The Rules Of Watering Out And Development Solutions Of Volcanic Gas Reservoir In A Block Of Xushen Gas Field

Watering out can decrease the output of gas wells,increasing the damage of wellhole and gas well abandonment pressure.Watering out also can reduce the oil recovery and increase the cost of development.The research for rule of watering out of sandstone gas reservoir has got mature enough.But the he research for volcanic rock gas reservoir in this way is under developing.The type of watering out in volcanic rock reservoir is various and it is difficult to control because of internal lithologic in reservoir changing fast,strong anisotropy strong and fracture development.So it is of great significance to identify watering out,calculate the size of total water and water influx,explore the mechanism of watering,analyze the rule of watering out and propose development solution for different types of watering-out wells.The identification of watering out is reached by combining water-gas ratio and contents of salinity and chloride ion.The qualitative classification of watering out is realized by water source and flowing channel and the quantitative classification is done with daily water rate,daily water-gas ratio,cumulative gas,cumulative water and cumulative water-gas ratio.The volumetric method is used to calculate the size of total water and effective water which is testified by numerical model.The state equation,volume factor of water invasion and apparent geological reserve method are combined to calculate water influx.The mechanism of watering out is explored and it indicates that different flow laws are applicable to different phases of watering out and there is critical water saturation for watering out.The rules of watering out are analyzed which contains the rules of gas-water distribution,effects on watering out of geological and engineering factors as well as effects on production and recovery.Finally,the project proposed a set of development solution for different types of watering-out wells.The research indicates that the methods of watering-out identification and classification,calculation of water size and water influx and analyzing the mechanism and rules of watering out are effective and applicable.The results can be applied in dynamic analysis,well planning,development planning,etc.,which is a strong support for efficient development of Xushen Gas Field and a guidance for similar gas field.