Features and causes of coal measures fluid pressure in Tucheng Syncline Songhe Block of western Guizhou

In order to have the features and causes of the coal measures fluid pressure in Tucheng Syncline Songhe Block of West Guizhou,a visualized reservoir p ressure method, injection pressure drop test well method and logging curve explanation method were applied to the prediction on the pressure features of the study block. And the pressure causes mechanism of the block were discussed from the structure condition and geostress, floor and roof lithology, dynamic field features of the coal measures underground water and"three histories"evolutions. The study showed that the pressure at 110 m of Songhe Minefield was too low, the pressure at 110~560 m of the Minefield was normal and the pressure at 560 m of the minefield was abnormally high. The normal fault development and the tectonic uplift of Yanshan late cru st were the major causes to make the shallow strata pressure too low. The low permeability of the seam caused by the tectonic stress, the excellent sealing function oft he seam roof and floor, the dynamic condition of Longtan coal measure low underground water and the uncompaction and the hydrocarbon generation joint functions in t he Palaeogeologic historic period made the abnormal high pressure in the coal reservoir at 560 m of the Minefield.