Study On Gas Channeling Plugging Gel In Heavy Oil Reservoir

China is one of the major heavy oil countries in the world.Steam injection is the main method for enhancing heavy oil recovery in China.Long-term steam huff and puff or steam flooding will produce steam channels,which can affect the use efficiency of steam.Serious situations will channel into oil wells and affect the normal production of oil wells.Therefore,it is of great significance to develop efficient channeling blocking agents.In this paper,two types of steam channeling plugging agents were mainly developed.In order to solve the problems of long gelation time and low gel strength of tannin extract at low temperature,the formula of tannin extract was improved in this paper.Poplar extract was selected as the gelling agent.Hydroquinone and urotropine were used as cross-linking agents.0.1%ammonium chloride was added as catalyst,and clay was used to strengthen the extract.The effects of component mass fraction on gelation properties and thermal stability of low temperature tannin extract system were further evaluated.The experimental results showed that the dehydration rate was 12%after the system was placed at 175°C for 30 d,and the plugging rate could reach more than 95%after 0.5 PV gel was injected.Optimized formation of tannin extract for plugging steam channeling in low formation temperature reservoirs during steam stimulation.The gelling time of commonly used channeling blocking agent at high temperature（250℃）is less than 1 h,which is difficult to meet the requirements of field injection of steam flooding.In this paper,SMP system was difficult to gel at low temperature and can gel at high temperature（250℃,3 h）.Two kinds of sulfonated phenolic resin were used as gelling agent and urotropine was used as crosslinking agent to compare the gelling properties of the two kinds of gel systems.The effects of various components on the gelation properties of SMP gel were analyzed.The experimental results showed both SMP-I and SMP-Ⅱ had good thermal stability.Among them,the appropriate salinity of SMP-I was 10000 mg·L^-1,and that of SMP-Ⅱ was 20000mg·L^-1.SMP-I has better sealing performance than SMP-Ⅱ.