Effect Of Cyclic Injection Production On Chang 8 Reservoir In Xifeng Oilfield And Its Influencing Factors

The Chang 8 reservoir in Xifeng oilfield has entered the high water cut stage at present.In order to reduce the production decline and control the water content,the cycle injection production technique has been implemented in the oilfield.In order to Chang 8 reservoir in Xifeng oilfield injection production cycle and evaluate the effect of factors in the recovery effect of the oil on cycle injection,selection of perforation in the long 8 layers in 88 wells,the 88 oil wells and its surrounding wells are divided into different groups with injection wells,injection wells group the unit of the production data of the 88 wells in accordance with the standard conditions of different statistics.The use of core experiment,numerical simulation of heterogeneous formation cycle injection experiments and the formation sensitivity experiment,the experiments of permeability,injection timing,injection,water injection,micro cracks,water cycle and other factors or combined with the analysis.Considering the effect of stress sensitivity on seepage in low permeability reservoir,oil gas water three phase under steady-state conditions into the dynamic equation,the inflow and the dynamic liquid level,thus determine the high-speed exit recovery area when wells;variation of oil well in the process of oil production cycle liquid surface with time,analysis the main factors affecting the pump efficiency,combined with the actual pump displacement relationship between discharge and dynamic liquid level,from the open wells high speed oil production area;using the annular volume balance principle in the oil production process by switching cycle time variation with the liquid level,combined with the relationship between low permeability reservoir and inflow outflow liquid volume thus,to determine the periodic oil production system.The results show that the permeability variation coefficient of the critical value of 0.6,higher than this value,not work well for more than 65%,higher than the critical value of the regional implementation of the periodinjection production technology effect after improvement is not obvious;the micro crack type water well after the periodinjection production efficiency by 82.4%,see the water pore type well after the periodinjection production the efficiency is 47.9%;pore water do not see well water dynamic connectivity coefficient threshold of 0.4,higher than this value,no effective oil accounted for 61%,beyond the scope of the periodinjection production effect becomes worse;when the time to see the water cycle is less than 1044 days,the implementation period of injection production wells by efficiency is 72.7%.When the water cycle is longer than 1044 days,the implementation cycle injection efficiency of 36.4% wells.The experimental results show that compared with the conventional water injection experiment,cyclic water injection can control the moisture content increased,and can enhance the ultimate recovery degree;permeability is,the better the effect of injection cycle,the final recovery rate will be higher as compared to conventional water injection;water injection timing sooner,the better the effect of injection cycle,the ultimate recovery the greater the degree of formation;Xifeng oilfield and seventeen district is no velocity sensitivity,medium water and salt sensitivity,weak acid sensitive formation.