Development And Evaluation Of High-temperature-resistant Fly Ash Plugging Agent For Steam Flooding In Block 9₆

For the ninth six district of qigu group heavy oil reservoir in xinjiang oilfield,the technical problems of steam overlap and fingering and difference of producing degree that existing in the development of steam flooding process,has developed high temperature resistant formula of fly ash profile control agent(the mass fraction range of main agent FA is 33.0%to 38.0%,the mass fraction range of suspending agent is 0.08%,the mass fraction range of curing agent GH is 4.0%to 5.0%,the mass fraction range of additive agent is 0.06%to 0.08%).The initial viscosity of the plugging agent solution at the temperature of 25 ? is 174 mPa.s.The initial curing time at the temperature of 100? is 8 hours and the final cure time is 19 hours,the strength is G level,has a good long-term stability under the high temperature condition.In this paper,the suspension mechanism and curing mechanism of the plugging agent have been discussed that the mainly suspension mechanisms are viscosity increasing and network bridging and the curing mechanism is that the alkali-activated fly ash formed Hydraulic gelation compounds in alkaline condition.The experimental results show that at the temperature range of 25 ? to 200 ?,when the temperature is lower than 100 ? the curing strength is unable to meet the requirements,at the temperature of 100 ? the strength is G level;within the limits of formation water salinity,the water salinity has a little influence on curing time and little effect of strength and stability;The plugging agent is hardly being cured;With the increase of pH,the curing time of plugging agent system being shorter,when the pH value reached 13,the curing time is rather short.Under the Crude oil condition,the curing time of plugging agent is slightly shorter and with increasing the percentage of oil,the curing strength gradually reduced.The results of evaluation tests show that the plugging agents dissolved an extent to ninety percent in hydrochloric acid which has a nine percent mass fraction in two hours.Physical simulation experiment results show that segmented into 0.6 PV of blocking remover for 0.3 PV of plugging agent,the core permeability recovery ratio is above ninety eight percent that indicate the plugging agents can be dissolved easily;0.3 PV of plugging agent reached a ninety nine percent high plugging ratio;Parallel core experiments results show that the plugginging agent got into high permeable zone prior,profile improvement ratio is ninety six percent.The research has a certain guiding significance for steam flooding of heavy oil reservoir in xinjiang oilfield to control the steam channeling and improve the development effect.