Research On Steam Flooding Assisted By Multi-media Injection For Enhancing Heavy Oil Recovery

Heavy oil is an unconventional hydrocarbon resource.Considering carbon neutrality and peak carbon dioxide emissions tendency in the world,how to develop and utilize heavy oil resources efficiently and economical has become an urgent problem to be solved in the oil industry.At present,most domestic heavy oil reservoirs have entered the late stage of steam drive development,and steam channeling and steam overlap are common,resulting in accelerated production decline and poor production efficiency.To solve this problem,based on the reservoir conditions of block Qi 40 in Liaohe Oilfield,the experiment of enhancing heavy oil recovery by air and flue gas assisted steam flooding is simulated in the laboratory,and its mechanism was analyzed at the same time,which improves the efficiency of simple steam flooding in the future and reduce carbon dioxide emission.In order to further improve the sweep efficiency of steam drive,a high temperature resistant plugging agent was developed,the injection production process parameters of plugging agent were optimized.Based on laboratory research results of theory and experiment,the field test of air assisted steam drive was carried out in Qi40 block.The following research results and understandings were obtained:(1)The recovery of air assisted steam flooding is higher than that of simple steam flooding.The air / steam ratio is related to the remaining oil saturation,and the air / steam ratio affects the coking range and recovery.The initial coking temperature is about 220 ℃.At 260 ℃,the oxygen content of the produced gas is less than 5%,which is within the safe range.With the increase of temperature,the overall composition of crude oil shows the decrease of light components,the increase of heavy components and the increase of viscosity.When the injection pressure changes in a certain range,the initial recovery increases with the increase of pressure.After reaching the peak pressure,the recovery decreases with the increase of pressure.(2)The recovery of flue gas assisted steam drive is higher than that of simple steam drive,but lower than that of air assisted steam drive.The higher the proportion of flue gas and the higher the displacement temperature,the higher the recovery rate;The higher the gas injection pressure is,the higher the recovery is.There is a pressure peak.If the peak pressure is exceeded,the recovery is reduced.Flue gas can be dissolved in heavy oil.After gas dissolution,the viscosity of heavy oil decreases,the rheology improved,the oil phase permeability increases,and the saturation pressure and expansion factor increase.(3)Based on the field actual block model,the EOR mechanism and development effectiveness of air and flue gas assisted steam drive are analysis and forecast by numerical simulation method.On the basis of steam flooding,after non hydrocarbon gases are injected respectively,the upward pressure of the reservoir is significantly supplemented,the gas saturation is increased,and the swept volume of steam is increased.Affected by steam overlap,the gas mainly accumulates in the upper part of the oil layer.The heat loss was reduced due to the specific volume and low thermal conductivity of air,which plays the role of heat insulation to a certain extent.At the same time,the injected gas can be partially dissolved into the crude oil,so that the volume expansion and viscosity of the crude oil are reduced,so as to further improve the development effect of steam flooding.From the perspective of different gas production effects,the development effect of air assisted steam drive is the best,and the recovery can be increased by 3.2%,the effect of flue gas assisted steam drive is the worse,with an enhanced recovery of 1.9%.(4)A high temperature resistant selective plugging control agent system(resin 15-20% +crosslinking agent 8-10% + inorganic 15-20%)suitable for thermal recovery reservoir has been developed.After the plugging control agent system stays at 280℃ for 100 days and is washed by 10 PV steam injection,the plugging rate of the core is still more than 98%.Based on the field actual block model,the plugging control parameters are designed by using the numerical simulation method,and the plugging control effect is predicted.It is estimated that the oil recovery can be improved by 5.6% after 10 years of mining.In addition,the plugging agent system has the advantages of low cost and convenient operation,and has the potential to be popularized and applied in the development of steam drive in block Qi 40.(5)The field test of air assisted steam drive in five well groups was carried out in Qi 40 block of Liaohe Oilfield.Among them,the average daily oil production and average oil-gas ratio of four well groups were significantly improved,and one well group was not effective.The monitoring data of observation well shows that air occupies the main producing layer of original steam drive in the upper part,the pressure of non main layer in the lower part of steam drive section increases,the degree of production increases,and the temperature profile is improved.The detection of tail gas shows that the oxygen content is 0.87%,which is within the safe range.Meanwhile,the temperature of wellhead liquid production has increased from 77 ℃ to 89 ℃.