Karst developmemt of buried dolomite hill reservoir in Wumishan formation of Renqiu oilfield

Based on the statistics of the features, dropping and leaking of well drilling, and the geophysical & logging data, the developing regulation of karst of buried hill in Renqiu oilfield was systematically studied. The results show that the period of the karst development is mainly in Tertiary, with spatial inhomogeneity. The inhomogeneity is mainly controlled by the geological construction in the horizontal direction. There are 3∼4 level karst developing zones in the profile section, which are mainly controlled by the intermittent subsidence of the earth’s crust started from Tertiary. The forming time of the lower karst zones is earlier than that of the upper ones. The horizontal karst zones are cut off by the latter faults. At present, the chief potential areas of residual oil of Renqiu oilfield are in the weak karst developing zones.