Sedimentary evolution pattern and architectural characteristics of mid-channel bars in sandy braided rivers: Understanding based on sedimentary numerical simulation
), Abstract
Mid-channel bars in sandy braided rivers, boasting a large scale, high connectivity, and favorable physical properties, serve as a significant type of hydrocarbon reservoirs. Complex and variable hydrodynamic conditions endow mid-channel bars with multiple types and complex internal architectures, which constrain efficient oil and gas exploitation. This study aims to explore the sedimentary evolution pattern and architectural characteristics of mid-channel bars in sandy braided rivers, with a specific focus on the influence of the sedimentary process. To this end, we conduct the dynamic simulation and process analysis of the sedimentary evolution of sandy braided rivers using a sedimentary numerical simulation method based on the real-time solution in hydrodynamic fields. The results are as follows: (1) Mid-channel bars in sandy braided rivers evolve in five stages, namely the sequential formation and continuous conversion of lozenge-shaped bars, tongue-shaped bars, unit bars, composite bars, and reworked composite bars. These bars differ significantly in planar morphology, cross-sectional structure, and scale; (2) Interactions between water currents and mid-channel bars act as the predominant mechanism governing the sedimentary evolution of sandy braided rivers. Specifically, the constant changes in the convergence and divergence characteristics and distribution styles of water currents facilitate the formation, accretion, migration, and deformation of the mid-channel bars, which are under frequent and complex superimposition and cutting. In turn, the evolutionary dynamics of the mid-channel bars further induces the above-mentioned changes in water currents; (3) Three types of accretion stemming from progradation, lateral accretion, and aggradation occur within the mid-channel bars. In the process from the formation of lozenge-shaped bars to the emergence of reworked composite bars, the accretion within mid-channel bars evolves from an initial dominance of progradation to the coexistence of progradation and lateral accretion, culminating in a combination of all three accretion types. During the transitional phase, the length and width of the mid-channel bars experience a rapid increase, followed by a slow increase, and finally stabilize. As revealed by sedimentary records, reservoirs of the mid-channel bar microfacies terminating at different evolutionary stages differ significantly in planar distribution pattern, internal architectural characteristics, and scale.
Keywords
References
YU Xinghe. Sedimentology of oil and gas reservoirs in clastic rock series[M]. 2nd ed. Beijing: Petroleum Industry Press, 2008: 379-380.
ZHANG Jinliang. Fluvial facies styles and their sedimentary facies models[J]. Xinjiang Petroleum Geology, 2019, 40(2): 244-252.
FAN Xiaoyi. Sedimentary Characteristics of Paleogene Shallow Braided River Delta in Chunguang Prospect Area Junggar Basin[J]. Special Oil & Gas Reserviors, 2022, 29(4): 47-54.
LIU Yangping, WU Boran, YU Zhongliang, et al. Reconstruction of 3D geological model of braided river sandstone reservoirs: A case study of Neogene Guantao Formation in Gaoshangpu block, Jidong Oilfield[J]. Lithologic Reservoirs, 2022, 34(4): 159-170.
SHEN Chunsheng, HU Zhihua, LIN Guosong, et al. Sedimentary mode of shallow braided river delta in PL oilfield of Bohai[J]. Petroleum Geology & Engineering, 2022, 36(6): 28-32.
SHAO Zhifang, LI Weicai, HUANG Yuyang, et al. Identification and characterization of multi-stage braided river sedimentary single sand bodies of Shawan formation in Chunguang exploration area[J]. Petroleum Geology & Engineering, 2021, 35(6): 18-24.
QIE Ying, WANG Jianli, MA Jiaguo, et al. Application of combined well-seismic analysis technology in complex fluvial reservoir characterization[J]. Fault-Block Oil and Gas Field, 2021, 28(5): 641-644.
CHEN Ke, ZHANG Xudong, HE Wei, et al. Influence of micro displacement effect of permeability on water flooding and the direction of tapping potential of fluvial reservoir[J]. Reservoir Evaluation and Development, 2021, 11(5): 694-702.
Xia Qinyu, Wu Shenghe, Feng Wenjie, et al. Controlling effects of syn depositional reverse fault associated folds on the deposition in alluvial fan sheet glutenites and braided channels: A case study of the Triassic Karamay Formation in Huwan area, northwestern margin of Junggar Basin[J]. Oil & Gas Geology, 2021, 42(2): 509-521.
