Paleokarst characteristics and the favorable reservoirs development in southern Jingbian gasfield

For figuring out the favorable reservoirs development rules in southern Jingbian gasfield,the vertical zoning,plane distribution and the relationships between karstification degree of paleokarst and the reservoir development were further analyzed on the basis of the study of identification palaeokarst trail signs.The results suggest that vertical karst profile can be divided into residual zone,vertical infiltration karst zone,the vertical-horizontal flow transition zone,horizontal subsurface karst zone and weak corrosion zone etc.There developed three geomorphic units from west to east,western karst highland,central karst slope and eastern karst depression,which are characterized by the fact thatwestern is high and eastern is low,the eastern area is low-lying and gently sloping,and deep trenches are under-developed.The rate of karst water flow is high-speed in western-eastern area and slowly in the central area,the erosion intensity is gradually weakening and the weathered crust is gradually thinning form west to east.Karst type and intensity determined the vertical distribution of reservoir,palaeokarst Landform and reservoir-cap combination controlled to the reservoir distribution characteristics.It is the favorable area for development reservoirs where near the trench and karst remnant hills flanks.This view is of guiding significance for the gas exploration and development.