Study On Multistage Slugs For In-depth Channeling Plugging In Steam Huff Puff Wells Of Heavy Oil Reservoir

According to the problems of steam channeling in the late oil extraction process of steam huff puff wells,channeling plugging agents have been studied.However,traditional channeling plugging agents were utilized singly and not effectively solved the problems of deep channeling plugging.Taking the optimization of slug formula and cost saving as the starting point,temperature distribution of heavy oil reservoir is analyzed,and combination of in-depth profile control slugs in steam huff puff wells of heavy oil reservoir was studied.Based on numerical simulation method,temperature distribution in high permeability layer of the heavy oil reservoir was analyzed,ultra high temperature zone(>250°C),high temperature zone(130~250°C),middle temperature zone(90~130°C)and low temperature zone(<90°C)were divided.Inorganic plugging agents of temperature resistance recommended to be used in ultra high temperature zone was not studied.In this paper,slugs of temperature resistance adapt to the other three temperature zones were studied to achieve the purpose of multistage channeling plugging.Solubility and viscosity concentration relationship of alkali lignin,tannin extract and polymer were studied,and the effects of polymer,cross-linking agents and additive agents concentrations on gelling property were evaluated with the method of bottle test experiment.The best formulas of channeling plugging slugs were confirmed.Appropriate formula of high temperature zone is 4~7% tannin extract XW + 1~2.5% cross-linking agent REL + 1~2.5% cross-linking agent MNE + 3.0% inorganic strengthening agent,that of middle temperature zone is 1.5~2% AWW + 0.6~1.0% cross-linking agent REL + 0.6~1.0% cross-linking agent MNE + 0.2~0.3% accelerator,that of low temperature zone is 1.5~2% AWW + 0.2~0.4% crosslinking agent REL + 0.2~0.3% cross-linking agent PNE + 0.07~0.15% accelerator.The application performances are studied with physical simulation trails.The experiments show that it is thermophilic and has good easy-to-injectivity,plugging property,flushing resistance and good selectivity.Performance prediction shows that after the injection of channeling plugging slugs,steam huff puff well adds two cysles of oil recovery and can achieve good effect of water control and oil production.