SUN Guangyuan, WANG Zhelin, LIU Peigang, et al. Dissolved micro-pores in alkali feldspar and their contribution to improved properties of tight sandstone reservoirs: A case study from Triassic Chang-63 sub-member, Huaqing area, Ordos Basin[J]. Oil & Gas Geology, 2022, 43(3): 658-669.
LI Jinbu, CUI Yuehua, HUANG Yougen, et al. Technologies and prospect of full-cycle development of low-permeability tight gas reservoirs with horizontal wells, Ordos Basin[J]. Oil & Gas Geology, 2023, 44(2): 480-494.
WU Gaokui, ZHANG Zhongmin, LIN Changsong, et al. Evolution of Mesozoic sedimentary fill in the Tabei uplift region, Tarim Basin[J]. Oil & Gas Geology, 2022, 43(4): 845-858.
ZHANG Changmin, ZHANG Shangfeng, LI Shaohua, et al. Advances in Chinese fluvial sedimentology from 1983 to 2003[J]. Acta Sedimentologica Sinica, 2004, 22(2): 183-192.
ZHANG Changmin, ZHU Rui, ZHAO Kang, et al. From end member to continuum: Review of fluvial facies model research[J]. Acta Sedimentologica Sinica, 2017, 35(5): 926-944.
CANT D J, WALKER R G. Fluvial processes and facies sequences in the sandy braided South Saskatchewan River, Canada[J]. Sedimentology, 1978, 25(5): 625-648.
MIALL A D. Architectural-element analysis: A new method of facies analysis applied to fluvial deposits[J]. Earth-Science Reviews, 1985, 22(4): 261-308.
LI Shunli, YU Xinghe, CHEN Bintao, et al. Quantitative characterization of architecture elements and their response to base-level change in a sandy braided fluvial system at a mountain front[J]. Journal of Sedimentary Research, 2015, 85(10): 1258-1274.
YANG Lisha, CHEN Bintao, LI Shunli, et al. Pattern of genesis-based mudstone distribution for sandy braided river: A case study of sandy braided-river outcrop, Datong, Shanxi Province, China[J]. Natural Gas Geoscience, 2013, 24(1): 93-98.
CHEN Bintao, YU Xinghe, WANG Lei, et al. Features and controlling factors of river pattern transition in fluvial deposition and its significance for petroleum geology: An insight from the Jimidi Formation in the Ruman area, Melut Basin, South Sudan[J]. Acta Sedimentologica Sinica, 2021, 39(2): 424-433.
HE Shunli, LAN Chaoli, MEN Chengquan. New braided river model in Sulige Gas Field of Ordos Basin[J]. Acta Petrolei Sinica, 2005, 26(6): 25-29.
WANG Yue, CHEN Shiyue, LI Tianbao, et al. Braided river sand body architecture and heterogeneity of Permian in Palougou outcrop[J]. Journal of China University of Petroleum (Edition of Natural Science), 2016, 40(6): 1-8.
JIN Zhenkui, YANG Youxing, SHANG Jianlin, et al. Sandbody architecture and quantitative parameters of single channel sandbodies of braided river: Cases from outcrops of braided river in Fukang, Liulin and Yanan areas[J]. Natural Gas Geoscience, 2014, 25(3): 311-317.
ASHMORE P E. Laboratory modelling of gravel braided stream morphology[J]. Earth Surface Processes and Landforms, 1982, 7(3): 201-225.
ASHWORTH P J, BEST J L, JONES M. Relationship between sediment supply and avulsion frequency in braided rivers[J]. Geology, 2004, 32(1): 21-24.
FIELDING C R, ALEXANDER J, ALLEN J P. The role of discharge variability in the formation and preservation of alluvial sediment bodies[J]. Sedimentary Geology, 2018, 365: 1-20.
HOEY T B, SUTHERLAND A J. Channel morphology and bedload pulses in braided rivers: A laboratory study[J]. Earth Surface Processes and Landforms, 1991, 16(5): 447-462.
MAO L, RAVAZZOLO D, BERTOLDI W. The role of vegetation and large wood on the topographic characteristics of braided river systems[J]. Geomorphology, 2020, 367: 107299.
