The discovery of the giant gas reservoir in the Leshan-Longnüsi paleo-uplift in the central Sichuan Basin reveals the immense exploration potential of the Lower Cambrian Longwangmiao Formation. Well WT1 in eastern Sichuan also encountered a beach facies reservoir with 12 m thickness in the Longwangmiao Formation, suggesting that gas reservoirs in this formation could expand further towards the eastern and northern parts of the Sichuan Basin. However, drilled wells indicate that the Longwangmiao Formation reservoirs in eastern Sichuan are thin, seismic data have low vertical resolution, and the reservoir prediction results are prone to significant errors, which cannot meet exploration needs. To address this issue, a physical model was constructed based on the drilled well information, and some forward models are conducted to study the seismic response characteristics of reservoirs under different thicknesses, porosities, and superposition patterns. On this basis, amplitude-preserving, high-fidelity, high-resolution processing of seismic data and post-stack seismic impedance inversion were carried out to predict the lateral distribution characteristics of the reservoirs. The research results show as follows. The spectral inversion method can improve the vertical resolution of the Longwangmiao Formation seismic data in eastern Sichuan. The dominant frequency of the seismic data increased from 25 Hz to 45 Hz, and the bandwidth expanded from 10 ~ 45 Hz to 10 ~ 80 Hz. Well-to-seismic calibration results indicate that the obtained high-resolution seismic data retain amplitude fidelity. Based on the high-resolution seismic data, post-stack seismic impedance inversion is performed, and the inverted impedance data volume can identify reservoirs with a thickness of 12 meters in the Longwangmiao Formation. The research results have improved the accuracy of reservoir identification in the Longwangmiao Formation in eastern Sichuan, providing a reliable basis for oil and gas exploration and development in the area.
JIANG Hang, MA Hua-ling, XU Zhe-hang, SUN Yi-ting, ZHOU Gang.
Improvement of Reservoir Identification Accuracy of the Lower Cambrian Longwangmiao Formation in Eastern Sichuan Basin Using Spectral Inversion Method[J].
Science Technology and Engineering, 2026, 26(6): 2301-2312 DOI:10.12404/j.issn.1671-1815.2502029
WangJixuan, LiShilin, HuZhonggui, et al. Hydrocarbon potential and hydrocarbon accumulation stages of reservoirs of Cambrian Gaotai Formation in eastern Sichuan Basin[J]. Science Technology and Engineering, 2024, 24(21): 8869-8878.
YangWeiqiang, LiTing, LanCaijun, et al. Distribution and controlling factors of dolostone in lower cambrian longwangmiao Formation, Sichuan Basin[J]. Earth Science, 2024, 49(7): 2388-2406.
DongJun, LiuShugen, QingPing, et al. Conditions and process of hydrocarbon accumulation in Sinian-Cambrian in Langzhong Area, north Sichuan[J]. Science Technology and Engineering, 2021, 21(30): 12879-1889.
YiYang, YangFei, WangShun, et al. Identification and application of karst traps in Longwangmiao Formation, Ziyang Area, Western Sichuan[J]. Science Technology and Engineering, 2021, 21(13): 5296-5305.
YangWeiqiang, LiuZheng, ChenHaoru, et al. Depositional combination of carbonate grain banks of the Lower Cambrian Longwangmiao Formation in Sichuan Basin and its control on reservoirs[J]. Journal of Palaeogeography, 2020, 22(2): 251-265.
LiuZiliang, DengKun, ShiZejin, et al. Sedimentary facies and model of shallow water carbonates platform of the Lower Cambrian Longwangmiao Formation in Sichuan Basin[J]. Journal of Palaeogeography, 2020, 22(3): 504-522.
ZhangWenji, LiShilin, RenXiaoli, et al. Sedimentary facies characteristics and favorable facies belt distribution of Cambrian Longwangmiao Formation, eastern Sichuan Basin[J]. Natural Gas Exploration and Development, 2019, 42(2): 56-65.
MenYupeng, XuXiaosong, MouChuanlong, et al. Sedimentary facies and palaeogeography of the evaporates in the middle upper Yangtze Area[J]. Sedimentary Geology and Tethyan Geology, 2010, 30(3): 58-64.
YangWei, XieRenwu, WeiGuoqi, et al. Sequence lithofacies paleogeography, favorable reservoir distribution and exploration zones of the Cambrian and Ordovician in Sichuan Basin, China[J]. Acta Petrolei Sinica, 2012, 33(S2): 21-34.
RenYing, ZhongDakang, GaoChonglong, et al. Sedimentary facies of the Lower Cambrian Longwangmiao Formation in eastern Sichuan Basin and its adjacent areas[J]. Journal of Palaeogeography, 2015, 17(3): 335-346.
XiCheng, HeYuan, LüYan, et al. Seismic response characteristics of the Lower Cambrian Longwangmiao Formation reservoirs in the eastern Sichuan Basin[J]. Natural Gas Industry, 2020, 40(9): 39-46.
DuJinhu, ZhangBaomin, WangZecheng, et al. Sedimentary model and reservoir genesis of dual grain banks at the Lower Cambrian Longwangmiao Fm carbonate ramp in the Sichuan Basin[J]. Natural Gas Industry, 2016, 36(6): 1-10.
ZhangManlang, GuoZhenhua, ZhangLin, et al. Characteristics of and main factors controlling the karst shoal reservoir of the lower Cambrian Longwangmiao Formation in the Anyue Gas Field, central Sichuan Basin, China[J]. Earth Science Frontier, 2021, 28(1): 235-248.
[33]
HamlynW. Thin beds, tuning, and AVO[J]. The Leading Edge, 2014, 33(12): 1394-1396.
[34]
PuryearC I, CastagnaJ P. Layer-thickness determination and stratigraphic interpretation using spectral inversion: theory and application[J]. Geophysics, 2008, 73(2): R37-R48.
ZhangH, HeZ H, LiY L, et al. Research and application of spectral inversion technique in frequency domain to improve resolution of converted PS-wave[J]. Applied Geophysics, 2017, 14(2): 247-257.
[37]
SunY G, CaoS Y, ChenS Y, et al. Blind spectral inversion of seismic data[J]. Geophysical Prospecting, 2024, 72(9): 3436-3447.
CaoJianhua, QiuZhihai, GuoDehai, et al. Post-stack seismic spectral-inversion technique and its application[J]. Progress in Geophysics, 2013, 28(1): 387-393.