A DISCUSSION OF CRETACEOUS BOTTOM UNCONFORMITY DIVISIONIN BACK\|LAND OF SHENGBEI DEPRESSION AND ITS SOUTHEAST, TUHA BASIN
吐哈盆地胜北洼陷腹地及其东南地区白垩系底界不整合面划分探讨

A new set of oil- and gas-bearing reservoirs between Cretaceous and Jurassic have been found in the Honglian oilfield, Tuha basin. But there are different opinions on its classification, which has negative effect on the naming, correlation of the stratum, and the evaluation of oil and gas exploration potential as well as the making of development technology policies. The unconformity surface between the Cretaceous and Jurassic resulted from the second episode of Yanshanian tectonic movement. This paper presents the correlation and demonstration of several opinions on the new oil- and gas-bearing reservoir classification based on the integration of multi-disciplinary information such as core, logging and seismic feature, etc. It is concluded that the new oil and gas-bearing reservoirs discovered in Well Hongnan9-12 should be classified to the Lower Cretaceous, for it is located above the unconformity surface between the Cretaceous and Jurassic.