OKAZAKI H, KWAK Y, TAMURA T. Depositional and erosional architectures of gravelly braid bar formed by a flood in the Abe River, central Japan, inferred from a three-dimensional ground-penetrating radar analysis[J]. Sedimentary Geology, 2015, 324: 32-46.
POSTMA G, KLEINHANS M G, MEIJER P T, et al. Sediment transport in analogue flume models compared with real-world sedimentary systems: A new look at scaling evolution of sedimentary systems in a flume[J]. Sedimentology, 2008, 55(6): 1541-1557.
ZHANG Xianguo, LIN Chengyan, ZHANG Tao, et al. New understanding of bar top hollows in dryland sandy braided rivers from outcrops with unmanned aerial vehicle and ground penetrating radar surveys[J]. Remote Sensing, 2021, 13(4): 560.
LIU Bo, ZHAO Hanqing, LI Guangyue, et al. Sand body identification of braided river reservoir——An example from the PI23 west of Lamadian-Saertu Oilfield, Daqing, China[J]. Acta Petrolei Sinica, 2002, 23(2): 43-47.
LIU Yuming, HOU Jiagen, WANG Lianmin, et al. Architecture analysis of braided river reservoir[J]. Journal of China University of Petroleum (Edition of Natural Science), 2009, 33(1): 7-11, 17.
XU Zhongbo, SHEN Chunsheng, CHEN Yukun, et al. Architecture characterization for sandy braided river reservoir and controlling factors of remaining oil distribution——A case study of P Oilfield (Neogene), Bohai offshore, China[J]. Acta Sedimentologica Sinica, 2016, 34(2): 375-385.
GUO Zhi, JIA Ailin, HE Dongbo, et al. Characteristics of braided river sedimentary system zones in Sulige Gasfield, Ordos Basin[J]. Oil & Gas Geology, 2016, 37(2): 197-204.
EDMONDS D A, SHAW J B, MOHRIG D. Topset-dominated deltas: A new model for river delta stratigraphy[J]. Geology, 2011, 39(12): 1175-1178.
LI Wei, COLOMBERA L, YUE Dali, et al. Controls on the morphology of braided rivers and braid bars: An empirical characterization of numerical models[J]. Sedimentology, 2023, 70(1): 259-279.
SCHUURMAN F, TA Wanquan, POST S, et al. Response of braiding channel morphodynamics to peak discharge changes in the Upper Yellow River[J]. Earth Surface Processes and Landforms, 2018, 43(8): 1648-1662.
ZHANG Ke, WU Shenghe, FENG Wenjie, et al. Bar dynamics in a sandy braided river: Insights from sediment numerical simulations[J]. Sedimentary Geology, 2020, 396: 105557.
FENG Wenjie, WU Shenghe, ZHANG Ke, et al. Depositional process and sedimentary model of meandering-river shallow delta: Insights from numerical simulation and modern deposition[J]. Acta Geologica Sinica, 2017, 91(9): 2047-2064.
ZHANG Ke, WU Shenghe, FENG Wenjie, et al. Discussion on evolution of bar in sandy braided river: Insights from sediment numerical simulation and modern bar[J]. Acta Sedimentologica Sinica, 2018, 36(1): 81-91.
XIAO Peiqing, YAO Wenyi. Comparison and analysis of sediment transportation equations[J]. Research of Soil and Water Conservation, 2006, 13(4): 6-8.
SCHUURMAN F, KLEINHANS M G. Bar dynamics and bifurcation evolution in a modelled braided sand-bed river[J]. Earth Surface Processes and Landforms, 2015, 40(10): 1318-1333.
TIAN Jingchun, WU Qi, WANG Feng, et al. Research on development factors and the deposition model of large area reservoir sandstones of He 8 section of Xiashihezi Formation of Permian in Ordos Basin[J]. Acta Petrologica Sinica, 2011, 27(8): 2403-2412.
SCHUURMAN F, MARRA W A, KLEINHANS M G. Physics-based modeling of large braided sand-bed rivers: Bar pattern formation, dynamics, and sensitivity[J]. Journal of Geophysical Research: Earth Surface, 2013, 118(4): 2509-2527.
京公网安备11010802044758号