Tahe Oilfield in Tarim Basin is a large-scaled unconformable and palaeokarst fractured-caved Ordovician carbonate reservoir. The extent of hydrocarbon displacement descends and residual water increases from the main part of the oilfield to the southern part. The oil-water interface declines irregularly from the top of the buried hill to the surrounding slope. The regional tectonic setting, fracture-cave system and dynamical process led to the heterogeneous fluid distribution during hydrocarbon accumulation. According to the pore structure of formation, the process of hydrocarbon displacement, and chemical-dynamical response of produced water during reservoir development, three types of formation water can be identified: residual water in bottoms of caves after hydrocarbon displacement, residual water in fractures and vugs around caves after hydrocarbon displacement, and interlayer water under reservoir. The alteration regulation of water breakthrough time, water energy, water content, and hydrochemical characteristics for various types of water are different.