Research On Low Production Reasons And Production Improvement Measures Of Chang 8 Ultra-low Permeability Reservoir In L247 Area

Chang 8 oil reservoir in L247 area is located in the south of Jiyuan Oilfield,which is a typical ultra-low permeability oil reservoir.Since its development in 2009,it has gone through various stages,including advanced water injection development for vertical wells with different well patterns,and deviated wells with advanced water injection development,but the single well production is low,and the decline is fast,and it is difficult to stabilize production.lt is urgent to analyze the main reasons for the low oil well production,and effectively improve the single well production technology,so as to lay the foundation for improving the single well production and the final oil recovery of the reservoir in the study area.This paper first studies and analyzes the geological characteristics of the reservoir,and then analyzes the reservoir productivity change law,water cut change law,pressure change characteristics,water drive status,and the law of water breakthrough in oil wells according to the production performance data to evaluate the reservoir development effect;Then,combined with the reservoir geology and performance analysis results,the causes of low production and low efficiency wells are analyzed in detail;Finally,aiming at the reasons of low production and low efficiency,the technology of improving single well production in Chang 8 reservoir in L247 area is proposed.The research results show that the poor physical properties,small pore throat radius,complex structure and large starting pressure gradient of Chang 8 reservoir in L247 area lead to the difficulty of oil well efficiency,which is an important reason for the low production of low liquid content and low water content wells.Fractured water flooded wells correspond to the large amount of advance water injection of water injection wells in the direction of water breakthrough,and the large transformation scale of highly deviated wells leads to fractured water breakthrough,which is the main reason for low production of highly deviated wells..Based on comprehensive research,9 wells were proposed for repeated fracturing in response to the low production and low efficiency wells caused by poor reservoir properties;In response to the unreasonable water injection technology policy leading to an increase in water content or flooding of oil wells,the reasonable injection production ratio,water injection volume,and injection allocation for different well types were optimized,and five separate injection plans were proposed for each well;Four well profile control and inter production injection plans have been proposed for wells with increased water content and flooding;For normal production of low water cut and low production wells,research on the corresponding relationship between injection and production has been carried out,and suggestions for hole filling for 5 wells have been proposed.By implementing the unit production technology plan,low production and low efficiency wells can be effectively treated.