, Zhu JX, Lu SF, Wang M (2014) Control factors of enrichment and producibility of shale oil: a case study of Biyang Depression. Earth Sci- J China U Geosci 39(7):848–857 ((in Chinese))
Li J, Zhou SX, Li YJ, Ma Y, Yang YA, Li CC (2016) Effect of organic matter on pore structure of mature lacustrine organic-rich shale: a case study of the Triassic Yanchang shale, Ordos Basin, China. Fuel 185:421–431. https://doi.org/10.1016/j.fuel.2016.07.100
Li P, Jia CZ, Jin ZJ, Liu QY, Zheng M, Huang ZK (2019) The characteristics of movable fluid in the Triassic lacustrine tight oil reservoir: a case study of the Chang 7 member of Xin’anbian Block, Ordos Basin, China. Mar Petrol Geol 102:126–137. https://doi.org/10.1016/j.marpetgeo.2018.11.019
Loucks RG, Reed RM, Ruppel SC, Jarvie DM (2009) Morphology, genesis, and distribution of nanometer-scale pores in siliceous mudstones of the mississippian barnett shale. J Sediment Res 79(11–12):848–861. https://doi.org/10.2110/jsr.2009.092
Ma Y, Zhong NN, Li DH, Pan ZJ, Cheng LJ, Liu KY (2015) Organic matter/clay mineral intergranular pores in the Lower Cambrian Lujiaping Shale in the north-eastern part of the upper Yangtze area, China: a possible microscopic mechanism for gas preservation. Int J Coal Geol 137:38–54. https://doi.org/10.1016/j.coal.2014.11.001
Mathia EJ, Bowen L, Thomas KM, Aplin AC (2016) Evolution of porosity and pore types in organic-rich, calcareous, Lower Toarcian Posidonia Shale. Mar Petrol Geol 75:117–139. https://doi.org/10.1016/j.marpetgeo.2016.04.009
Milliken KL, Esch WL, Reed RM, Zhang TW (2012) Grain assemblages and strong diagenetic overprinting in siliceous mudrocks, Barnett Shale (Mississippian), Fort Worth Basin. Texas AAPG Bull 96(8):1553–1578. https://doi.org/10.1306/12011111129
Montgomery SL, Jarvie DM, Bowker KA, Pollastro RM (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. https://doi.org/10.1306/09170404042
Ning CX, Ma ZL, Jiang ZX, Su SY, Li TW, Zheng LJ, Wang GZ, Li FX (2020) Effect of shale reservoir characteristics on shale oil movability in the lower third member of the Shahejie formation. Zhanhua Sag Acta Geol Sin-Engl 94(2):352–363. https://doi.org/10.1111/1755-6724.14284
Ross DJK, Bustin RM (2009) The importance of shale composition and pore structure upon gas storage potential of shale gas reservoirs. Mar Petrol Geol 26(6):916–927. https://doi.org/10.1016/j.marpetgeo.2008.06.004
Song DJ, Wang XQ, Tuo JC, Wu CJ, Zhang MF, Su L, He W (2021) A comprehensive study on the impacts of rock fabric on hydrocarbon generation and pore structure evolution of shale under semi-confined condition. Mar Petrol Geol. https://doi.org/10.1016/j.marpetgeo.2020.104830
Su KM, Lu JG, Zhang HX, Chen SJ, Li Y, Xiao ZL, Qiu W, Han MM (2020) Quantitative study on hydrocarbon expulsion mechanism based on micro-fracture. Geosci Front 11(6):1901–1913. https://doi.org/10.1016/j.gsf.2020.05.013
Sun LN, Tuo JC, Zhang MF, Wu CJ, Wang ZX, Zheng YW (2015) Formation and development of the pore structure in Chang 7 member oil-shale from Ordos Basin during organic matter evolution induced by hydrous pyrolysis. Fuel 158:549–557. https://doi.org/10.1016/j.fuel.2015.05.061
Sun LN, Tuo JC, Zhang MF, Wu CJ, Chai SQ (2019) Pore structures and fractal characteristics of nano-pores in shale of Lucaogou formation from Junggar Basin during water pressure-controlled artificial pyrolysis. J Anal Appl Pyrol 140:404–412. https://doi.org/10.1016/j.jaap.2019.04.020
Tian H, Xiao XM, Wilkins RWT, Tang YC (2008) New insights into the volume and pressure changes during the thermal cracking of oil to gas in reservoirs: Implications for the in-situ accumulation of gas cracked from oils. AAPG Bull 92(2):181–200. https://doi.org/10.1306/09210706140
Tian H, Pan L, Xiao XM, Wilkins RWT, Meng ZP, Huang BJ (2013) A preliminary study on the pore characterization of lower Silurian black shales in the Chuandong Thrust Fold Belt, southwestern China using low pressure N2 adsorption and FE-SEM methods. Mar Pet Geol 48:8–19
Topor T, Derkowski A, Ziemianski P, Szczurowski J, McCarty DK (2017) The effect of organic matter maturation and porosity evolution on methane storage potential in the Baltic Basin (Poland) shale-gas reservoir. Int J Coal Geol 180:46–56. https://doi.org/10.1016/j.coal.2017.07.005
Wang QT, Lu H, Greenwood P, Shen CC, Liu JZ, Peng PA (2013) Gas evolution during kerogen pyrolysis of Estonian Kukersite shale in confined gold tube system. Org Geochem 65:74–82. https://doi.org/10.1016/j.orggeochem.2013.10.006
Wang PF, Jiang ZX, Yin LS, Chen L, Li Z, Zhang C, Li TW, Huang P (2017) Lithofacies classification and its effect on pore structure of the Cambrian marine shale in the Upper Yangtze Platform, South China: Evidence from FE-SEM and gas adsorption analysis. J Petrol Sci Eng 156:307–321. https://doi.org/10.1016/j.petrol.2017.06.011
Wu ST, Zhu RK, Cui JG, Bai CJW, B, Zhang XX, Jin X, Zhu DS, You JC, LI X, (2015) Characteristics of lacustrine shale orosity evolution, Triassic Chang 7 Member, Ordos Basin. NW China Petrol Explor Dev 42(2):167–176 ((in Chinese))
Wu CJ, Tuo JC, Zhang LF, Zhang MF, Li J, Liu Y, Qian Y (2017) Pore characteristics differences between clay-rich and clay-poor shales of the Lower Cambrian Niutitang Formation in the Northern Guizhou area, and insights into shale gas storage mechanisms. Int J Coal Geol 178:13–25. https://doi.org/10.1016/j.coal.2017.04.009
Zhao WZ, Hu SY, Hou LH, Yang T, Li X, Guo BC, Yang Z (2020) Types and resource potential of continental shale oil in China and its boundary with tight oil. Petrol Explor Dev+ 47(1):1–11. https://doi.org/10.1016/S1876-3804(20)60001-5