Palaeo-karst Research of the Carbonate Oil-gas Field and Its Application to Oil-Gas Exploration and Development
碳酸盐岩油气田古岩溶研究及其在油气勘探开发中的应用

Palaeo-karst was formed under an ancient stress condition in geological history, and deep karst was formed in a deep buried condition not controlled by the base level of erosion. The major carbonate reservoir space consists of dissolved pores, fractures and caves with obvious heterogeneous anisotropic characteristics and complex distribution features because of the endless karstic process. The formation conditions and controlling factors are composed of the inner factors of carbonate, such as the type of structure, the physical mechanic property, and the geo-environment in every geological epoch. This paper emphasizes the formation mechanism of palaeo-karst and the relationship between palaeo-karst and oil-gas accumulation, and forecasts the favorable areas of oil-gas accumulation on the basis of a systematic study of the formation conditions, the controlling factors and the developmental characteristics of palaeo-karst and deep karst.