USING APS LOGGING TO IDENTIFY LOW-RESISTIVITY VOLCANIC ROCK GAS RESERVOIR

In the volcanic reservoir with low permeability,the signal-to-noise ratio of the logging data is relatively low due to the influence of borehole environment and lithologic framework on Compensation Neutron Logging(CNL),which will result in low coincidence rate for gas reservoir recognition,especially,for low-resistivity gas reservoir.Therefore,the paper introduced a new logging method,accelerating neutron porosity logging(APS),which will increase neutron yield and the number of the detectors,adopting back screen design and optimizing the source spacing selection of the detectors.The measure results show that this method can not only reduce the influence of the borehole environment and the rock framework,but also provide various porosity measure results.Taking the well-8 in Xushen Gasfield as an example,this paper described how APS logging was used in gas-bearing/water volcanic reservoirs with low porosity and low permeability,and suggesting the method rather than conventional logging methods could distinguish oil,gas,and water easily,and its validity could be further verified by the perforation test as well.The comprehensive application effects indicate that APS has lots of advantages in identifying the gas reservoirs with the low resistivity.