| Based on the data of seismic, drilling, logging and production performance, underground river in Lungu Ordovician buried-hill of Tarim Basin are described in detail, and 174 rivers are identified, and the river area is up to 70.37 km2. It is also expounded that the development of the underground rivers are obviously controlled by faults. At the same time, the underground river system is divided into main channel, branch channel and cave roof fissure. According to the size and filling degree of the tunnel, the main channel is further divided into deep zone of the big ditch, corridor zone and silting zone. The branch channel is further divided into vertical type, slope type and flat type according to the vertical angle of the branch channel entering the main channel. Statistical analysis and drilling practice showed that the deep zone of the big ditch of the main channel, the vertical and slope types of the branch channel, and the cave roof fissure of the underground river are the most favorable development area of karst reservoir and the favorable play for oil and gas accumulation. |
