西南石油大学学报(自然科学版)

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Diagenetic Facies Characteristics of the Chang 9 Oil-bearing Layer of the
Upper Triassic Yanchang Formation in the Jiyuan Area,Ordos Basin

Xiang Fang, Chen Kang, Li Fengjie, Meng Fanxing, Meng Lina   

  1. Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu,Sichuan 610059,China
  • Online:2013-10-20 Published:2013-10-20

Abstract:

On the basis of comprehensive research,the characteristics of reservoir,diagenetic process and diagenetic facies
of Chang 9 oil-bearing layer in Jiyuan area can be researched. The results indicate that:(1)the reservoir sandstones of the
Chang 9 oil-bearing layer are mainly composed of coarser feldspar sandstones and lithic-feldspathic sandstones. Cementing
materials are mainly chlorite and laumontite and matrix content is less. Reservoir spaces are mainly intergranular pores and
intragranular dissolved pores;(2)reservoir sandstones are in the A to B stage of middle diagenetic phase. Weak compaction,
limited filling of cements materials and authigenic minerals,and feldspar and laumontite dissolution have very important influence
on retention of original intergranular pores and forming of secondary dissolved pores;(3)three diagenetic facies can be
divided:laumontite intragranular pore diagenetic facies,rim chlorite residual intergranular pore diagenetic facies and siliceous
cementation diagenetic facies. The distribution of these diagenetic facies is related to supply of material sources,sedimentary
characteristics and water dynamic action;(4)rim chlorite residual intergranular pore diagenetic facies and laumontite intragranular
pore diagenetic facies,which are connected with distributary channel sand body,are the most advantageous diagenetic
facies in the area.

Key words: Jiyuan area, Chang 9 oil-bearing layer, characteristics of reservoir, diagenetic process, diagenetic facies division