Well HK-2 is located  320 km  northwest of Atelao City of Atelao State， western Kazakhstan. Rock types of the Middle Carboniferous in Well HK-2 include dolostone， limestone， siliceous rocks， sandstone and claystone. Siliceous rocks and claystone are the dominant types with mixed components， frequent interclayering， abundant organic materials and floating and swimming microbials of deep water facies. The Middle Carboniferous in this area was identified as deposits of a deep water environment， according to the high content of siliceous radiolarian fossils in the rocks， the complete preservation of siliceous sponge spicules， combined with high content of organic materials， dark color， finegrained components， muddy and siliceous components as the dominant ones， and single bioassemblages. It is still unclear whether deep water hydrocarbon accumulations exist in  the Wulaer block where Well HK-2 is  located. The authors propose that further studies should be carried out on deep water hydrocarbon accumulations. At the same time seismic profiles in this block and the adjacent blocks should be analyzed.