Research Of Two-phase Flow Mechanism Of Gas Water Interaction In Puguang Gas Field During The Water Invasion

Puguang gas reservoir is a tectonic-lithologic gas reservoir.The main reservoir of the gas field is of good physical property,with medium pore medium permeability and high porosity and high permeability reservoir.Due to the active edge and bottom water,the water invasion occurs in the gas reservoir during the mining process,resulting in the water locking damage of the gas reservoir,and the low recovery degree makes the gas reservoir stable and efficient in the long term and the difficulty of efficient development is greatly improved.In order to study the mechanism of water invasion of gas micro,make clear the influence of invasion effect on gas reservoir development,for the follow-up in the macro to further explore the mechanism of water invasion in Puguang gas field,put forward the countermeasure of edge and bottom water control,realize the efficient development of gas reservoirs to provide,launched a study of "Research of the Water Invasion Law of Puguang Gas Field".From the gas water core microscopic visualization mutual flooding,mesoscale water gas mutual flooding and long core flooding water flooding experiment.The following conclusions are drawn:? by analyzing the geological characteristics and development status of Puguang gas field,it is found that in recent years,the water production and the ratio of liquid to gas increase linearly,and the release of water locks is imminent.?by analyzing the porosity and permeability parameters and critical flow state of core 72,we can conclude that the reservoir heterogeneity is strong,and the water saturation of core is proportional to starting pressure.?Core permeability is negatively correlated with breakthrough pressure.Through the research on micro physical modeling of water invasion mechanism,found that the matrix core seepage capacity is mainly affected by the size and distribution of pore and micro cracks,water lock formation,using gas drive to relieve water lock damage process shows that the gas water front along the large pore throat ratio for migration,matrix fracture dense core.Water invasion into the cracks after affected by capillary imbibition,water will diffuse along the crack surface to the matrix imbibition,infiltration of water to form a certain depth in the unadorned cracks in the walls,thereby forming a high-pressure air bag in the rock matrix is surrounded by cracks,reduce the degree of natural gas recovery.?The research of dual medium water invasion mechanism,water invasion after gas injection flooding formation water,the water relative permeability decreases quickly,relative permeability of gas rises quickly,the residual water saturation is high,the two-phase flow area is narrow,the intersection of high water saturation,strong hydrophilic core,gas flooding water,bound water saturation increased the gas flow rate curve,gas water front flat rate in gas flooding after water breakthrough soon reached the maximum value of gas,can be seen at the same time,relieve water lock and low efficiency is characteristic of non piston type gas channeling.This paper provides a basis for the analysis of water invasion mechanism and water control measures in the macro direction.