| All along,oil and gas resources have occupied a dominant position in the economic development.In recent years,heavy oil steam flooding technology has been greatly developed at home and abroad.However,due to the serious steam channeling,the utilization degree of heavy oil reservoir and the effect of steam flooding were seriously affected.Therefore,in order to improve the steam flooding effect after the occurrence of steam channeling,there is an urgent need for a method to effectively suppress steam channeling,minimize the harm of steam channeling,and achieve the best oil recovery effect.In view of the above problems,this paper studied the heavy oil recovery technology,analyzed the heavy oil steam injection recovery mechanism and the existing steam channeling problems.The research status of the temperature-resistant plugging system at home and abroad was investigated,and the characteristics of steam channeling in the steam flooding reservoir and the plugging mechanism of the plugging system with solid particles were studied.The laboratory experiment method was used to develop the formulation of the gel carrier liquid for solid particles,the formulation was optimized,the formulation of the final gel system was determined,and the relevant performance evaluation was carried out.The screening of solid phase particles was carried out,and an experimental study on the compatibility of solid phase particles and gel systems was conducted.The sand filling model physical simulation experiment was used to evaluate the injectability,selective plugging and oil displacement effect evaluation of the solid particles and gel system,and finally a temperature-resistant plugging system for plugging the steam channel was finally obtained.Studies show that the formation of steam channeling is affected by geological factors,crude oil viscosity,production schemes,etc.When high-temperature and high-pressure steam is injected into the reservoir,a new type of pore throat"hot earthworm"is created in the original pores.The hole throat channel is clean,and the width is generally about 5?10?m.The formulation of the polymer gel system is determined to be 200m L distilled water+1.2g konjac powder+1.0g polyacrylamide+chromium acetate 1.4g+sodium lignosulfonate 0.8g+sodium sulfite 0.1g+120mesh nitrile rubber powder,150 mesh 1.0g each of glass beads and secondary fly ash.When the shear rate is 10s-1and 150?,the viscosity of the gel is maintained at 4352.36m Pa·s;when the salinity reaches 1.4g/L,the viscosity is about10000m Pa·s;when heating continuously at 85?for 10d,the viscosity The viscosity is2350.7m Pa·s,indicating that the gel formulation has good temperature resistance,salt resistance,and long-term stability.The plugging performance experiment shows that when the gel injection volume is 0.2PV and 0.5PV,the plugging rate reaches 95.86%and 98.35%,respectively.Through compatibility experiments,organic and inorganic particles have good compatibility with gels.The performance evaluation of the solid-phase particles and gel system shows that the injection speed of the gel and solid-phase particles is between1.0m L/min?1.5m L/min;after heating at 300?for 14h,it still has a strong blocking effect The blocking rate can reach 92.96%.In the double-pipe parallel oil displacement experiment,after two injections of 0.8PV solid particles and a gel system were used for plugging,the recovery rate increased by 59.04%,and the comprehensive recovery rate of crude oil in the double pipes reached 91.49%.The solid phase particle polymer gel compounding system has a better effect on preventing steam channeling in steam flooding reservoirs and improving crude oil recovery. |
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