Study On The Carbonate Fracture Cavity Unit Of The Tuscao Ordovician In

Basing on the geology, logging data of Lun Gu Xi,applying the technical means of GC fingerprint analysis,this paper has discussed the form, distributed and Controlling factor of reservoir fracture-vug unit in Lun Gu Xi.The main achievements made in this paper are as follows(1) Because of the two substantial uplift movement in Hercynian period, the Silurian and middle-upper Ordovician on the Ordovician of Lun Gu Xi were denuded. In the late Hercynian-Indo period, in the role of the regional compressive stress,the anticline of buried-hill continues to uplift and lift,the margin of anticline continues to increase. In the context of large anticline,the layers of Carboniferous were overlap and the buried-hill was buried gradually.So it has formed the stratigraphic features of Lun Gu Xi now.(2) Reservoir lithology of Lun Gu Xi Ordovician is grainstone and second is micrite. Karst reservoir is the main reservoir. Carbonate reservoirs of Yingshan group belongs the reservoir of low porosity and permeability.And the size of the reservoir permeability is not controlled by the porosity size.(3) In terms of quantity and quality developmental, the caves of Lun Gu Xi reservoir are better then other blocks. Therefore, it is presumed that Lun Gu Xi haw better reservoir and be more conducive to oil and gas reservoirs than other blocks in Lun Gu Oilfield.(4) The reservoirs of Lun Gu Xi Ordovician Carbonate Rock are mainly concentrated in the epikarst and horizontal subsurface flow area.A few reservoirs are found in the vertical seepage area and it is not significant distribution.(5) Combined with results of previous studies, on the basis of the principle of division of fracture-vug unit,this paper has divided the fracture-vug reservoirs of Lun Gu Xi area. Among them,there are seven fracture-vug units which include two or over two wells. The remaining fracture-vug units belong to single well-controlled fracture-vug units.(6) The well connectivity distribution is no specific law in Lun Gu Xi. But the connectivity layers are mainly concentrated in epikarst and a few are distribution in horizontal subsurface flow with.Because of the depth of the region is generally about100meters under the Ordovician roof, therefore can not fully determine the level undercurrent with of Ordovician in Lun Gu Xi is the critical areas.