Influence Of Water Blocking Damage To Productivity Of F Low Porosity And Low Permeability Gas Reservoir

The low porosity and low permeability reservoirs are nearly 75%of the total natural gas in China.However,due to their poor porosity and permeability properties,such reservoirs usually have high heterogeneity and original water saturation,and are extremely susceptible to water blocking damage.The F Gas reservoir is a typical low porosity and low permeability reservoir.At present,gas wells are seriously reduced or even shut down under the influence of water blocking.Therefore,make clear the mechanism of water blocking and establish a method to identify it in such reservoirs,has great significance for ensuring the normal development of low porosity and low permeability gas reservoirs.Based on the geological characteristics of F gas reservoir,this paper carried out water blocking research from both experimental and theoretical aspects,and obtained the following results:(1)By analyzing the geological characteristics and development status of F gas reservoir,the causes of water blocking damage in low porosity and low permeability reservoirs are studied.(2)Through the reservoir sensitivity experiment,the relationship between stress sensitivity,water sensitivity,rapid sensitivity and water blocking was studied,and establish the basis of water blocking experimental.(3)Through the water blocking injury experiment,the water blocking caused by the water invasion and the self-absorption is studied.The water blocking mechanism and the main control factors affecting water blocking are determined according to the experimental results.(4)According to the effect of different methods in water blocking release experiment,the corresponding measures and suggestions for water blocking release are proposed for different degrees of water-locking damage.(5)Deduce a productivity equation after considering the influence of water blocking,establish a method for calculating the degree of water blocking by using the basic data of the gas well.Analyze the influence of water blocking on the production and pressure of the gas well.On this basis,a set of methods to identify water blocking is established.(6)Based on the above research results,a set of "water blocking identification and water blocking degree calculation software" has been compiled.In the actual application process of F gas reservoir,the software can accurately identify the water blocking gas well and calculate the water blocking degree.