Automatic discrimination of sedimentary facies and lithologies in reef-bank reservoirs using borehole image logs

Reef-bank reservoirs are an important target for petroleum exploration in marine carbonates and also an essential supplemental area for oil and gas production in China. Due to the diversity of reservoirs and the extreme heterogeneity of reef-banks, it is very difficult to discriminate the sedimentary facies and lithologies in reef-bank reservoirs using conventional well logs. The borehole image log provides clear identification of sedimentary structures and textures and is an ideal tool for discriminating sedimentary facies and lithologies. After examining a large number of borehole images and cores, we propose nine typical patterns for borehole image interpretation and a method that uses these patterns to discriminate sedimentary facies and lithologies in reeI^bank reservoirs automatically. We also develop software with user-friendly interface. The results of applications in reef-bank reservoirs in the middle Tarim Basin and northeast Sichuan have proved that the proposed method and the corresponding software are quite effective.

新西兰的灯塔邮票

太平洋西南部的新西兰,由北岛、南岛及附近的一些小岛组成。新西兰沿岸海岬壁立、滩礁密布、风急浪高而且时常被浓雾笼罩。在漫长的新西兰海岸边,过去由于没有任何灯塔导航,船员辨不清港湾位置,经常发生海难事故。据该国航海史记载,至1945年共有102艘船只沉没在新西兰海域中。