Comprehensive identification method of water production sources of gas wells in tight sandstone gas reservoirs
In view of the difficulty in identifying the sources of water production of gas wells in tight sand-stone gas reservoirs in Suligexi area without single well water production measurement,a comprehensive identification method was established by introducing hydro-chemical diagrams and combining mineraliza-tion analysis,production performance,and nuclear magnetic resonance.This method was used to identify condensate water,working fluid,and formation water.The results show that the Stiff chart of condensate water and working fluid in the gas well is cut into two parts by the auxiliary line,while the Stiff chart of for-mation water is located on one side of the auxiliary line,and the Stiff chart at different times can determine whether water invasion has occurred in the gas well.The working fluid has a salinity greater than 20 000 mg/L,while the condensate water has a salinity less than 20 000 mg/L.For formation water,the oil casing pressure inside the formation is stable and the pressure difference is less than 2 MPa before liquid accumula-tion in the wellbore,while the interlayer water oil casing pressure fluctuates greatly and the pressure differ-ence is higher than 2 MPa.When the water saturation is less than the nuclear magnetic saturation of the dis-placement pressure of 0.51 MPa,the formation water is bound water.As for the nuclear magnetic satura-tion,when the water saturation is greater than that of at the displacement pressure of 0.51 MPa or less than 0.032 MPa,the formation water is capillary water;when the water saturation is greater than that of at a dis-placement pressure of 0.032 MPa,the formation water is free water.
Sulige west districtdense sandstonecomprehensive identification of water sourcesstiff plate methodnuclear magnetic resonance
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