Abstract:

The control of high resolution sequence stratigraphy on the vertical distribution of sedimentary microfacies and reservoirs in upperMa 5 member of Majiagou Formation in Tong 5 well block of Jianbian Gas Field in Ordos Basin is studied. Ma 5 _{1- 4} submember is an asymmetric long-term base level cycle which can be divided into five middle-term base level cycles and more than 26 short-termbase level cycles. The study result shows that the sedimentarymicrofacies and reservoirs of Ma 5 member of Majiagou Formation in Tong 5 wellblock of Jingbian Gas Field are probably dominated by long-term base level cycle. The control action of middle-term and short-term base level cycles on the distribution of sedimentary microfacies and reservoirs is distinguished. Middle-term and short-term base level cycles control the vertical subtle change of sedimentary microfacies of carbonate tidal flat in continental sea tableland, and control the vertical distribution of vugular dolomite reservoir ofweathered crust. It is feasible to divide the cycles ofMa 5 _{1- 4} by high resolution sequence stratigraphy. The achievement of this research can be applied to the analogous reservoir studies in other areas.