An investigation of subfacies and representative microfacies of the Cretaceous Chishan Group in the Wubao fault zone of Gaoyou sag, Subei basin, China

Document Type: Research Paper


1 School of Geosciences, China University of Petroleum

2 SINOPEC Exploration & Production Research Institute

3 School of Geo-Sciences, China University of Petroleum


This study aims to identify favorable oil–gas reservoir facies in the Chishan group of the Wubao fault zone (Gaoyou sag, Subei basin, China) using the methods of outcrops and cores observation, granularity analysis, scanning electron microscope, log data, etc. The results suggest that the Chishan group in the studied area mainly develops desert sedimentary system, and contains five kinds of facies from bottom to top, namely dry salt lake, aeolian sand, intermittent river, fan delta, and salt lake facies; the Chishan group was divided two members according to the lithology and a sedimentary cycle of base-level. The lower member of the Chishan group in the Wubao fault zone contained dry salt lake, intermittent river, and aeolian sand facies. The upper member of the Chishan group in the Chenbao area consisted mainly of aeolian sand. The southwestern Zhousong area contained (from east to west) a succession of aeolian sand, intermittent river, fan delta, and salt lake facies. Among these facies, aeolian sand was divided into aeolian sand dune, interdune, and aeolian sand sheet three sub-lithofacies. In the aeolian sand dune, the sand dune was a typical micro-lithofacies and had a scattered distribution. The fan delta had a bead-like distribution along the main fault, in which mainly underwater distributary channel and sand bank were developed. The sand bodies of the sand dune, underwater distributary channel, and sand bank were all well developed, and had average porosity values of >20%, meaning that they were favorable oil–gas reservoirs. The interdune sediments were fine-grained and had low porosity and permeability. Hence the reservoir properties of the interdune sediments were poor, and they could represent either fluid interlayers of reservoirs or source beds.


      [1]     Ronglin Ch., “The Plain Research of the Aeolian Sandstones of Chishan group the Cretaceous Period, South Jiangsu Province,” Petroleum Geology & Experiment, 1982, 4, 220–224.##

      [2]     Wenzhe Y., Zhizheng Y., and Yuehua J., “Sedimentary Environment of the Late Cretaceous Chishan Formation in the Jiangsu Province,” Acta Sedimentologica Sinica, 1997, 15, 1–7.##

      [3]     Qinghua Ch., Fei P., and Dongfang Q., “Depositional and Reservoir Haracteristics of the Cretaceous Chishan Formation in Subei Basin and their Significance,” Marine Geology & Quaternary Geology, 2008, 28, 95–100.##

      [4]     Sheng D., Chengyan L., Baojn M., Jian L., et al., “Sedimentary and Diagenetic Characteristics of Aeolian Sandstones of Chenbao Oilfield in Northern Jiangsu and its Petroleum Searching Significance,” Journal of China University of Petroleum, 2010, 34, 8–18.##

      [5]     Wenzhe Y. and Baoliang D., “Study on Cretaceous Stratigraphic Sequence of Continental Basin in Jiangsu,” Olcanology & Mineral Resources, 1999, 20, 287–344.##

      [6]     “Bureau of Geology and Mineral Resources of Jiangsu Province,” Regional geology of Jiangsu Province and Shanghai Beijing: Geological Publishing House, 1984, 292–301.##

      [7]     “Bureau of Geology and Mineral Resources of Jiangsu Province,” Geology of Nanking Hills Nanjing: Jiangsu Science and Technology Publishing House, 1989, 163–164.##

      [8]     Mader D., “Depositional Mechanisms and Facies Models of Intertonguing Aeolian Environment and Fluvial Milieu in the Middle Buntsandstein in Aspects of Fluvial Sedimentation in the Lower Triassic Buntsandstein of Europe,” Lecture Notes in Earth Sciences, Verlag Berlin Heidelberg (Springer), 1985, 127–164.##

      [9]     Yuwen L., Leyao Ch., and Xinsheng J., “Cretaceous–Eogene Desert Facies in Southern Sichuan and Northern Guizhou and Its Significance,” Sedimentary Facies and Palaeogeography, 1996, 16, 42–51.##

    [10]    Yuan X., Jian W., Xinsheng J., Minghui L., et al., “Sedimentary Characteristics of the Cretaceous Desert Facies in Ordos Basin and their Hydrogeological Significance,” Acta Sedimentologica Sinica, 2005, 23, 73–83.##

    [11]    Rodriguez-Lopez J. P., Melendez N., De Boer P. L., and Soria A. R., “Aeolian Sand Sea Development along the Mid-cretaceous Western Tethyan Margin (Spain): Erg. Sedimentology and Palaeoclimate Implications,” Sedimentology, 2008, 55, 1253–1292.##

    [12]    Hao W., Xiaozhuang C., Guoqing X., Yujie Z., et al., “Earkly Cretaceous Desert and the Reconstruction of Palaeowind Belts in Gaolan-Baiyin-Jingyuan Area, Gansu Province,” Geological Bulletin of China, 2011, 30, 1077–1084.##

    [13]    Li’an L. and Zaixing J., “Depositional Features of the Desert in the Paleogene Sichuan Basin and the Significance for the Reconstruction of Palaeowind Direction,” Geological Science and Technology Information, 2011, 30, 63–68.##

    [14]    Jing Y., Chengling Z., and Shanwen Z., “Genetic Model of the Deep Water Salt Lake of the Paleogene Sha4 Member in Dongying Sag,” Acta Sedimentologica Sinica, 2000, 18, 114–118.##

    [15]    Jing Y., “Study of Tempsetite Sedimentary of Paleogene in Huimin Depression,” China University of petroleum, 2006, 30, 1–6.##

    [16]    Jianbo G., Jianhua Z., Xiaolin X., Zhifeng W., et al., “The Fan Delta in the Altun
Slope Bounded by the Altun Rift System in the Qaidam Basin,” Acta Sedimentologica Sinica, 2004, 22, 206–215.##

    [17]    Liqiong Ch., Hao L., Qidong L., and Ming Z., “Control of the Wubao Faulted Structure over the Migration of Petroleum in the Chenbao Oilfield of the Gaoyou Depression, Jiangsu,” Acta Geoscientica Sinica, 2009, 30, 404–412.##

    [18]    Reading H. G., “Sedimentary and Facies,” Beijing, Science Press, 1985, 105–126.##

    [19]    Jiang Xinsheng., “Cretaceous Desert in China and Its Paleoclimate”, Chengdu: Chengdu University of Technology Press, 2005, 5–8.##