ACCUMULATION MECHANISM OF NATURAL GAS IN UPPER PALEOZOIC, HANGJINQI BLOCK, NORTH ORDOS BASIN

The phenomenon of multi-types of natural gas generating together has been found in more and more basins.Lots of researchers have paid much more attention to this phenomenon.However,researches on multi-types of natural gas generating together have not attracted enough attention in China.Most researchers only focus on single gas.Researchers on multi-types of natural gas have been carried out in the Hangjinqi block of North Ordos Basin,indicating that the Upper Paleozoic in the block is suitable for generation of multi-types of natural gas.Coal-bed methane,source-contacting gas(deep basin gas) and conventional gas generate together in the block.Accumulation mechanism of 3 different types of gas reservoir transfer from absorption to piston and replacement mechanism.Coal-bed methane,source-contacting gas(deep basin gas) and conventional gas reservoirs generate in turn in space,forming accumulation mechanism spectrum.In actual exploration,only source-contacting gas(deep basin gas) and conventional gas reservoirs have commercial value.