Research and Application of Gel Plugging Agent for High-Temperature and High-Salt Reservoir
In response to the poor high-temperature resistance of existing gel blocking agents,a gel water plugging agent with high tem-perature and salt resistance is obtained by reaction of the main agent of quaternary hydrophobic associative temperature and salt resistant polymer(AM/AMPS/DMC/NVP),the crosslinking agent of multicomponent phenolic resin,sodium thiosulfate,and nano silica,and its gelation law was studied.The effects of component concentration,formation water salinity,temperature,and shear degree on the gelation performance of it are evaluated.The experimental results indicate that gel can be formed within the concentration range of the formula;The formation water salinity has a relatively small impact on the gel strength and sealing performance of the plugging agent;The dehy-dration rate of the plugging agent after 60 days of curing at 130℃is less than 10%,indicating its good long-term thermal stability;The plugging agent has a plugging rate of over 90%on the rock cores,its plugging performance is good;Sheared at 5 000 r/min for 10 mi-nutes,and the gelation performance of the gel blocking agent is stable.The optimal formula for the gel blocking agent is 0.6%polymer+0.6%multicomponent phenolic resin crosslinking agent+0.2%sodium thiosulfate+0.3%nano silica.The site test result of the plugging agent in a well in Block Yue 13 of Qinghai Oilfield shows that the water cut decreased by 23.7%after plugging.
water plugginggel plugging agentformulateperformance evaluationhigh temperature and high salinity oil reservoirs